(23) SEX COMPARISON OF COUNTERMOVEMENT JUMP PERFORMANCE IN COLLEGIATE BASKETBALL ATHLETES

PURPOSE: It has been established in the literature that differences exist between males and females regarding vertical jump performance. Specifically, evidence points to differences that exist between sexes in the strategy that is used it achieve the highest jump possible. When comparing high and low performers in males during the countermovement jump (CMJ), propulsive times and braking rate of force development were different between groups. In a sample of women no differences were seen in the force variables between high and low performers, while loading durations were different between groups. This suggests that potentially women use more of a braking strategy while males use more of a propulsive strategy.  Thus, this investigation sought to examine phase specific force and time variables between males and females while performing the CMJ.

Methods: 29 NCAA Division I basketball athletes (15 males, 14 females) (age 20.74 ± 0.83 years, height 193.8 ± 5.75 cm, body mass 78.28 ± 7.73 kg) took part in this investigation. Jump testing took place the week before the first week of competition. Testing was conducted as part of a routine athlete monitoring program. Participants were instructed to perform three maximal countermovement jumps while holding a dowel rod resting on their shoulders, standing with feet shoulder width apart. They took a 30 second rest period between each jump. With each trial they were instructed to “jump as high as possible”. All testing was performed on a portable force platform sampling at 1000 Hz. The braking phase was defined as the point in which force values return to the calculated body mass until the point of zero velocity. The propulsive phase was defined as the end of the braking phase to the point of take-off. All data processing occurred using a customized Excel spreadsheet. Independent t-tests were performed on all variables of interest. Variables of interest for this investigation were phase duration, force, and impulse as well as time to take-off, jump height, and reactive strength index modified (RSIm). An apriori alpha level 0.05 was used for all analyses.

Results: Statistically significant differences were seen between groups in mean propulsive force (p = 0.005) and net propulsive impulse (p < 0.001) with males having greater outputs. Additionally, differences were seen in time to take-off (p = 0.047) with females having shorter durations. Lastly males displayed significantly greater jump heights (p < 0.001) and RSIm (p = 0.003). CONCLUSION: The differences seen between groups in this investigation demonstrate that the propulsive phase is responsible for the differences seen between males and females in CMJ performance. This warrants further investigation as the exact cause of the differences seen in the propulsive phase. PRACTICAL APPLICATION: The data presented provided, in conjunction with previous literature point to differences in vertical jump strategies used in men and women. This would be important when selecting meaning variables to be used to assess training outcomes and during the monitoring of athletes over a competitive season.

Acknowledgements: None