The Effects of Vertical Jump Fatigue and Sprint Fatigue on Total-Body Biomechanics

Abstract

INTRODUCTION: Motion capture systems (MCS) can be used to assess an individual’s upper-and lower-body motions, both explosive and functional in nature. Advancements in technology and screening protocols are capable of detecting acute biomechanical alterations of the lower-extremities following fatiguing tasks. PURPOSE: This study compared the kinetic and kinematic variables measured by a 3-dimesional video MCS to identify alterations in lower-extremity performance following VJ and sprint fatiguing tasks. METHODS: Eleven healthy, recreationally active women (X ̅±SD; age=20.81.1 yrs., hgt.=172.27.4 cm, wgt.=68.07.2 kg) and eleven men (age=23.02.6 yrs., hgt.=180.34.8 cm, wgt.=80.47.3 kg) volunteered for this investigation, and were screened using the Performance Motion Analysis (PMA) protocol, consisting of 19 motions. These include shoulder ranges of motions (i.e., shoulder abduction and adduction, horizonal abduction and adduction, internal and external rotation, flexion and extension). Also assessed were trunk rotation, bilateral overhead squat, unilateral squats, forward lunges, single leg balance, bilateral counter-movement vertical jump (CMVJ), unilateral CMVJs, concentric-only VJ, multiple unilateral CMVJs, and depth VJ. A three-dimensional markerless MCS (DARI Motion, Scientific Analytics, Lincoln, NE) was used to analyze the kinetic and kinematic data, from which 192 variables were calculated and reported in PMA Scores (i.e. Composite Score, Power Score, Functional Strength Score, Dysfunction Score, Vulnerability Score, and Exercise Readiness Score). Each subject completed one familiarization session, three experimental sessions consisting of three randomized acute fatiguing protocols (i.e. Control Session, Modified jump test, 25-sec Sprint Test). PMA Test, accumulated lactate and heart rate (HR) was collected pre-and post-fatigue tests. Statistical analyses were conducted for the performance measures using the scores [Composite Score, Power Score, Functional Strength Score, Dysfunction Score, Exercise Readiness Score (ERS), and Vulnerability Score] x conditions (VJ, Sprint, CON) x time (pre-test, post-test) x within sex (females, males) repeated measures MANOVA. RESULTS: The MANOVA indicated a three-way interaction (score x condition x time). Follow-up analyses indicated significant differences between pre-and post-tests for the ((X ) ̅± SD for pre-test; post-tests) Composite Score (1556.43±307.8; 1368.00±264.62), Power Score (813.34±242.39; 687.32±164.83), and ERS (18.16±4.75; 16.02±3.54) during the VJ experimental sessions. Significant increases in accumulated lactate and HR were indicated for the post-test during the modified VJ and 25-sec sprint tests. CONCLUSION: The current investigation demonstrated the viability of a MCS test to evaluate changes in performance due to acute fatigue. The investigation determined the MCS was capable of detecting acute lower-body biomechanical changes. The PMA Scores suggested decrements in performance are first observed in the decreases in power production during high velocity movements (i.e. VJs). PRACTICAL APPLICATION: Documentation and tracking of changes in performances will give future insights on how fatigue can be rated and evaluated. Advancements in technology and screening protocols may be capable of predicting increased risk of season ending injuries. This may provide the strength and conditioning professional helpful longitudinal information as an athlete/patient/client progresses through a training program and season.