Evaluation of a Newly-Designed, Dynamic Knee Extension Device for the Study of Muscle Fatigue in Humans
Abstract
A device utilizing a simple pulley system was developed to study muscle fatigue during dynamic, submaximal exercise isolated to the knee-extensor muscles of one or both legs. The purposes of this study were to determine the following: (1) oxygen consumption requirements for various submaximal and maximal power outputs and to compare these data to values obtained from published reports using modified bicycle ergometers (criterion devices), (2) intraindividual test-retest variability, and (3) muscle fatigability during exercise. On each of 2 separate days, 8 male volunteers (mean age 18.6 + or - 0. 3 yr (SE), weight 79.5 + or 5.1 kg, and height 179.1 + or - 2.0 cm) performed a graded, intermittent (4 min bouts) exercise test using the knee-extensor muscles of one leg to determine one-legged peak oxygen consumption. Maximal voluntary contractions (MVC) were obtained at the beginning, at 2 min, and at the end of each exercise bout as a means to monitor rate of muscle fatigue. The slope and intercept of the relationship of the increase in power output and oxygen consumption were 13.80 ml O2,/watt and 470 ml/min, respectively, with r2 = 0.96. These values for slope and intercept are similar to those reported previously: slopes 13.10 and 14.70 ml O2,/watt; intercepts, 400 and 471 ml/min; and r2 = 0. 99. Also, there was minimal intra-individual variation (r2 = 0.90) in oxygen consumption values for identical power outputs. Test-retest oxygen consumption values did not differ from a line of identity. Stepwise accelerations in muscle fatigability were discernable with small increments in exercise intensity and elapsed exercise time. Our device represents a low-cost, expanded capability alternative compared to previous units utilizing modified bicycle ergometers as a testing mode.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 02, 1994
- Accession Number
- ADA284974
Entities
People
- Charles S. Fulco
- Peter N. Frykman
- Robert Boushel
- Sinclair Smith
- Steven F. Lewis
Organizations
- United States Army Research Institute of Environmental Medicine