Lower Extremity Kinetic Demands During Dance Leap Takeoffs and Landings

Abstract

Participation in dance requires performance of different types of skills requiring artistry and athleticism, including frequent jumping and leaping tasks. High demands are placed on the lower extremity joints during jumping tasks; foot and ankle injuries are often associated with jump takeoffs, while jump landings are thought to contribute more to knee injuries. However, little research has focused on the specific demands that jumping places on lower extremity joints during different phases within the same jump. PURPOSE: to compare biomechanical demands placed on the lower extremity joints during the takeoff and landing phases of saut de chat leaps METHODS: Six (age= 27.4±1.3 years; weight= 58.9±7.8 kg; height= 1.6±0.1 m) healthy, experienced dancers with an average 22.6±2.1 years of dance training performed 5 saut de chat leaps; these leaps involve taking off from one leg, quickly rotating the legs in opposite directions toward a 180° split position in the air, and landing on the opposite leg. A three-dimensional motion analysis system and force plates were used to collect kinematic and kinetic data. Ground reaction force (GRF) impulse and sagittal plane kinematics and kinetics of the hip, knee, ankle, and metatarsophalangeal (MTP) joints were calculated for the takeoff and landing phases of each leap. GRF impulse and net joint moments were compared between takeoff and landing using paired t-tests. RESULTS: Saut de chat takeoffs demonstrated greater braking (posterior) GRF impulse (+.67 N/kg*s p=.002), while landings demonstrated greater vertical GRF impulse (+5.58 N/kg*s p=.038). During takeoff, greater kinetic demands were placed on the MTP (+.18 N/kg p=.038) and ankle (+.49 N/kg p=.004) joints, while during landing greater kinetic demands were placed on the knee (+.56 N/kg p=.04) and hip (+.81 N/kg p=.039) joints. CONCLUSIONS: Both takeoff and landing phases of saut de chat leaps place significant demands on a dancer’s body. Takeoff involves greater demands on the more distal joints and requires more braking forces, while the landing phase involves greater demands on the more proximal joints of the lower extremity and requires the dancer to absorb more vertical force. These demands, combined with extensive repetition of movements during training, may contribute to the high number of chronic injuries seen in dance.