Compression garments including shorts, tights, and socks have gained in popularity among both amateur and professional runners. Manufacturers and athletes claim improved circulation, recovery, and performance can be found using these products either during or after a run. As with many products in health, fitness, and performance these claims should be taken with a grain of salt until supported by research institutions.
A recent article in the journal Sports Medicine evaluated the available evidence on the psychological, physiological, and performance effects of compression garments (socks, calf sleeves, shorts, and tights) in runners (Engel et al. 2016). The authors found moderate beneficial effects for delayed onset muscle pain/soreness and delayed muscle fatigue in athletes wearing compression garments during run. Additionally, smaller beneficial effects were noted for improvements in running economy and time to exhaustion suggestion these garments may slightly improve performance. Important to note is the lack of significant effects on sprint, middle, or long distance timed runs or physiologic variables such as cardiac output, blood lactate levels, or body temperature were noted in the review.
In short, compression garments seem to have their greatest impact on perceived muscle pain/soreness and recovery, but performance effects are small.