Circadian rhythm effects on muscle strength and power: a review.

Abstract

Different physiological and psychological functions which are subject to change in relation to the 24-hour solar cycle. These variations are known as circadian rhythms and produce maximum peaks (acrophase) and minimum (batiphase) on motor function depending on the time-of-day. It is shown that many components related to athletic performance possess these circadian rhythms, so that, the aim of this review is to update the knowledge of how the circadian rhythm affects on muscle strength and power in short duration exercises. A review of the literature revealed 20 items neuromuscular performance measured at different times of the day. In order to compare the effects that different times-of-day have had on neuromuscular performance it has been calculated descriptive statistics of the percent change and the size of the effect on the dependent variable studied, which have been reflected in a results table. Generally speaking, the main conclusions of this review have been that, i) neuromuscular performance in exercises of short duration is maximized evening hours regarding morning; ii) not all types of exercise (isometric, isokinetic and isoinertial) and all the muscle groups are more neuromuscular performance at the same time of day; iii) the increase in body temperature (both active heating as passive heating) and / or intake of certain ergogenic aids can offset the impact of circadian rhythms on sports performance in A.M.; iv) the circadian rhythm on neuromuscular performance in women does not seem so obvious; v) the circadian rhythm in blind neuromuscular performance is free running.