Isokinetic ankle eversion and inversion strength profiling of female ballet dancers

Ankle injuries are highly prevalent in ballet, with strength highlighted as a primary risk factor. To profile ankle strength, fourteen female ballet dancers (age: 19.29 +/- 1.59 years) completed an isokinetic testing protocol comprising concentric eversion (CONEV) and inversion (CONINV), and, eccentric inversion (ECCINV) trials at four angular velocities (30 degrees center dot s(-1), 60 degrees center dot s(-1), 90 degrees center dot s(-1), 120 degrees center dot s(-1)) for both the dominant and non-dominant limb. In addition to Peak Torque (PT) and the corresponding Dynamic Control Ratios (DCRs), angle-specific derivatives of strength (AST) and Functional Range (FR) were calculated. There was no evidence of any significant bilateral strength asymmetry (p = 0.90) across all metrics, and no significant interactions with limb and contraction mode or velocity. A significant main effect for contraction mode (p = 0.001) highlighted greater ECC(INV)strength - which was maintained with increasing isokinetic velocity - in contrast to reductions in CON(EV)and CON(INV)strength. Specifically, dancers are ECC(INV)dominant at angular velocities greater than 60 degrees center dot s(-1), which is likely to be characteristic of most functional tasks. The lack of bilateral asymmetry may be attributed to dance training interventions that facilitate bilateral development, but ipsilateral mode and velocity-specific asymmetries have implications for injury risk and the training needs of female ballet dancers.

Automated summary

Ankle strength asymmetry was not significant in ballet dancers, but ipsilateral mode and velocity-specific asymmetries may have implications for injury risk and training needs.