Int J Sports Med 2002; 23(1): 33-39
DOI: 10.1055/s-2002-19269
Training and Testing

© Georg Thieme Verlag Stuttgart · New York

The Effect of Concurrent Endurance and Strength Training on Quantitative Estimates of Subsarcolemmal and Intermyofibrillar Mitochondria

P.  D.  Chilibeck1 , D.  G.  Syrotuik1 , G.  J.  Bell1
  • 1Faculty of Physical Education and Recreation, University of Alberta, Edmonton Alberta, Canada
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Publikationsverlauf

March 30, 2001

Publikationsdatum:
20. Dezember 2001 (online)

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Abstract

We examined the effect of combined strength and endurance training on quantitative estimates of mitochondria in subsarcolemmal and intermyofibrillar regions of muscle fibers. Ten subjects (five males, five females) participated in a 12 week program of combined strength and endurance training. Seven subjects (three males and four females) served as controls. Biopsy samples from the vastus lateralis were obtained before and after training in both groups and also at the mid-point of training in the exercise group. Measurement of succinate dehydrogenase activity throughout muscle fibers, as a quantitative estimate of mitochondrial subpopulations, revealed no differences between exercise and control groups before and after training. Within the exercise group, there was a significant increase in succinate dehydrogenase activity in all regions of muscle fibers from before to after training. There was also a significant increase in succinate dehydrogenase activity in the subsarcolemmal, relative to the intermyofibrillar region from mid-(six weeks) to after-training ( regional distribution × time; p < 0.05). This may have been associated with an oxidative shift in fiber types, as type I fiber percentage was increased in the exercise, compared to the control group (group × time; p < 0.05). We conclude that mitochondrial populations undergo differential changes throughout training. IMF mitochondria increase in a linear manner throughout training, while SS mitochondria undergo a preferential increase late in training. This increase late in training may be related to an increase in proportion of type I fibers.

References

P. D. Chilibeck

College of Kinesiology · University of Saskatchewan

Saskatoon SK, S7N 5C2 · Canada ·

Telefon: +1 (306 966) 6469

Fax: +1 (306 966) 6464

eMail: chilibec@duke.usask.ca