Author(s): HIRATSUKA, K., IKEDA, N.2, YOKOZAWA, S.3, HATASHIMA, K.4, KUMAGAWA, D.4, TANAKA, S.4, Institution: HACHINOHE GAKUIN UNIVERSITY, Country: JAPAN, Abstract-ID: 1003

INTRODUCTION:
Fatigue influences athletic performance and can also increase the risk of injury in sports, and most of the methods to evaluate it require an additional voluntary effort. Recently, tensiomyography (TMG) has received attention as a non-invasive assessment of muscle contractile properties. TMG is independent of motivation or volitional effort. For this reason, TMG has been investigated as a means to assess muscle contractile properties after fatigue. However, no previous study has compared muscle contractile function changes over days after eccentric versus concentric exercise. Thus, the aim of the present study was to investigate muscle contractile properties occurring in the early and recovery phases after concentric and eccentric exercise using TMG.
METHODS:
Eleven healthy males (mean ± standard deviation [SD] age: 21.4± 0.5 years; height: 172.2± 4.3 cm; weight: 68.8± 7.7 kg) participated in this study. Subjects performed eccentric contraction exercise (ECC) of elbow flexor with one arm, and concentric contraction exercise (CON) of elbow flexor with the other arm with the same total work (ECC: 3455.5± 927.9 J, CON: 3455.7± 929.0 J). Maximal voluntary isometric contraction (MVC) torque, range of motion (ROM), upper arm circumference (CIR), muscle soreness (SOR) and muscle contractile properties (TMG parameters: maximum displacement [Dm], contraction time [Tc] and velocity of deformation [Vd]) were assessed before, 1 hour and 1–5 days after exercise.
RESULTS:
There was no significant difference in total work during exercise between the two exercise types. Significantly larger changes in MVC, ROM, and CIR were evident following ECC compared to CON, and only ECC resulted in significant increases in SOR. Significant differences existed between ECC and CON for changes in muscle contractile properties. Dm and Vd in ECC were significantly lower than CON 1 hour after exercise and remained low for up to 5 days after exercise. Tc showed a significant increase following ECC compared with CON, and no significant changes in Tc from the pre-exercise values were evident for CON.
CONCLUSION:
In conclusion, despite the total work being the same, TMG parameters varied depending on the type of muscle contraction. These results are particularly important to understand how TMG parameters are modified with the type of contraction, and indicate that TMG can be highly sensitive in detecting fatigue-induced changes and its recovery.