Method to Evaluate Energy Expenditure During Exercise by Using Accelerometer

Abstract

Rowing has a unique exercise characteristic, that is, moving body toward back and forth to generate power output, and the work for that kind of movement was not considered when predicting energy expenditure. The aim of this study was to evaluate aerobic and anaerobic energy supplies during 2000 m rowing test with using a newly developed accumulated oxygen deficit （AOD） method which takes the exercise characteristic of rowing into account. Thirteen male university rowers conducted 2000 m test. In each 250-m section, utilized anaerobic energy was determined by subtracting measured oxygen uptake from predicted oxygen demand which was predicted by power output and accelerometer output measured by rowing ergometer and tri-accelerometer sensor being put on rower's back, respectively. The highest sectional anaerobic energy utilization was observed at the first section, then sectional anaerobic energy utilization gradually decreased with time course, however, contribution of anaerobic metabolism maintained around 10 % during second half of the test. Although entire contribution of anaerobic metabolism reached 18.3 ± 6.2 %, total amount of anaerobic energy was not correlated with average power output of 2000 m test （r = -0.15, p = 0.625）， however, maximal oxygen uptake was （r = 0.83, p = 0.001）．The highest sectional power output was observed at the first section and gradually decreased with time course, meanwhile, power output at the final section was not significantly different from its previous section. Amount of available anaerobic energy at the final section and the second from final section were significantly correlated with relative power output at the final section （r = 0.66, p = 0.015 and r = 0.57, p = 0.04）．These results suggested that rowing performance is mainly related to aerobic ability as reported previously, and anaerobic capacity would be important to maintain higher power output during second half of the test and especially at the final section.