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dc.contributor.authorHäkkinen, Keijo
dc.date.accessioned2020-10-02T10:15:17Z
dc.date.available2020-10-02T10:15:17Z
dc.date.issued1986
dc.identifier.isbn978-951-39-7903-4
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/71984
dc.description.abstractTo investigate prolonged training-induced changes in electromyographic, muscle fibre and force production characteristics of leg extensor muscles and in serum hormones, eleven trained male subjects went through heavy resistance (loads between 70 and 120 %) and ten comparable male subjects through explosive type (jumping exercises with low loads) strength training for 24 weeks. Great increase in maximal strength (26.8-30.2 %, p<.001) during heavy resistance strength training was accompanied by significant (p<.05-.01) increases in the neural activation (IEMG) of the trained muscles during the periods with higher training loads. Explosive force development was slight during the entire training. Large muscular hypertrophy of especially FT fibre type (p<.001) occurred primarily during the first half of the training. Individual alterations in serum testosterone/cortisol ratio correlated (p<.01) with changes in muscular strength during the last training month. Great (24.1-32.5 %, p<.001) improvement in rapid force production during explosive type strength training correlated (p<.05-.001) with significant (p<.05-.01) increases noted in the neural activation of the trained muscles observable both during rapid isometric and concentric contractions and during high velocity stretch-shortening cycle exercises. Maximal strength development and hypertrophic changes were relatively slight. Selected decreases (p<.05-.001) occurred in IEMG, muscle fibre areas and in muscular strength during the following detraining periods for 12 weeks. The present findings indicate that training-induced enhancements in various aspects of force production are explainable by specific adaptations in the neuromuscular system and in endogenous hormone balance taking place in part with regard to type, loading and duration of strength training and perhaps to subject material.en
dc.relation.ispartofseriesStudies in Sport, Physical Education and Health
dc.relation.haspart<b>Artikkeli I:</b> Häkkinen, K., Pakarinen, A., Alen, M., Komi, P.V. (1985). Serum hormones during prolonged training of neuromuscular performance. <i>European Journal of Applied Physiology and Occupational Physiology 53, 287–293.</i> DOI: <a href="https://doi.org/10.1007/BF00422840"target="_blank">10.1007/BF00422840</a>
dc.relation.haspart<b>Artikkeli II:</b> Häkkinen, K., Alen, M., Komi, P.V. (1985). Changes in isometric force- and relaxation-time, electromyographic and muscle fibre characteristics of human skeletal muscle during strength training and detraining. <i>Acta Physiologica Scandinavica 125(4), 573-585.</i> DOI: <a href="https://doi.org/10.1111/j.1748-1716.1985.tb07759.x"target="_blank"> j.1748-1716.1985.tb07759.x </a>
dc.relation.haspart<b>Artikkeli III:</b> Häkkinen, K., Komi, P.V., Alen, M. (1985). Effect of explosive type strength training on isometric force- and relaxation-time, electromyographic and muscle fibre characteristics of leg extensor muscles. <i>Acta Physiologica Scandinavica 12, 587-600.</i> DOI: <a href="https://doi.org/10.1111/j.1748-1716.1985.tb07760.x"target="_blank">10.1111/j.1748-1716.1985.tb07760.x </a>
dc.relation.haspart<b>Artikkeli IV:</b> Häkkinen, K., Komi, P. V. (1985). Changes in electrical and mechanical behavior of leg extensor muscles during heavy resistance strength training. <i>Scandinavian journal of sports sciences 7 (2), 55-64.</i>
dc.relation.haspart<b>Artikkeli V:</b> Häkkinen, K., Komi, P. V. (1985). Effect of explosive type strength training on electromyographic and force production characteristics of leg extensor muscles during concentric and various stretch-shortening cycle exercises. <i>Scandinavian journal of sports sciences 7(2), 65-76.</i>
dc.relation.haspart<b>Artikkeli VI:</b> Häkkinen, K., Komi, P. V. (1986). Training-induced changes in neuromuscular performance under voluntary and reflex conditions. <i>European Journal of Applied Physiology and Occupational Physiology, 55, 147–155.</i> DOI: <a href="https://doi.org/10.1007/BF00714997"target="_blank">10.1007/BF00714997 </a>
dc.subjectharjoittelu
dc.subjectjalat
dc.subjectkuntoutus
dc.subjectlihakset
dc.subjectliikuntalääketiede
dc.subjectvoimaharjoittelu
dc.subjectexercise
dc.subjectexertion
dc.subjectleg
dc.subjectsports medicine
dc.titleTraining and detraining adaptations in electromyographic, muscle fibre and force production characteristics of human leg extensor muscles, with special reference to prolonged heavy resistance and explosive type strength training
dc.identifier.urnURN:ISBN:978-951-39-7903-4
dc.date.digitised2020


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