title: Distribution of strength training volume into one or two daily sessions and neuromuscular adaptations in female athletes.
abstract: Neuromuscular adaptations were investigated in ten female athletes during a "normal" intensive strength training period for 3-weeks (I) as well as during a separate second 3-week training period (II), when the same total training volume was distributed into two daily sessions. No systematic changes took place in the maximal voluntary neural activation (averaged integrated EMG) of the leg extensor muscles, in the cross-sectional area (CSA) of the quadriceps femoris muscle or in maximal voluntary isometric strength of the leg extensor muscles over training period I with one daily sessions. However, a significant increase was observed in maximal strength from 2493 +/- 553 to 2620 +/- 598 N (p < 0.05) during period II accompanied also by a significant (p < 0.05) enlargement in the cross-sectional area of the muscle and by slight (ns.) increases in the maximum IEMGs of the trained muscles. The individual changes in the maximum IEMGs of the trained muscles during period II correlated significantly (p < 0.01) with the individual changes in maximal strength. The present results with female athletes suggest that the distribution of the volume of intensive strength training into smaller units, such as two daily sessions, may create more optimal conditions not only for muscular hypertrophy but by producing effective training stimuli especially for the nervous system. These kinds of training conditions may lead to further strength development in athletes being greater than obtained during "normal" strength training of the same duration.
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Häkkinen
authors.forename: M
authors.initials: M
authors.lastname: Kallinen
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D009132:Muscles / Q000502:physiology*; D009424:Nervous System Physiological Phenomena; D010806:Physical Education and Training / Q000379:methods*; D013177:Sports; D013997:Time Factors; D014891:Weight Lifting / Q000502:physiology*