Effect of different visual feedback conditions on maximal grip-strength assessment

Grip strength was assessed using the Grip-ball dynamometer for twenty-one subjects (11 men and 10 women). Five different verbal feedback conditions were tested: no visual feedback (NVF), non-quantified visual feedback (IVF), accurate visual feedback (CVF), and both over-estimated (OVF) and under-estimated (OVF) visual feedback. In the latter three conditions, subjects were presented with a target force to strive for. Significantly greater grip strength was observed for the CVF condition in comparison with the NVF and IVF conditions (6% increase for both comparisons, p<0.05). No other significant differences were observed. The magnitude of the differences suggests that visual feedback could be of clinical relevance when maximal grip strength testing is performed.