Difference between revisions of "How Often To Run"

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[[File:Supercompensation-small.png|right|thumb|500px| [[Supercompensation]] is the idea that exercise initially weakens the body, but it repairs itself to become stronger.]]
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There is a natural human belief that if some is good, more is better. This idea is all too often false, and can be destructive with training. There's an old adage that "running does not make you a fitter, it's the rest that follows running that makes you fitter". Getting the right balance of running and rest is a critical part of your training, and there are a number of factors to consider. I've reviewed the available research (see below) and literature to come to some initial conclusions.
There is a natural human belief that if some is good, more is better. This idea is all too often false, and can be destructive with training. There's an old adage that "running does not make you a better runner, it's the rest that follows running that makes you a better runner". Getting the right balance of running and rest is a critical part of your training.
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* While it's quite possible to do the same run every day, this type of training isn't generally effective at improving fitness. The only training plans I'm aware of that train the same every day are for beginners just learning to run.  
 
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* Most training plans have at least a mix of easier and harder workouts, as well as some rest days. Only [[FIRST]] attempts some level of scientific validation, but even this plan doesn't seem to take into account the available research.  
=Supercompensation and Monotony =
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* Because running includes an eccentric component (see below) it is quite different to cycling and swimming. There is clear scientific evidence, as well as plenty of anecdotal that excessive eccentric exercise can take many weeks to recover from. This is shown most clearly in longer runs and downhill running, where runners can struggle to walk down stairs for days after a marathon. One way of looking at this is that a longer period is needed to recover from long and/or downhill runs. However, it's probably better to focus on building up the long and/or downhill runs so that the recovery period is reasonable.
It's well accepted that exercise improves fitness, and there are many different [[Endurance Adaptations]] that occur. The primary mechanism for these adaptations is that exercise causes damage and this damage is repaired to be stronger than before the exercise. This is seen in the fatigue that occurs after exercise, and the need for rest. The term for this mechanism is [[Supercompensation]], and is a key principle for creating training programs. One way of evaluating a training program is {{TrainingMonotony}} which looks at the variation in daily training stress. Higher levels of {{TrainingMonotony}} are associated with reduced benefits and a greater risk of [[Overtraining Syndrome]]. This need to optimize the ratio and timing of exercise and rest has been known for many years. Weight training regimes have exercised particular muscle groups on alternating days and most endurance training programs have used harder days and easier days.  
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* Shorter distance running, even at race effort, can be recovered from quite quickly in well trained runners. Race distances of 5-10Km could be recovered from in 2-3 days, though this time is likely to be longer in slower and/or less established runners. (For slower runners, the duration becomes longer, increasing eccentric stress, and less established runners will have less [[Delayed Onset Muscle Soreness]] resistance.)
 
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* [[High Intensity Interval Training]] may require the least recovery time, thought this is likely to be highly dependent on the mode and load. I recommend using a stationary bike for HIIT to reduce injury risk and to precisely control the workout. It seems that for some modes of HIIT, recovery can be as short as 24 hours.
=Easy Days and Junk Miles=
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* Easy running or training between hard workouts doesn't seem to have any support in the research.
[[[[File:Supercompensation-continued-small.png|right|thumb|500px|The correct balance of exercise stress, rest, and the timing of the two is important for achieving improved fitness.]]
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Putting this together, it suggests a workout plan should fit this outline.
A common approach to optimizing [[Supercompensation]] and {{TrainingMonotony}} is to have 3 or fewer hard training days combined with a number of easier days. For this approach to work, the easy days need to be sufficiently easy. Carl Foster said "for best results make your hard days very, very hard and your easy days very, very easy". Running on the easy days is often referred to as "junk miles" as the only result of these miles is impaired recovery. If the benefits of training go down as the effort on easy days increases, why train at all on the easy days? So far I have found no evidence to indicate there is any training benefit from running on the easy days. In fact, all the evidence supports [[Supercompensation]] and {{TrainingMonotony}}, therefore I recommend only 3-4 times a week for most people.  
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* Endurance training through long and/or downhill running should be built up carefully so that soreness lasts 2-4 days, with the gaps between the endurance runs about 3 times the length of the soreness.  
 
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* HIIT workouts or short/fast runs about 3 times/week. (HIIT could be more frequent.)
=Running Patterns=
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=Supercompensation =
There are various patterns of running that I would generally recommend. I'll use an abbreviation for the patterns, where each day is a character, with 'R' for a running day and 'x' for a day off or a cross training day. So "RxRxRxx" would be running the first, third and fifth days with the other four off.  
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It's well accepted that exercise is a critical part of improving fitness, and there are many different [[Endurance Adaptations]] that occur. The primary mechanism for these adaptations is that exercise causes damage and this damage is repaired to be stronger than before the exercise. This is seen in the fatigue that occurs after exercise, and the need for rest. The term for this mechanism is [[Supercompensation]], and is a key principle for creating training programs.  
* '''3 days/week (RxRxRxx)'''. This is the pattern used by [[FIRST]], which is the only marathon training plan I've found that has performed scientific studies to evaluate its effectiveness. Running 3 days/week requires that every days is hard, and typically involves a [[Long Run]] and two speedwork days. The ratio of running to rest gives 2 days of rest, and these typically follow the long run. 
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[[File:Supercompensation-small.png|none|thumb|500px| [[Supercompensation]] is the idea that exercise initially weakens the body, but it repairs itself to become stronger.]]
* '''4 days/week (RxRxRRx)'''. Having two back to back running days allows for one training day that has incomplete recovery. Typically these two back to back days are used for long runs, so that the second day simulates a longer distance [[Long Run]].  
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=Long and Downhill Running=
* '''4 days/week (RRxRRxx)'''. It is possible to arrange 4 days/week as two sets of back to back days, but this is not common. If all the running days are [[Long Run]]s then fatigue will build up over the five RRxRR days, and the two consecutive rest days will be needed for recovery.  
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The recovery required for longer or downhill running incurs more [[Delayed Onset Muscle Soreness]] (DOMS), which has a much longer recovery time. Most training plans have longer runs every 7 or 14 days, but the research suggests that the actual recovery period will depend on the severity of the DOMS. Recovery periods could be as long as 30-90 days, which is obviously so long that detraining is likely. In practice, I believe that we need to invert the problem. Instead of working out the recovery period for the long/downhill running, we need to optimize the running impact so that recovery occurs in the right time period. A long/downhill run that produces performance deficits that are not resolved well before the next long/downhill run are too stressful and the effort needs to be reduced.  
* '''3.5 days/week'''. Running every other day is a great pattern, but logistically it is hard to organize.
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=The Science of Recovery=
 
