| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1Department of Physiology and Biophysics, The University of Alabama at Birmingham and 2Muscle Research Laboratory, Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Birmingham, Alabama
Submitted 18 March 2004 ; accepted in final form 1 September 2004
The purposes of this study were to examine age and gender differences in knee extensor strength, power, and fatigue using open- and closed-chain testing procedures. We tested the hypothesis that specific strength (strength/unit muscle mass) would not differ by age, whereas age differences in specific power and fatigue would remain consequent to blunted maximal contractile velocity. Skeletal muscle performance was examined in 28 young (26.9 ± 0.7 yr) and 24 older (63.6 ± 0.8 yr) men and women. Assessments included one-repetition maximum strength for knee extension, leg press, and squat; concentric knee extensor peak power, velocity, and fatigability; and sit-to-stand power, fatigability, and relative neural activation (electromyograph activity during sit-to-stand movement normalized to electromyograph activity during isometric maximum voluntary contraction). Thigh lean mass (TLM; kg) was assessed by dual-energy X-ray absorptiometry. Specific strength (N/kg TLM) and specific power (W/kg TLM) were estimated by dividing absolute values by TLM. Age differences in specific strength were observed for knee extension only (young, 41.2 ± 1.0 N/kg TLM; older, 32.4 ± 1.0 N/kg TLM; P < 0.05). Adjustment for TLM did not negate age differences in knee extension specific power (25–41% lower in older; P < 0.05) across loads tested. Older adults experienced fatigue across 10 repetitions of knee extension as peak velocity fell by 24% (P < 0.05). Deficits in concentric power persist after adjustment for TLM as maximum contractile velocity falls markedly with aging. Older adults are less capable of sustaining maximum concentric velocity during repetitive contractions. These findings suggest that velocity impairments are a possible contributor to mobility loss and falls risk among older adults. Interventions for improving contractile velocity should be pursued.
older adults; specific strength; specific power; sit-to-stand task
This article has been cited by other articles:
|
|
 |
|
  D. L. Mayhew, J.-s. Kim, J. M. Cross, A. A. Ferrando, and M. M. Bamman Translational signaling responses preceding resistance training-mediated myofiber hypertrophy in young and old humans J Appl Physiol, November 1, 2009; 107(5): 1655 - 1662. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Koopman and L. J. C. van Loon Aging, exercise, and muscle protein metabolism J Appl Physiol, June 1, 2009; 106(6): 2040 - 2048. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Kosek and M. M. Bamman Modulation of the dystrophin-associated protein complex in response to resistance training in young and older men J Appl Physiol, May 1, 2008; 104(5): 1476 - 1484. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-s. Kim, J. K. Petrella, J. M. Cross, and M. M. Bamman Load-mediated downregulation of myostatin mRNA is not sufficient to promote myofiber hypertrophy in humans: a cluster analysis J Appl Physiol, November 1, 2007; 103(5): 1488 - 1495. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. H. Chung, D. M. Callahan, and J. A. Kent-Braun Age-related resistance to skeletal muscle fatigue is preserved during ischemia J Appl Physiol, November 1, 2007; 103(5): 1628 - 1635. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Helbostad, S. Leirfall, R. Moe-Nilssen, and O. Sletvold Physical Fatigue Affects Gait Characteristics in Older Persons J. Gerontol. A Biol. Sci. Med. Sci., September 1, 2007; 62(9): 1010 - 1015. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. McNeil and C. L. Rice Fatigability Is Increased With Age During Velocity-Dependent Contractions of the Dorsiflexors J. Gerontol. A Biol. Sci. Med. Sci., June 1, 2007; 62(6): 624 - 629. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. McNeil, A. A. Vandervoort, and C. L. Rice Peripheral impairments cause a progressive age-related loss of strength and velocity-dependent power in the dorsiflexors J Appl Physiol, May 1, 2007; 102(5): 1962 - 1968. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. K. Petrella, J.-s. Kim, J. M. Cross, D. J. Kosek, and M. M. Bamman Efficacy of myonuclear addition may explain differential myofiber growth among resistance-trained young and older men and women Am J Physiol Endocrinol Metab, November 1, 2006; 291(5): E937 - E946. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Kosek, J.-s. Kim, J. K. Petrella, J. M. Cross, and M. M. Bamman Efficacy of 3 days/wk resistance training on myofiber hypertrophy and myogenic mechanisms in young vs. older adults J Appl Physiol, August 1, 2006; 101(2): 531 - 544. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-s. Kim, D. J. Kosek, J. K. Petrella, J. M. Cross, and M. M. Bamman Resting and load-induced levels of myogenic gene transcripts differ between older adults with demonstrable sarcopenia and young men and women J Appl Physiol, December 1, 2005; 99(6): 2149 - 2158. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. J. Cheng and C. L. Rice Fatigue and recovery of power and isometric torque following isotonic knee extensions J Appl Physiol, October 1, 2005; 99(4): 1446 - 1452. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-s. Kim, J. M. Cross, and M. M. Bamman Impact of resistance loading on myostatin expression and cell cycle regulation in young and older men and women Am J Physiol Endocrinol Metab, June 1, 2005; 288(6): E1110 - E1119. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
