Reoxygenation rate immediately after static short-term high intensity exercise indicates muscle oxidative capacity
Ryotaro Kime, Toshihito Katsumura, Takafumi Hamaoka, Takuya Osada, Takayuki Sako, Motohide Murakami, Sang Yong Bae, Koji Toshinai, Shukoh Haga, Teruichi Shimomitsu

The purpose of this study was to determine whether the reoxygenation rate (Reoxy-rate) immediately after static exercise at various submaximal intensities could indicate the muscle oxidative capacity. 
Seven healthy male subjects performed a static hand grip exercise for 10 seconds at 30%, 60% and 90% MVC.  The Reoxy-rate was monitored by near infrared spectroscopy (NIRS).  The muscle oxidative capacity was evaluated by the time constant (Tc) of the phosphocreatine (PCr) resynthesis rate by using ³¹-phosphorus magnetic resonance spectroscopy (³¹P-MRS).
There was no correlation between the muscle oxidative capacity and Reoxy-rate at 30% and 60% MVC.  However, the Reoxy-rate at 90% MVC was significantly correlated to the muscle oxidative capacity (r=0.825, p<0.05).

In conclusion, in the case of static short-term contraction at 90% MVC, the Reoxy-rate after exercise is an indicator of the muscle oxidative capacity.  However, Reoxy-rate may not be correlated to muscle oxidative capacity at 60%MVC and lower.

Keywords: muscle oxidative capacity, near infrared continuous wave spectroscopy, ³¹-phosphorus magnetic resonance spectroscopy, reoxygenation rate

Applied Cardiopulmonary Pathophysiology 9: 343-347, 2000

Ryotaro Kime, M.Sci.
Department of Preventive Medicine and Public Health
Tokyo Medical University
6-1-1 Shinjuku, Shinjuku-ku
Tokyo 160-8402
Japan
E-mail: ZXC06104@nifty.ne.jp