ISSN:
1439-6327
Keywords:
Fiber type composition
;
Capillary density
;
Enzyme activities
;
Aerobic power and capacity
;
Muscle strength
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary This study describes the influence of muscle fiber type composition, enzyme activities and capillary supply on muscle strength, local muscle endurance or aerobic power and capacity. Muscle biopsies were obtained from m. vastus lateralis in thirteen physically active men. Histochemical staining procedures were applied to assess the percentage of fast twitch (FT) fibers, muscle fiber area, and capillary density. Also, the activity of citrate synthase (CS), creatine kinase (CK), hexokinase (HK), lactate dehydrogenase (LDH), and phosphofructokinase (PFK) were analysed using fluorometrical assays. Peak torque at ‘low’ and ‘high’ angular velocities was measured during leg extension. Similarly, muscle fatigue (e. g. peak torque decline) and recovery from a short-term exercise task were measured during maximal, voluntary consecutive leg extensions. Aerobic power ( $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ ) and aerobic capacity (e.g. onset of blood lactate concentration; OBLA), as defined by a blood lactate concentration of 4 mol · l−1 were measured during cycling. Peak torque at a high angular velocity was positively correlated with % FT area (p〈0.001). Fatigue and recovery were correlated with LDH · CS−1 (p〈0.001). WOBLA was best correlated with PFK and PFK · CS−1 (p〈0.001). Hence, muscle strength was partly determined by fiber type composition whereas local muscle endurance, recovery and aerobic capacity reflect mainly capillary supply and the activity of key enzymes involved in aerobic and anaerobic metabolism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00426139
Permalink
