Adaptation of muscle mechanical properties as a result of training.

Objectives - The aim of this review is to present the mechanical properties of muscle and examine their modifications when training programmes are performed. Topics - These adaptations are presented using a three component model of muscle in which mechanical properties are analysed in terms of behaviour of a contractile component associated with two elastic components. Concerning the contractile component, a force-length relationship and a force-velocity relationship are presented with special reference to specificity of gains in force. Difficulties of interpretation, in terms of muscle, of results from movement analysis are underlined. Concerning the elastic components (in parallel and in series), their tension-extension characteristics are modified by training. Conclusions - The fact that, as a result of training, a fibre type transition phenomenon is associated with changes in muscle stiffness is emphasized. These results are discussed in terms of improvement in muscle efficiency. (C) 2001 Editions scientifiques et medicales Elsevier SAS.