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Below are the studies I've found looking at the timeline of recovery from exercise stress. Overall, the time to recover from varies enormously between different types of training and different subject groups. My conclusions from the research are that [[High Intensity Interval Training| HIIT]] can be recovered as quickly as 24 hours, short race distances in 48 hours, but marathon, ultramarathon, and [[Delayed Onset Muscle Soreness| DOMS]] inducing exercise can potentially take weeks to recover from. Importantly, subjective feelings of recovery seem to be inadequate in evaluating the actual recovery.  
=Exceptions=
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==Recovery from Eccentric and Downhill Exercise==
If your running is not hard enough to require 48 hours recovery, you may be better off running more often.
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Because running always involves an eccentric component, this modality is quite important as it produces [[Delayed Onset Muscle Soreness| DOMS]]. The eccentric component is particularly important for endurance running, especially when it includes downhill running. The immediate muscular weakness that occurs with eccentric exercise compromises performance in longer runs. The repeated bout effect, which provides significant subsequent protection from DOMS has to be carefully balanced with the potentially elongated recovery periods. The research suggests that recovery can take many weeks, something that is likely to produce impaired subsequent training.  
* If you are just [[Starting to run]] then you may not running hard enough to require the days off. However, I believe that 3 days/week is probably optimal.
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* A study of 192 subjects undergoing eccentric muscle damage found that recovery was extremely protracted<ref name="SayersClarkson2001"/>. The eccentric damage resulted in peak force being reduced to 43% of the pre-exercise level immediately after the exercise. There was no recovery at 36 hours, and by 132 hours (5.5 days) they were still reduced by 33%. Of the 32 subjects that had their peak force reduced to <30% of their initial levels, 20 were retested after 26 days and had only regained 81% (males) and 93% (females.) A further subset of 9 subjects did weekly testing that recovery took between 33 and 89 days! ''This suggests that recovery from eccentric exercise can be extremely protracted, and that the "eccentric dose" needs to be built up carefully''.
* If you are running for fun and not pushing your body hard, then running 5-6 days a week may work for you.  
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* Ten soccer playing students with an average [[VO2max|V̇O<sub>2</sub>max]] of 54.6 were evaluated before and several times after performing 30 minutes of downhill running<ref name="ChenNosaka2007"/>. They ran downhill at -15%, a fairly steep gradient, with speed set to 70% [[VO2max|V̇O<sub>2</sub>max]]. Maximum strength was reduced by an average of 21%, 1 hour after the descent and recovered slowly until day 5 when they were back to normal. Muscle soreness peaked on day two, and returned to near baseline (no soreness) by day 5. Interestingly, creatine kinase (CK), a marker of muscle damage remained elevated for the 5 days of the study (~420-460 U/l.) Their [[Running Economy]] was impaired from 1-hour post descent through to day 3 at speeds varying from 65% to 85% of [[VO2max|V̇O<sub>2</sub>max]], but returned to baseline by day 4. Likewise, many other markers such as respiration, and heart rate were elevated though to day 3, returning to baseline at day 4. ''This suggests that as little as 30 minutes of downhill running produces noticeable muscle soreness will create impairment for 3-5+ days, and that muscle soreness is not a reliable indicator of recovery''.  
* If you have [[Delayed Onset Muscle Soreness| DOMS]], such as after a long race, more frequent [[Recovery Runs]] may help.
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* A shorter study of 9 well trained runners and triathletes found that 30 minutes of downhill running at 70% [[VO2max|V̇O<sub>2</sub>max]] resulted in impaired [[Running Economy]] 48 hours<ref name="BraunDutto2003"/>. Unfortunately, no other time periods were evaluated, but ''this study also suggests recovery from downhill running lasts more than 2 days''.
* During a [[Practical Tapering| Taper]] it may be appropriate to increase frequency while dramatically reducing intensity and duration. Currently there is insufficient evidence to reach a recommendation.
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* A study of 14 fit, active subjects underwent 45 minutes of downhill running at 10 degrees (17.6%) and evaluated before, after, then at days 1, 4, and 7<ref name="KoskinenHoyhtya2001"/>. They found that the CK marker of muscle damage was elevated for the first day, returning to baseline at day 4. The study found that CK levels were higher after running in cold (5c) rather than warm (22f) conditions. The CK levels were quite high, peaking at nearly 1,200 U/l. ''This study suggests that recovery from downhill running could be much shorter than other studies''.
 
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* A study looked at 10 female runners, [[VO2max|V̇O<sub>2</sub>max]] 48 (42-56), who underwent 30 minutes of downhill running at 74% of [[Maximum Heart Rate| Max HR]] and -15 degrees (26.8%)<ref name="HamillFreedson1991"/>. The runners had no change in [[Running Economy]] 2 or 5 days later, which is a little surprising given the steepness of the downhill running. Looking at the results, muscle soreness was higher on day 2 but near baseline on day 5, though the scale is not clear. The CK values were elevated on both days, but the levels were lower than in other studies, reaching 150 on day 2 and 106 on day 5. By comparison, another study had CK values of well over 400<ref name="ChenNosaka2007"/>. This ''suggests the runners were accustomed to downhill running, which creates a large protective effect from [[Delayed Onset Muscle Soreness]]''.
=Mental Health Runs=
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* A study looked at 50 male students ([[VO2max|V̇O<sub>2</sub>max]] 55 +/-6) underwent 30 minutes of downhill running at 15% (8.5 degrees) at 70% [[VO2max|V̇O<sub>2</sub>max]]<ref name="ChenNosaka2008"/>. Muscle soreness peaked after 1-2 days and lasted 4 days, while muscular weakness peaked at 20% down immediacy after the downhill, but was still down by 5% after 7 days. CK peaked around 1-2 days, but was still elevated at day 7. [[Running Economy]] was reduced by 5% after two days and was reduced by 2% after 7 days. ''This suggests that the impact of downhill running can last more than 7 days''.
One of the complaints concerning running 3 or 4 days/week is that every run is hard and therefore there is no running for fun. Sometimes a short, easy run can provide mental benefits, and these can be worthwhile overall, even if these "mental health runs" degrade the overall training program effectiveness.
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* It's worth noting that Glycogen replenishment is much slower after eccentric exercise and this <ref name="DoyleSherman1993"/>
 
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==Recovery from High Intensity Interval Training Recovery==
=Overload Training=
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There is some indication that recovery from [[High Intensity Interval Training| HIIT]] can occur in as little as 24 hours. It seems likely that different modalities of HIIT will produce different recovery periods, but it also seems likely that recovery from effective HIIT can be far faster than other forms of training.
Running hard or long everyday will build up cumulative fatigue as the body does not have sufficient time to recover. If this is kept up too longer, then some type of failure will occur; either injury or some form of [[Overtraining]]. However, it is possible to run for a number of days consecutively, building up deeper cumulative fatigue, and then taking a longer rest period. This is one of the principles of the [[Three Phase Taper]].
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* A study of netball players looked at their recovery from a simulated game<ref name="KingDuffield2009"/>. The players underwent performance testing before and after simulated games on two consecutive days. The simulated game involved sprinting and I believe is close to [[High Intensity Interval Training]]. The study used various recovery protocols lasting 15 minutes after each simulated game, with no differences found between interventions. Of interest here, there was no degradation in performance between days. ''This suggests a rapid recovery, within a day, from HIIT''.
 
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* A similar study using a simulated rugby game, repeated after 24 hours found no performance differences on the second day<ref name="DuffieldEdge2008"/>. The simulated rugby game was an 80-minute-long, high-intensity exercise circuit, and performance determined by repeated 20-m sprints and peak power. ''This study also suggests recovery from HIIT within a day''.
=Doubles=
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* A study of 10 healthy volunteers compared to training protocols that were identical other than the frequency of training<ref name="Parra-2000"/>. Both protocols used 30 seconds of maximal cycling with 12-minute recovery periods (unusually long), and the number of repetitions was increased during the study as the subjects became fitter. Both groups performed 14 training sessions. In one group, the subjects trained every day for 2 weeks, while the other group had two-day rest periods between each training session, spreading the 14 sessions over 6 weeks. The subjects without rest days did not improve either average or peak power during a 30-second Sprint test, while the subjects that did have rest days improved both of values. ''This could mean that rest days between HIIT sessions are good idea, or it could mean that it takes more than two weeks to see the benefit of this type of training''.
Running 3 or 4 days/week does not mean running at most once per day. It can be effective or necessary to run more than once per day while running fewer days per week. Running more than once in a day can provide some of the training stress of a single longer run.
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* Most studies of [[The Science of High Intensity Interval Training]] use 3 or 4 sessions per week, but there is rarely a control using other training frequencies. ''This suggests that 3 or 4 sessions per week is effective, but there's no indication of what is optimal''.
 
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==Recovery from Short Race Distances==
=Cross Training=
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The research into shorter distances suggests that even race efforts at 5-10Km can be recovered from in 48-72 hours.
Running is different to many other forms of exercise because a [[Downhill Running| large portion of the training stress is eccentric]], and eccentric exercise tends to require a longer recovery period. Performing some non-eccentric cross training such as cycling may be possible between running days without unduly compromising recovery. The research performed with the [[FIRST]] training program suggests that this cross training may be useful.  
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* A directly relevant study for runners looked at recovery from a completive 10Km track race<ref name="Gómez-2002"/>. The 10 male subjects were former collegiate athletes, and their 10Km times averaged 35 minutes with other indications this was an "all out" race effort. Immediately after the race there was some impairment of force production in the hamstrings, but not the quads. This hamstring impairment is believed to be predominantly in slow twitch fibers with fast twitch remaining unaffected. Both hamstrings and quads fatigued more quickly after the race compared with prior. After 48 hours, most measurements have returned to pre-race levels, though the hamstrings still fatigued more quickly, only recovering about half of the prior capacity. ''This suggests that 48 hours is sufficient to mostly recovery from a 10Km race''.
 
