The association between static biomechanical parameters and musculoskeletal injury in lower extremities in male recreational weight trainers

Abstract

Background: Anatomical alignment of the lower extremity has been proposed as a risk factor for acute and chronic lower extremity injuries such as ACL injuries, patellofemoral syndrome, and plantar fasciitis. Lower extremity malalignment influences the load distribution on the joints, mechanical efficiency of the muscles and proprioceptive orientation and feedback from the hip and knee, resulting in altered neuromuscular function and control of the lower extremities. During recreational weight training, the weight trainer performs exercises with gradual load on machines or free weights, aimed to improve their muscular condition, fitness, power, or performance in other sports. The weight trainer uses his own bodyweight or specialised forms of equipment such as barbells, dumbbells and resistance training machines to target specific muscle groups and to perform specific joint actions. Various intrinsic and extrinsic factors contribute to injury. Anatomical alignment – amongst others - is regarded as an intrinsic factor. Studies state that suggested risk factors for injuries include heavy loads in extreme joint positions, training frequency, intensity, volume, muscle strength, stability and foot morphology. Several studies have examined musculoskeletal injuries in specific weight training populations such as powerlifters, weightlifters and bodybuilders. Very few studies have investigated the recreational weight training population. The purpose of this study is to identify whether associations exist between the relevant biomechanical parameters and injury, to prevent or correct these abnormalities. Objectives: This study aimed to establish lower extremity static biomechanical parameters of the hip (flexion, extension and Craig’s test), knee (quadriceps angle and tibial torsion test), ankle (dorsiflexion, Feiss line, hindfoot, and forefoot alignment) and leg length discrepancy, and to establish if an association exists between the above- mentioned parameters and musculoskeletal injuries in the lower extremities in male recreational weight trainers. Method: 30 Male recreational weight trainers were recruited from fitness centres within the greater Durban area to the DUT Chiropractic clinic, where the assessment took place. Each participant was assessed for injury and static biomechanical measurements were taken. The statistical analysis was performed using Stata version 16. For normally distributed continuous variable the mean and 95% CI was done. Shapiro Wilk test was used to test for normality. For not normally distributed variables, median and interquartile range was performed. 15 participants were diagnosed as injured and 15 participants as uninjured. As the sample size of this study is small, Fisher’s exact test was used to evaluate the association between two categorical variables. Results: The statistical analysis was performed using Stata version 16. For normally distributed continuous variables the mean and 95% CI were done and Shapiro Wilk test was used to test for normality. For not normally distributed variables, median and interquartile range were performed. As the sample size of this study is small, Fisher’s exact test was used to test the association between two categorical variables. Prevalence of injury was thus 50%. In the injured population, 46.67% were acute and chronic injuries. 16.67% of injuries were traumatic and 33.3% were non-traumatic. Fisher’s exact test was used to see the association between biomechanical measurement and existence of injury. Accordingly, Fisher’s exact test with p-value 0.036 indicated that there was enough evidence of association between right quadriceps angle and injury. The injured participants were more likely to have a low right quadriceps angle. However, the rest of the biomechanical measurements have no association with injury Conclusion: The injured participants were more likely to have a low right quadriceps angle. The rest of the biomechanical measurements have no association with injury.