Individual Differences In Response To Endurance And Strength Training

Abstract

Large individual differences in the responsiveness of VO2peak to regular endurance training have been observed in healthy subjects. Mean improvements in VO2peak have been about 10–15% of the baseline values, but the training induced changes have ranged from a 0% to a 40% increase. The effect of exercise training mode to increase VO2peak of low responders are largely unknown. PURPOSE To study the effect of training mode on improvement of VO2peak for subjects whose responsiveness to exercise training according current guidelines of American College of Sports Medicine is low. METHODS The study population included healthy subjects (n=91, 42 ± 5 yr) who were assigned to either an exercise training (n=73) or to a control group (n=18) via stratified random selection. Subjects of the training group were divided to start exercise intervention either with endurance or resistance training. The laboratory controlled training period was 2 weeks, including 5 sessions a week for 40 min/session. Intensity of endurance training was 70–80% of the maximum heart rate. Resistance training consisted of 15 exercises involving the major muscle groups performed with a one set of 8–12 repetitions to near fatigue. After detraining period of 2 months the subjects performed a new training period of 2 weeks at the training mode vice versa. RESULTS VO2peak increased by 8 ± 6% (P <0.001) after the endurance training (range −5 – +22%), and by 4 ± 5% (P <0.001) after the resistance training (range −8 – +16%). When the study group was divided into quartiles according to the endurance training response (1 ± 3, 6 ± 1, 9 ± 1 and 16 ± 3% increase in VO2peak, respectively), a significant increase in VO2peak (7 ± 5%) was observed in the lowest responder group after resistance training intervention (P <0.001). The groups did not differ from each other at the baseline in the terms of baseline VO2peak, BMI or age. Similarly, when the study group was divided into quartiles according to the resistance training response (−1 ± 2, 2 ± 1, 6 ± 1 and 11 ± 3% increase in VO2peak, respectively), a significant increase in VO2peak (8±3%) was observed in the lowest responder group after endurance training intervention (P <0.001). None of the measured variables changed within the control group during the study. CONCLUSION The individual responsiveness in cardiorespiratory fitness after exercise training is dependent on exercise training mode. If the training response is absent or low, cardiorespiratory fitness can be improved effectively by changing the training mode among the healthy subjects. Supported by the Ministry of Education, Helsinki, Finland, the Medical Council of the Finnish Academy of Science, Helsinki, Finland.