The purpose of this study was to examine the influence of linear polarized near-infrared light (PL) irradiation on the recovery of a force exertion value and the physiological response after sustained static gripping work (SSGW). Eighteen healthy college students participated in the experiment under the conditions of both irradiation and no irradiation. They performed the SSGW (W1 and W2) for 3 minutes before and after the rest period. After the W1, the muscle fatigue state was confirmed. In case of the PL irradiation condition, during the rest for 16 minutes, each subject was irradiated in an area surrounding the flexor digitorum superficialis muscle for 10 minutes. After the rest, W2 was carried out. Blood lactate accumulation and subject's perception of muscle fatigue were measured before W1 and before and after the rest. There was no significant difference between irradiation and no irradiation conditions for the recovery rate of a force exertion value and muscle fatigue perception. It is considered that PL irradiation is not greatly effective in contributing to the recovery of force exertion after the W1. However, the influence of PL irradiation was found on blood lactate accumulation and muscle oxygenation kinetics during PL irradiation. It was inferred that PL irradiation influences an increase of blood flow, and promotes the elimination of blood lactate. The influence of PL irradiation for total hemoglobin (Hb) and Oxy-Hb tended to appear in the latter period of the rest. It was suggested that the influence of PL irradiation on the recovery of muscle fatigue becomes clearer by extending the irradiation period. Further, it will be necessary to examine the influence of PL irradiation on the recovery of a greater degree of muscle fatigue using a longer irradiation period.

DESCENTE SPORTS SCIENCE Vol.23/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE