Circuit weight training on stable and unstable surfaces : differences in energy cost, blood lactate and rate of perceived exertion.

Abstract

Unstable surfaces have been used in resistance training, but there are no studies that compared energy cost between stable and unstable surfaces in circuit weight training. This study compared energy cost, post-exercise peak blood lactate and perceived exertion rate between stable surface and unstable surface. Twenty healthy men (24.65 ± 3.48 years, 1.79 ± 0.08 m, 80.61 ± 9.14 kg and 11.86 ± 3.49% body fat) participated in the study. Test and retest of 15 maximum repetitions were performed on stable and unstable surfaces to define workload. The circuit weight training consisted of one set of 15 repetitions at 80% of 15 maximum repetitions in bench press, back squat, rowing bent prone, dead-lift, shoulder press, elbow extension and elbow flexion. Energy cost was measured by indirect calorimetry during and post-circuit weight training. Peak blood lactate and perceived exertion rate were measured post-exercise. Total energy cost was higher on unstable surface compared to stable surface (70.7 ± 10.0 vs. 66.6 ± 7.8 kcal; p = 0.01), as was perceived exertion rate (8.1 ± 0.9 vs. 7.6 ± 1.3; p = 0.02). However, peak blood lactate was higher on stable than unstable surfaces (13.6 ± 2.6 vs. 12.5 ± 1.9 mmol·L−1; p = 0.05). In conclusion, circuit weight training on unstable surfaces can be performed with less weight in comparison to stable surfaces, thereby lowering mechanical stress on joints and bones, while still providing a higher metabolic impact.