News & Views from the Editor-in-Chief - L. Bruce Gladden
Out of many excellent articles in this month's issue, I am pleased to direct attention to three of them. First, is it better to eat less or exercise more for improving glucose homeostasis? This is the question Ding et al. attempted to answer by evaluating the effects of progressive negative energy balance induced by aerobic exercise or hypocaloric diet on insulin action and insulin secretion. They found that exercise increased muscle insulin sensitivity in a dose-dependent fashion whereas equivalent energy deficits (20%–40% of energy requirements) induced by caloric restriction had no such beneficial effect. On the contrary, both exercise and diet decreased pancreatic insulin secretion. These results indicate that exercise and diet have tissue-specific metabolic effects and, although preliminary, suggest that aerobic exercise is a better treatment option than caloric restriction for insulin resistance, whereas either intervention can favorably affect hyperinsulinemia.
Next, Jonvik et al. investigated the effects of protein supplementation on whole-body aerobic power (VO2max) and endurance exercise performance during chronic endurance exercise training in recreationally active males. Their study showed robust improvements in VO2max (11%), 10-km time-trial performance (14%), and muscular endurance (6%) following 12 weeks of endurance exercise training. However, these adaptations were not further augmented by supplementation of protein after exercise and before sleep. A habitual daily protein intake of 1.2 g·kg-1 bodyweight appears sufficient to support adaptations to endurance exercise training in moderately trained individuals. Although the potential benefits of protein supplementation remain to be explored in elite endurance athletes, the current study suggests that many individuals will not gain any advantage from protein supplementation during their endurance training.
Finally, Syväoja et al. performed a two-year longitudinal study of adolescents, examining direct and indirect associations of both motor skills and physical fitness with academic achievement. This is the first study showing the dependent, predictive role of motor skills and physical fitness in association with academic performance. Their results suggested that academic achievement may be more strongly associated with motor skills performance than with aerobic or muscular fitness. Further, motor skills may also underlie the associations of aerobic and muscular fitness with academic success. Therefore, these results highlight the importance of physical activities that enhance motor skills, when the aim is to support academic outcomes via increased physical activity.
L. Bruce Gladden
School of Kinesiology