Effect of training status on oxygen consumption in women after resistance exercise

This study compared acute postexercise oxygen consumption in 11 trained women (age, 46.5 ± 1.6 years; body mass index [BMI], 28.4 ± 1.7 kg·m -2) and 11 untrained women (age, 46.5 ± 1.5 years; BMI, 27.5 ± 1.5 kg·m -2) after resistance exercise (RE). Resistance exercise consisted of 3 sets of 8 exercises (8-12 repetitions at 50-80% 1 repetition maximum). Oxygen consumption (Vo 2 ml·min -1) was measured before and after (0, 20, 40, 60, 90, and 120 minutes) RE. Immediately after cessation of RE (time 0), oxygen consumption increased in both trained and untrained women and remained significantly above baseline through 60 minutes after exercise (p < 0.01). Total oxygen consumption during recovery was 31.3 L in trained women and 27.4 L in untrained women (p 0.07). In trained women, total oxygen consumption was strongly related to absolute (kg) lean mass (r 0.88; p < 0.001), relative (kilogram per square meter) lean mass (r 0.91; p < 0.001), and duration of exercise (r 0.68; p ≤ 0.05), but in untrained women, only training volume-load was related to total oxygen consumption (r 0.67; p ≤ 0.05). In trained women, 86% of the variance in oxygen consumption was explained by lean mass and exercise duration, whereas volume-load explained 45% in untrained women. Our findings suggest that, in women, resistance training increases metabolic activity of lean tissue. Postexercise energy costs of RE are determined by the duration of stimulation provided by RE rather than absolute work (volume-load) performed. This phenomenon may be related to type II muscle fibers and increased protein synthesis.