OBJECTIVE The purpose of this study was to investigate changes in muscle oxygenation of knee extensor and plantar flexor muscles during repeated muscle contractions under the same condition. In addition, we compared changes in muscle oxygenation between superficial and deep regions of both muscles. METHODS Eleven healthy males participated in this study. During repeated knee extensions and plantar flexions (50 repetitions at 50% of the isometric maximum voluntary contraction for 3 s with 3 s relaxations), blood volume and oxygen saturation (StO₂) of the vastus lateralis and medial gastrocnemius muscles (superficial and deep region of each muscle) were measured using near infrared spectroscopy. RESULTS The decrement of StO₂at the end of exercises was greater in plantar flexor muscle than in knee extensor muscle (P<0.001). For both muscles, the decrement of StO₂at the end of exercises was greater in the deep region than in the superficial one (both P<0.001). CONCLUSIONS These results suggested that the oxygen utilization of plantar flexor muscle and deep regions of each muscle were higher than that of knee extensor muscle and superficial regions of each muscle.