Muscle strength imbalance between hamstring and quadriceps among professional dancers

Abstract

ABSTRACT:The aim of this study was to evaluate the unilateral strength in knee flexion and extension, and the Hamstring/Quadriceps Ratio (H/Q Ratio), in dominant and non-dominant lower limbs in professional dancers. This was a cross-sectional study, carried out with 12 health adults (27.5±1.27years, 66.6±3.11kg, 173±0.02cm, 22.1±0.51kg/m 2 ), professional dancers of a national company. The volunteers, after physical measurements, were submitted to a 1 Repetition Maximum (1RM) test, unilaterally, in both lower limbs at Flexor and Extensor Bench seat exercises. After 1 week, a 1RM retest was carried out to confirm the real total load for each limb. The torque and H/Q Ratio were calculated unilaterally. In knee extension, the dominant limb presented strength 18.77% higher than nondominant limb (p<0.01), and in knee flexion, the strength of the dominant limb was 16.38% higher than the non-dominant limb (p=0.04). The H/Q Ratio was higher in the non-dominant limb 90.12 ± 0.22% than dominant limb 86. 36±0.37% (p=0.04). The results showed difference in the strength between dominant and non-dominant members in both movements, knee flexion and extension. The H/Q Ratio presented values that evidenced imbalance in lower limbs. The population of dancers under study presented risk for injuries in lower limbs, requiring a specific training intervention.

Body asymmetries as risk factors for musculoskeletal injuries in dancesport, hip-hop and ballet dancers?

“…The commonly used criterion of 10% for the presence of clinically relevant asymmetries was used. 26,27 To calculate the percentage of dancers with body asymmetries, the results were divided into five groups of functional asymmetries: maximum torque and rate of torque development (trunk, hip, knee and ankle dynamometry), stability (single leg stance test and unilateral landing), explosive muscle power (squat and countermovement jump) and RoM (hip, knee and ankle). Agonist/antagonist asymmetries were calculated as quotients (multiplied by 100): flexion/extension (trunk, knee and hip), dorsi/plantar flexion (ankle), abduction/adduction (hip), internal/external rotation (hip).…”

“…The commonly used criterion of 10% for the presence of clinically relevant asymmetries was used. 26 , 27 …”