title: Anthropometric characteristics account for time to exhaustion in cycling.
abstract: This study examined the relationship between the phenotypic and anthropometric characteristics and the cycling time to exhaustion (Tlim) at the maximal aerobic power output (Pmax). 12 (7 men, 5 women) physically-active participants performed a square-wave test at Pmax to determine the maximal time limit. Muscle histochemistry, enzymatic activities and buffer capacity were determined from a vastus lateralis muscle biopsy, lean body mass (LBM) by hydrostatic weighing, and total (TV) and lean (LV) volumes of the thigh by anthropometric measurements. The mean (±SD) Tlim was 235±84 s (score range: 108-425 s). No relationship was found between Tlim and any muscle phenotypes. However, we observed a strong, linear relationship between Tlim and LBM (r=0.84, P<0.05). Thigh TV and LV displayed weaker correlation coefficients with Tlim (r=0.66 and r=0.73, respectively; P<0.05). We further estimated the femur length and found this measure to correlate with Tlim (r=0.81, P<0.05). This study suggests that muscle phenotypes may not be representative of Tlim. Rather, anthropometric characteristics account for such performance by conferring a biomechanical advantage in cycling. We conclude that, in addition to metabolic factors, anthropometric characteristics with reasonable accuracy predict Tlim in cycling, and may account for the large inter-subject variability observed in previous studies.
authors: Memorial University, School of Human Kinetics and Recreation, St. John's, Canada.
authors: F A
authors: FA
authors: Basset
authors: Institut National du Sport de Quebec, Physiology, Montreal, Canada.
authors: F
authors: F
authors: Billaut
authors: Universite Laval, Kinesiology, Quebec, Canada.
authors: D R
authors: DR
authors: Joanisse
mesh_terms: D000328:Adult; D000886:Anthropometry; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism; D010807:Physical Endurance / Q000502:physiology*; D013848:Thigh / Q000033:anatomy & histology; D055815:Young Adult