Analysis of the Rotational Degree of Hip of Classic Dancers

Abstract

Introduction: Among the various possible movements in the hip joint one of them is the external rotation of the femur in the socket of the acetabulum. A high degree of range of motion is required for the perfection of classical ballet lines, and this is one of the principles outlined in the technique that is specifically described in the dancer's vocabulary: the en dehors' hip skill is an important fundamental physical attribute in classical ballet.Objective: to evaluate the degree of external and internal rotation of the hip region in classical dancers and to determine if they have a greater range of internal and external rotational movement in this region, compared to normality parameters in a control group.Method: 60 female volunteers aged 12 to 25 years, divided into two groups: A -group practitioners: 30 young people who practiced classical ballet for at least 2 years and B -control group: 30 young sedentary women. It was used to measure the degree of amplitude of the internal and external hip joint of groups A and B, a universal 360 degrees' goniometer, metallic, in a total circle.Results: According to the data collected, there was no significant difference between the groups, however we can observe angular differences in both groups. In the comparison between the degrees of external rotation of both lower limbs (LL), group A presented a mean of 34.6° in the lower right limb (LRL) and 32.8° in the lower left limb (LLL). While group B presented an average of 31.3° of rotation in LRL and 31.3° of rotation in LLL. In the internal hip rotation of both LL, group A presented an average of 36.6° in LRL and 41° in LLL. While group B, presented an average of 36° rotation in LRL and 37.4° rotation in LLL.

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“…However, the dancers were closer to the maximum range of motion that is 45 degrees. 14,22 On the other hand, there are authors who report that the internal rotation of the hip has its degree between 0 -30/60 degrees. 24 The Classic Ballet is characterized by the constant search for aesthetic movement's patterns, i.e., movements of great joint amplitude that go beyond the anatomical limits.…”

“…7 The en dehors, which in French means the external rotation of the femur in the socket of the acetabulum, 9 should be performed only at the hip joint and be completed by the feet abduction. 13,14 The normal degree, adding up both sides is from 80 to 100 degrees. In dancers with their feet in 1st position en dehors (heels united and feet slightly turned outwards) they reach 180 degrees.…”

“…16 For some authors, the degree of internal hip rotation may have altered its graduation considerations being between 0 to 30degrees/60. 14 In addition, usually the dancers measure their external rotation observing the position of the feet on the ground. [...] "Often they will try to increase this rotation".…”

“…Being broader and nearly cylindrical, femoral bone heads are more widely separated in females and have a greater potential for range of motion than males. 14 In order to adequately measure the joint range of hip movement, it is necessary to follow adequate protocols and use the reference standards presented in the scientific literature. In addition, it is paramount to choose an equipment and/or technique that meets the needs of these protocols and is used correctly.…”