Relationship between the shortening of the posterior muscle chain and the forward shift of the head and shoulder in female athletes from the youth category

Abstract

The aim of the present study was to analyze the relationship between the shortening of the posterior muscle chain, mainly the hamstrings and the forward shift of the head and shoulder, as a possible adaptation in high level/performance athletes. The sample involved 59 female athletes from the youth category of different sports modalities. Group 1: 35 athletes with significant hamstrings’ shortening evaluated by the “bear’s position”; Control group: 24 athletes without hamstrings’ shortening, evaluated by the same position. Data collection was performed using digital analysis of pictures taken with the athlete standing (lateral vision) in the “bear’s position”. Luminous markers were placed in the temporomandibular joint, lateral region of the acromio, femur great trochanter, external femoral condyle and lateral malleolus. Variables were measured by the computerized angular cinematic analysis, using the software for posture evaluation SAPO, 0.68 version, always performed by the same rater. Statistical analysis was performed with the Shapiro Wilk test, Unpaired t test and Pearson’s correlation coefficient. The level of significance was set at p?0.05. Group 1 showed 2.5 degrees (SD=1,12) of forward inclination in the lateral view and 43.15 degrees (SD=9,41) of knee flexion in the “bear’s position”. In group 2, there was 2.77 (DP=1.02) degrees in the lateral analysis and -2.19 (DP=4.05) degrees in the “bear’s position”. The statistical analysis between the two groups showed p=0.50 for the comparison of the anterior trunk imbalance in the lateral view and p=0,00 for the comparison of the “bear’s position”. The correlation analysis between the anterior trunk imbalance and the posterior muscle chain shortening, emphasizing the hamstrings, showed r=0.04 in the group with posterior chain shortening and r=0.1 in the control group. It can be concluded that the hamstrings’ muscle shortening did not show any relation with the forward shift of the head and shoulder. On the other hand, in the group with greater flexibility of the muscles from the posterior chain, a greater forward shift of the head and shoulder was observed, without significant results.