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* A study of 12 well trained runners (9 male) looked at their recovery from a 5Km time trial<ref name="BosakBishop2005"/>. Runners performed the 5Km time trial and then either had 24 hours or 72 hours of rest before doing another 5Km time trial. The average time for the first 5Km was 19:49 (16:41-22:18), so these were reasonable, but not elite runners ([[VO2max|V̇O<sub>2</sub>max]] was 63 for the men and 60 for the women.) The 5Km time after only 24 hours recover was 10 seconds slower (p=0.03) while the time after 72 hours was not different from the baseline run. Notably the runners felt the same before each run, both in terms of soreness and fatigue, so the degradation was not noticeable to the runners. ''This suggests that 24 hours is insufficient for recovering from a 5Km time trial, while 72 hours adequate. It also suggests that subjective feelings of recovery may be misleading.''
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==Recovery from Marathons==
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The research shows a wide variation in recovery times from a marathon, with as little as 5 days to greater than 7 days. No studies checked for longer than 7 days, which means we have no indication of the upper limit. My personal experience is that recovery from a marathon can often take more than 14 days for those unused to the distance, but with practice, recovery can be as short as 48 hours. Much of the difference seems likely to do with resistance to [[Delayed Onset Muscle Soreness| DOMS]] that occurs with repeated bouts.
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* A 1984 study of 10 marathon runners looked at their recovery<ref name="Sherman-1984"/>. The runners had previously run marathons, but not in the previous 6 months and trained an average of 104Km/~60miles week in the 3 months leading up to the race and all achieved personal bests in the race. They had a [[VO2max|V̇O<sub>2</sub>max]] of ~68 and marathon times around the 3-hour mark. The runners were tested before, ~20 minutes after the race, then at 1, 3, 5, and 7 days post-race. The runners were split into two groups, with one resting and the other did "active recovery" of easy (50-60% [[VO2max|V̇O2max]]) runs for 20, 25, 30, 35, 40, 45 minutes each day post-race. Ratings of perceived soreness peaked on the first day and returned to baseline (no soreness) by the 5th day, with no differences in soreness between the two groups. Work capacity measured over 50 leg extensions was reduced in both groups on day one to the same level. Work capacity didn't improve in the rest group on day 1 after the marathon, while the active group recovered partly. On days 3, 5, 7 the active group did not recovery work capacity any further, while the resting group regained all the lost work capacity. A similar result occurs with the maximum strength, with the active recovery group regaining less strength than the rest group. However, both groups were still below their pre-race maximum strength after 7 days. ''While this is a small sample size, this suggests that recovery from a marathon race can occur within 7 days if the runner rests, and it suggests that muscle soreness is not a good measure of recovery.''
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* A test of compression garments found that maximum strength was impaired at 48 hours after a marathon, but returned to baseline after 72 hours, though markers of muscle damage (CRP) were still elevated at 72 hours<ref name="HillHowatson2014"/>. However, there was wide individual variability in the time course of both strength and muscle damage markers. ''This suggests that some runners can recover strength from a marathon within 72 hours, even though markers of muscle damage remain. ''
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* A study of the impact of a marathon on muscle fiber damage (necrosis) in 10 male marathon runners found the damage lasted at least 7 days<ref name="HikidaStaron1983"/>. The study used biopsies pre-race, post-race, then days 1, 3, 5, and 7. The damage was most prevalent on days 1 and 3, but persisted to day 7. This damage appears to be very similar to [[Delayed Onset Muscle Soreness]], but unfortunately there were no samples after day 7 to indicate when full recovery occurred. (The runners' times varied between 2:31 and 3:39.) ''This suggests that recovery from a marathon may not be complete in some runners after 7 days.''
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* A study on eight elite male marathon runners found that maximum voluntary contraction was reduced post marathon race (2:34 average time), but recovered by five days. Rather strangely, [[Running Economy]] at marathon pace was impaired immediately after the race, but two- and five-days post-race their RE was better than before the race<ref name="PetersenHansen2007"/>. ''This suggests that some runners (including elites) can recovery from a marathon in less than five days. ''
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* A study of 7 experienced triathletes (6 male) were evaluated before, during, after 2 hours, then after 2, 4, and 6 days following a marathon distance treadmill run<ref name="KyröläinenPullinen2000"/>. Their [[Running Economy]] fell during the run, and was impaired at 2 h (14%), 2 days (10%), 4 days (2.4%), and 6 days (2.4%) post marathon. CK was elevated after the marathon, returning to baseline at day 6. ''This suggests recovery from a marathon can take longer than 6 days. ''
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* A study of 7 runners in the 1979 Stockholm Marathon found that they had predominantly depleted the [[Glycogen]] in slow twitch fibers of the quad, and they had reduced fatigue resistance but not reduced maximum strength<ref name="Jacobs-1981"/>. The runners finished the marathon between 2:22 and 3:30. Another group of 10 subjects used a combination of 30 min cycling, 75 min running and sprinting to reduce the glycogen of both fast and slow twitch fibers, resulting in both reduced fatigue resistance and reduced maximum strength immediately after the exercise. ''This doesn't indicate the timeline for recovery, but shows that a marathon race produces muscular weakness''.
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==Recovery from Ultramarathons==
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There is even less research into ultramarathons than marathons, but not surprisingly, recovery from an ultramarathon effort can be protracted. It's unclear if ultramarathons can produce an improvement in fitness. It seems probable that some aspects of fitness may improve (such as DOMS resistance), but some detraining may occur during the protracted recovery.
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* A study of runners in the 90Km/56-mile Comrades Marathon found [[Running Economy]] was reduced for the 32 days after the race, though only day 25 was statistically significant<ref name="ChambersNoakes1998"/>. Muscular strength as measured by jumping was reduced for 32 days, though only statistically significant for 3-18 days depending on the jump type. The study only included 8 runners, so statistical power was low. ''This suggests that recovery from an ultramarathon can take up to 32 days.''
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* A study of 72 runners at the 100 mile/161Km Western States Endurance Run found 400m run time was slower 3- and 5-days post-race, while muscle soreness peaked on race day and gradually declined over the following 7 days<ref name="HoffmanBadowski2016"/>. Subjective muscle fatigue peaked immediately post-race and returned to near baseline by 7 days post-race. ''This suggests that recovery from an ultramarathon can take more than 5 days. ''
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==Recovery from Strength training==
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There are many studies on strength training, but the one below is noteworthy as it calls out the time supercompensation. After all, maintaining baseline performance is not the goal of training.
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* A 2003 study of the recovery from strength training showed the time course for [[Supercompensation]] <ref name="McLester-2003"/>.  The 30 male subjects were experienced in strength training, having used a protocol of training 3-4/week for at least 12 weeks. 20 were in their 20s, 10 in their 50s. The exercise was 7 sets to failure for the older men and half of the younger, or 3 sets to failure for the remaining 10 younger men, each over 8 muscle groups. All subjects were weaker after 24 hours, with performance returning to baseline after 48 hours, with Supercompensation to above baseline at 72 hours. This suggests that 48 hours may be insufficient for optimum recovery from strength training. ''This is study suggests that supercompensation can occur in 72 hours after strength training when recovery to baseline is complete within 48 hours.  ''
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==Recovery and Elite Athletes==
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There is very little evidence of the optimal recovery from elite athletes that I could find in the available research. However, it's been noted<ref name="BishopJones2008"/> that the improvement in performance after a [[Practical Tapering| Taper]] suggests that athletes are typically under-recovered. This improvement is typically 2%, with a range of -2.3% to 8.9%, which is a huge benefit for an elite athlete in such a short period<ref name="BosquetMontpetit2007"/>.
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=The Science of Measuring Recovery=
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A key problem in knowing how frequently to train is measuring recovery. It seems intuitively obvious that different modes of training and different training loads will result in different recovery periods. Running an easy mile will result in no appreciable need for recovery, while running hilly 100-mile race could leave me impaired for weeks.
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* A common approach in research is to use maximum strength<ref name="SayersClarkson2001"/> or maximum power output<ref name="Busso-2002"/> as a measure of recovery. This seems to be one of the best measures, but obviously the test itself incurs a training load. It seems possible that a short test, using a brief (2-3 minute warm up) followed by 20-30 seconds "all out" might provide insight into recovery without significant training stress on the athlete.
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* Using blood markers, such as creatine phosphokinase (a marker of muscle damage) can be used to track the impact of exercise and recovery<ref name="ChevionMoran2003"/>. Of course, this is of little use outside of a research context.
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* There's been a lot of interest in using Heart Rate Variability (HRV) for measuring training stress and recovery. However, I've never seen any relationship between HRV and my training/recovery status. A study of 57 elite Nordic-skiers over five years also found no relationship between HRV and training load<ref name="SchmittRegnard2018"/>.
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=The Science of Training Frequency=
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There's relatively little research that goes beyond recovery into training frequency and recovery from repeated bouts. There are some indications that lower frequencies might be more effective it's hard to be more definitive. Based on the research above on recovery, it seems likely that the specifics of the exercise may have a huge impact on the appropriate frequency.
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* A study of six untrained subjects looked at how training frequency effected both recovery and gains in fitness<ref name="Busso-2002"/>. The study used intermittent cycle training three times per week for 8 weeks (low frequency) followed by a week without training, followed by training five times per week for 4 weeks (high frequency). The study then fitted their recovery measured using the maximum power over 5 minutes into a mathematical model. The low frequency training subjects recovered in 0.9 days, but the high frequency took 3.6 days to recover. In addition, the high frequency training produced lower benefits from the training effort. The main flaw in this study is that the high frequency training follows the lower frequency training, so the subjects have improved their fitness, which normally results in a slower fitness improvement. ''This study suggests that training 5/week impairs recovery compared with 3/week, but the study flaws means this could be an artifact of the design''.
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* A 1986 review of 30+ studies looked at training to improve [[VO2max|V̇O<sub>2</sub>max]] <ref name="WengerBell1986"/>. The study found that across all fitness levels and intensities, fitness improvements increase with training frequency up to 6/week (no study looked at 7/week.) For lower fitness individuals ([[VO2max|V̇O<sub>2</sub>max]] 30-40), improvements were proportional to frequency, with 2/week producing improvements, but 5-6/week being most effective. For [[VO2max|V̇O<sub>2</sub>max]] 40-50, training for 4/week or 6/week seemed to be most effective. Finally, for [[VO2max|V̇O2max]] 50-60, 3/week might be the most effective. However, the wide disparity in the protocols of the underlying studies creates means the results have to be used with caution.
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=The Science of Active Recovery=
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Active recovery is the idea that low intensity exercise improves recovery from high intensity exercise. In the context of easy exercise on the day after hard exercise, one study found that indicated that active recovery does nothing to help<ref name="Andersson-2008"/>. Another found that active recovery after a marathon significantly impaired strength and work capacity, even though muscle soreness was gone<ref name="Sherman-1984"/>. An analysis of the evidence on active recovery noted that "evidence that active recovery enhances recovery between training sessions is currently lacking"<ref name="Barnett-2006"/>. A study looked at the recovery from downhill running in 50 male students ([[VO2max|V̇O<sub>2</sub>max]] 55 +/-6)<ref name="ChenNosaka2008"/>. The runners either rested or ran for 30 minutes each day for 6 days. The post-downhill runs were at 40%, 50%, 60%, or 70% of [[VO2max|V̇O<sub>2</sub>max]]. There were no differences between rest and running in measures of muscle soreness or [[Running Economy]].
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==Other Uses of the Term "Active Recovery"==
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Note that "Active Recovery" can have other meanings:
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* 'Active Recovery' can also refer to doing low intensity exercise between the work periods of [[Introduction to Interval Training| Interval Training]], which is effective as it metabolizes lactate and speeds up the short-term recovery needed before the next interval. Active recovery also limits the additional cardiac stress that occurs when you stop running as the muscle compressions help venous return to the heart, maintaining blood pressure.
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* Doing gentle exercise immediately after intense exercise as a [[Cooldown]] may have some benefits. There is anecdotal evidence that walking for 20-30 minutes after a [[Long Run]] reduces [[Muscle| muscle]] soreness.  
 
