The Relationship Between A New Test Of Trunk Control To Cutting Mechanics

Abstract

Poor neuromuscular control of the trunk in laboratory studies has been identified as a significant risk factor for lower extremity injuries in females. To date few clinical tests have been developed that capture trunk control which have been compared to trunk and lower extremity control. Establishing the relationship between multidirectional trunk control and lower extremity control during a cutting task would serve as the first step in establishing a measure to identify females at risk for injury in a clinical setting. PURPOSE: To determine the association between a new seated trunk test and trunk and lower extremity kinematics during an unanticipated cutting task. METHODS:8 female subjects (20.9± 1.6 ages, 20.6 ± 2.0 BMI) with no prior lower extremity injuries performed an instrumented three dimensional assessment of an unanticipated cutting task. Visual 3D was used to analyze frontal plane trunk, hip, and knee kinematics at initial contact (IC). Subjects were asked to sit on a wobble board placed on a solid surface on a plinth with their feet approximately 0.1 m off the ground with their eyes closed. Errors were counted and averaged during the two 30 second trials. Errors included uncrossing the arms, opening eyes, or if the wobble board touched the plinth. Pearson Product Moment Correlations were calculated between kinematics at IC and the mean number of trunk errors. RESULTS: Mean frontal plane angles were trunk -1.1±1.8°, hip, -4.7±3.5°, knee 2.9±4.1° and the numbers of trunk errors were 1.7±1.5. A significant relationship was observed with errors and hip adduction (r=0.84, p=0.009). Significant associations were not observed at the trunk (r=0.23, p=0.578) and knee (r=-0.59, p=0.126). CONCLUSIONS: There was a significant relationship between greater hip adduction which is associated with numerous injuries to the errors on the seated trunk test. While not significant the relationship to the frontal plane knee motion did have a high r value indicating a strong relationship that may become significant with additional subjects. The lack of relationship to trunk mechanics could be due to a greater contribution of trunk rotation than frontal plane motion during cutting from the trunk. Future analysis will further assess this possibility.