Hip and ankle range of motion and hip muscle strength in young novice female ballet dancers and controls

Objectives-To compare the hip and ankle range of motion and hip muscle stre ngth in 8-11 year old novice female ballet dancers and controls. Methods-Subjects were 77 dancers and 49 controls (mean (SD) age 9.6 (0.8) a nd 9.6 (0.7) years respectively). Supine right active hip external rotation (ER) and internal rotation (IR) were measured using an inclinometer. A tur nout protractor was used to assess standing active turnout range. The measu re of ER achieved from below the hip during turnout (non-hip ER) was calcul ated by subtracting hip ER range from turnout range, and hip ER:IR was deri ved by dividing ER range by IR range. Range of right weight bearing ankle d orsiflexion was measured in a standing lunge using two methods: the distanc e from the foot to the wall (in centimetres) and the angle of the shank to the vertical via an inclinometer (in degrees). Right calf muscle range was measured in weight bearing using an inclinometer. A manual muscle tester wa s used to assess right isometric hip flexor, internal rotator, external rot ator, abductor, and adductor strength. Results-Dancers had less ER (p<0.05) and IR (p<0.01) range than controls bu t greater ER:IR (p<0.01). Although there was no difference in turnout betwe en groups, the dancers had greater non-hip ER. Dancers had greater range of ankle dorsiflexion than controls, measured in both centimetres (p<0.01) an d degrees (p<0.05), but similar calf muscle range. After controlling for bo dy weight, controls had stronger hip muscles than dancers except for hip ab ductor strength which was similar. Regression analyses disclosed a moderate relation between turnout and hip ER (r = 0.40). There were no significant correlations between range of motion and training years and weekly training hours. Conclusions-Longitudinal follow up will assist in determining whether or no t hip and ankle range in young dancers is genetically fixed and unable to b e improved with further balletic training.