Effect of high-intensity running in rectus femoris muscle fiber in rats.
The effect of a 12-week high-intensity intermittent exercise program on fiber type composition and the oxidative capacity of rectus femoris skeletal muscle from 20 male Wistar rats (Trained, n = 10; Sedentary, n = 10) was histochemically determined. The training exercise program was developed in a motorized treadmill. It consisted of four running bouts of 2 min duration at 48 m/min, alternated with recovery intervals of 4 min. Training increased relative cross-sectional area of oxidative fibers (I, IIA, IIX) and decreased the same parameter in type IIB non-oxidative fibers (P < 0.001). Our results suggest that this type of strength exercise program is enough to induce changes in muscle fiber composition. This opens a possibility to use this kind of exercise in preventing and treating muscle atrophy.
Diaz-Herrera
P
P
Departamento de Morfología, Facultad de Medicina, Universidad de Las Palmas de Gran Canaria, Spain. pilard@cicei.ulpgc.es
García-Castellano
J M
JM
Torres
A
A
Morcuende
J A
JA
Calbet
J A
JA
Sarrat
R
R
D000818:Animals; D006614:Hindlimb; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000145:classification / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar; D012420:Running