title: The effect of sprung (suspended) floors on leg stiffness during grand jeté landings in ballet.
abstract: This study compared stiffness of the landing leg in ballet dancers performing grand jeté on a sprung floor to leg stiffness during the same movement on a hard floor (wood on concrete). Leg stiffness was calculated as the ratio of vertical ground reaction force (in Newtons) to  compression of the lower limb (in meters). Thirteen female dancers were measured for five repetitions each at the point of maximum leg compression while landing grand jeté on both of the surfaces, such that 20 milliseconds of data were represented for each trial. The stiffness of the  landing leg at the point of maximum compression was decreased by a mean difference score of 6168.0 N/m ± 11,519.5 N/m on the hard floor compared to the sprung floor. Paired t-test yielded a one-tailed probability of p = 0.038. This effect was seen in 11 of the 13 participants. The finding  of increased stiffness of the landing leg in the sprung floor condition suggests that some of the force of landing the leap was absorbed by the surface, and therefore did not need to be absorbed by the landing leg itself. This in turn implies that a sprung dance floor may help to prevent dance-related  injuries.
authors: Department of Physical Therapy, Missouri State University, Springfield 65897, USA. jameshackney@missouristate.edu
authors: James
authors: J
authors: Hackney
authors: Sara
authors: S
authors: Brummel
authors: Kara
authors: K
authors: Jungblut
authors: Carissa
authors: C
authors: Edge
mesh_terms: D001696:Biomechanical Phenomena; D003615:Dancing / Q000293:injuries / Q000502:physiology; D005260:Female; D005430:Floors and Floorcoverings; D006801:Humans; D007718:Knee Injuries / Q000517:prevention & control*; D007719:Knee Joint / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D004856:Postural Balance / Q000502:physiology; D016059:Range of Motion, Articular; D013314:Stress, Mechanical; D014034:Toes / Q000502:physiology*; D055815:Young Adult