The metabolic responses of human type I and II muscle fibres during maximal treadmill sprinting.

Greenhaff, PL, Nevill, ME ORCID: https://orcid.org/0000-0003-2498-9493, Soderlund, K, Bodin, K, Boobis, LH, Williams, C and Hultman, E, 1994. The metabolic responses of human type I and II muscle fibres during maximal treadmill sprinting. The Journal of Physiology, 478 (1), pp. 149-155. ISSN 0022-3751

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Abstract

1. Muscle biopsy samples were obtained from the vastus lateralis of six healthy volunteers before and after 30 s of treadmill sprinting. A portion of each biopsy sample was used for mixed‐fibre metabolite analysis. Single fibres were dissected from the remaining portion of each biopsy and were used for ATP, phosphocreatine (PCr) and glycogen determination. 2. Before exercise, PCr and glycogen contents were higher in type II fibres (79.3 +/- 2.7 and 472 +/- 35 mmol (kg dry matter (DM)-1, respectively) compared with type I fibres (71.3 +/- 3.0 mmol (kg DM)-1, P < 0.01 and 375 +/- 25 mmol (kg DM)-1, P < 0.001, respectively). 3. Peak power output was 885 +/- 66 W and declined by 65 +/- 3% during exercise. Phosphocreatine and glycogen degradation in type II fibres during exercise (74.3 +/- 2.5 and 126.3 +/- 15.8 mmol (kg DM)-1, respectively) was greater than the corresponding degradation in type I fibres (59.1 +/- 2.9 mmol (kg DM)-1, P < 0.001 and 77.0 +/- 14.3 mmol (kg DM)-1, P < 0.01, respectively). The decline in ATP during exercise was similar when comparing fibre types (P > 0.05). 4. Compared with previous studies involving similar durations of maximal cycling exercise, isokinetic knee extension and intermittent isometric contraction, the rates of substrate utilization recorded in type I fibres were extremely high, being close to the rapid rates observed in this fibre type during intense contraction with limb blood flow occluded.

Item Type:	Journal article
Publication Title:	The Journal of Physiology
Creators:	Greenhaff, P.L., Nevill, M.E., Soderlund, K., Bodin, K., Boobis, L.H., Williams, C. and Hultman, E.
Publisher:	Wiley-Blackwell
Date:	1 July 1994
Volume:	478
Number:	1
ISSN:	0022-3751
Identifiers:	Number Type 10.1113/jphysiol.1994.sp020238 DOI 1433354 Other
Divisions:	Schools > School of Science and Technology
Record created by:	Jonathan Gallacher
Date Added:	28 Apr 2021 15:09
Last Modified:	28 Apr 2021 15:09
URI:	https://irep.ntu.ac.uk/id/eprint/42771

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