title: Effects of intermittent ischemia on contractile properties and myosin isoforms of skeletal muscle.
abstract: OBJECTIVE
  This study determined the effects of intermittent ischemia on the contractile properties, fatigue (Tf), and myosin heavy chain composition (MHC) in the rat gastrocnemius-plantarissoleus muscle (GPS) complex.
  
  
  METHODS
  Fifty rats were divided into four groups: control (C, N = 12), severed (femoral artery) (S, N = 12), exercise (E, N = 13), and severed/exercise (SE, N = 13). Ischemia was elicited only in the SE group by daily exercise and the other groups served as controls. Exercise in the E and SE groups consisted of running on a treadmill approximately 35 min.d-1, 5 d.wk-1 for 7 wk.
  
  
  RESULTS
  Body weight, muscle weight, and absolute force were less in the SE group compared with those in C (12, 18, and 12% respectively). However, relative force (N.g-1 of muscle) was greater in the SE group compared with that in C (8%). Maximal shortening velocity (Vmax) was lower in the SE group compared with that in all others (10-14%). Tf was less in the S group compared with that in C and E (28 and 30%, respectively). Type IIx MHC increased and type IIb decreased in gastrocnemius and plantaris muscles in SE compared with those in C.
  
  
  CONCLUSIONS
  These data indicate that intermittent ischemia caused a decrease in muscle mass, maximal force development, and Vmax, but had no effect on Tf. The decrease in Vmax may have been related to myosin alterations in the muscles.
authors.affiliation: Department of Exercise and Sports Sciences, University of Florida, Gainesville, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Dodd
authors.forename: I S
authors.initials: IS
authors.lastname: Vrabas
authors.forename: D S
authors.initials: DS
authors.lastname: Stetson
mesh_terms: D000818:Animals; D001835:Body Weight; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D018908:Muscle Weakness / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000737:chemistry; D018995:Myosin Heavy Chains / Q000032:analysis*; D010805:Physical Conditioning, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018995:Myosin Heavy Chains