Int J Sports Med 2003; 24(3): 183-189
DOI: 10.1055/s-2003-39085
Physiology & Biochemistry
© Georg Thieme Verlag Stuttgart · New York

31P-MRS Characterization of Sprint and Endurance Trained Athletes

L.  Johansen1 , B.  Quistorff2
  • 1 Team Danmark Testcenter, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Main Campus: Odense University, Denmark
  • 2 NMR-Center, Panum Institute, University of Copenhagen, Copenhagen, Denmark
Further Information

Publication History

Accepted after revision: 20 July 2002

Publication Date:
12 May 2003 (online)

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Abstract

Muscle metabolism and force production were studied in sprint trained runners, endurance trained runners and in untrained subjects, using 31P-MRS. 31P-spectra were obtained at a time resolution of 5 s during four maximal isometric contractions of 30-sec duration, interspersed by 60-sec recovery intervals. Resting CrP/ATP ratio averaged 3.3 ± 0.3, with no difference among the three groups. The sprint trained subjects showed about 20 % larger contraction forces in contraction bouts 1 and 2 (p < 0.05). The groups differed with respect to CrP breakdown (p < 0.05), with sprinters demonstrating about 75 % breakdown in each contraction compared to about 60 % and 40 % for untrained and endurance trained subjects, respectively (p < 0.05). The endurance trained runners showed almost twice as fast CrP recovery (t1/2 = 12.5 ± 1.5) compared to sprint trained (t1/2 = 22.5 ± 2.53) and untrained subjects (t1/2 = 26.4 ± 2.8). From the initial rate of CrP resynthesis the rate of maximal aerobic ATP synthesis was estimated to 0.74 ± 0.07, 0.73 ± 0.10 and 0.33 ± 0.07 mmol ATP × kg-1 wet muscle × sec-1 for sprint trained, endurance trained and untrained subjects, respectively.

Only the sprint trained and the untrained subjects displayed a significant drop in pH and only during the first of the four contractions, about 0.2 and 0.1 pH units, respectively, indicating that only under those contractions was the glycolytic proton production larger than the proton consumption by the CK reaction. Also, in the first contraction the energy cost of contraction was higher for the sprinters compared to the two other groups.

The simple 31P-MRS protocol used in the present study demonstrates marked differences in force production, aerobic as well as anaerobic muscle metabolism, clearly allowing differentiation between endurance trained, sprint trained and untrained subjects.

References

L. Johansen

Team Danmark Testcenter · Institute of Sports Science and Clinical Biomechanics · University of Southern Denmark · Main Campus: Odense University

Campusvej 55 · 5230 Odense M ·Denmark ·

Phone: +45 6550 3440

Fax: +45 6550 3480

Email: ljohansen@health.sdu.dk