Improved Swimming Pool Achieves Higher Reproducibility and Sensitivity to Effect of Food Components as Ergogenic Aids

Abstract

A previously developed current swimming pool for mice has been used to evaluate many food components that enhance endurance exercise performance. In this article, to improve reproducibility, reliability and sensitivity of this assay system, we improved the spout part to generate a uniform current and divided the pool into six lanes to avoid physical interference between swimming mice. The stability of the current flow was assessed by measuring the surface current speed and water volume from the spout part. Maximum swimming times of ddY and BALB/c mice were measured to assess the reproducibility of the maximum swimming time. The improvement in sensitivity compared to the original equipment was estimated under three physiological conditions: low carbohydrate diet feeding, low blood hemoglobin level, and carbohydrate supplementation during exercise. The new spout part improved uniformity and quick adjustment of surface current, yielding an increase of workload in a stepwise manner during swimming. Exercise workload was increased in proportion to surface current speed, as evidenced by cadence of kicks and serum lactic acid levels. The improved swimming pool showed higher reproducibility of swimming time until fatigue (p<0.0001). Correspondence between blood hemoglobin concentration and swimming time was improved in the swimming pool. The improved swimming pool yielded higher sensitivity for low carbohydrate diet feeding (p<0.0001) and carbohydrate supplementation during exercise (p<0.01) compared to the original swimming pool. The improvement of the swimming pool achieved higher sensitivity and reproducibility in assessing various diet and food components compared to the original swimming pool.