Metabolic enzyme activity patterns in muscle biopsy samples in different athletes

Summary

Citrate synthase (CS) and aldolase (ALD) activities and muscle fiber composition were compared in the muscles of high jumpers, sprinters, race walkers, middle distance runners and untrained men. Muscle biopsy samples were taken from vastus lateralis (VL) and gastrocnemius (G) in each group. Oxidative enzyme activity (CS, IU×g⁻¹ ww) was highest (24.64 and 15.0 in G and VL, respectively) in endurance-trained top race walkers, followed in order by the middle distance runners (G: 17.28, VL: 12.29), untrained controls (G: 11.17, VL: 8.10) and the high jumpers (G: 11.51, VL: 8.89). All athletes performing intense endurance exercise with the leg musculature displayed 30 to 60% higher CS activity and 20 to 40% higher ST% in G than in VL. Glycolytic enzyme activity (ALD∼28 IU · g⁻¹ ww) was highest in both muscles in the sprinters, followed by the high jumpers (23 IU · g⁻¹ ww). Novice runners had 30 to 50% lower ALD and CS activity than experienced sportsmen. The differences arise not only from age, but also from the periods of regular exercise and adaptation to training in elite sportsmen.

It was concluded that the more intensive the sporting activity of a muscle, the higher its enzyme activity (as with oxidative or glycolytic metabolism). The correlations between fiber composition and enzyme activities differed in VL and G in the same sportsmen. Thus, the degree of adaptation due to training also differed.