Physical activity levels, medical health, quality of life and dietary status of the subjects was assessed by a validated questionnaire (36-Item Short-Form Health Survey questionnaire; Ware and Sherbourne, 1992 (link); Howley et al., 2003 ), basic anthropometry, imaging based assessment of body composition and quadriceps muscles. Aerobic fitness was estimated based on a two-legged O2peak test on a stationary cycle ergometer. One-week later subjects performed a standardized single bout of exhaustive one-legged cycle exercise under the collection of biopsies prior to, 0.5 and 8 h post cycling exercise from vastus lateralis muscle. The collected biopsies were used to quantify muscle composition, ACE transcript levels and activity, VEGFA and tenascin-C protein content, and muscle metabolites. The ACE-I/D polymorphism was determined in a double-blind manner from a mucosal swab as collected during the functional exploration and assessed post-hoc for its influence only after the physiological and biochemical measurements had been performed. For the analysis subjects were group ed based on their training status and ACE-I/D genotype as assessed by questionnaire, functional exploration and genotyping. Subjects were deemed to be endurance-trained if they documented a history of 5 years of regular endurance type training (endurance running, cycling, football, rugby), documented a level of intense physical activity above 6 h per week (in the 36-Item Short-Form Health Survey questionnaire), and if they demonstrated a O2peak above 50 mL min−1 kg−1. Healthy subjects which complied to the inclusion criteria, but which documented a level of intense physical activity below 6 h per week or demonstrated a O2peak below 50 mL min−1 kg−1 were considered as not being endurance-trained, i.e., being untrained.
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