=Training Plans=
 
=Training Plans=
 
The [[FIRST]] plan is based around running three days a week, and is the only plan I am aware of that has undergone scientific evaluation about its effectiveness. Hal Higdon's Advanced II Marathon<ref name="Hal"/> plan has 6 days of running, but two days are trivial. Jeff Galloway<ref name="Jeff"/> uses four days/week. The Runner's World beginners plan <ref name="RW"/>is four days/week. (The RW intermediary & advanced are 5 days.) [[Jack Daniels Running Formula| Jack Daniels]] defines just two work outs a week, and leaves it up to you how you fit in the other miles.
 
The [[FIRST]] plan is based around running three days a week, and is the only plan I am aware of that has undergone scientific evaluation about its effectiveness. Hal Higdon's Advanced II Marathon<ref name="Hal"/> plan has 6 days of running, but two days are trivial. Jeff Galloway<ref name="Jeff"/> uses four days/week. The Runner's World beginners plan <ref name="RW"/>is four days/week. (The RW intermediary & advanced are 5 days.) [[Jack Daniels Running Formula| Jack Daniels]] defines just two work outs a week, and leaves it up to you how you fit in the other miles.
 
+
=Advanced Topics=
=Active Recovery=
+
==Overload Training==
What about 'active recovery'? This is the idea that low intensity exercise improves recovery from high intensity exercise. In the context of easy exercise on the day after hard exercise, I've only found one scientific study <ref name="neuro"/><ref name="Active"/> and that indicated that active recovery does nothing to help. Note that "Active Recovery" can have other meanings:
+
Running hard or long everyday will build up cumulative fatigue as the body does not have sufficient time to recover. If this is kept up to long, then some type of failure will occur; either injury or some form of [[Overtraining]]. However, it is possible to run for a number of days consecutively, building up deeper cumulative fatigue, and then taking a longer rest period. This is one of the principles of the [[Three Phase Taper]].
* 'Active Recovery' can refer to doing low intensity exercise between the work periods of [[Introduction to Interval Training| Interval Training]], which is effective.
+
==Multiple Workouts Per Day==
* Doing gentle exercise immediately after intense exercise as a [[Cooldown]] may have some benefits. There is anecdotal evidence that walking for 20-30 minutes after a [[Long Run]] reduces [[Muscle| muscle]] soreness.
+
Running 3 or 4 days/week does not mean running at most once per day. It can be effective or necessary to run more than once per day while running fewer days per week. Running more than once in a day can provide some of the training stress of a single longer run.
 
 
=How Often I Run=
 
I did my first ultra in 2005 using a fairly conventional pattern of running. I would run six days a week, with two days as the long run back-to-back days. Around July 2008 I started to focus on making my hard days harder and my easy days easier. Gradually this became more extreme, and I won my first race in April 2009. In August 2009 I started running 4 days/week and I found my performance continue to improve. I tried [[Notes from a high mileage experiment| running more frequently]] for six months and found it ineffective and counterproductive.
 
* I have found the most effective pattern for me is to run four days a week. I aim to run 16-27 miles, which gives me lots of long running, with enough rest to support that mileage.
 
