Muscle Typology of World-Class Cyclists across Various Disciplines and Events

Abstract

Purpose: Classical track-and-field studies demonstrated that elite endurance athletes exhibit a slow muscle typology, while elite sprint athletes have a predominant fast muscle typology. In elite cycling, conclusive data on muscle typology are scarce, which may be due to the invasive nature of muscle biopsies. The non-invasive estimation of muscle typology through the measurement of muscle carnosine enabled to explore the muscle typology of 80 world-class cyclists of different disciplines. Methods: The muscle carnosine content of 80 cyclists (4 bicycle motor cross racing (BMX), 33 track, 8 cyclo-cross, 24 road and 11 mountain bike) was measured in the soleus and gastrocnemius by proton magnetic resonance spectroscopy and expressed as a z-score relative to a reference population. Track cyclists were divided into track sprint and endurance cyclists based on their UCI-ranking. Moreover, road cyclists were further characterized based on the percentage of UCI points earned during either single- and multi-stage races. Results: BMX cyclists (carnosine aggregate z-score of 1.33) are characterized by a faster muscle typology than track, cyclo-cross, road and mountain bike cyclists (carnosine aggregate z-score of –0.08, -0.76, -0.96 and –1.02, respectively: P<0.05). Track cyclists also possess a faster muscle typology compared to mountain bikers (P=0.033) and road cyclists (P=0.005). Moreover, track sprinters show a significant faster muscle typology (carnosine aggregate z-score of 0.87) compared to track endurance cyclists (carnosine aggregate z-score of -0.44) (P<0.001). In road cyclists, the higher the carnosine aggregate z-score, the higher the percentage of UCI points gained during single-stage races (r=0.517, P=0.010). Conclusions: Prominent differences in the non-invasively determined muscle typology exist between elite cyclists of various disciplines, which opens opportunities for application in talent orientation and transfer.