Effect of trunk posture on toe grip strength

Abstract

: [Purpose] This study aimed to clarify the effect of changes in trunk-leg posture on toe grip strength by comparing the toe grip strength and lower extremity muscle activity measured during upright and forward-tilted trunk postures and investigating these values in terms of reproducibility and exertion of the maximum muscle strength. [Subjects and methods] The study subjects were 18 healthy adult males. Toe grip strength was measured under two conditions: in the upright trunk posture and the anteriorly tilted trunk posture. In addition to toe grip strength, muscle activity of the rectus femoris, the long head of the biceps femoris, the anterior tibialis, and the medial head of the gastrocne-mius were also measured. [Results] The results showed internal correlation coefficients (1, 1) of r=0.921 and r=0.950 for the upright and anteriorly tilted trunk postures, respectively. Although the toe grip strength did not differ between the two measurement conditions, the percentage integrated electromyography (%IEMG) of the medial head of the gastroc-nemius was significantly higher in the upright posture than that in the anteriorly tilted posture. [Conclusion] The results of this study showed that the different trunk postures-upright and anteriorly tilted-did not affect the reproducibility or the maximum muscle force of toe grip strength but did affect the %IEMG of the medial head of the gastrocne-mius.