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BioMed Research International
Volume 2013 (2013), Article ID 417901, 10 pages
http://dx.doi.org/10.1155/2013/417901
Clinical Study

Noninvasive Monitoring of Training Induced Muscle Adaptation with -MRS: Fibre Type Shifts Correlate with Metabolic Changes

1Clinic for Orthopaedics, Center for Musculoskeletal Surgery and Julius Wolff Institute, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
2Berlin-Brandenburg Center for Regenerative Medicine, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany
3Institute for Sports Medicine, Humboldt University of Berlin, 10115 Berlin, Germany
4Institute for Cell and Neurobiology, Charité-Universitätsmedizin Berlin, 13353 Berlin, Germany

Received 9 April 2013; Revised 2 June 2013; Accepted 11 June 2013

Academic Editor: P. Bryant Chase

Copyright © 2013 Eike Hoff et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. To evaluate training induced metabolic changes noninvasively with magnetic resonance spectroscopy ( -MRS) for measuring muscle fibre type adaptation. Methods. Eleven volunteers underwent a 24-week training, consisting of speed-strength, endurance, and detraining (each 8 weeks). Prior to and following each training period, needle biopsies and -MRS of the resting gastrocnemius muscle were performed. Fibre type distribution was analyzed histologically and tested for correlation with the ratios of high energy phosphates ([PCr]/[ ], [PCr]/[βATP] and [PCr +  ]/[βATP]). The correlation between the changes of the -MRS parameters during training and the resulting changes in fibre composition were also analysed. Results. We observed an increased type-II-fibre proportion after speed-strength and detraining. After endurance training the percentage of fast-twitch fibres was reduced. The progression of the [PCr]/[ ]-ratio was similar to that of the fast-twitch fibres during the training. We found a correlation between the type-II-fibre proportion and [PCr]/[ ] ( , ) or [PCr]/[βATP] ( , ); the correlations between its changes (delta) and the fibre-shift were significant as well (delta[PCr]/[ ] , delta[PCr]/[βATP] , ). Conclusion. Shifts in fibre type composition and high energy phosphate metabolite content covary in human gastrocnemius muscle. Therefore -MRS might be a feasible method for noninvasive monitoring of exercise-induced fibre type transformation.