Acute hormone responses to heavy resistance lower and upper extremity exercise in young versus old men |
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Authors: | K H?kkinen A Pakarinen R U Newton and W J Kraemer |
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Institution: | (1) Department of Biology of Physical Activity, University of Jyv?skyl?, P.O. Box 35, FIN-40351, Jyv?skyl?, Finland, FI;(2) Laboratory, Oulu University Central Hospital, Oulu, Finland, FI;(3) School of Exercise Science and Sport Management, Southern Cross University, Lismore, Australia, AU;(4) Laboratory for Sports Medicine, The Pennsylvania State University, University Park, Pennsylvania, USA, US |
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Abstract: | Acute hormone responses of growth hormone (GH), total and free testosterone (TT and FT) and cortisol (C) to heavy resistance
isometric exercise were examined in ten young men YM 26.5 (SD 4.8) years] and ten old men OM 70.0 (SD 3.7) years]. Loading
conditions of the same relative intensity were created for the lower and upper extremity actions separately as well as for
both of them together – lower extremity exercise (LE; knee extension), upper extremity exercise (UE; bench press extension),
and lower and upper extremity exercise (LUE) performed simultaneously in a seated position. Single voluntary maximal isometric
actions lasting for 5 s were performed repeatedly for ten repetitions (with a recovery of 5 s) for a total of four sets. The
recovery time between the sets was 1 min. Each exercise led to large acute decreases in maximal isometric force in both YM
(P < 0.001) and OM (P < 0.001) ranging from 41% to 26% with no significant differences between the groups. Serum GH concentrations increased in
both YM (P < 0.05–0.01) and OM (P < 0.05) but the postexercise value in YM during LE was greater (P < 0.05) than for OM. The TT increased (P < 0.01–0.001) in YM in all three exercises, while in OM the increase occurred only during LE (P < 0.01). The exercises led to increases in FT in YM (P < 0.05 for LE and LUE), while in OM the increase occurred only during LUE (P < 0.05). The pre and postexercise FT were greater in YM (P < 0.001) than in OM. No significant changes occurred in C either in YM or in OM. The blood lactate concentrations increased
during the exercises in both YM (P < 0.001) and OM (P < 0.05–0.001) but the postexercise values during LE and LUE in YM were greater (P < 0.05) than in OM. The present data would indicate that the responses of GH, TT and FT to heavy resistance isometric exercise
are lowered with increasing age. The reduced acute hormone response together with the lowered basal values in FT in the older
men compared to the young men may indicate decreased anabolic effects on muscles and may explain in part the loss of muscle
mass and strength associated with aging.
Accepted: 18 August 1997 |
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Keywords: | Serum hormones Aging Heavy resistance exercise Isometric action |
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