Send to

Choose Destination
J Electromyogr Kinesiol. 2009 Oct;19(5):e290-300. doi: 10.1016/j.jelekin.2008.07.007. Epub 2008 Sep 17.

Resistance training of long duration modulates force and unloaded shortening velocity of single muscle fibres of young women.

Author information

Department of Experimental Medicine, Human Physiology Unit, and Interuniversity Institute of Miology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy.


The aim of the present study was to clarify the impact of long term (1 year) resistance training (RT) on structure and function of single muscle fibres of vastus lateralis in young female subjects. Five young women (age: 25.4+/-6.2 year) performed exercise sessions at 60% of single subject own repetition maximum (1 RM) 1h twice a week. Maximum voluntary force was determined pre- and post-RT and was found to significantly increase post-RT ensuring a successful impact of RT on muscle performance in vivo. Needle muscle biopsy samples were obtained both pre- and post-RT and the following determinations were performed: myosin heavy chain isoform (MHC) distribution of the whole muscle samples by SDS-PAGE; cross sectional area (CSA), specific force (Po/CSA) and maximum shortening velocity (Vo) of a large population (n=358) of single skinned muscle fibres classified on the basis of MHC isoform composition by SDS-PAGE. The results suggest that the long duration of RT can determine a significant increase in specific force (Po/CSA) and unloaded shortening velocity (Vo) of single muscle fibres in female subjects, whereas no muscle fibre hypertrophy and no shift in MHC isoform content was observed.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center