Cook, S. B., Faust, K. F., Ploutz-Snyder, L. L., & Kanaley, J. A. (2008). The effects of an acute bout of plyometrics on muscle fatigue in female athletes. ACSM 55th Annual Meeting Indianapolis. Presentation number 539.

This study evaluated muscle fatigue in female athletes accustomed to plyometric training immediately after and 24 hours after an acute bout of plyometric exercises. Females aged 18-22 years (N = 23) from the Syracuse University soccer and field hockey teams completed 10 plyometric exercises consisting of various forms of squat jumps, lateral jumps, box jumps and skipping with one minute rest periods between exercises. Force production of the knee extensors and knee flexors, vertical jump height, and the Illinois Agility Test were used to assess muscle fatigue and athletic performance. Surface electromyogram signals were collected from the thigh muscles and analyzed for root mean square alterations during maximal and submaximal contractions. These tests were completed prior to, immediately after, and 24 hours after the plyometric exercises.

Knee extensor and knee flexor force production decreased 14 and 10% respectively immediately after the exercise. Knee extensor force remained 7% lower than pre-exercise at 24-hours post exercise. During submaximal contractions, the root mean square electromyogram was significantly elevated immediately after the exercise only in the rectus femoris and vastus medialis muscles. Immediately after the exercise, the time to complete the Illinois Agility Test increased 3% and vertical jump ability declined 6%.

Implication. Decrements in performance were seen immediately after plyometric exercise indicating that fatigue had occurred, but most measurements (with the exception of knee-extensor strength) returned to pre-exercise values by 24-hours after exercise. A conservative interpretation of this finding is that an intense bout of plyometrics should not be performed the day before competition because muscle strength may not be fully recovered the following day.

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