News & Views from the Editor-in-Chief - L. Bruce Gladden
For my farewell News & Views, I have chosen three diverse, excellent articles. First, few “high-intensity interval training" (HIT) or “sprint interval training" (SIT) programs have used truly “all-out" exercise with very short exercise times (e.g., 4 s) and recovery periods (e.g., 15 s) with a high number of repetitions (e.g., 30 bouts) in a workout of only 10 min total duration. Using such a regimen, Satiroglu et al. reported that eight weeks of training on an inertial-load ergometer (ILE) increased VO2peak by 13.2% with a 7.6% increase in blood volume while maximal anaerobic power also increased 17.2%. It is noteworthy that the ILE exercise was not perceived as being hard, probably because muscle lactate levels were not high. This short and effective ILE program seems to be a promising modality for eliciting exercise health benefits in numerous populations, especially among those who normally lack time for exercise.
Next, Kaartinen and co-workers provided novel insights into the diversity of leisure-time physical activities by using longitudinal genetically informative twin data. They demonstrated that genetic effects have an important influence on participation in diverse leisure-time physical activities both in adolescence and adulthood. Moreover, genetic factors mostly explain the association of participation in diverse leisure-time physical activities between adolescence and adulthood. Although genetic influences are highlighted, the results also reveal that environmental influences contribute to the diversity of leisure-time physical activities. The environmental influences are shared by both twins (i.e., family and peer effects) in adolescence, while individual-specific environmental influences dominate in adulthood. These findings suggest that adolescent participation in diverse leisure-time physical activities may benefit from interventions carried out in family and school environments or peer networks, whereas individual-based interventions may work better among adults.
On a different topic, Lee and colleagues studied whether smaller blood pressure responses in females during muscle metaboreflex activation with post-exercise circulatory occlusion are influenced by sex differences in absolute exercise intensity, sympathetic activity, or resting sympathetic transduction. Their results demonstrated that absolute exercise intensity was the only significant predictor of blood pressure responses to muscle metaboreflex activation and that controlling for absolute exercise intensity (either by statistical methods or strength-matched cohorts) abolished sex differences. These results provide support against an innate sex difference in blood pressure responses to muscle metaboreflex activation following handgrip exercise and highlight the importance of accounting for absolute intensity when interpreting hemodynamic responses to fixed-duration relative intensity exercise or post-exercise circulatory occlusion.
L. Bruce Gladden
School of Kinesiology