Accession Number : AD0753933

Title :   Effort Scaling of Isometric Muscle Contractions.

Descriptive Note : Progress rept.,

Corporate Author : ARMY MEDICAL RESEARCH LAB FORT KNOX KY

Personal Author(s) : Caldwell,Lee S. ; Grossman,Eugene E.

Report Date : 22 SEP 1972

Pagination or Media Count : 13

Abstract : The purpose of this study was to examine the formal characteristics of equal effort functions obtained with moderate to maximum initial force levels. Maximum voluntary manual pull was measured on 18 subjects. These values were then used to determine the forces at 10% intervals from 30% to 100% of maximum strength for each subject. This procedure defined eight relative effort levels. In subsequent sessions, the subjects were required to start an exertion at one of these effort levels and then, without informational feedback, they were required to maintain an equal sensation of effort for 60 sec. The data at all eight effort levels were closely approximated by triple exponential decay functions. The percentage error between observed and calculated values ranged from 0.7% for the 100% effort data to 2.5% for the 20% condition. The mean error for all effort levels was 1.3%. The function generated by a maximum voluntary contraction was not qualitatively different from effort functions produced by adjusting output level to maintain equal sensation of submaximum effort. Thus, it would seem that the fatigue curve may be viewed as a maximum effort function and, as such, involves the same processes that generate the lower intensity effort functions. (Author)

Descriptors :   (*MUSCLES, EXERCISE(PHYSIOLOGY)), FATIGUE(PHYSIOLOGY), ENDURANCE(PHYSIOLOGY), PHYSICAL FITNESS, PSYCHOPHYSICS, SENSES(PHYSIOLOGY)

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE