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[[File:Supercompensation-small.png|right|thumb|500px| [[Supercompensation]] There is the idea a natural human belief that exercise initially weakens the body, but it repairs itself to become stronger.]]There is a natural human belief that if some is 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. =Supercompensation , and Monotony =there are a number of factors to consider. I've reviewed the available research (see below) and literature to come to some initial conclusions. It* While it's well accepted that exercise is a critical part quite possible to do the same run every day, this type of training isn't generally effective at improving fitness, and there are many different [[Endurance Adaptations]] that occur. The primary mechanism for these adaptations is only training plans I'm aware of that exercise causes damage and this damage is repaired train the same every day are for beginners just learning to be stronger than before the exerciserun. This is seen in the fatigue that occurs after exercise* Most training plans have at least a mix of easier and harder workouts, and the need for as well as some restdays. The term for this mechanism is Only [[SupercompensationFIRST]]attempts some level of scientific validation, and is a key principle for creating training programsbut even this plan doesn't seem to take into account the available research. One way of evaluating a training program * Because running includes an eccentric component (see below) it is {{TrainingMonotony}} which looks at the variation in daily training stressquite different to cycling and swimming. Higher values There is clear scientific evidence, as well as plenty of {{TrainingMonotony}} indicate anecdotal that each day's training excessive eccentric exercise can take many weeks to recover from. This is similarshown most clearly in longer runs and downhill running, while lower values indicate greater variationswhere runners can struggle to walk down stairs for days after a marathon. Higher levels One way of {{TrainingMonotony}} are associated with reduced benefits and looking at this is that a greater risk of [[Overtraining Syndrome]]. This need longer period is needed to recover from long and/or downhill runs. However, it's probably better to optimize focus on building up the ratio long 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/or downhill runs so that the recovery period is reasonable. =Easy Days and Junk Miles=A common approach to optimizing [[Supercompensation]] and {{TrainingMonotony}} * 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 have 3 be longer in slower and/or fewer hard training days combined with a number of easier daysless established runners. (For this approach to workslower runners, the easy days need to be sufficiently easyduration becomes longer, increasing eccentric stress, and less established runners will have less [[Delayed Onset Muscle Soreness]] resistance. Carl Foster said "for best results make your hard days very) * [[High Intensity Interval Training]] may require the least recovery time, very hard and your easy days very, very easy". Running on the easy days thought this is often referred likely to as "junk miles" as be highly dependent on the only result of these miles is impaired recoverymode and load. If I recommend using a stationary bike for HIIT to reduce injury risk and to precisely control the benefits workout. It seems that for some modes of training go down HIIT, recovery can be as short as the effort on easy days increases, why run at all on the easy days? So far I 24 hours.* Easy running or training between hard workouts doesn't seem to have found no evidence to indicate there is any training benefit from running on support in the easy daysresearch. In factPutting this together, all the evidence supports [[Supercompensation]] it suggests a workout plan should fit this outline. * Endurance training through long and {{TrainingMonotony}}, therefore I recommend /or downhill running only 3should be built up carefully so that soreness lasts 2-4 days of , with the week for optimal resultsgaps between the endurance runs about 3 times the length of the soreness. [[File:Supercompensation-continued-small* HIIT workouts or short/fast runs about 3 times/week. (HIIT could be more frequent.png|none|thumb|500px|The correct balance of exercise stress, rest, and the timing of the two is important for achieving improved fitness.]])=Running PatternsSupercompensation =There are various patterns of running It's well accepted that I would generally recommend. I'll use an abbreviation for the patterns, where each day exercise is a charactercritical part of improving fitness, with 'R' for a running day and 'x' there are many different [[Endurance Adaptations]] that occur. The primary mechanism for a day off or a cross training day. So "RxRxRxx" would be running the first, third these adaptations is that exercise causes damage and fifth days with this damage is repaired to be stronger than before the other four off. * '''3 days/week (RxRxRxx)'''exercise. This is seen in the pattern used by fatigue that occurs after exercise, and the need for rest. The term for this mechanism is [[FIRSTSupercompensation]], which and is the only marathon a key principle for creating training plan I've found that has performed scientific studies to evaluate its effectiveness. Running 3 days/week requires that every day is hard, and typically involves a programs. [[Long Run]] and two speedwork daysFile:Supercompensation-small. The ratio of running to rest gives 2 days of rest, and these typically follow png|none|thumb|500px| [[Supercompensation]] is the long runidea that exercise initially weakens the body, but it repairs itself to become stronger. ]]=Long and Downhill Running=* '''4 days/week (RxRxRRxThe recovery required for longer or downhill running incurs more [[Delayed Onset Muscle Soreness]] (DOMS)''', which has a much longer recovery time. Having two back to back running days allows for one Most training day that has incomplete recovery. Typically these two back to back plans have longer runs every 7 or 14 days are