Thigh girth is often used as an indicator of muscle hypertrophy or atrophy during the rehabilitation process following knee surgery. The measurement of thigh girth, using a conventional plastic tape measure, in an attempt to detect muscle hypertrophy or atrophy may be misleading. It is an inaccurate measure of thigh muscle bulk. Although the sample size is small, the results show that measurements are heavily biased by the expectations of observers, with the result that a considerable change in thigh girth is likely to be ignored.
Eric Maylia, Leonard D.M. Nokes, and Michael D. Jones are with the Medical Engineering Research Unit, Cardiff School of Engineering, University of Wales Cardiff, P.O. Box 917, Cardiff, Wales, CF2 1XH, UK. John A. Fairclough is with the Department of Orthopaedics and Trauma, Cardiff Royal Infirmary, Cardiff, Wales, CF2 1XH, UK.