Vertical jump height as an indicator of lower-extremity muscular fatigue in recreational Crossfit athletes

Crossfit is a sport that combines multiple facets of aerobic and anaerobic fitness, such as resistance training, cardiovascular training, and gymnastic movements into workouts designed to improve individuals’ overall level of fitness. The vertical jump motion is a primary component used in the design of many Crossfit workouts and is a common measure of athletic performance and fatigue. The purpose of this study is to investigate the acute effects of performing an aerobic high intensity functional training workout entitled Cindy. The workout’s effect on vertical jump and landing impact performance will be measured via a bounce jump test completed pre- and post- exercise. Sixteen university students (6 females, 10 males) completed a single trial of three consecutive countermovement maximum height bounce jumps recorded by the G-VERT system prior to (PRE) and immediately after (POST) the Crossfit workout ‘Cindy’. Jump height and landing impacts were calculated by the G-VERT. The study population experienced a significant decrease in jump height from PRE to POST workout (PRE= 15.90 in. ± 2.64 in; POST= 14.98 in. ± 2.52 in., p=0.01) and a nonsignificant increase in landing impact from PRE to POST workout (PRE= 7.73 in. ± 3.04 in; POST= 8.52 in. ± 3.50 in., p=0.127). These results suggest that, over the course of a single aerobic high intensity functional training session, muscular fatigue may affect the ability of the lower extremities to produce forces necessary to achieve desired jump performance