used for long runs, so but the research suggests that the second day simulates a longer distance [[Long Run]]. * '''4 actual recovery period will depend on the severity of the DOMS. Recovery periods could be as long as 30-90 days/week (RRxRRxx)'''. It , which is possible obviously so long that detraining is likely. In practice, I believe that we need to arrange 4 daysinvert the problem. Instead of working out the recovery period for the long/week as two sets of back to back daysdownhill running, but this is not common. If all we need to optimize the running days impact so that recovery occurs in the right time period. A long/downhill run that produces performance deficits that are [[Long Run]]s then fatigue will build up over not resolved well before the five RRxRR days, next long/downhill run are too stressful and the two consecutive rest days will effort needs to be needed for recoveryreduced. * '''3.5 days/week''=The Science of Recovery=Below are the studies I've found looking at the timeline of recovery from exercise stress. Running every other day is a great patternOverall, but logistically it is hard to organizethe time to recover from varies enormously between different types of training and different subject groups.=Exceptions=If your running is not hard enough to require 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 recovery, you may be better off running more often. * If you are just but marathon, ultramarathon, and [[Starting to run]Delayed Onset Muscle Soreness| DOMS] then you may not running hard enough ] inducing exercise can potentially take weeks to recover from. Importantly, subjective feelings of recovery seem to require be inadequate in evaluating the days off. However, I believe that 3 days/week is probably optimalactual recovery.* If you are ==Recovery from Eccentric and Downhill Exercise==Because running for fun and not pushing your body hardalways involves an eccentric component, then running 5-6 days a week may work for you. * If you have this modality is quite important as it produces [[Delayed Onset Muscle Soreness| DOMS]]. The eccentric component is particularly important for endurance running, such as after a long race, more frequent [[Recovery Runs]] may helpespecially when it includes downhill running. The immediate muscular weakness that occurs with eccentric exercise compromises performance in longer runs.* During a [[Practical Tapering| Taper]] it may The repeated bout effect, which provides significant subsequent protection from DOMS has to be appropriate to increase frequency while dramatically reducing intensity and durationcarefully balanced with the potentially elongated recovery periods. Currently there The research suggests that recovery can take many weeks, something that is insufficient evidence likely to reach a recommendationproduce impaired subsequent training. =Mental Health Runs=One * A study of the complaints concerning running 3 or 4 days192 subjects undergoing eccentric muscle damage found that recovery was extremely protracted<ref name="SayersClarkson2001"/week is that every run is hard and therefore there is no running for fun>. Sometimes a short, easy run can provide mental benefitsThe 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 these can be worthwhile overall, even if these "mental health runs" degrade the overall training program effectivenessby 132 hours (5.=Overload Training=Running hard or long everyday will build up cumulative fatigue as 5 days) they were still reduced by 33%. Of the body does not have sufficient time 32 subjects that had their peak force reduced to recover. If this is kept up too longer, then some type <30% of their initial levels, 20 were retested after 26 days and had only regained 81% (males) and 93% (females.) A further subset of failure will occur; either injury or some form 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 [Overtraining[VO2max|V̇O₂max]]of 54. However, it is possible to run for a number 6 were evaluated before and several times after performing 30 minutes of days consecutivelydownhill running<ref name="ChenNosaka2007"/>. They ran downhill at -15%, building up deeper cumulative fatiguea fairly steep gradient, and then taking a longer rest periodwith speed set to 70% [[VO2max|V̇O₂max]]. This is one Maximum strength was reduced by an average of 21%, 1 hour after the principles of the [[Three Phase Taper]]descent and recovered slowly until day 5 when they were back to normal.=Doubles=Running 3 or 4 days/week does not mean running at most once per day. It can be effective or necessary Muscle soreness peaked on day two, and returned to run more than once per near baseline (no soreness) by day while running fewer days per week5. Running more than once in Interestingly, creatine kinase (CK), a day can provide some marker of muscle damage remained elevated for the training stress 5 days of a single longer runthe study (~420-460 U/l.=Cross Training=) Their [[Running is different Economy]] was impaired from 1-hour post descent through to day 3 at speeds varying from 65% to many other forms 85% of exercise because a [[Downhill RunningVO2max| large portion of the training stress is eccentricV̇O₂max]], and eccentric exercise tends but returned to require a 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% [[VO2max|V̇O₂max]] 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''. * 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''. * A study looked at 10 female runners, [[VO2max|V̇O₂max]] 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]]''.* A study looked at 50 male students ([[VO2max|V̇O₂max]] 55 +/-6) underwent 30 minutes of downhill running at 15% (8.5 degrees) at 70% [[VO2max|V̇O₂max]]<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''. ==Recovery from High Intensity Interval Training Recovery==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. * 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''. * 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''. * 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''.* 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''. ==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<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''.