title: Endurance exercise effects on the contractile properties of single, skinned skeletal muscle fibres of young rats.
abstract: 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.
authors.affiliation: Department of Physiology, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: G S
authors.initials: GS
authors.lastname: Lynch
authors.forename: D G
authors.initials: DG
authors.lastname: Stephenson
authors.forename: D A
authors.initials: DA
authors.lastname: Williams
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D046508:Culture Techniques; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000033:anatomy & histology* / Q000502:physiology; D010805:Physical Conditioning, Animal; D010807:Physical Endurance; D051381:Rats; D011919:Rats, Inbred Strains; D013324:Strontium / Q000494:pharmacology; D013550:Swimming
chemical_list: D002118:Calcium; D013324:Strontium