Feedback and maximum voluntary contraction

Abstract
The results of maximum voluntary contraction (MVC) studies have been criticized on grounds of reliability and validity. The amount and form of feedback given to the subject is a factor that is likely to affect the results. An experiment was performed using the CYBEX dynamometer to measure the MVC of isometric quadriceps activity with different forms of feedback. The effect of auditory encouragement coupled with direction of the subjects' attention to concurrent visual information about their achievement resulted in a significant increase of approximately 10% over the no-feedback condition. These findings have clear implications for the conduct of MVC studies for job design and selection purposes and for the way in which physiotherapists and athletic trainers provide feedback to their clients.