Evaluation of the Throwing Influence on Dominant and Nondominant Shoulder Kinesthesia in Throwing Athletes

Since joint kinesthesia is under the influence of glenohumeral joint capsule and range of motion, and significant capsular laxity and changed range of motion in throwing shoulder is determinant in their functional and dynamic stability; the objective of this study was to compare throwing influence on dominant and nondominant shoulder kinesthesia among volleyball, bowling players and nonathlete women before an injury. This non-experimental, cross sectional study included 45 women in 2 purpose groups of volleyball and bowling players and 1 nonathlete control group, with age range of 20 to 30 years old from the city of Tehran. Their shoulder kinesthesia was measured by Continuous Passive Motion device. For data analysis, descriptive statistic including mean, standard deviation, and for reliability analysis Correlation Coefficient, were performed. Kolmogorov-smirnov and Leven’s tests were performed for assessing the data normality and group variance equality. Chi-square test was used for comparing shoulder kinesthesia between dominant and nondominant sides and also for comparing between groups of volleyball, bowling players and nonathlete control group. Statistical significant was set at a level of p≤0.05. Kinesthesia error difference between dominant and nondominant shoulders in all three groups, were not statistically significant (p=0.33). Also, No significant difference was found in comparing shoulder in each group with the same sides of other group (p=0.21 nonathlete and volleyball, p=0.19 nonathlete and bowling, p=0.63 volleyball and bowling). Capsular laxity and changed range of motion in dominant shoulder, probably with produce microtruma, have negative influence on kinesthesia. However, on the other hand repetitive circumduction motions in dominant shoulder cause perceptual learning, therefore, probably has a positive influence on increasing accuracy in signal analyze and improve kinesthesia, hence, counteract the negative influence of capsular laxity and changed range of motion on kinesthesia. Probably, repetitive circumduction motions in rehabilitation can also reciprocate the influence of microtruma that cause stability disorder and pain in dominant shoulder by neuromuscular adaptations and it may not related to the kind of overarm or underarm rotation.