COMPARATIVE STUDY OF ISOKINETIC DYNAMOMETRY AND THE STANDING HEEL-RISE TEST FOR ASSESSING ANKLE PLANTAR FLEXION STRENGTH. Julie A. Coplan*; Roland Starr; Kathy Brucker; Cindy Schreiber; Anil Bhave; Scott Tennis; Michele Nickey; Trisha Grifffith Rubin Institute PT, Sinai Hospital, Baltimore, MD PURPOSE: The purpose of this study was improve physical therapy evaluation techniques for addressing ankle function. The study compared two methods of testing ankle plantar flexion strength; 1) Isokinetic Dynamometer Biodex 3 System, 2)the Perry Standing Heel-Raise Test. The results of the two tests were compared. Normative data as it relates to age and gender was also collected for the two tests. BACKGROUNDS/SIGNIFICANCE: The plantar flexor muscles are very important in everyday activities, such as standing,walking, running and jumping. Manual muscle testing is the current clinical standard used to assess strength of most muscle groups. This method has been shown to be insensitive in detecting mild weakness of the plantar flexors when compared to more sensitive measures of strength such as isokinetic dynamometry. This study collected normative isokinetic dynamometry data for plantar flexor strength, and looked for correlations between the SHRT and isokinetic dynamometry strength tests. The results will be used to improve the reliability and validity of physical therapy evaluation techniques when addressing ankle function and gait. SUBJECTS: All subjects were normal with no significant history of lower extremity injury or problems. The study included 28 subjects age 22-69 years of age with the mean age of 38 years. Fourteen subjects were younger than 35 years of age and 14 subjects were 35 years of age or over. There were 17 female and 11 male subjects. METHODS AND MATERIALS: The subject's dominant limb was tested on the Biodex System 3 to gather data on their plantar flexion peak torque and peak torque per body weight output. A set protocol for measurement testing of the plantar flexor strength on the Biodex, and then re-testing after five minutes of rest, was strictly followed. The subject then performed the Perry Standing Heel-Raise Test to measure the maximum number of heel-raises the subject could perform. A maximun number of 50 heel- raises was allowed to prevent overstrain of the plantar flexor muscles. ANALYSES: Comparisons were made between the measured variables using Statview v5.0.1 (SAS Institute Inc., Cary, NC). The variables considered were the peak torque per body weight for the initial test measured using the Biodex system (Biodex Medical, Shirley New York), the peak torque per body weight for the retest as measured from the Biodex system five minutes after the first test, and the number of heel raises the subject could perform after a rest period, using the previously tested limb. Two factors were considered. The first factor was age, with two levels for age used. The first level (group) was anyone younger than thirty-five years old, the second level (group) was anyone thirty-five or older. The second factor was gender, with male and female the two levels (groups). A paired t-test was performed, between the second measured peak torque per body weight and the first measured peak torque per body weight. Based on the results, the second peak torque per body weight was used in the further analyses. An ANOVA was performed on the second peak torque per body weight with age and gender as factors. A second ANOVA was performed on the number of heel raises with age and gender as factors. A simple linear regression was performed with heel raises as the independent variable and peak torque per body weight as the dependent variable. RESULTS: The paired t-test between the second measured peak torque per body weight and the first measured peak torque per body weight showed a significant difference between the groups ( p<0.0001), with the second test yielding a higher result, indicating a learning curve in the testing procedure. The ANOVA on the second peak torque per body weight with age and gender as factors show that there was a significant difference at the 5% significance level between males and females with males producing a higher peak torque per body weight and also between younger and older subjects, with the younger subjects producing a higher peak torque per body weight. The second ANOVA on the number of heel raises performed with age and gender as factors showed no significant difference between age groups (p = 0.906), but there was a statistical difference between the genders (p = 0.015), with males performing more than the females. The simple linear regression between the peak torque per body weight and the number of heel raises showed that there was no correlation between the two variables (R2 = 0.162). CONCLUSIONS: Based on the results in our normal subjects we found no correlation in Perry's Standing Heel-Rise Test and the results of the Biodex peak torque per body weight test. There was statistical and significant evidence of increased peak torque in men compared to women and younger subjects compared to older subjects when normalized for body weight. There was a significant difference between the first and second Biodex test of plantar flexion peak torque with the second test being greater than the first test indicating a learning curve in the testing procedure. FUNDING SOURCE: None KEYWORDS: manual muscle testing, plantar flexor strength, isokinetic dynamometry, standing heel rise test, Biodex plantar flexion strength test T-test between second peak torque per body weight and first peak torque per body weight ANOVA on peak torque per body weight with Age and Gender as factors ANOVA on number of heel raises with Age and Gender as factors Copyright 2009 by the American Physical Therapy Association. Requests for reprints should be directed to the corresponding author of the article. Educators, students, and other academic customers may receive permission to reprint copyrighted material from Physical Therapy (ISSN 1538-6724) by contacting the Copyright Clearance Center Inc, 222 Rosewood Dr, Danvers, MA 01923. 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