Comparison of Take Off Kinematics During Loaded Countermovement Jumps in Division One Female Gymnasts and Soccer Athletes

Purpose: The purpose of this study was to compare takeoff kinematics of incrementally loaded countermovement jumps (CMJ) in water and land in female gymnasts and soccer athletes. Methods: 24 Division I student athletes (12 gymnastics, 12 soccer) volunteered for this study. Subjects performed CMJ on land and water at a level of the xiphoid process without an arm swing. CMJs with loads of body weight (BW), 10% BW, 20% BW, and 30% BW were performed three times per trial at each load. 15 kinematic variables related to the lower extremity were examined. Results: For environment, significant (p less than 0.001) segment ROM values were greater on land than in water. Segmental velocities displayed mixed results, as thigh positive (countermovement) velocities were greater in water than land, and shank positive velocities were greater on land than water. During propulsion, all segmental velocities displayed significant o (mean plus/minus SD). In the propulsive phase, gymnasts displayed 23.3 plus/minus 3.7o greater plantarflexion than their soccer counterparts Segmental velocities of the foot followed suit with gymnasts\u27 findings relating to the foot velocity were greater by 103o/second. Physical properties of water, specifically buoyancy and drag, played a vital role in environmental differences. When comparing sport, gymnasts displayed greater foot ROM likely due tot he aesthetic aspect of gymnastics compared to soccer in regards to improving an athlete\u27s score based on how well the gymnast can point their toes during competition. No significant findings were identified by the effect of load on both environment and sport. Conclusion: These results suggest the buoyancy of water may facilitate the countermovement phase yet the extensive drag forces during propulsion restrict segmental velocities during propulsion