Measuring and managing pain and performance.
Pain and movement dysfunction are invariant sensory and motor expressions of health disorders. They are also complex, inter-related problems and may be accompanied by fatigue and depressed mood. Optimum management is predicated on the appropriate selection, application and interpretation of assessment measures. Research on pain and physical function using physical performance tests has shown that regardless of whether pain and impairment is a consequence of musculo-skeletal injury or systemic disease such as cancers, pain-free individuals outperform those with pain in terms of movement speed and endurance ability across a variety of performance tests (e.g. walk and reach tests, and repeated sit-to-stand and trunk flexion tests). Slow movements are characterized by fractionated and extraneous movement patterns. They are also associated with a relatively high level of muscle activity (amplitude and duration) throughout the task compared to fast movements. Slow movements are also relatively inefficient in terms of physiological energy and time burden. For a similar level of effort, individuals with pain are able to perform significantly less work. Our research has shown that individuals with pain move slower across a range of self-selected movement speeds i.e. slow, preferred and fast speeds. It is also apparent that patients systematically over estimate expected pain during task performance at faster speeds. Preliminary work using speed targeted treatment shows promise in terms of improving physical performance and reducing the burden of illness and physical dysfunction.