kinetic analysis of the lower limb during the pirouette in ballet n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Kinetic Analysis of the Lower Limb during the Pirouette in Ballet PowerPoint Presentation
Download Presentation
Kinetic Analysis of the Lower Limb during the Pirouette in Ballet

Loading in 2 Seconds...

play fullscreen
1 / 20

Kinetic Analysis of the Lower Limb during the Pirouette in Ballet - PowerPoint PPT Presentation


  • 472 Views
  • Uploaded on

Kinetic Analysis of the Lower Limb during the Pirouette in Ballet. D. Gordon E. Robertson, PhD, FCSB Cristina Fulop Tama Davis Courtney Timm Biomechanics, Laboratory, School of Human Kinetics, University of Ottawa, Ottawa, Canada. Introduction.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Kinetic Analysis of the Lower Limb during the Pirouette in Ballet' - Mia_John


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
kinetic analysis of the lower limb during the pirouette in ballet
Kinetic Analysis of the Lower Limb during the Pirouette in Ballet

D. Gordon E. Robertson, PhD, FCSB

Cristina Fulop

Tama Davis

Courtney Timm

Biomechanics, Laboratory,

School of Human Kinetics,

University of Ottawa, Ottawa, Canada

introduction
Introduction
  • pirouette is a basic ballet skill that involves spin about the vertical axis while in single support
  • can be done with 1, 2 or 3 turns from a two-foot stance
  • more turns (fouetté) require additional motions of the free leg
  • very little data exists in literature concerning how this maneuver is performed
review
Review
  • Laws (1978) used a turntable with large moment of inertia to indirectly measure total body angular momentum of pirouettes en dedans and en dehors and an arabesque turn.
  • Laws (2002) outlined the various categories of pirouettes (en dedans, en dehors etc.) and suggested that the torque necessary for creating the spin comes from a force couple created by the two feet.
  • He had no data to support this concept.
purpose
Purpose
  • to identify the net moments of force using inverse dynamics that create the pirouette
  • to examine how moments of force change as the number of turns increases
  • to determine the roles of the stance and swing legs during the pirouette
methods
Methods
  • one female subject with 10 years training
  • full-body (49) marker set (extension of Vicon’s plug-in gait)
  • seven Vicon MX13 cameras sampling at 200 fps
  • two force platforms (Kistler) sampled at 1000 Hz
  • 5 trials each from fourth position
    • half turns
    • full turns
    • double turns
methods1
Methods
  • processed with Visual3D
  • 3D moments computed bilaterally at ankles, knees and hips
  • moment powers computed from products of joint angular velocities and moments of force

PM = M w

results
Results

3D markers

3D model with GRFs

double turn fl ex trail leg

knee flexors flex knee during turn

hip flexors initiate turn

knee extensors resist flexion

plantiflexors later provide a small impulse before single support occurs

Double turn (Fl/Ex) – trail leg
double turn fl ex stance leg

knee extensors initially resist flexion then help to extend limb

hip extensors extend support limb then hip moments work isometrically

plantiflexors provide a larger impulse just as single-support occurs

Double turn (Fl/Ex) – stance leg
double turn ab ad stance leg

hip abductors initially resist adduction then knee abductors perform negative work

ankle ab/adductors contribute little work before or during stance

Double turn (Ab/Ad) – stance leg
all turns trail leg fl ex
All turns - Trail Leg (Fl/Ex)
  • greatest change occurs with the work done by the hip flexors of trail leg for double pirouette
all turns stance leg fl ex
All turns - Stance Leg (Fl/Ex)
  • no change in ankle work
  • hip extensors increased only for double pirouette
all turns stance leg ab ad
All turns - Stance Leg (Ab/Ad)
  • greatest changes occur with the negative work done by the hip abductors of stance leg
discussion
Discussion
  • torque during a pirouette is created by trail leg initiating a moment while support leg applies resistance, not by a force couple
  • support leg lifts dancer en pointe or demi pointe once single support occurs
  • during single support, trail (gesture) leg flexes to reduce the body’s moment of inertia and thereby increase spin rate
  • arms main purpose was to increase and decrease body’s moment of inertia, first to increase angular momentum then to increase and decrease spin rate
discussion1
Discussion
  • when increasing number of spins main changes were:
    • trail leg hip flexors
    • stance hip extensors
    • stance hip abductors
  • almost no change in trail leg push-off
  • shoulder work increases for double turn
initial stance
Initial Stance
  • en dedans is a right turn to a left supporting leg or vice versa
  • from fourth position