Leading up to attending The International Association for Dance Medicine & Science next week, I decided it was a good week for Research Shows, on DH! So no quote, beautiful story, pretty pictures – well for today anyway…Yet today, I’ll educate you from inside the Journal of Dance Medicine & Science.
The journal I will be reviewing today is titled, “Effect of Reduced Stiffness Dance Flooring on Lower Extremity Joint Angular Trajectories During a Ballet Jump.”
James Hackney, P.T., Ph.D., Sara Brummel, M.F.A., Mary Newman, P.T., D.P.T, Shannon Scott, P.T., D.P.T., Matthew Reinagel, B.S., S.P.T., and Jennifer Smith, B.S., S.P.T.
Dance has a high rate of lifetime injury, this journal stating an estimated 84% rate, in ballet dancers. Therefore, dancers, dance educators, and those who support dance programs are interested in interventions that may help in reducing this rate. One such intervention is a “sprung floor.”
A few factors help factor in the significance of how a “sprung floor” can help reduce injuries. These include:
- Joint Angle – If the maximum joint flexion angle is lower on a low stiffness surface, then the maximum external moment would also tend to be proportionally less, as long as the landing force is equal.
- Joint Angel Velocity – The faster a joint flexes in order to absorb the force of landing a leap or jump, the greater the velocity of the eccentric muscle contraction.
Therefore, they carried out this study to investigate the effect of floor stiffness during performance of a, “saute,” jump.
- Maximum joint flexion would be less acute on “sprung floor.”
- Maximum joint angular negative velocity would be slower for the hips, knees and ankles when dancers perform “saute” on a low stiffness “sprung floor” compared to a hard wood floor of wood over concrete.
Conclusion: (with sprung floor)
- Maximum joint flexion was less. When angles are less acute, the length of the external knee flexion moment arm is shorter and therefore requires less internal force to control.
- Angular negative velocity was less allowing unnecessary contraction of muscles to not occur.
Findings suggest that using a reduced stiffness floor for dance rehearsal might reduce the likelihood of a variety of overuse lower extremity injuries including knee, ankle and hip injuries.
Thanks for learning. Remember to dancehealthier.