Single muscle fiber adaptations with marathon training
Open Access
- 1 September 2006
- journal article
- clinical trial
- Published by American Physiological Society in Journal of Applied Physiology
- Vol. 101 (3), 721-727
- https://doi.org/10.1152/japplphysiol.01595.2005
Abstract
The purpose of this investigation was to characterize the effects of marathon training on single muscle fiber contractile function in a group of recreational runners. Muscle biopsies were obtained from the gastrocnemius muscle of seven individuals (22 ± 1 yr, 177 ± 3 cm, and 68 ± 2 kg) before, after 13 wk of run training, and after 3 wk of taper. Slow-twitch myosin heavy chain [(MHC) I] and fast-twitch (MHC IIa) muscle fibers were analyzed for size, strength (Po), speed ( Vo), and power. The run training program led to the successful completion of a marathon (range 3 h 56 min to 5 h 35 min). Oxygen uptake during submaximal running and citrate synthase activity were improved ( P < 0.05) with the training program. Muscle fiber size declined ( P < 0.05) by ∼20% in both fiber types after training. Po was maintained in both fiber types with training and increased ( P < 0.05) by 18% in the MHC IIa fibers after taper. This resulted in >60% increase ( P < 0.05) in force per cross-sectional area in both fiber types. Fiber Vo increased ( P < 0.05) by 28% in MHC I fibers with training and was unchanged in MHC IIa fibers. Peak power increased ( P < 0.05) in MHC I and IIa fibers after training with a further increase ( P < 0.05) in MHC IIa fiber power after taper. These data show that marathon training decreased slow-twitch and fast-twitch muscle fiber size but that it maintained or improved the functional profile of these fibers. A taper period before the marathon further improved the functional profile of the muscle, which was targeted to the fast-twitch muscle fibers.Keywords
This publication has 32 references indexed in Scilit:
- The effect of ageing and immobilization on structure and function of human skeletal muscle fibresThe Journal of Physiology, 2003
- Specific contributions of various muscle fibre types to human muscle performance: an in vitro studyJournal of Electromyography and Kinesiology, 1999
- Muscle MechanicsExercise and Sport Sciences Reviews, 1996
- Long Slow Distance Training in Novice MarathonersResearch Quarterly for Exercise and Sport, 1994
- The velocity of unloaded shortening and its relation to sarcomere length and isometric force in vertebrate muscle fibres.The Journal of Physiology, 1979
- Skeletal muscle enzymes and fiber composition in male and female track athletesJournal of Applied Physiology, 1976
- Physiology of Marathon RunningPublished by American Medical Association (AMA) ,1972
- Perceived Exertion ScalePublished by American Psychological Association (APA) ,1970
- Energetics of marathon runningMedicine & Science in Sports & Exercise, 1969
- Studies in muscular activityThe Journal of Physiology, 1930