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Biomechanics/Neuromuscular

(10) THE IMPACT OF UNILATERAL VS BILATERAL ANKLE BRACING ON RATE OF FORCE DEVELOPMENT AND REACTIVE STRENGTH INDEX MODIFIED DURING JUMPING

Saturday, July 13, 2024
10:00 AM – 11:30 AM East Coast USA Time
Location: Exhibit Hall
Abstract Details: Volleyball is characterized by repeated vertical jumps and rapid changes in direction but the incidence of ankle injury in these athletes is high. Ankle bracing has been shown to be an effective means of preventing ankle injuries. Volleyball players will wear braces either unilaterally or bilaterally, however, the current research has not considered the comparison of unilateral and bilateral bracing on the force-time characteristics seen during jumping. During the countermovement jump, eccentric rate of force production (RFDECC) can be considered a determinant of jump performance. The Reactive Strength Index Modified (RSIMOD) assesses the ability to generate maximal vertical impulse in a minimal amount of time during jumping and represents the level of “explosiveness” of an athlete. PURPOSE: To examine the impact of wearing ankle braces both unilaterally and bilaterally on RFDECC and RSIMOD during the countermovement jump in volleyball players. METHODS: Twenty university volleyball players were recruited, both males (n = 13) and females (n = 7) (males: age = 21.5 ± 2.2 years; mass = 77.5 ± 7.0 kg; height = 183.9 ± 5.8 cm; females: age = 19.9 ± 1.2 years; mass = 65.1 ± 7.0 kg; height = 174.9 ± 5.6 cm). After completing a standardized warm-up, participants performed three maximal effort vertical jump trials on a force platform while wearing an ASO ankle brace under the following conditions: unilaterally, bilaterally, or with no ankle brace worn. The three test conditions were performed in random order across participants, and the data for the three jumps were averaged to determine a mean value for each participant under each condition which was included in the analysis. RFDECC (N‧s-1) was calculated as the average slope during the braking phase on the force-time curve. RSIMOD was calculated as jump height (m) determined from the ground reaction force data divided by the elapsed time from movement initiation to toe-off. A one-way repeated measures ANOVA was used to examine the differences among the three bracing conditions for each dependent variable, with Bonferroni post-hoc analysis performed for pairwise comparisons. All analyses were performed with an alpha level set a priori at p ≤ 0.05. RESULTS: The mean ± SD RFDECC across the three bracing conditions were: unilateral = 4546 ± 1469 N‧s-1; bilateral = 4621 ± 1879 N‧s-1; no bracing = 4494 ± 1691 N‧s-1.  The mean ± SD RSIMOD were: unilateral = 0.44 ± 0.14; bilateral = 0.45 ± 0.15; no bracing = 0.46 ± 0.15. No significant differences were found in RFDECC (p > 0.05) or in RSIMOD (p > 0.05) across the three bracing conditions. CONCLUSIONS: The results indicate that wearing ankle braces, whether unilaterally or bilaterally, has no impact on RFDECC and RSIMOD during the countermovement jump. PRACTICAL APPLICATION: Ankle braces are designed to reduce the motion at the ankle in the sagittal and frontal planes to minimize the risk of ankle injury, most notably lateral ankle sprains. Despite this functional design characteristic, the results of this study suggest that neither unilateral nor bilateral ankle bracing will affect the rate of force production or level of explosiveness seen during jumping. This information is important as it helps athletes, coaches, and training staff to better understand the impact of wearing ankle braces to minimize the occurrence or recurrence of ankle injury on athlete performance.

Acknowledgements: None