Meta-analysis of 12 trials; 785 adults
Slow breathing and stress
Breathwork reduced reported stress by a small-to-medium amount (g = −0.35). Ten of the 12 trials used slow-paced breathing.
What this does not show
Most studies had some risk of bias. The findings concern reported stress, anxiety, and depression. They do not show faster muscle repair or better running recovery.
28-day randomized trial; non-athletes
A brief breathing practice
Participants practiced for 5 min per day. Cyclic sighing, with a longer exhale, improved positive mood more than mindfulness meditation.
What this does not show
This exploratory study measured mood and breathing, not sports recovery or tissue repair. One trial does not establish the best breathing method or dose.
Systematic review and meta-analysis
Mindfulness and sleep quality
Mindfulness improved sleep quality versus nonspecific active controls (g = 0.33). The review rated this evidence as moderate strength.
What this does not show
The review found no clear benefit over specific active treatments for sleep. It studied general adults, not runners or muscle repair.
Athlete sleep consensus; small basketball study
Sleep extension and athletic performance
Eleven collegiate basketball players extended time in bed to at least 10 h for 5–7 weeks. Sprint times, shooting accuracy, mood, and alertness improved.
What this does not show
The study had no control group and included only male basketball players. It did not compare sleep with other recovery methods or establish one sleep target for all athletes.
Crossover trial; 20 male athletes
Yoga and short-term recovery
After HIIT, 15 min of yoga improved short-term heart-rate variability and breathing rate more than static stretching.
What this does not show
The trial measured short-term recovery markers after HIIT. It did not test rest-day videos, soreness, muscle repair, or running performance.
11 recreational runners, tested before and 7 days after a marathon
Recovery after a marathon
Soreness was highest in the first days and was near normal by day 4. Aerobic fitness and running economy showed no clear change at day 7.
What this does not show
A small study that did not measure muscle damage. The rest and easy days after each race distance are app conventions from common coaching guidance, not trial results.
Two meta-analyses (27 and 14 studies); training logs of 158,117 marathoners
How to taper for a race
The largest gains came from cutting volume by 41–60% over 1–3 weeks, with intensity and frequency kept. Marathoners whose volume went down each week for 3 weeks finished fastest. A 4th week added nothing.
What this does not show
The marathon data is observational, not a trial. The exact weekly steps and the shorter taper for a 5K, 10K or half are app conventions inside the studied range.