Changes

* 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.

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.

<ref name="ChambersNoakes1998">C. Chambers, T. D. Noakes, E. V. Lambert, M. I. Lambert, Time course of recovery of vertical jump height and heart rate versus running speed after a 90-km foot race, Journal of Sports Sciences, volume 16, issue 7, 1998, pages 645–651, ISSN [http://www.worldcat.org/issn/0264-0414 0264-0414], doi [http://dx.doi.org/10.1080/026404198366452 10.1080/026404198366452]</ref>

<ref name="HoffmanBadowski2016">Martin D. Hoffman, Natalie Badowski, Joseph Chin, Kristin J. Stuempfle, A Randomized Controlled Trial of Massage and Pneumatic Compression for Ultramarathon Recovery, Journal of Orthopaedic & Sports Physical Therapy, volume 46, issue 5, 2016, pages 320–326, ISSN [http://www.worldcat.org/issn/0190-6011 0190-6011], doi [http://dx.doi.org/10.2519/jospt.2016.6455 10.2519/jospt.2016.6455]</ref>

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