Mechanical efficiency in rowing

Summary

Five university oarsmen participated in a determination of mechanical efficiency when rowing in a tank. In the tank, water was circulated at 3 m · s⁻¹ by a motor driven pump. The subjects rowed with the stepwise incremental loading, in which the intensity increased by 10% of the maximum force of rowing (max F_C) every 2 min. Power ($\dot W$ _O) was calculated from the force applied to the oarlock pin (F_C) and its angular displacement (θ_H). Oxygen uptake and heart rate were measured every 30 s during rowing. Anaerobic threshold (AT) was determined from expired gas variables by Wasserman's method. AT of oarsmen was 74.6±6.01% as a percentage of $\dot V_{{\text{O}}_{\text{2}} {\text{max}}}$. As the displacement of the handgrip in the stroke was independent of $\dot W$ _O, the increment of $\dot W$ _O was caused by the increase of both F_C and stroke frequency. Gross efficiency without base-line correction (GE) increased with F_C with low intensities of rowing. In the region of 124–182 W of $\dot W$ _O GE was almost constant at 17.5%. Efficiency was 19.8±1.4%, with resting metabolism as base-line correction (net efficiency), and 27.5±2.9% when using the unloaded rowing as the base-line correction (work efficiency), and 22.8±2.2% when calculating the work rate as the base-line correction (delta efficiency).