Assessing muscular fatigue with a portable tremor measurement system suitable for field use.
Behav Res Meth Instrum Comput 1990; 22(6):507-516
The usefulness of a system for detecting muscular fatigue was demonstrated, and an attempt was made to determine which summary measures of tremor should be reported by the system. This evaluation involved deciding which of the various measures produced by the system would be most sensitive to fatigue, and determining which measures would be most reliable. Static exertion in muscles of the head, arm and shoulder was used to induce fatigue. Eighty individuals ranging in age from 18 to 44 served as subjects. A probe containing two accelerometers held in the extended hand, recorded horizontal and vertical tremor oscillations in the 1 to 18 hertz range. Several summary amplitude and frequency measures were then derived to analyze hand/arm tremor in the unfatigued and fatigued states. Large increases from unfatigued to fatigued states were noted in all of the amplitude measures in both axes. Summary frequency measures were far less sensitive to fatigue. The findings indicate that muscular fatigue in the hand and arm was best described by changes in tremor amplitude as opposed to tremor frequency. The tremor measurement system was useful for depicting the accumulation of fatigue in the hand, arm and shoulder during continuous static exertions. The apparatus could be easily adapted to measure oscillations from different sites, and the procedure could be modified to measure enhanced tremor resulting from dynamic muscular exertion.
Musculoskeletal-system; Muscle-function; Physical-exercise; Muscle-stress; Muscle-tension; Measurement-equipment; Physiological-fatigue; Humans
Behavior Research Methods, Instruments, and Computers