PRE-ACTIVITY STRETCHING IMPAIRS REACTION TIME AND EXPLOSIVE POWER
Chavez, C., & McLester, J. R. (2006). Stretching negatively affects reaction time but not jump height during repetitive vertical jump performance. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 1753.
The purpose of this study was to examine whether stretching affects repeated vertical jump performance. Ss (N = 20) performed three separate trials. During each trial, Ss performed two bouts of four consecutive vertical jumps. Ss performed the two bouts in random order under the following conditions: A) a pre-first bout only stretching trial (with seven minutes of passive rest between bouts), B) a between-bout only stretching trial (with a seven-minute stretching protocol between bouts), and C) a non-stretching trial (seven minutes of passive rest between bouts). The stretching protocol included static stretching of the gluteus maximus, hamstrings, quadriceps, and triceps surae. Reaction time between jumps, jump height, and explosive leg power factor (ELPF = air time/ground time) were measured for each bout.
Stretching immediately prior to the first bout significantly impaired reaction time and decreased the explosive leg power factor on the first bout. There were no significant differences between the non-stretching or stretching only between bouts conditions for reaction time or explosive leg power factor. A significant increase in jump height was observed in the between-bout stretch condition but not in the other conditions.
Implication. Stretching immediately before a repeated vertical jump performance hinders reaction time and leg power on the first bout. After seven minutes of passive recovery, negative effects are no longer evident. Jump height was not adversely affected by stretching.