Abstract

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 se ts/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 and 226.7, respectively. Isokinetic peak torque of extensors and flexors measured on a Cybex II dynamometer increased 10.0 and 18.5 at 60 degrees/s and 16.7 and 14.7 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 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 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 by an average 40.8. Strength gains in older men were associated with significant muscle hypertrophy and an increase in myofibrillar protein turnover. Verf.-Referat