title: Single-leg cycle training is superior to double-leg cycling in improving the oxidative potential and metabolic profile of trained skeletal muscle.
abstract: Single-leg cycling may enhance the peripheral adaptations of skeletal muscle to a greater extent than double-leg cycling. The purpose of the current study was to determine the influence of 3 wk of high-intensity single- and double-leg cycle training on markers of oxidative potential and muscle metabolism and exercise performance. In a crossover design, nine trained cyclists (78 ± 7 kg body wt, 59 ± 5 ml·kg(-1)·min(-1) maximal O(2) consumption) performed an incremental cycling test and a 16-km cycling time trial before and after 3 wk of double-leg and counterweighted single-leg cycle training (2 training sessions per week). Training involved three (double) or six (single) maximal 4-min intervals with 6 min of recovery. Mean power output during the single-leg intervals was more than half that during the double-leg intervals (198 ± 29 vs. 344 ± 38 W, P < 0.05). Skeletal muscle biopsy samples from the vastus lateralis revealed a training-induced increase in Thr(172)-phosphorylated 5'-AMP-activated protein kinase α-subunit for both groups (P < 0.05). However, the increase in cytochrome c oxidase subunits II and IV and GLUT-4 protein concentration was greater following single- than double-leg cycling (P < 0.05). Training-induced improvements in maximal O(2) consumption (3.9 ± 6.2% vs. 0.6 ± 3.6%) and time-trial performance (1.3 ± 0.5% vs. 2.3 ± 4.2%) were similar following both interventions. We conclude that short-term high-intensity single-leg cycle training can elicit greater enhancement in the metabolic and oxidative potential of skeletal muscle than traditional double-leg cycling. Single-leg cycling may therefore provide a valuable training stimulus for trained and clinical populations.
authors.affiliation: School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia. c.abbiss@ecu.edu.au
authors.forename: Chris R
authors.initials: CR
authors.lastname: Abbiss
authors.forename: Leonidas G
authors.initials: LG
authors.lastname: Karagounis
authors.forename: Paul B
authors.initials: PB
authors.lastname: Laursen
authors.forename: Jeremiah J
authors.initials: JJ
authors.lastname: Peiffer
authors.forename: David T
authors.initials: DT
authors.lastname: Martin
authors.forename: John A
authors.initials: JA
authors.lastname: Hawley
authors.forename: Naeem N
authors.initials: NN
authors.lastname: Fatehee
authors.forename: James C
authors.initials: JC
authors.lastname: Martin
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*