The Effect Of An Added Reaction Time Challenge On Vertical Jump And Ballistic Push-up Performance

The rapidly changing, chaotic nature of the athletic environment does not always permit individuals to coordinate an ideal movement strategy. However, current assessments that evaluate upper and lower extremity power do not typically have any constraints to assess performance under this unavoidable pressure, limiting the ecological validity. PURPOSE: To determine the effect of a reaction time task on max vertical jump and ballistic push-up performance. METHODS: 35 physically active adults (age: 19.31 ± 1.30y; height: 173.75 ± 9.76 cm; weight: 75.79 ± 14.01 kg) in the reserve officers’ training corps completed max vertical jumps and ballistic push-ups in one visit to the lab. For the max vertical jump, participants stood with one foot on each force plate and completed five max vertical jumps. For the reactive condition, a sensor in front of the participant at eye level illuminated red and the participant reached down with their hand and deactivated a second sensor between their feet, immediately followed by completing a max vertical jump. Average peak power normalized to body weight was recorded (Watts per kilogram; W/kg). For the ballistic pushup, participants placed one hand on each force plate in a high plank position. On cue, participants performed a ballistic push-up. For the reactive condition, participants completed the ballistic push-up when a sensor in front of them illuminated red. A second sensor under their chest recorded when their chest dropped within 30 cm of it. Peak force was recorded and averaged across three trials for each condition (Newtons; N). The standard and reactive conditions were analyzed using paired t-tests with corresponding Cohen’s d effect sizes. RESULTS: The normalized vertical jump peak power (43.31 ± 8.58 W/kg) was significantly greater than the reactive vertical jump (42.046 ± 8.32 W/kg; p = 0.006; d = 0.50). The ballistic push-up peak force (809.88 ± 327.75 N) was not significantly different than the reactive ballistic push-up (809.79 ± 327.12 N; p = 0.997; d = 0.001). CONCLUSIONS: The reaction time component of the vertical jump diminished the achieved power. This may be ability to plan and select optimal movement strategies, resulting in decreased lower body power. However, the reaction time challenge did not impact performance on the ballistic push-up. The views and information presented are those of the authors and do not represent the official position of the U.S. Army Medical Center of Excellence, the U.S. Army Training and Doctrine Command, or the Departments of the Army, Department of Defense, or the U.S. Government