The measurement characteristics of upper-quarter posture in female adolescents : a comparison between competitive freestyle swimmers and non-swimmers

Abstract

BACKGROUND & AIM : Upper-quarter postural changes and their associated injury is a growing concern in female adolescent competitive swimmers. Postural changes in female adolescent competitive freestyle swimmers is hypothesized to develop because of high training loads, physiological and mechanical demands of freestyle swimming and its associated intrinsic and extrinsic risk factors. Studies comparing upper-quarter postural changes between highly competitive adolescent swimmers to adolescent non-swimmers have not been conducted. Therefore, the aim of this was to prospectively identify the incidence of upper-quarter postural differences in female adolescent competitive freestyle swimmers, by comparing their upper-quarter postural measurement characteristics to the upper-quarter postural measurement characteristics of female adolescent non-swimmers. METHODS : A total of 116 female adolescents were recruited for this study. Overall, 71 participants (35 evaluation group; 36 control group, mean age = 15±3 yrs) complied with the inclusion criteria. Cervical and shoulder range of motion, dynamic stability through the Y-Balance test, photographic postural analysis, and shoulder and scapular muscular strength measures were conducted on both groups. A prospective observational and comparative cross-sectional study design was used. Data was analysed using the STATA 13 software application. Quantitative data collected were subjected to descriptive and inferential statistics. The One-way ANOVA was performed using the Kruskal-Wallis test for non-parametric data for more than 2 groups or the Mann-Whitney test when 2 groups were compared. The Wilcoxon signed rank test was used to gauge differences within groups. Statistical significance was determined by P-value equal to or less than 0.05. RESULTS : Analysis showed significant differences (p≥0.05) between the EVAL and CON groups for all variables measured, except for cervical lateral flexion. When comparing the difference between groups, the EVAL group achieved lower mean scores for range of motion measures in horizontal shoulder adduction, shoulder flexion, -extension, and –internal rotation, and cervical forward flexion. Additionally, the EVAL group scored lower mean values for static upper-quarter cervical angle, protraction and retraction angle; and muscular strength measures in shoulder extension and scapular retraction, than the CON group. The EVAL group achieved higher mean scores for range of motion measures in shoulder abduction, -external rotation, cervical extension, -lateral flexion, and –lateral rotation; the mean absolute value for the Y-balance test; static upper-quarter head tilt and thoracic angles; and muscular strength measures in shoulder flexion; -external rotation; -internal rotation; -abduction; and –adduction, scapular elevation, -depression, and –protraction measures, than the CON group. Furthermore, the mean scores attained by the EVAL group for horizontal shoulder adduction (right & left = 10 deg, difference), shoulder internal rotation (right = 8 deg & left = 9 deg, difference), -extension (right = 8 deg & left = 9 deg, difference), and –flexion (right & left = 23 deg, difference) range of motion and static upper-quarter head tilt, cervical, and thoracic angles, deviated from the normative values. CONCLUSION : The significant differences in the upper-quarter characteristics noted between the EVAL and CON groups indicate that the female adolescent competitive freestyle swimmers were at greater risk of attaining a forward head – rounded shoulder posture. Subsequently, a number of the EVAL group’s measures deviated from the norm, therefore leading to the presumption that they were also at risk of injury and pain associated with the forward head – rounded shoulder posture. The results propose that the extrinsic risk factors associated with competitive swimming, may have had an influence on the upper-quarter posture of the female adolescent competitive freestyle swimmers of this study. These findings highlight the interplay between the intrinsic - and extrinsic risk factors of swimming. It is, therefore, recommended that sport scientists and coaches screen for postural changes and implement preventative strength and conditioning training sessions for their female adolescent competitive freestyle swimmers. Moreover, future research should aim at investigating the influence of the extrinsic risk factors on upper-quarter posture of both male and female adolescent competitive swimmers.