Effect of musculoskeletal disorders on prehension strength

The purpose of this study was to compare the maximum and job simulated hand grip strength in both healthy workers and those suffering from mild and severe stages of musculoskeletal disorders. Three groups of 10 female industrial workers each were recruited after a detailed screening for musculoskeletal disorders: one group of 10 healthy workers (GI) and two other groups (GII and GIII) consisting of workers suffering from mild and severe upper limbs disorders, respectively. A special device was built to reproduce a similar prehension pattern (open palmar) to that used on the job. This was calibrated against a Jamar dynamometer. Job simulated and maximum prehension strength were tested in three consecutive trials. Pearson's correlation coefficient was calculated for the calibration procedure. Descriptive analysis of the musculoskeletal data was computed. ANOVA and Duncan post hoc multiple comparisons were conducted to test the main effects on muscular strength and interactions. Significant differences between types of strength (p<0.00001) and groups of subject (p<0.0001) were identified. The maximum strength decreased progressively from groups I to III. Although job simulated strength also decreased as disorder severity increased, this trend was weaker than the one observed for the maximum strength. These results suggest that a re-allocation of workers suffering from musculoskeletal disorders be considered.