* Two of my runs are back to back. The idea is that I have not fully recovered from Friday when I do the Saturday run, so I am doing a [[Long Run]] on tired legs. I do this because I cannot afford the time that it would take to run the distances that would otherwise be required. I consider Friday/Saturday to be a single training unit, though not as effective as the mileage would be if I could do it on a single day.
 
* If I were training for the marathon distance or shorter, I would train three days per week. For these shorter races it would not be as difficult to get an adequately long [[Long Run]].
 
* I will occasionally do extra "mental health runs", but I keep these short, typically only 10-15% of the length of my usual runs.
 
* I will often run more frequently during a [[Practical Tapering| Taper]] or after a race, especially if I have [[Delayed Onset Muscle Soreness| DOMS]].
 
* Occasionally I will run twice a day, but typically the second run is for [[Heat Acclimation Training]] rather than to fit in extra miles.
 
 
 
=The Psychology of Running Frequency=
 
Running 3-4 days a week is not just tough physically; it's tough mentally as well. Obviously it is tough to run hard enough to need the 48 hours recovery. However, the feeling that days off mean not doing enough, or that a rest day will cause fitness to dissipate is corrosive.  
 
 
 
 
=See Also=
 
=See Also=
 
* [[Supercompensation and Why exercise does not make you fit]]
 
* [[Supercompensation and Why exercise does not make you fit]]
Line 60: Line 79:
 
* [[Recovery Runs]]
 
* [[Recovery Runs]]
 
* [[FIRST]]
 
* [[FIRST]]
 
 
=References=
 
=References=
 
<references>
 
<references>
<ref name="neuro">http://www.ncbi.nlm.nih.gov/pubmed/18202563 http://www.ncbi.nlm.nih.gov/pubmed/18202563 Neuromuscular fatigue and recovery in elite female soccer: effects of active recovery.</ref>
+
<ref name="Barnett-2006">A. Barnett, Using recovery modalities between training sessions in elite athletes: does it help?, Sports Med, volume 36, issue 9, pages 781-96,  2006, PMID [http://www.ncbi.nlm.nih.gov/pubmed/16937953 16937953]</ref>
<ref name="Active">http://evidencebasedfitness.blogspot.com/2008/02/rest-vs-active-recovery.html Rest v Active Recovery</ref>
+
<ref name="Andersson-2008">H. Andersson, T. Raastad, J. Nilsson, G. Paulsen, I. Garthe, F. Kadi, Neuromuscular fatigue and recovery in elite female soccer: effects of active recovery., Med Sci Sports Exerc, volume 40, issue 2, pages 372-80, Feb 2008, doi [http://dx.doi.org/10.1249/mss.0b013e31815b8497 10.1249/mss.0b013e31815b8497], PMID [http://www.ncbi.nlm.nih.gov/pubmed/18202563 18202563]</ref>
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<ref name="Busso-2002">T. Busso, H. Benoit, R. Bonnefoy, L. Feasson, JR. Lacour, Effects of training frequency on the dynamics of performance response to a single training bout., J Appl Physiol (1985), volume 92, issue 2, pages 572-80, Feb 2002, doi [http://dx.doi.org/10.1152/japplphysiol.00429.2001 10.1152/japplphysiol.00429.2001], PMID [http://www.ncbi.nlm.nih.gov/pubmed/11796666 11796666]</ref>
 
<ref name="Jeff">http://www.jeffgalloway.com/training/marathon.html</ref>
 
<ref name="Jeff">http://www.jeffgalloway.com/training/marathon.html</ref>
 
<ref name="Hal">http://www.halhigdon.com/marathon/advanced2/advancedII.htm</ref>
 
<ref name="Hal">http://www.halhigdon.com/marathon/advanced2/advancedII.htm</ref>
 
<ref name="RW">http://www.runnersworld.com/article/0,7120,s6-238-244--6946-2-3X5X7-4,00.html</ref>
 
<ref name="RW">http://www.runnersworld.com/article/0,7120,s6-238-244--6946-2-3X5X7-4,00.html</ref>
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<ref name="Sherman-1984">WM. Sherman, LE. Armstrong, TM. Murray, FC. Hagerman, DL. Costill, RC. Staron, JL. Ivy, Effect of a 42.2-km footrace and subsequent rest or exercise on muscular strength and work capacity., J Appl Physiol Respir Environ Exerc Physiol, volume 57, issue 6, pages 1668-73, Dec 1984, doi [http://dx.doi.org/10.1152/jappl.1984.57.6.1668 10.1152/jappl.1984.57.6.1668], PMID [http://www.ncbi.nlm.nih.gov/pubmed/6511541 6511541]</ref>
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<ref name="Jacobs-1981">I. Jacobs, P. Kaiser, P. Tesch, Muscle strength and fatigue after selective glycogen depletion in human skeletal muscle fibers., Eur J Appl Physiol Occup Physiol, volume 46, issue 1, pages 47-53,  1981, PMID [http://www.ncbi.nlm.nih.gov/pubmed/7194784 7194784]</ref>
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<ref name="Gómez-2002">AL. Gómez, RJ. Radzwich, CR. Denegar, JS. Volek, MR. Rubin, JA. Bush, BK. Doan, RB. Wickham, SA. Mazzetti, The effects of a 10-kilometer run on muscle strength and power., J Strength Cond Res, volume 16, issue 2, pages 184-91, May 2002, PMID [http://www.ncbi.nlm.nih.gov/pubmed/11991769 11991769]</ref>
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<ref name="ChevionMoran2003">S. Chevion, D. S. Moran, Y. Heled, Y. Shani, G. Regev, B. Abbou, E. Berenshtein, E. R. Stadtman, Y. Epstein, Plasma antioxidant status and cell injury after severe physical exercise, Proceedings of the National Academy of Sciences, volume 100, issue 9, 2003, pages 5119–5123, ISSN [http://www.worldcat.org/issn/0027-8424 0027-8424], doi [http://dx.doi.org/10.1073/pnas.0831097100 10.1073/pnas.0831097100]</ref>
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<ref name="SayersClarkson2001">Stephen P. Sayers, Priscilla M. Clarkson, Force recovery after eccentric exercise in males and females, European Journal of Applied Physiology, volume 84, issue 1-2, 2001, pages 122–126, ISSN [http://www.worldcat.org/issn/1439-6319 1439-6319], doi [http://dx.doi.org/10.1007/s004210000346 10.1007/s004210000346]</ref>
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<ref name="WengerBell1986">Howard A. Wenger, Gordon J. Bell, The Interactions of Intensity, Frequency and Duration of Exercise Training in Altering Cardiorespiratory Fitness, Sports Medicine, volume 3, issue 5, 1986, pages 346–356, ISSN [http://www.worldcat.org/issn/0112-1642 0112-1642], doi [http://dx.doi.org/10.2165/00007256-198603050-00004 10.2165/00007256-198603050-00004]</ref>
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<ref name="BosakBishop2005">Andy M. Bosak, Phil Bishop, Joe Smith, James M. Green, Mark Richardson, Mike Iosia, Comparison Of 5km Running Performance After 24 And 72 Hours Of Passive Recovery, Medicine & Science in Sports & Exercise, volume 37, issue Supplement, 2005, pages S77–S78, ISSN [http://www.worldcat.org/issn/0195-9131 0195-9131], doi [http://dx.doi.org/10.1249/00005768-200505001-00430 10.1249/00005768-200505001-00430]</ref>
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<ref name="KingDuffield2009">Monique King, Rob Duffield, The Effects of Recovery Interventions on Consecutive Days of Intermittent Sprint Exercise, Journal of Strength and Conditioning Research, volume 23, issue 6, 2009, pages 1795–1802, ISSN [http://www.worldcat.org/issn/1064-8011 1064-8011], doi [http://dx.doi.org/10.1519/JSC.0b013e3181b3f81f 10.1519/JSC.0b013e3181b3f81f]</ref>
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<ref name="DuffieldEdge2008">Rob Duffield, Johann Edge, Robert Merrells, Emma Hawke, Matt Barnes, David Simcock, Nicholas Gill, The Effects of Compression Garments on Intermittent Exercise Performance and Recovery on Consecutive Days, International Journal of Sports Physiology and Performance, volume 3, issue 4, 2008, pages 454–468, ISSN [http://www.worldcat.org/issn/1555-0265 1555-0265], doi [http://dx.doi.org/10.1123/ijspp.3.4.454 10.1123/ijspp.3.4.454]</ref>
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<ref name="ChenNosaka2008">Trevor C. Chen, Kazunori Nosaka, Chia-Ching Wu, Effects of a 30-min running performed daily after downhill running on recovery of muscle function and running economy, Journal of Science and Medicine in Sport, volume 11, issue 3, 2008, pages 271–279, ISSN [http://www.worldcat.org/issn/14402440 14402440], doi [http://dx.doi.org/10.1016/j.jsams.2007.02.015 10.1016/j.jsams.2007.02.015]</ref>
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Latest revision as of 16:25, 19 August 2019

