title: Effect of acute exercise on clinically measured reaction time in collegiate athletes.
abstract: OBJECTIVE
  We have developed a reliable and valid clinical test of reaction time (RTclin) that is sensitive to the acute effects of concussion. If RTclin is to be used as a sideline concussion assessment tool then the acute effects of exercise on RTclin may need to be controlled for. The purpose of this study was therefore to determine the effect of exercise on RTclin.
  
  
  METHODS
  A gender-balanced group of 42 collegiate athletes were assigned to an exercise (n = 28) and a control (n = 14) group using 2:1 block randomization. The exercise group completed a graded four-stage exercise protocol on a stationary bicycle (100 W × 5 min; 150 W × 5 min; 200 W × 5 min; sprint × 2 min), whereas the control group was tested at identical periods without exercising. Mean RTclin was calculated for eight trials as the fall time of a vertically suspended rigid shaft after its release by the examiner before being caught by the athlete. RTclin was measured at baseline and after each of the four stages.
  
  
  RESULTS
  As both HR and RPE significantly increased for the four stages in the exercise group (P < 0.001), mean RTclin showed a significant overall decline during repeated test administration (P < 0.008). However, there were no significant group (exercise vs control, P = 0.822) or group-by-stage interaction (P = 0.169) effects on RTclin as assessed by repeated-measures analysis of variance.
  
  
  CONCLUSIONS
  Exercise did not appear to affect RTclin performance in this study. This suggests that RTclin measured during a sideline concussion assessment does not need to be adjusted to account for the acute effects of exercise.
authors.affiliation: 1College of Human Medicine, Michigan State University; Grand Rapids, MI; 2Department of Physical Medicine and Rehabilitation, University of Michigan; Ann Arbor, MI; 3Michigan NeuroSport, University of Michigan; Ann Arbor, MI; and 4Department of Neurology, University of Michigan; Ann Arbor, MI.
authors.forename: Shailesh
authors.initials: S
authors.lastname: Reddy
authors.forename: James T
authors.initials: JT
authors.lastname: Eckner
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Kutcher
mesh_terms: D000293:Adolescent; D056352:Athletes; D001924:Brain Concussion / Q000175:diagnosis; D015444:Exercise / Q000502:physiology*; D005260:Female; D005538:Football / Q000502:physiology; D006801:Humans; D008297:Male; D018763:Muscle Fatigue; D011930:Reaction Time / Q000502:physiology*; D012916:Soccer / Q000502:physiology; D055815:Young Adult