| Abstrakt: |
Currently little research has been conducted in training using body weight reduction (BWR) as a means to enhance sports performance. PURPOSE: The purpose of this study was to investigate the effects of different conditions of assisted jumping via elastic cords on peak velocity (PV), takeoff velocity (TOV), and relative rate of force development (RFD/Mass with reduction %). METHODS: Thirty recreationally trained college students (male = 15, female = 15) completed three testing sessions consisting of five experimental conditions: 0%, 10%, 20%, 30%, and 40%. In all BWR experimental conditions, subjects wore a full body harness while attached to two elastic cords, suspended and bolted to the ceiling. Subjects performed three maximal countermovement jumps with arm swing on a force platform for all conditions. Maximum values from the PV repetition for each condition were used for analysis. RESULTS: No interaction of condition by sex for any analysis was found. There was a significant (P < 0.05) main effect for condition with an increase trend across all variables. PV 30% BWR (PV30-3.09 ± .04m/s) was significantly greater than 0%, 10%, and 20% (PV0-2.96 ± .04m/s, PV10-2.97 ± .04m/s, and PV20-3.00 ± .03m/s). TOV 40% BWR (TOV40-2.79 ± .05m/s) was significantly greater than 0%, 10%, and 20% (TOV0-2.59 ± .05m/s, TOV10-2.63 ± .04m/s, and TOV20-2.66 ± .03m/s). RFD/Mass with reduction % 30% and 40% BWR (RFDkg30-92.83 ± 11.65N/s/kg and RFDkg40-97.42 ± 10.26N/s/kg) were significantly greater than 0%, 10%, and 20% (RFDkg0-46.64 ± 4.77N/s/kg, RFDkg10-63.91 ± 6.18N/s/kg, and RFDkg20-75.56 ± 8.18N/s/kg), but no significant differences between 30% and 40%. There was also a main effect for sex for PV and TOV, but no significant (P > 0.05) differences were found for RFD/Mass with reduction %. Conclusion: This study demonstrated a linear increase for PV, TOV, and RFD/Mass with reduction % as BWR increased. The use of assisted jumping may enhance high velocity performance. Practical Applications: Incorporating assisted jumping using elastic cords might elicit an adaptation when applied in a training study. [ABSTRACT FROM AUTHOR] |