There is a natural human belief that if some is good, more is better. This idea is all too often false, and can be destructive with training. There's an old adage that "running does not make you a fitter, it's the rest that follows running that makes you fitter". Getting the right balance of running and rest is a critical part of your training, and there are a number of factors to consider. I've reviewed the available research (see below) and literature to come to some initial conclusions.

  • While it's quite possible to do the same run every day, this type of training isn't generally effective at improving fitness. The only training plans I'm aware of that train the same every day are for beginners just learning to run.
  • Most training plans have at least a mix of easier and harder workouts, as well as some rest days. Only FIRST attempts some level of scientific validation, but even this plan doesn't seem to take into account the available research.
  • Because running includes an eccentric component (see below) it is quite different to cycling and swimming. There is clear scientific evidence, as well as plenty of anecdotal that excessive eccentric exercise can take many weeks to recover from. This is shown most clearly in longer runs and downhill running, where runners can struggle to walk down stairs for days after a marathon. One way of looking at this is that a longer period is needed to recover from long and/or downhill runs. However, it's probably better to focus on building up the long and/or downhill runs so that the recovery period is reasonable.
  • Shorter distance running, even at race effort, can be recovered from quite quickly in well trained runners. Race distances of 5-10Km could be recovered from in 2-3 days, though this time is likely to be longer in slower and/or less established runners. (For slower runners, the duration becomes longer, increasing eccentric stress, and less established runners will have less Delayed Onset Muscle Soreness resistance.)
  • High Intensity Interval Training may require the least recovery time, thought this is likely to be highly dependent on the mode and load. I recommend using a stationary bike for HIIT to reduce injury risk and to precisely control the workout. It seems that for some modes of HIIT, recovery can be as short as 24 hours.
  • Easy running or training between hard workouts doesn't seem to have any support in the research.

Putting this together, it suggests a workout plan should fit this outline.

  • Endurance training through long and/or downhill running should be built up carefully so that soreness lasts 2-4 days, with the gaps between the endurance runs about 3 times the length of the soreness.
  • HIIT workouts or short/fast runs about 3 times/week. (HIIT could be more frequent.)

1 Supercompensation

It's well accepted that exercise is a critical part of improving fitness, and there are many different Endurance Adaptations that occur. The primary mechanism for these adaptations is that exercise causes damage and this damage is repaired to be stronger than before the exercise. This is seen in the fatigue that occurs after exercise, and the need for rest. The term for this mechanism is Supercompensation, and is a key principle for creating training programs.

Supercompensation is the idea that exercise initially weakens the body, but it repairs itself to become stronger.

2 Long and Downhill Running

The recovery required for longer or downhill running incurs more Delayed Onset Muscle Soreness (DOMS), which has a much longer recovery time. Most training plans have longer runs every 7 or 14 days, but the research suggests that the actual recovery period will depend on the severity of the DOMS. Recovery periods could be as long as 30-90 days, which is obviously so long that detraining is likely. In practice, I believe that we need to invert the problem. Instead of working out the recovery period for the long/downhill running, we need to optimize the running impact so that recovery occurs in the right time period. A long/downhill run that produces performance deficits that are not resolved well before the next long/downhill run are too stressful and the effort needs to be reduced.

3 The Science of Recovery

Below are the studies I've found looking at the timeline of recovery from exercise stress. Overall, the time to recover from varies enormously between different types of training and different subject groups. My conclusions from the research are that HIIT can be recovered as quickly as 24 hours, short race distances in 48 hours, but marathon, ultramarathon, and DOMS inducing exercise can potentially take weeks to recover from. Importantly, subjective feelings of recovery seem to be inadequate in evaluating the actual recovery.

3.1 Recovery from Eccentric and Downhill Exercise

Because running always involves an eccentric component, this modality is quite important as it produces DOMS. The eccentric component is particularly important for endurance running, especially when it includes downhill running. The immediate muscular weakness that occurs with eccentric exercise compromises performance in longer runs. The repeated bout effect, which provides significant subsequent protection from DOMS has to be carefully balanced with the potentially elongated recovery periods. The research suggests that recovery can take many weeks, something that is likely to produce impaired subsequent training.

  • A study of 192 subjects undergoing eccentric muscle damage found that recovery was extremely protracted[1]. The eccentric damage resulted in peak force being reduced to 43% of the pre-exercise level immediately after the exercise. There was no recovery at 36 hours, and by 132 hours (5.5 days) they were still reduced by 33%. Of the 32 subjects that had their peak force reduced to <30% of their initial levels, 20 were retested after 26 days and had only regained 81% (males) and 93% (females.) A further subset of 9 subjects did weekly testing that recovery took between 33 and 89 days! This suggests that recovery from eccentric exercise can be extremely protracted, and that the "eccentric dose" needs to be built up carefully.
  • Ten soccer playing students with an average V̇O2max of 54.6 were evaluated before and several times after performing 30 minutes of downhill running[2]. They ran downhill at -15%, a fairly steep gradient, with speed set to 70% V̇O2max. Maximum strength was reduced by an average of 21%, 1 hour after the descent and recovered slowly until day 5 when they were back to normal. Muscle soreness peaked on day two, and returned to near baseline (no soreness) by day 5. Interestingly, creatine kinase (CK), a marker of muscle damage remained elevated for the 5 days of the study (~420-460 U/l.) Their Running Economy was impaired from 1-hour post descent through to day 3 at speeds varying from 65% to 85% of V̇O2max, but returned to baseline by day 4. Likewise, many other markers such as respiration, and heart rate were elevated though to day 3, returning to baseline at day 4. This suggests that as little as 30 minutes of downhill running produces noticeable muscle soreness will create impairment for 3-5+ days, and that muscle soreness is not a reliable indicator of recovery.
  • A shorter study of 9 well trained runners and triathletes found that 30 minutes of downhill running at 70% V̇O2max resulted in impaired Running Economy 48 hours[3]. Unfortunately, no other time periods were evaluated, but this study also suggests recovery from downhill running lasts more than 2 days.
  • A study of 14 fit, active subjects underwent 45 minutes of downhill running at 10 degrees (17.6%) and evaluated before, after, then at days 1, 4, and 7[4]. They found that the CK marker of muscle damage was elevated for the first day, returning to baseline at day 4. The study found that CK levels were higher after running in cold (5c) rather than warm (22f) conditions. The CK levels were quite high, peaking at nearly 1,200 U/l. This study suggests that recovery from downhill running could be much shorter than other studies.
  • A study looked at 10 female runners, V̇O2max 48 (42-56), who underwent 30 minutes of downhill running at 74% of Max HR and -15 degrees (26.8%)[5]. The runners had no change in Running Economy 2 or 5 days later, which is a little surprising given the steepness of the downhill running. Looking at the results, muscle soreness was higher on day 2 but near baseline on day 5, though the scale is not clear. The CK values were elevated on both days, but the levels were lower than in other studies, reaching 150 on day 2 and 106 on day 5. By comparison, another study had CK values of well over 400[2]. This suggests the runners were accustomed to downhill running, which creates a large protective effect from Delayed Onset Muscle Soreness.
  • A study looked at 50 male students (V̇O2max 55 +/-6) underwent 30 minutes of downhill running at 15% (8.5 degrees) at 70% V̇O2max[6]. Muscle soreness peaked after 1-2 days and lasted 4 days, while muscular weakness peaked at 20% down immediacy after the downhill, but was still down by 5% after 7 days. CK peaked around 1-2 days, but was still elevated at day 7. Running Economy was reduced by 5% after two days and was reduced by 2% after 7 days. This suggests that the impact of downhill running can last more than 7 days.
  • It's worth noting that Glycogen replenishment is much slower after eccentric exercise and this [7]

3.2 Recovery from High Intensity Interval Training Recovery

There is some indication that recovery from HIIT can occur in as little as 24 hours. It seems likely that different modalities of HIIT will produce different recovery periods, but it also seems likely that recovery from effective HIIT can be far faster than other forms of training.

