Validation of a Musculoskeletal Model of Lifting and its Application for Biomechanical Evaluation of Lifting Techniques

Background: Strategies of lifting, including stance width and techniques have significant effects on spine loading and stability. Previous studies examined the influence of them on muscular and postural response. However it is not clear how the impact of stance width on human musculoskeletal might vary according to the chosen lifting technique, so we verified this in our study. Methods: The present biomechanical study was carried out in 2011. In this study, a whole body musculoskeletal model of lifting was built and validated by experimental data in order to evaluate stance width conditions impact on muscle activation patterns and spine loading during each lifting techniques. Narrow, normal and wide stance conditions were investigated in squat, stoop and semi-squat lifting techniques. Results: The model muscleʹs activities were validated by comparing with the experimental muscle activities which resulted in Pearsonʹs coefficients of greater than 0.8. Results indicate significant effect of stance width on muscle activities and joint forces of lower extremity which is dependent on the used lifting techniques. For instance, the anterior posterior force of knee has been affected by stand width in squat more than stoop. Conclusions: Stance width conditions in each lifting technique exhibit positive and negative aspects and therefore, neither of them can be recommended as the as the perfect technique in terms of biomechanical parameters