Acute neuromuscular and metabolic responses to concurrent endurance and resistance exercise

Metabolic and neurological responses to 4 bouts of lower-body or upper-body resistance exercise preceded by cycle ergometry or rest were assessed. Nine resistance-trained men (26.7 ± 6.6 years) underwent bouts of (a) cycle ergometry then bench press, (b) bench press only, (c) cycle ergometry then back squat, and (d) back squat only. Cycle ergometry was performed at 75% maximum heart rate for 45 minutes. Bench press and back squat protocols required 6 sets to volitional fatigue at 80% 1RM with 2 minutes rest between sets. Significantly more repetitions were performed during set 1 for back squat without preceding aerobic exercise (12.6 ± 4.5 vs. 10.0 ± 3.5, p = 0.000) and cumulatively at set 3 (27.1 ± 10.6 vs. 23.1 ± 9.2, p = 0.014), and no differences were noted for bench press repetitions. Inclusion of cycle ergometry results in impaired back squat, but not bench press, performance likely because of a combination of local metabolic stress and various neuromuscular effects.