QUANTIFICATION AND COMPARISON OF ECCENTRIC AND CONCENTRIC MUSCLE ACTIVITY OF THE LOWER LEG MUSCLES DURING UNCHALLENGING TYPES OF LEVEL AND DOWNHILL WALKING

Muscle force production and adaptation are influenced by a range of factors but important to these are the length, and rate of change of length, of the active fibres involved in the activity (Rassierand Pun, 2010; Rassier and Herzog, 2002). When fibres are extended - usually by an external joint moment caused by a ground reaction force -the activity is termed eccentric. Similarly, when the muscles are shortening the activity is termed concentric.