Author(s): TANAKA, S.1, ARAI, C.1, YOKOZAWA, S.2, HIRATSUKA, K.3, Institution: KOKUSHIKAN UNIVERSITY , Country: JAPAN, Abstract-ID: 1562

INTRODUCTION:
Tensimyography (TMG) method has been utilized to evaluate muscle contractile properties (1). Furthermore, the muscle contraction sensor method (MC) can evaluate muscle tension as mechanical activity during contraction. The signals by MC sensor have been reported to correlate with elbow flexion force on isometric contraction (2, 3). Therefore, the purpose of this study was to examined the merits and applications of TMG and MC sensor method for evaluate the muscle activity before and after fatigue task.
METHODS:
Seven males without disabilities to knee joint were participated in this study. The contractile properties of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis obliquus (VMO) were evaluated using TMG (TMG-BMC). The TMG parameters were maximum displacement (Dm) and contraction time (Tc). The subjects were performed fatigue task with knee extension exercises consisting of 5 sets of 20 maximal effort eccentric contractions with 90 seconds of rest. The maximum voluntary isometric knee extension torque at the knee joint angle of 80 degrees in before, after the fatigue task were measured by a dynamometer (Biodex co.). At the same time, the muscle tension as an index of muscle mechanical activity at RF, VL and VMO were measured by MC Sensor (TMG-BMC) method.
RESULTS:
The knee extension torque decreased significantly after the fatigue task, with a reduction rate of approximately 23%. The Dm of the RF and VL decreased significantly in the after compared to the before. However, no significant difference was observed in the VMO. On the other hand, Tc as an indicator of muscle contraction time, showed no significant difference in all muscles. The maximum muscle tension during voluntary contraction measured by the MC sensor method decreased by 23% for the RF, 17% for the VL, and 26% for the VMO due to the fatigue task.
CONCLUSION:
The TMG is independent of motivation or volitional effort. Therefore, the TMG method was suggested to be effective for evaluating the contractile properties of the knee extensor muscles after the high-intensity fatigue tasks. The muscle tension before and after the fatigue task, as evaluated by the MC sensor method, differed depending on the muscle. This result suggested that differences in the contribution of the muscles participating in the knee extension may affect the before and after fatigue task. From these results, it was suggested that the factors contributing to muscle force decline due to fatigue tasks could potentially be evaluated from the contraction characteristics by TMG and the contribution level of each muscle by MC sensor method.

REFERENCES:
1) Hiratsuka et al., ECSS, 2025
2) Srdjan et al., Sensor, 2014
3) Tanaka et al., ECSS, 2025