  • A study of netball players looked at their recovery from a simulated game[8]. The players underwent performance testing before and after simulated games on two consecutive days. The simulated game involved sprinting and I believe is close to High Intensity Interval Training. The study used various recovery protocols lasting 15 minutes after each simulated game, with no differences found between interventions. Of interest here, there was no degradation in performance between days. This suggests a rapid recovery, within a day, from HIIT.
  • A similar study using a simulated rugby game, repeated after 24 hours found no performance differences on the second day[9]. The simulated rugby game was an 80-minute-long, high-intensity exercise circuit, and performance determined by repeated 20-m sprints and peak power. This study also suggests recovery from HIIT within a day.
  • A study of 10 healthy volunteers compared to training protocols that were identical other than the frequency of training[10]. Both protocols used 30 seconds of maximal cycling with 12-minute recovery periods (unusually long), and the number of repetitions was increased during the study as the subjects became fitter. Both groups performed 14 training sessions. In one group, the subjects trained every day for 2 weeks, while the other group had two-day rest periods between each training session, spreading the 14 sessions over 6 weeks. The subjects without rest days did not improve either average or peak power during a 30-second Sprint test, while the subjects that did have rest days improved both of values. This could mean that rest days between HIIT sessions are good idea, or it could mean that it takes more than two weeks to see the benefit of this type of training.
  • Most studies of The Science of High Intensity Interval Training use 3 or 4 sessions per week, but there is rarely a control using other training frequencies. This suggests that 3 or 4 sessions per week is effective, but there's no indication of what is optimal.

3.3 Recovery from Short Race Distances

The research into shorter distances suggests that even race efforts at 5-10Km can be recovered from in 48-72 hours.

  • A directly relevant study for runners looked at recovery from a completive 10Km track race[11]. The 10 male subjects were former collegiate athletes, and their 10Km times averaged 35 minutes with other indications this was an "all out" race effort. Immediately after the race there was some impairment of force production in the hamstrings, but not the quads. This hamstring impairment is believed to be predominantly in slow twitch fibers with fast twitch remaining unaffected. Both hamstrings and quads fatigued more quickly after the race compared with prior. After 48 hours, most measurements have returned to pre-race levels, though the hamstrings still fatigued more quickly, only recovering about half of the prior capacity. This suggests that 48 hours is sufficient to mostly recovery from a 10Km race.
  • A study of 12 well trained runners (9 male) looked at their recovery from a 5Km time trial[12]. Runners performed the 5Km time trial and then either had 24 hours or 72 hours of rest before doing another 5Km time trial. The average time for the first 5Km was 19:49 (16:41-22:18), so these were reasonable, but not elite runners (V̇O2max was 63 for the men and 60 for the women.) The 5Km time after only 24 hours recover was 10 seconds slower (p=0.03) while the time after 72 hours was not different from the baseline run. Notably the runners felt the same before each run, both in terms of soreness and fatigue, so the degradation was not noticeable to the runners. This suggests that 24 hours is insufficient for recovering from a 5Km time trial, while 72 hours adequate. It also suggests that subjective feelings of recovery may be misleading.

3.4 Recovery from Marathons

The research shows a wide variation in recovery times from a marathon, with as little as 5 days to greater than 7 days. No studies checked for longer than 7 days, which means we have no indication of the upper limit. My personal experience is that recovery from a marathon can often take more than 14 days for those unused to the distance, but with practice, recovery can be as short as 48 hours. Much of the difference seems likely to do with resistance to DOMS that occurs with repeated bouts.

  • A 1984 study of 10 marathon runners looked at their recovery[13]. The runners had previously run marathons, but not in the previous 6 months and trained an average of 104Km/~60miles week in the 3 months leading up to the race and all achieved personal bests in the race. They had a V̇O2max of ~68 and marathon times around the 3-hour mark. The runners were tested before, ~20 minutes after the race, then at 1, 3, 5, and 7 days post-race. The runners were split into two groups, with one resting and the other did "active recovery" of easy (50-60% V̇O2max) runs for 20, 25, 30, 35, 40, 45 minutes each day post-race. Ratings of perceived soreness peaked on the first day and returned to baseline (no soreness) by the 5th day, with no differences in soreness between the two groups. Work capacity measured over 50 leg extensions was reduced in both groups on day one to the same level. Work capacity didn't improve in the rest group on day 1 after the marathon, while the active group recovered partly. On days 3, 5, 7 the active group did not recovery work capacity any further, while the resting group regained all the lost work capacity. A similar result occurs with the maximum strength, with the active recovery group regaining less strength than the rest group. However, both groups were still below their pre-race maximum strength after 7 days. While this is a small sample size, this suggests that recovery from a marathon race can occur within 7 days if the runner rests, and it suggests that muscle soreness is not a good measure of recovery.
  • A test of compression garments found that maximum strength was impaired at 48 hours after a marathon, but returned to baseline after 72 hours, though markers of muscle damage (CRP) were still elevated at 72 hours[14]. However, there was wide individual variability in the time course of both strength and muscle damage markers. This suggests that some runners can recover strength from a marathon within 72 hours, even though markers of muscle damage remain.
  • A study of the impact of a marathon on muscle fiber damage (necrosis) in 10 male marathon runners found the damage lasted at least 7 days[15]. The study used biopsies pre-race, post-race, then days 1, 3, 5, and 7. The damage was most prevalent on days 1 and 3, but persisted to day 7. This damage appears to be very similar to Delayed Onset Muscle Soreness, but unfortunately there were no samples after day 7 to indicate when full recovery occurred. (The runners' times varied between 2:31 and 3:39.) This suggests that recovery from a marathon may not be complete in some runners after 7 days.
  • A study on eight elite male marathon runners found that maximum voluntary contraction was reduced post marathon race (2:34 average time), but recovered by five days. Rather strangely, Running Economy at marathon pace was impaired immediately after the race, but two- and five-days post-race their RE was better than before the race[16]. This suggests that some runners (including elites) can recovery from a marathon in less than five days.
  • A study of 7 experienced triathletes (6 male) were evaluated before, during, after 2 hours, then after 2, 4, and 6 days following a marathon distance treadmill run[17]. Their Running Economy fell during the run, and was impaired at 2 h (14%), 2 days (10%), 4 days (2.4%), and 6 days (2.4%) post marathon. CK was elevated after the marathon, returning to baseline at day 6. This suggests recovery from a marathon can take longer than 6 days.
  • A study of 7 runners in the 1979 Stockholm Marathon found that they had predominantly depleted the Glycogen in slow twitch fibers of the quad, and they had reduced fatigue resistance but not reduced maximum strength[18]. The runners finished the marathon between 2:22 and 3:30. Another group of 10 subjects used a combination of 30 min cycling, 75 min running and sprinting to reduce the glycogen of both fast and slow twitch fibers, resulting in both reduced fatigue resistance and reduced maximum strength immediately after the exercise. This doesn't indicate the timeline for recovery, but shows that a marathon race produces muscular weakness.

