Correlation of Grip Strength and Weight Bearing Capacity through the Upper Extremity

握力與上肢承重能力之關聯性

張家豪(Chia-Hao Chang) ； 王子娟(Tzyy-Jiuan Wang) ； 曾國維(Kuo-Wei Tseng) ； 陳文英(Wen-Yin Chen)

《物理治療》 42卷4期 (2017/12) Pp. 365-366

https://doi.org/10.6215/FJPT.2017.74.P36

摘要

Background and Purpose: Reduced power grasps with difficulty or inability to bear weights on the hands are the symptoms in individuals with dynamic carpal instability. Both of the symptoms are related to abnormal arthrokinematics generated during the wrist motions. Positional faults of the carpal bones could affect both the ability of power grip and weight bearing capacity on the hand. We therefore expected the ability of power grip and weight bearing capacity on the hand would be correlated, especially in athletes requiring repetitive weight bearing capacity on the hand. This study aimed to assess the correlation of the maximal pain-free grip strength and the weight bearing capacity in athletes with dynamic carpal instability. Methods: Thirty-two athletes with dynamic carpal instability were recruited and received 6-week treatment of neuromuscular exercises plus carpal mobilization or neuromuscular exercises only. The maximal pain-free grip strength was measured with a hand-held dynamometer, and the weight bearing capacity was measured with a transducer on a self-constructed supporting frame. The within-day and between-day measurement reliability was excellent (intraclass correlation coefficient ＞ 0.9). Results: The maximal pain-free grip strength and the weight bearing capacity were moderately and significantly correlated, with the correlation coefficient of 0.45 before the treatment and 0.51 after 6-week intervention. These correlation coefficient was similar to the one found in the healthy non-athlete population (0.54). Conclusion: The maximal pain-free grip strength and the weight bearing capacity were significantly correlated, indicating the two measurements had some component in common within the construct. However, because the two measurements were only moderately correlated, with less than 30% of the explained variance, meaning the two constructs were not replaceable by each other, and each could offer different measurable characteristics about the athlete's wrist performance. Clinical Relevance: Both the maximal pain-free grip strength and weight bearing capacity should be assessed to appreciate an athlete's wrist performance in case of carpal instability.