Impaired muscle glycogen resynthesis after eccentric exercise.
Eight men performed 10 sets of 10 eccentric contractions of the knee extensor muscles with one leg [eccentrically exercised leg (EL)]. The weight used for this exercise was 120% of the maximal extension strength. After 30 min of rest the subjects performed two-legged cycling [concentrically exercised leg (CL)] at 74% of maximal O2 uptake for 1 h. In the 3 days after this exercise four subjects consumed diets containing 4.25 g CHO/kg body wt, and the remainder were fed 8.5 g CHO/kg. All subjects experienced severe muscle soreness and edema in the quadriceps muscles of the eccentrically exercised leg. Mean (+/- SE) resting serum creatine kinase increased from a preexercise level of 57 +/- 3 to 6,988 +/- 1,913 U/l on the 3rd day of recovery. The glycogen content (mmol/kg dry wt) in the vastus lateralis of CL muscles averaged 90, 395, and 592 mmol/kg dry wt at 0, 24, and 72 h of recovery. The EL muscle, on the other hand, averaged 168, 329, and 435 mmol/kg dry wt at these same intervals. Subjects receiving 8.5 g CHO/kg stored significantly more glycogen than those who were fed 4.3 g CHO/kg. In both groups, however, significantly less glycogen was stored in the EL than in the CL.
Costill
D L
DL
Human Performance Laboratory, Ball State University, Muncie, Indiana 47306.
Pascoe
D D
DD
Fink
W J
WJ
Robergs
R A
RA
Barr
S I
SI
Pearson
D
D
D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology*; D006003:Glycogen / Q000096:biosynthesis* / Q000378:metabolism; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D009132:Muscles / Q000293:injuries / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors
D004040:Dietary Carbohydrates; D006003:Glycogen