1. Twenty-five minute daily muscle stretching, perpendicular to the fibre direction of the adductor muscles without movement of the hip, was performed in patients with osteoarthritis of the hip.
2. Before and after treatment hip abduction was measured and muscle biopsies were taken for analysis of fibre cross-sectional areas of type 1 and type 2 fibres as well as adenosine 5′-triphosphate, creatine phosphate and glycogen contents.
3. From the results it is concluded that passive muscle stretching leads to a significant increase in hip abduction of 8.3° (P < 0.05). There was also a significant increase of type 1 and type 2 fibre cross-sectional area and of glycogen content after the treatment period (P < 0.05), but the concentrations of adenosine 5′-triphosphate and creatine phosphate did not change significantly.