Endurance exercise effects on the contractile properties of single, skinned skeletal muscle fibres of young rats

✍ Scribed by Gordon S. Lynch; D.George Stephenson; David A. Williams

• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 735 KB
• Volume: 418
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00370466

✦ Synopsis

Single fibres were isolated from the extensor digitorum longus (EDL) and the soleus (SOL) muscles of the hindlimb from young male Wistar rats which had undergone a 10-week programme of endurance swimming from the age of 2 weeks. Fibres were mechanically skinned and activated with Ca(2+)- and Sr(2+)-buffered solutions. Muscle fibres were classified by means of well-defined criteria concerning various aspects of their contractile behaviour. Most fibres could be allocated into specific groups; however, a significant proportion (13% of the sampled population) did not fit these rigid classifications but displayed contractile activation characteristics common to more than one fibre type. In these cases models which used a combination of both fast- and slow-twitch contractile and regulatory properties were used to characterise the activation behaviour of fibres. It is proposed that the exercise, initiated at a young age, induced changes in the contractile characteristics of the single fibres by modifying protein isoforms of the contractile apparatus.