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Eric M. Mosier1, Andrew C. Fry1, Michael T. Lane2, Patrick G. Moodie3, and Jonathan R. Moodie3 1University of Kansas, Lawrence, KS, 2Eastern Kentucky University, Richmond, KY, 3Dynamic Athletics Research Institute, Lenexa KS.

The counter-movement vertical jump (CMVJ) is a complex multi-joint activity where muscles of the lower and upper extremities collectively summate forces to produce movement. PURPOSES: This study determined the effects of an arm swing on lower limb kinematics (joint ranges of motion; ROM) and kinetics (peak joint torques; Nm) during a CMVJ. METHODS: Fourteen healthy, recreationally active men (X±SD; age=24.1±3.9 yrs, height=1.76±0.05 m, weight=82.6±10.6 kg) performed 6 CMVJ, 3 with an arm swing (AS) and 3 with no arm swing (NAS), in random order. The AS CMVJ began with the participant standing upright with arms fully raised above the head. The NAS CMVJ began with the dominant upper limb fully raised overhead, while the non-dominant hand remained on the iliac crest during the entire CMVJ. All jumps were performed by descending to an internal knee angle of 90o, using maximal effort, and reaching for an overhead target. A three dimensional markerless motion capture system (MCS; DARI, Lenexa, KS) was used to analyze the kinetic and kinematic data. T-tests and ANOVAs (*AS vs. NAS, †eccentric [ECC] vs. concentric [CON]; p<0.05) were performed on mean values from all 3 jumps for AS and NAS for each subject. RESULTS: Results for AS and NAS CMVJs are shown in the table. The AS CMVJ produced greater vertical jump height (VJH) an average of 0.07±0.03 m (3.0±1.3 in). The hips and ankles produced greater ECC and CON torques, less hip flexion, and greater time in the concentric phase during the AS CMVJ. The knees produced greater concentric torque, however there were no differences between jump conditions. The AS CMVJ also had greater time in the concentric phase of the jump. CONCLUSION: Compared to NAS, use of an AS produced a 13% increase in CMVJ height, and greater peak torques for the hips and ankles, even when comparing eccentric and concentric phases. The AS CMVJ also increased the duration of the concentric phase, thus permitting greater torque generation to increase CMVJ height.

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