Effects of strength training on muscle power and serum hormones in middle-aged and older men

• Published in: Journal of applied physiology (1985) Vol. 90; no. 4; pp. 1497 - 1507
• Main Authors: Izquierdo, M, Hakkinen, K, Ibanez, J, Garrues, M, Anton, A, Zuniga, A, Larrion, J. L, Gorostiaga, E. M
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.04.2001; American Physiological Society
• Subjects: Aged; Aging; Aging - physiology; Androgens; Arm - physiology; Biological and medical sciences; Body Composition - physiology; Body Weight - physiology; Effects; Exercise; Exercise Test; Fundamental and applied biological sciences. Psychology; Hormones - blood; Humans; Hydrocortisone - blood; Leg - physiology; Male; Men; Middle Aged; Muscle, Skeletal - physiology; Muscular system; Physical Fitness - physiology; Striated muscle. Tendons; Vertebrates: osteoarticular system, musculoskeletal system; Weight Lifting; Human; Senescence; Physical training; Androgen; Physical performance; Force; Lower limb; Striated muscle; Testosterone; Hormonal regulation; Upper limb; Testicular hormone; Sex steroid hormone
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2001.90.4.1497

1  Centro de Investigación y Medicina del Deporte de Navarra, Gobierno de Navarra, and 3  Servicio Navarra de Salud, Hospital de Navarra, 31002 Pamplona, Navarra, Spain; and 2  Department of Biology of Physical Activity and Neuromuscular Research Center, University of Jyväskylä, FIN-40351 Jyväskylä, Finland Effects of 16-wk strength training on maximal strength and power performance of the arm and leg muscles and serum concentrations [testosterone (T), free testosterone (FT), and cortisol] were examined in 11 middle-aged (M46; 46 ± 2 yr) and 11 older men (M64; 64 ± 2 yr). During the 16-wk training, the relative increases in maximal strength and muscle power output of the arm and leg muscles were significant in both groups ( P  < 0.05-0.001), with no significant differences between the two groups. The absolute increases were higher ( P  < 0.01-0.05) in M46 than in M64 mainly during the last 8 wk of training. No significant changes were observed for serum T and FT concentrations. Analysis of covariance showed that, during the 16-wk training period, serum FT concentrations tended to decrease in M64 and increase in M46 ( P  < 0.05). However, significant correlations between the mean level of individual serum T and FT concentrations and the individual changes in maximal strength were observed in a combined group during the 16-wk training ( r  = 0.49 and 0.5, respectively; P  < 0.05). These data indicate that a prolonged total strength-training program would lead to large gains in maximal strength and power load characteristics of the upper and lower extremity muscles, but the pattern of maximal and power development seemed to differ between the upper and lower extremities in both groups, possibly limited in magnitude because of neuromuscular and/or age-related endocrine impairments. aging; maximal strength; muscle power; testosterone