Acute effects of eccentric versus concentric exercise on executive function and attention of older adults.

ABSTRACT

Cognitive function is improved acutely after aerobic and/or resistance exercise, but it is unclear if the types of muscle contraction can influence this effect. This study tested the hypothesis that undertaking an acute bout of exercise with eccentric than concentric contractions would be more beneficial for improving cognitive function post-exercise in older adults. Twenty healthy older adults (66-75y) performed descending stair walking (DSW), ascending stair walking (ASW), and resistance exercise of the knee extensors with eccentric-only (RE-ECC) or concentric-only contractions (RE-CON) for 20 minutes each with a week between exercises in a randomized order. The Stroop tests of color naming (STCN) and conflicting color words (STCC), symbol digit modalities test, digit span test (DST), and two types of the trail making test (TMT-A, TMT-B) were assessed before and after sitting for 20 minutes (control session), and each exercise. A significant (p<0.05) improvement in the baseline test scores was found from the control session to the fourth exercise session. Time to complete the tests was significantly (p<0.05) reduced from pre- to post-exercise as well as after sitting for 20 minutes for STCN (-5.9±7.4s, Cohen's d=0.79), STCC (-8.9±11.1s, d=0.80), TMT-A (-22.6±9.7s, d=2.34) and TMT-B (-23.1±13.7s, d=1.69) without significant difference among the four exercise conditions. A significant (p<0.05) improvement of DST score was found from pre- to post-exercise for DSW (9.0±17.6%, d=0.51) and RE-ECC (6.5±10.6%, d=0.61), but not for ASW and RE-CON. These results partially supported the hypothesis that eccentric exercise could affect acute changes in cognitive function greater than concentric exercise.