TheInfluence of Different Target Values and Measurement Times on Decreasing Force Curve during Sustained Static Gripping Work

The purposes of rhis study were to clarify the decreasing properties oC and to examine usefu1 measurernent tjmes fbr eyaluating muscle endurance in a comparison among various parameters using measuremcnt times of 1, 3 and 6mins and target values of 50, 75 and 100% MVC. Fifteen males and l5 femalcs participated in this study. All subjects carried out sustained isometric gripping under nine conditions of measurement tjmes and target forces, (1, 3 and 6mins vs. 50, 75 and 100% MVC) with an interval of one or two days, The property of decreasing force in the initial phase <marked decreasing phase) differed among the target values, and thc decreasing spccd of the gripping force was highest for 100(ra MVC. However, the decreasing property after about 60sec, in which the force decreased to about 309,6 MVC from the onset of grip, was similar among all target values, and then the gripping fbrce reached an almost steady state phase at about 150-180sec. In other words, the difference of the decreasing property during the initial phase with different arget va]ues was considered not to infiuence the property in thc later phase, in which the force decreases to about 30% MVC. When muscle endurance is evaluated from the phase until reaching the steady state, it may be possible to evaluate the same property of the decreasing phase at 6 min as the rneasurement at 3min. The measurement fbr 1 min at 50ea) MVC was not valid as an evaluation time becausc thc grip force did not decrease nough. The integrated area in the initial phase was considered to depend on the magnitude ofthe target value, and the integrated area for 30 sec or 60 sec at 75% MVC was larger than that at 1OO% MVC. It was inferred that higher pain at 100% MVC resu[ted in a greater decrease in thc speed of the force, J Physiol Anthfizpot 25rlV: 23-28, 2006 http:1/www.jstage.jst.go.jplbrowseijpa2 [DOI: 1021 14ijpa2.25.23]