The Effects of Wrist Splints on When Females Reach the Peak Grip Strength Under Different Wrist and Forearm Positions

Abstract

When peak grip strength is reached may be a useful and interesting index for evaluating strength generation and the relationship between resistance and response time, and as one of selected criteria to quantify the muscle fatigue and the static peak strengths. The present study investigates the influence of wearing splints under different forearm and wrist postures on grip MVC (maximum volitional contraction) as well as the time needed to reach the MVC (denoted by T MVC ). Twenty female college students took part in this experiment voluntarily. The factorial design with four fixed factors (subject, forearm position, wrist deviation, and splint (with and without)) was employed. The forearm positions were set at 0 and 30 degrees internal (Internal-0 and 30) and 30 degrees external shoulder rotation (External-30). The wrist deviations are extension 30 o (E30 o ), neutral (N0 o ), flexion 30 o (F30 o ). The results show that the effect of forearm posture changes the grip MVC pronouncedly, but not the T MVC . The forearm at External-30 generates the least MVC (234.5N), and the other two postures are indifferent from each other (250.3 N vs. 253.2 N). As to the effect of wrist posture, it influences both selected responses, the MVC and the T MVC . The wrist at neutral generates the optimum force (254.4 N), and the other two wrist postures are indifferent (239.6 N vs. 244.0 N). Moreover, wrist posture at E30 o also has the longest T MVC , and the rate of force development is the lowest among the three specified wrist positions. Finally, the presence or absence of splints shifted neither the MVC nor the T MVC .