Strength conditioning in older men: skeletal muscle hypertrophy and improved function.
The effects of strength conditioning on skeletal muscle function and mass were determined in older men. Twelve healthy untrained volunteers (age range 60-72 yr) participated in a 12-wk strength training program (8 repetitions/set; 3 sets/day; 3 days/wk) at 80% of the one repetition maximum (1 RM) for extensors and flexors of both knee joints. They were evaluated before the program and after 6 and 12 wk of training. Weekly measurements of 1 RM showed a progressive increase in strength in extensors and flexors. By 12 wk extensor and flexor strength had increased 107.4 (P less than 0.0001) and 226.7% (P less than 0.0001), respectively. Isokinetic peak torque of extensors and flexors measured on a Cybex II dynamometer increased 10.0 and 18.5% (P less than 0.05) at 60 degrees/s and 16.7 and 14.7% (P less than 0.05) at 240 degrees/s. The torque-velocity relationship showed an upward displacement of the curve at the end of training, mainly in the slow-velocity high-torque region. Midthigh composition from computerized tomographic scans showed an increase (P less than 0.01) in total thigh area (4.8%), total muscle area (11.4%), and quadriceps area (9.3%). Biopsies of the vastus lateralis muscle revealed similar increases (P less than 0.001) in type I fiber area (33.5%) and type II fiber area (27.6%). Daily excretion of urinary 3-methyl-L-histidine increased with training (P less than 0.05) by an average 40.8%. Strength gains in older men were associated with significant muscle hypertrophy and an increase in myofibrillar protein turnover.
Frontera
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United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111.
Meredith
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O'Reilly
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Knuttgen
H G
HG
Evans
W J
WJ
D000368:Aged; D001835:Body Weight; D003404:Creatinine / Q000652:urine; D005081:Exercise Therapy; D006801:Humans; D006984:Hypertrophy; D008297:Male; D008762:Methylhistidines / Q000652:urine; D008875:Middle Aged; D009132:Muscles / Q000033:anatomy & histology / Q000502:physiology*; D009929:Organ Size; D014057:Tomography, X-Ray Computed
D008762:Methylhistidines; D003404:Creatinine; C028118:3-methylhistidine