Affiliations: [a] Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA | [b] College of Human Sciences, Kinesiology, University of Texas at El Paso, TX, USA | [c] School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, FL, USA
Correspondence:
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Corresponding author: John Paul V. Anders, Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE 68501, USA. E-mail: [email protected].
Abstract: BACKGROUND: Few studies have examined sex differences in performance fatigability and the bilateral deficit in a dynamic modality. OBJECTIVES: The purpose of this study was to examine: 1) Leg-, mode-, and sex-specific differences in performance fatigability during maximal, dynamic leg extension muscle actions and; 2) the time course of fatigue-induced changes in the bilateral deficit for both men and women. METHODS:Eleven men and 11 women participated in 3 test visits consisting of 50 maximal, concentric, isokinetic leg extensions at 60∘/s. Each visit was randomized to perform either unilateral right leg only (RL), unilateral left leg only (LL), or bilateral (BL) leg extensions. RESULTS: The BL performance fatigability was significantly (p< 0.001) less than RL and LL. Both men and women demonstrated significant (p< 0.001) declines in moment and an attenuation of the bilateral deficit throughout the fatiguing task. There were no differences between sex for performance fatigability (p= 0.128) or the bilateral deficit (p= 0.102). CONCLUSIONS:Unilateral muscle actions were more susceptible to fatigue than BL muscle actions. Men exhibited an earlier decline in moment than women, however, men and women exhibited similar magnitudes and patterns of decline in the bilateral deficit.
Keywords: Performance fatigability, bilateral deficit, dynamic, isokinetic, sex differences, fatigue
