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The amplitude of the slow component of oxygen uptake is related to muscle contractile properties
- Source :
- European Journal of Applied Physiology. 91:192-198
- Publication Year :
- 2004
- Publisher :
- Springer Science and Business Media LLC, 2004.
-
Abstract
- During constant-load exercise above the lactate threshold, oxygen-uptake kinetics deviate from the pattern seen below the threshold, with an additional, delayed component superimposed on the monoexponential pattern. It was hypothesised that this slow component is due to the progressive recruitment of type II muscle fibres. Oxygen uptake was measured for six male power athletes (group P) and six male endurance athletes (group E) during constant-load knee extension exercise tests in order to determine slow component amplitude. In addition, an electrical stimulation protocol was employed in order to assess the functional contractile profile and fatiguability of the knee extensors. The amplitude of the slow component during exercise was significantly ( P0.05) greater in group P than in group E when expressed as an absolute value [mean (SEM)=77 (17) ml min(-1) and 24 (16) ml min(-1)] and when normalised to end-exercise oxygen uptake, VO(2) [8.2 (0.5)% and 2.6 (1.8)%]. Group differences were observed for percentage force loss during the electrical stimulation protocol [50.0 (3.4)% and 31.5 (3.7)% for groups P and E, respectively], increase in relaxation time from start to end of the fatigue test [87.9 (15.5)% and 31.1 (11.9)%], and relaxation time for fresh muscle [32.4 (1.0) ms and 40.6 (2.1) ms]. These contractile parameters may indicate a higher proportion of type II fibres in group P compared with group E. These experiments have shown evidence of a relationship between the amplitude of the slow component and muscle contractile properties, indicating that the origin of the slow component may lie in the pattern of different muscle fibre types.
- Subjects :
- Adult
Male
medicine.medical_specialty
Knee Joint
Physiology
Muscle Fibers, Skeletal
Stimulation
Physical exercise
Slow component
Oxygen Consumption
Physiology (medical)
Internal medicine
medicine
Humans
Orthopedics and Sports Medicine
Muscle, Skeletal
Exercise
Pulmonary Gas Exchange
Chemistry
Lactate threshold
Public Health, Environmental and Occupational Health
General Medicine
Anatomy
Oxygen uptake
Oxygen
Endocrinology
Amplitude
Component (group theory)
Fatiguability
Muscle Contraction
Sports
Subjects
Details
- ISSN :
- 14396327 and 14396319
- Volume :
- 91
- Database :
- OpenAIRE
- Journal :
- European Journal of Applied Physiology
- Accession number :
- edsair.doi.dedup.....692edf97cb51f7c7883b69e49dde6121