Doctor of Philosophy (PhD) in Physical Therapy
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College of Health Care Sciences - Physical Therapy Department
Cheng, M. Samuel
Publication Date / Copyright Date
Nova Southeastern University
Steven Marc Jackson. 2015. Investigation of relationships between physical characteristics of recreational runners and lower extremity injuries. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, College of Health Care Sciences - Physical Therapy Department. (55)
Purpose: The purpose of this study was to investigate the relationship between anthropometric measurements, proximal and distal lower extremity muscle performance, core muscle endurance, lower extremity flexibility, and neuromuscular control with the incidence of injury in recreational runners over one season. Also, when a relationship was established, we sought to evaluate the predictive validity for any of the variables being investigated for risk of injury in this population. Study Design: Prospective cohort Methods: Anthropometric measurements, proximal and distal isometric lower extremity muscle performance, isometric core muscle endurance, lower extremity flexibility and neuromuscular control were measured in 75 recreational runners prior to the start of a graded marathon training program. Incidence of injury was tracked over the course of 18 weeks, May 2014 – October 2014. Data was analyzed comparing the differences between injured and non-injured groups. Results: There were 33 repetitive stress injuries yielding a gross injury rate of 46% (male n=13, female n=20). Of all the variables analyzed, 5 variables emerged as possible a predictors including age, dominant limb rear foot posture, non dominant limb ankle DF ROM (extended), limb difference of Y balance scale composite scores and limb difference in the 6 M hop test. These variables were entered into a binary logistic regression analysis. Results of the regression indicated only the composite Y balance score difference variable as yielding a significant contribution (p = 0.01), with and predictive validity, (OR = 1.46, 95% CI =1.127 – 1.892). The model predicted 69.2% of the injuries with a specificity of 82% and sensitivity of 54.5%. A cutoff point of 3.6% was determined using a receiver operating characteristic curve. Runners were 3 times more likely to get injured with an asymmetry ≥ 3.6%. Conclusions: An asymmetry of lower extremity neuromuscular control ≥ 3.6% measured by the Y balance scale has been identified as a potential risk factor for injury in recreational runners. Clinical Relevance: This test can be performed as part of a pre-training screening or physical and may be helpful in identifying recreational runners at risk for injury.