* 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|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.''==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 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 [[FIRSTthan 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. * 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|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% [[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.'' * 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. ''* 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.''* 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. ''* 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. ''* 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''. ==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<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.''* 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. ''==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]] <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. ''=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<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. * 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. * 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"/>.=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<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''. * A 1986 review of 30+ studies looked at training to improve [[VO2max|V̇O₂max]] <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|V̇O₂max]] 30-40), improvements were proportional to frequency, with 2/week producing improvements, but 5-6/week being most effective. For [[VO2max|V̇O₂max]] 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. =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<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|V̇O₂max]] 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|V̇O₂max]]. There were no differences between rest and running in measures of muscle soreness or [[Running Economy]]. ==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 [[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. * 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]] training program suggests that this cross training may be usefulsoreness.

=Training Frequency, Recovery, & GainsAdvanced Topics=A study of six untrained subjects looked at how training frequency effected both recovery and gains in fitness<ref name="Busso-2002"/>. The study compared intermittent cycle training three times per week (low frequency) with training five times per week (high frequency). The low frequency training had a recovery time of 0.9 days, but the high frequency had a recovery time of 3.6 days. In addition, the high frequency training produced lower benefits from the training effort. =Active RecoveryOverload Training==What about 'active recovery'? This is the idea that low intensity exercise improves recovery from high intensity exercise. In Running hard or long everyday will build up cumulative fatigue as the context of easy exercise on the day after hard exercise, I've only found one scientific study <ref name="Andersson-2008"/> and that indicated that active recovery body does nothing not have sufficient time to helprecover. An analysis of the evidence on active recovery noted that "evidence that active recovery enhances recovery between training sessions If this is currently lacking"<ref name="Barnett-2006"/>. Note that "Active Recovery" can have other meanings:* 'Active Recovery' can refer kept up to doing low intensity exercise between the work periods long, then some type of failure will occur; either injury or some form of [[Introduction to Interval Training| Interval TrainingOvertraining]]. However, which it is effective. * Doing gentle exercise immediately after intense exercise as a [[Cooldown]] may have some benefits. There is anecdotal evidence that walking possible to run for 20-30 minutes after a [[Long Run]] reduces [[Muscle| muscle]] soreness. =How Often I Run=I did my first ultra in 2005 using a fairly conventional pattern number of running. I would run six days a weekconsecutively, 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 extremebuilding up deeper cumulative fatigue, 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 then taking a high mileage experiment| running more frequently]] for six months and found it ineffective and counterproductivelonger rest period. * I have found the most effective pattern for me This is to run four days a week. I aim to run 16-27 miles, which gives me lots one of long running, with enough rest to support that mileage. * Two the principles 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 RunThree Phase Taper]] 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 ==Multiple Workouts Per Day==Running 3 or shorter, I would train three 4 days /week does not mean running at most once per weekday. For these shorter races it would not It can be as difficult effective or necessary 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 in specific situations:** During the [[Overload]] part of a [[Three Phase Taper]] I will normally run long distances 6-7 than once per day while running fewer days per week. ** My frequency for reduced training part of the [[Practical Tapering| Taper]] tends to vary. Sometimes I will run Running more frequently, but with a dramatic reduction than once in duration. ** If I'm recovering, either from a race or injury, I will often run short distances more frequently. This sometimes includes recovering from [[Delayed Onset Muscle Soreness]].* Occasionally I will run twice a day, but typically can provide some of the second run is for [[Heat Acclimation Training]] rather than to fit in extra miles. [[File:RunningFrequency.png|none|thumb|500px|This is a histogram of how frequently I've been running in 2013. As you can see, I normally run 4 days/week, though I sometimes run more frequently as noted above.]]=The Psychology training stress 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 single longer 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.