3.5 Recovery from Ultramarathons

There is even less research into ultramarathons than marathons, but not surprisingly, recovery from an ultramarathon effort can be protracted. It's unclear if ultramarathons can produce an improvement in fitness. It seems probable that some aspects of fitness may improve (such as DOMS resistance), but some detraining may occur during the protracted recovery.

  • A study of runners in the 90Km/56-mile Comrades Marathon found Running Economy was reduced for the 32 days after the race, though only day 25 was statistically significant[19]. Muscular strength as measured by jumping was reduced for 32 days, though only statistically significant for 3-18 days depending on the jump type. The study only included 8 runners, so statistical power was low. This suggests that recovery from an ultramarathon can take up to 32 days.
  • A study of 72 runners at the 100 mile/161Km Western States Endurance Run found 400m run time was slower 3- and 5-days post-race, while muscle soreness peaked on race day and gradually declined over the following 7 days[20]. Subjective muscle fatigue peaked immediately post-race and returned to near baseline by 7 days post-race. This suggests that recovery from an ultramarathon can take more than 5 days.

3.6 Recovery from Strength training

There are many studies on strength training, but the one below is noteworthy as it calls out the time supercompensation. After all, maintaining baseline performance is not the goal of training.

  • A 2003 study of the recovery from strength training showed the time course for Supercompensation [21]. The 30 male subjects were experienced in strength training, having used a protocol of training 3-4/week for at least 12 weeks. 20 were in their 20s, 10 in their 50s. The exercise was 7 sets to failure for the older men and half of the younger, or 3 sets to failure for the remaining 10 younger men, each over 8 muscle groups. All subjects were weaker after 24 hours, with performance returning to baseline after 48 hours, with Supercompensation to above baseline at 72 hours. This suggests that 48 hours may be insufficient for optimum recovery from strength training. This is study suggests that supercompensation can occur in 72 hours after strength training when recovery to baseline is complete within 48 hours.

3.7 Recovery and Elite Athletes

There is very little evidence of the optimal recovery from elite athletes that I could find in the available research. However, it's been noted[22] that the improvement in performance after a Taper suggests that athletes are typically under-recovered. This improvement is typically 2%, with a range of -2.3% to 8.9%, which is a huge benefit for an elite athlete in such a short period[23].

4 The Science of Measuring Recovery

A key problem in knowing how frequently to train is measuring recovery. It seems intuitively obvious that different modes of training and different training loads will result in different recovery periods. Running an easy mile will result in no appreciable need for recovery, while running hilly 100-mile race could leave me impaired for weeks.

  • A common approach in research is to use maximum strength[1] or maximum power output[24] as a measure of recovery. This seems to be one of the best measures, but obviously the test itself incurs a training load. It seems possible that a short test, using a brief (2-3 minute warm up) followed by 20-30 seconds "all out" might provide insight into recovery without significant training stress on the athlete.
  • Using blood markers, such as creatine phosphokinase (a marker of muscle damage) can be used to track the impact of exercise and recovery[25]. Of course, this is of little use outside of a research context.
  • There's been a lot of interest in using Heart Rate Variability (HRV) for measuring training stress and recovery. However, I've never seen any relationship between HRV and my training/recovery status. A study of 57 elite Nordic-skiers over five years also found no relationship between HRV and training load[26].

5 The Science of Training Frequency

There's relatively little research that goes beyond recovery into training frequency and recovery from repeated bouts. There are some indications that lower frequencies might be more effective it's hard to be more definitive. Based on the research above on recovery, it seems likely that the specifics of the exercise may have a huge impact on the appropriate frequency.

  • A study of six untrained subjects looked at how training frequency effected both recovery and gains in fitness[24]. The study used intermittent cycle training three times per week for 8 weeks (low frequency) followed by a week without training, followed by training five times per week for 4 weeks (high frequency). The study then fitted their recovery measured using the maximum power over 5 minutes into a mathematical model. The low frequency training subjects recovered in 0.9 days, but the high frequency took 3.6 days to recover. In addition, the high frequency training produced lower benefits from the training effort. The main flaw in this study is that the high frequency training follows the lower frequency training, so the subjects have improved their fitness, which normally results in a slower fitness improvement. This study suggests that training 5/week impairs recovery compared with 3/week, but the study flaws means this could be an artifact of the design.
  • A 1986 review of 30+ studies looked at training to improve V̇O2max [27]. The study found that across all fitness levels and intensities, fitness improvements increase with training frequency up to 6/week (no study looked at 7/week.) For lower fitness individuals (V̇O2max 30-40), improvements were proportional to frequency, with 2/week producing improvements, but 5-6/week being most effective. For V̇O2max 40-50, training for 4/week or 6/week seemed to be most effective. Finally, for V̇O2max 50-60, 3/week might be the most effective. However, the wide disparity in the protocols of the underlying studies creates means the results have to be used with caution.

6 The Science of Active Recovery

Active recovery is the idea that low intensity exercise improves recovery from high intensity exercise. In the context of easy exercise on the day after hard exercise, one study found that indicated that active recovery does nothing to help[28]. Another found that active recovery after a marathon significantly impaired strength and work capacity, even though muscle soreness was gone[13]. An analysis of the evidence on active recovery noted that "evidence that active recovery enhances recovery between training sessions is currently lacking"[29]. A study looked at the recovery from downhill running in 50 male students (V̇O2max 55 +/-6)[6]. The runners either rested or ran for 30 minutes each day for 6 days. The post-downhill runs were at 40%, 50%, 60%, or 70% of V̇O2max. There were no differences between rest and running in measures of muscle soreness or Running Economy.

6.1 Other Uses of the Term "Active Recovery"

Note that "Active Recovery" can have other meanings:

  • 'Active Recovery' can also refer to doing low intensity exercise between the work periods of Interval Training, which is effective as it metabolizes lactate and speeds up the short-term recovery needed before the next interval. Active recovery also limits the additional cardiac stress that occurs when you stop running as the muscle compressions help venous return to the heart, maintaining blood pressure.
  • Doing gentle exercise immediately after intense exercise as a Cooldown may have some benefits. There is anecdotal evidence that walking for 20-30 minutes after a Long Run reduces muscle soreness.

7 Training Plans

The FIRST plan is based around running three days a week, and is the only plan I am aware of that has undergone scientific evaluation about its effectiveness. Hal Higdon's Advanced II Marathon[30] plan has 6 days of running, but two days are trivial. Jeff Galloway[31] uses four days/week. The Runner's World beginners plan [32]is four days/week. (The RW intermediary & advanced are 5 days.) Jack Daniels defines just two work outs a week, and leaves it up to you how you fit in the other miles.

8 Advanced Topics

8.1 Overload Training

Running hard or long everyday will build up cumulative fatigue as the body does not have sufficient time to recover. If this is kept up to long, then some type of failure will occur; either injury or some form of Overtraining. However, it is possible to run for a number of days consecutively, building up deeper cumulative fatigue, and then taking a longer rest period. This is one of the principles of the Three Phase Taper.

8.2 Multiple Workouts Per Day

Running 3 or 4 days/week does not mean running at most once per day. It can be effective or necessary to run more than once per day while running fewer days per week. Running more than once in a day can provide some of the training stress of a single longer run.

9 See Also

10 References

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  2. 2.0 2.1 Trevor C. Chen, Kazunori Nosaka, Jui-Hung Tu, Changes in running economy following downhill running, Journal of Sports Sciences, volume 25, issue 1, 2007, pages 55–63, ISSN 0264-0414, doi 10.1080/02640410600718228
  3. William A. Braun, Darren J. Dutto, The effects of a single bout of downhill running and ensuing delayed onset of muscle soreness on running economy performed 48 h later, European Journal of Applied Physiology, volume 90, issue 1-2, 2003, pages 29–34, ISSN 1439-6319, doi 10.1007/s00421-003-0857-8
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  30. http://www.halhigdon.com/marathon/advanced2/advancedII.htm
  31. http://www.jeffgalloway.com/training/marathon.html
  32. http://www.runnersworld.com/article/0,7120,s6-238-244--6946-2-3X5X7-4,00.html