title: Treadmill but not wheel running improves fatigue resistance of isolated extensor digitorum longus muscle in mice.
abstract: OBJECTIVE
  The present study is the first to compare the physiological impact of either forced treadmill or voluntary wheel running exercise on hindlimb muscle in mice.
  
  
  METHODS
  Male C57BL/6 mice were subjected to either 6 weeks of forced treadmill or voluntary wheel running exercise. Mice in the treadmill running exercise group (TRE; n = 8) ran 1.9 km day(-1) at a speed of 16 m min(-1) against an uphill incline of 11 degrees. In the running wheel exercise group (RWE; n = 8) animals ran 8.8 +/- 0.2 km per day (average speed 42 +/- 2 m min(-1)). After the experimental period, animals were killed and mechanical performance and oxygen consumption of isolated extensor digitorum longus (EDL) muscle were determined during serial electrical stimulation at 0.5, 1 and 2 Hz.
  
  
  RESULTS
  Steady-state half-width time (HWT) of twitch contraction at 0.5 Hz was significantly shorter in TRE and RWE than controls (CON) (41.3 +/- 0.2, 41.3 +/- 0.1 and 44.3 +/- 0.1 s respectively; P < 0.05). The rate of fatigue development and HWT lengthening at 2 Hz was the same in RWE and CON but lower in TRE (1.2-fold and twofold respectively; P < 0.05). EDL oxygen consumption, mitochondrial content and myosin heavy chain (MyHC) composition were not different between the groups.
  
  
  CONCLUSIONS
  These results indicate that both exercise modalities have an effect on a hindlimb fast-twitch muscle in mice, with the greatest impact seen with forced treadmill running.
authors: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors: J A L
authors: JA
authors: Jeneson
authors: M W
authors: MW
authors: de Snoo
authors: N A T
authors: NA
authors: Verlinden
authors: B J L J
authors: BJ
authors: Joosten
authors: A
authors: A
authors: Doornenbal
authors: A
authors: A
authors: Schot
authors: M E
authors: ME
authors: Everts
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004558:Electric Stimulation / Q000379:methods; D006614:Hindlimb; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000032:analysis; D010101:Oxygen Consumption / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000379:methods*; D005082:Physical Exertion / Q000502:physiology; D013997:Time Factors
chemical_list: D002950:Citrate (si)-Synthase; D018995:Myosin Heavy Chains