Human skeletal sarcoplasmic reticulum Ca2+ uptake and muscle function with aging and strength training.
This study investigated the adaptations of skeletal muscle sarcoplasmic reticulum (SR) Ca2+ uptake, relaxation, and fiber types in young (YW) and elderly women (EW) to high-resistance training. Seventeen YW (18-32 yr) and 11 EW (64-79 yr) were assessed for 1) electrically evoked relaxation time and rate of the quadriceps femoris; and 2) maximal rates of SR Ca2+ uptake and Ca2+-ATPase activity and relative fiber-type areas, analyzed from muscle biopsies of the vastus lateralis. EW had significantly slower relaxation rates and times, decreased SR Ca2+ uptake and Ca2+-ATPase activity, and a larger relative type I fiber area than did YW. A subgroup of 9 young (YWT) and 10 elderly women (EWT) performed 12 wk of high-resistance training (8 repetition maximum) of the quadriceps and underwent identical testing procedures pre- and posttraining. EWT significantly increased their SR Ca2+ uptake and Ca2+-ATPase activity in response to training but showed no alterations in speed of relaxation or relative fiber-type areas. In YWT none of the variables was altered after resistance training. These findings suggest that 1) a reduced SR Ca2+ uptake in skeletal muscle of elderly women was partially reversed with resistance training and 2) SR Ca2+ uptake in the vastus lateralis was not the rate-limiting mechanism for the slowing of relaxation measured from electrically evoked quadriceps muscle of elderly women.
Hunter
S K
SK
School of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, New South Wales 2141, Australia.
Thompson
M W
MW
Ruell
P A
PA
Harmer
A R
AR
Thom
J M
JM
Gwinn
T H
TH
Adams
R D
RD
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006651:Histocytochemistry; D006801:Humans; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D009124:Muscle Proteins / Q000378:metabolism; D009126:Muscle Relaxation / Q000502:physiology; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D010809:Physical Fitness / Q000502:physiology*; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*; D014891:Weight Lifting / Q000502:physiology*
D009124:Muscle Proteins; D000252:Calcium-Transporting ATPases; D002118:Calcium