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Effect of resistance training on muscle fatigue and recovery in intact rats.

Willems ME; Stauber WT

Med Sci Sports Exerc 2000 Nov; 32(11):1887-1893

https://doi.org/10.1097/00005768-200011000-00011

20029517

To examine the effect of resistance training on muscle fatigue from intermittent contractions and subsequent recovery in intact rats. By using electrical stimulation, plantar flexor muscles were trained with eccentric and concentric contractions (5 x 10 repetitions, 5 d x wk(-1) for 6 wk) during ankle rotations. By using nerve stimulation, concentric contractions (40) imposed on isometric contractions (stimulation time, 1.9 s; rest period, 13.6 s; intermittent contractions) induced fatigue. During recovery, equivalent contractions were used every 5 min for 30 min. Training increased isometric forces (19% and 23% at ankle positions of 1.57 and 0.70 rad), but muscle weights were not changed. After training, smaller declines in isometric (control, 68.9+/-1.4%; trained, 58.8+/-2.9%) and average concentric force (control, 71.6+/-0.7%; trained, 65.5+/-2.8%) occurred from fatigue. Recovery for 5 min returned isometric and average concentric force to 61.7+/-2.2% and 65.1+/-2.5% of initial values for controls and 76.9+/-2.2% and 77.1+/-2.2% after training. After recovery for 30 min, these forces were 87.6+/-0.7% and 89.2+/-1.1% of initial values for controls and recovered almost completely (94.2+/-1.3% and 94.6+/-1.6%) in trained muscles. During fatigue, the decline in force during successive concentric contractions was larger after training (from 19.7+/-1.1% to 50.1+/-2.0%; controls, from 19.9+/-2.0% to 41.7+/-1.4%). Recovery of this decline in force was training-independent and complete within 5 min. Rat plantar flexor muscles adapt to 6 wk of 5 d x wk(-1) resistance training with: 1) increased isometric force, 2) smaller losses in isometric and average concentric force during fatigue, 3) larger force decline during concentric contractions during fatigue, and 4) improved recovery following fatigue. Different mechanisms might account for the recovery of the average concentric force and the decline in force during concentric contractions.

Muscles; Laboratory animals; Animals; Animal studies; Fatigue; Skeletal system; Musculoskeletal system

Department of Biochemistry, P.O. Box 9142, West Virginia University Health Sciences Center, Morgantown, WV 26506-9142

MSPEDA

20001101

Journal Article

868663

Grant

2001

Grant-Number-R01-OH-002918

11

0195-9131

Disease and Injury: Musculoskeletal Disorders of the Upper Extremities

Medicine and Science in Sports and Exercise

WV

West Virginia University, Morgantown, West Virginia