Abstract
Fatigue is a multitudinous phenomenon, influenced by both central and peripheral factors that may impair performance or increase the risk of injury due to reductions in force and power generation. However, knowledge of the impact of fatigue on performance and injury risk is sparse. Previously used protocols do not account for the complexity of fatigue that occurs during an actual competition and fail to replicate the degree of physiologic stress in an intermittent way that would be equivalent to athletic exposure.
PURPOSE: The purpose of this study is to examine changes in the kinetic parameters of collegiate athletes performing a double legged drop jump under varying degrees of fatigue.
METHODS: 15 healthy, 18-27 year old NCAA Division II collegiate athletes (nine female, six male) volunteered to participate in this study (age 20.7 ± 1.2 years; height 173.5 ± 10.1 cm; weight 71.8 ± 10.7 kg; BMI 23.8 ± 2.8 Kg/m2). Prior to testing, participants completed a subjective fatigue questionnaire and performed 3 baseline drop jumps from a 31 cm box. Participants completed 3 trials of the fatigue protocol, each consisting of 3 Wingate Anaerobic Power Tests (WAPT) interspersed with 60 seconds of cycling at 50 watts, on a Lode cycle ergometer. Each trial was followed by 3 drop jumps. Kinetic parameters for each jump were recorded using BTS force plates. Statistical analysis by ANOVA (p < .05) was applied to the data.
RESULTS: There were significant differences in peak velocity (PV), landing rate of force development (LRFD), and right landing peak medial force (RLPMED). Post Hoc analysis revealed that PV, LRFD, and RLPMED were significantly different between baseline and post-WAPT trial one jumps (2.13 ± 0.42 m/s vs. 1.71 ± 0.33 m/s; 24810.3 ± 11524.7 vs. 9978.5 ± 6995.1; and 90.2 ± 49.5 vs. 44.4 ± 21.5 N, respectively). There were no significant differences in vertical ground reaction force variables across all conditions.
CONCLUSION: Fatigue has an impact on various kinetic variables. The lack of evidence to support kinetic changes across the continuum of fatigue may be related to kinematic alterations in completing the task. Further research will be required to correlate these findings with injury risk and to promote injury risk reduction programs.