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Titolo:
CHANGES IN MUSCLE MORPHOLOGY, ELECTROMYOGRAPHIC ACTIVITY, AND FORCE PRODUCTION CHARACTERISTICS DURING PROGRESSIVE STRENGTH TRAINING IN YOUNG AND OLDER MEN
Autore:
HAKKINEN K; NEWTON RU; GORDON SE; MCCORMICK M; VOLEK JS; NINDL BC; GOTSHALK LA; CAMPBELL WW; EVANS WJ; HAKKINEN A; HUMPHRIES BJ; KRAEMER WJ;
Indirizzi:
UNIV JYVASKYLA,NEUROMUSCULAR RES CTR,POB 35 SF-40351 JYVASKYLA FINLAND UNIV JYVASKYLA,DEPT BIOL PHYS ACTIV SF-40351 JYVASKYLA FINLAND PENN STATE UNIV,LAB SPORTS MED UNIVERSITY PK PA 16802 CENT HOSP JYVASKYLA,DEPT PHYSIATRY JYVASKYLA FINLAND
Titolo Testata:
The journals of gerontology. Series A, Biological sciences and medical sciences
fascicolo: 6, volume: 53, anno: 1998,
pagine: 415 - 423
SICI:
1079-5006(1998)53:6<415:CIMMEA>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
HUMAN SKELETAL-MUSCLE; DIFFERENT FIBER TYPES; CROSS-SECTIONAL AREA; MYOFIBRILLAR ATPASE ACTIVITY; HEAVY-CHAIN COMPOSITION; HIGH-INTENSITY STRENGTH; ELDERLY MEN; NEURAL ACTIVATION; VASTUS LATERALIS; BODY-COMPOSITION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Science Citation Index Expanded
Citazioni:
67
Recensione:
Indirizzi per estratti:
Citazione:
K. Hakkinen et al., "CHANGES IN MUSCLE MORPHOLOGY, ELECTROMYOGRAPHIC ACTIVITY, AND FORCE PRODUCTION CHARACTERISTICS DURING PROGRESSIVE STRENGTH TRAINING IN YOUNG AND OLDER MEN", The journals of gerontology. Series A, Biological sciences and medical sciences, 53(6), 1998, pp. 415-423

Abstract

Effects of a 10-week progressive strength training program composed of a mixture of exercises for increasing muscle mass, maximal peak force, and explosive strength (rapid force production) were examined in 8 young (YM) (29 +/- 5 yrs) and 10 old (OM) (61 +/- 4 yrs) men. Electromyographic activity, maximal bilateral isometric peak force, and maximal rate of force development (RFD) of the knee extensors, muscle cross-sectional area (CSA) of the quadriceps femoris (QF); muscle fiber proportion, and fiber areas of types I, IIa, IIb, and IIab of the vastus lateralis were evaluated Maximal and explosive strength values remainedunaltered in both groups during a ii-week control period with no training preceding the strength training After the 10-week training period, maximal isometric peak force increased from 1311 +/- 123 N by 25.6% (p < .05) in YM and from 976 +/- 168 N by 16.5% (p < .01) in OM. The pretraining RFD values of 4049 +/- 791 Ns(-1) in YM and 2526 +/- 1197 Ns(-1) in OM remained unaltered. Both groups showed significant increases (p < .05) in the averaged maximum IEMGs of the vastus muscles. The CSA of the QF increased from 90.3 +/- 7.9 cm(2) in YM by 12.2% (p < .05) and from 74.7 +/- 7.8 cm(2) ill OM by 8.5% (p < .001). No changesoccurred in the muscle fiber distribution of type I during the training, whereas the proportion of subtype IIab increased from 2% to 6% (p < .05) in YM and that of type IIb decreased in both YM from 25% to 16%(p < .01) and in OM from 15% to 6% (p < .05). The mean fiber area of type I increased after the 10-week training in YM (p < .001) and OM (p< .05) as well as that of type IIa in both YM(p < .01) and OM (p < .01). The individual percentage values for type I fibers were inversely correlated with the individual changes recorded during the training inthe muscle CSA of the QF (r = -.56, p < .05). The present results suggest that both neural adaptations and the capacity of the skeletal muscle to undergo training-induced hypertrophy even in older people explain the gains observed in maximal force in older men, while rapid forceproduction capacity recorded during the isometric knee extension action remained unaltered during the present mixed strength training program.

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Documento generato il 19/09/20 alle ore 09:29:16