Thesis - NSU Access Only
Master of Physical Therapy (MPT)
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College of Health Care Sciences - Physical Therapy Department
Publication Date / Copyright Date
Nova Southeastern University
Jonathan Di Gregorio. 1998. Muscle Imbalance in the Lower Leg and Lateral Ankle Instability in Adolescents. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, College of Health Care Sciences - Physical Therapy Department. (110)
Purpose: To establish normative data for muscle strength ratios in the lower leg among adolescent males ages 11-13 years.
Subjects: The subject sample consisted of 15 adolescent males from one little league baseball team from the Plantation Athletic League.
Methods: Subjects were evaluated for muscle strength in evertors/invertors, and plantarflexors/dorsiflexors of the ankle. Utilizing a Cybex 6000 isokinetic dynamometer, measurements were taken for one bout of three repetitions at 30 degrees/second, and two bouts of four repetitions at 120 degrees/second for each activity. Each subject performed a warm up bout consisting of three repetitions at 30 degrees/second for each activity to get familiar with the apparatus, and allow for maximum muscle output. They then rested for 30 seconds before beginning the measurement bouts. An additional 30 seconds of rest was permitted between each measurement bout. In total, four bouts were performed for each activity, with three actually being recorded.
Results: Data analysis reveals that on the average, the mean peak torque of invertors is approximately 25% higher than that of evertors, with the mean peak torque of plantarflexors being approximately 50% higher than dorsiflexors;
Conclusion: The results of this study have illustrated that adolescents exhibit muscle imbalance in the lower leg similar to adults, indicating that the implementation of preventative exercise programs may reduce the incidence of ankle sprains across the life span. Therefore, the argument may be made that if these programs are initiated during adolescence, health care cost pertaining to ankle injury may be reduced dramatically.