FOREAM VO2 PEAK WAS REDUCED BY FOREARM ELEVATION

Abstract

PURPOSE: The hypothesis that the forearm VO2peak is influenced by forearm position was tested during incremental handgrip exercise with three forearm positions. METHODS: Five healthy male subjects (age: 25 to 35 years) performed an incremental dynamic handgrip exercise with three forearm positions as 40 (BELOW), 90 (HORIZONTAL) and 140 degrees (ABOVE) of shoulder abducent angle. The work load started at 0.5w and increased at 0.5w every 1 minute until exhaustion. Muscle oxygenation was measured in the forearm flexor muscles by near infrared continuous-wave spectrometer (NIRcws: Omron Inc. HEO-200). To calculate muscle O2 consumption (VO2mus)1 brief arterial occlusion method was performed during NIRcws measurement (Hamaoka et al. 1996, Sako et al. 2001). VO2mus was quantified by the data obtained by 31-phosphorus magnetic resonance spectroscopy (Otsuka Electronics Inc. BEM250/80) during 15 min arterial occlusion (Blei et al. 1994). RESULTS: Resting VO2mus did not differ between three positions. At the start of exercise, VO2mus increased linearly and tended to being leveled off over the 2.5w of exercise at each position. The VO2mus was significantly smaller at 2.5w when the forearm position was ABOVE position compared with BELOW and HORIZONTAL positions (p < 0.05). Peak VO2mus at the BELOW, HORIZONTAL and ABOVE positions were 9.74 ± 1.05, 9.87 ± 0.73 and 8.29 ± 0.65μMO2/sec, respectively. There was a significantly lower the peak value of VO2mus with ABOVE position compared with BELOW and HORIZONTAL positions (p < 0.01). CONCLUSION: This data supports the hypothesis that forearm elevation reduces forearm VO2peak.