title: Gross efficiency during flat and uphill cycling in field conditions.
abstract: OBJECTIVE
  While a number of studies have investigated gross efficiency (GE) in laboratory conditions, few studies have analyzed it in field conditions. Therefore, the aim of this study was to analyze the effect of gradient and cadence on GE in field conditions.
  
  
  METHODS
  Thirteen trained cyclists (mean ± SD age 23.3 ± 4.1 y, stature 177.0 ± 5.5 cm, body mass 69.0 ± 7.2 kg, maximal oxygen uptake [VO2max] 68.4 ± 5.1 mL · min-1 ·kg-1) completed an incremental graded exercise test to determine ventilatory threshold (VT) and 4 field trials of 6 min duration at 90% of VT on flat (1.1%) and uphill terrain (5.1%) with 2 different cadences (60 and 90 rpm). VO2 was measured with a portable gas analyzer and power output was controlled with a mobile power crank that was mounted on a 26-in mountain bike.
  
  
  RESULTS
  GE was significantly affected by cadence (20.6% ± 1.7% vs 18.1% ± 1.3% at 60 and 90 rpm, respectively; P < .001) and terrain (20.0% ± 1.5% vs 18.7% ± 1.7% at flat and uphill cycling, respectively; P = .029). The end-exercise VO2 was 2536 ± 352 and 2594 ± 329 mL/min for flat and uphill cycling, respectively (P = .489). There was a significant difference in end-exercise VO2 between 60 (2352 ± 193 mL/min) and 90 rpm (2778 ± 431 mL/min) (P < .001).
  
  
  CONCLUSIONS
  These findings support previous laboratory-based studies demonstrating reductions in GE with increasing cadence and gradient that might be attributed to changes in muscle-activity pattern.
authors.affiliation: Sport and Exercise Sciences, University of Applied Sciences, Wiener Neustadt, Austria.
authors.forename: Alfred
authors.initials: A
authors.lastname: Nimmerichter
authors.forename: Bernhard
authors.initials: B
authors.lastname: Prinz
authors.forename: Kevin
authors.initials: K
authors.lastname: Haselsberger
authors.forename: Nina
authors.initials: N
authors.lastname: Novak
authors.forename: Dieter
authors.initials: D
authors.lastname: Simon
authors.forename: James G
authors.initials: JG
authors.lastname: Hopker
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D004526:Efficiency / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D010101:Oxygen Consumption; D012119:Respiration; D055815:Young Adult
chemical_list: D019344:Lactic Acid