EFFECTS OF RESISTANCE TRAINING ON CO₂ EXCESS AND SWIMMING PERFORMANCE IN COMPETITIVE SWIMMERS

Abstract

The purpose of the present study was to determine the change in total excess volume of CO₂output (CO₂excess) due to bicarbonate buffering of lactic acid produced during exercise and change in swimming performance following resistance training for 8 weeks in competitive swimmers. Ten healthy university competitive swimmers were assigned to either a resistance training and swimming training group (COMBINE: N=5) or a swimming training only group (SWIM: N=5) . Muscle mass was measured using magnetic resonance imaging (MRI) . CO₂excess and blood lactate concentration were measured during incremental exercise on a cycle ergometer and swimming performance was measured during competition. COMBINE showed a significantly higher percentage change in muscle mass (11.1±4.5%) than SWIM (3.5±2.5%) . The percentage change in CO₂excess, CO₂excess per body weight (CO₂excess/BW) and CO₂excess/BW per blood lactate accumulation (CO₂excess/BW/ΔLa) during exercise was significantly higher in COMBINE (107.3±60.1, 102.6±56.8, 59.1±37.7%, respectively) than in SWIM (42.5±10.0, 42.9±10.4, 13.4±22.4%, respectively) . The percentage change in swimming performance was significantly higher in COMBINE (2.2±1.8%) than in SWIM (-2.0±3.6%) . A negative correlation between percentage change of muscle mass and percentage change of CO₂excess/BW/ ΔLa (SWIM: r=-0.993, P<0.01, COMBINE: r=-0.744, P>0.05) was found. It was suggested that combined swim and resistance training resulted in greater increases in the bicarbonate buffering system (CO₂excess/BW/ΔLa) . However, increases in muscle mass may have subsequently caused a relative decrease in the contribution of the bicarbonate buffering system.