1. SIMULATION OF THE AIRBORNE PHASE OF THE GRAND JETÉ IN BALLET
D. Gordon E. Robertson, PhD, FCSB
Pamela Galler, BSc
Lisa Stanley, BSc
Biomechanics Laboratory,
School of Human Kinetics,
University of Ottawa, Ottawa, CANADA

2. Introduction Grand jeté is one of the strongest jumps in ballet
It is characterized by a leap that travels horizontally
Laws (2002) proposed that it is possible for the upper body to appear to translate in flight while the centre of gravity follows its parabolic path

3. Grand Jeté

4. Methods Two experienced ballet dancers/instructors
Performed several grand jetés in sequence with a step in between jumps
Some trials were done landing on a force platform
Video taped at 60 fps
10-segment model of body (i.e., hands and feet ignored)
Planar motion analysis

5. Methods
Takeoff velocity determined from data preceding and after takeoff
Initial estimate of total body angular momentum taken from average of flight phase momenta
Joint displacements, initial position at takeoff, initial velocity and angular momentum were then used to iteratively obtain changes in trunk angle during flight (Lemaire & Robertson 1990)
Total body angular momentum was adjusted by comparing simulated motion with actual motion

6. Methods

7. Methods Once a successful simulation was achieved:
Hip joint displacements were modified to elevate lower extremities to produce full “split” in the air prior to reaching peak height
Shoulder joint displacements were then modified to raise the upper extremities until a “flat” trajectory of the head and shoulders was achieved

8. Results
Neither dancer had a flat trajectory of the upper body during their jumps
Raising the legs to achieve a “split” configuration in the air was insufficient to achieve a flat trajectory
Raising the arms past the horizontal was necessary to achieve the linear translation illusion with both dancers

9. Arms High, Legs Horizontal

10. Initial Jump

11. Jump after Legs Raised to Horizontal

12. Jump with Legs and Arms Raised

13. Jump Height versus Shoulder Rise
Subject: LS PG
Actual jump height
25 cm
21 cm
Actual rise of shoulders
19 cm
With legs raised
14 cm
13 cm
With legs and arms
0 cm

14. Discussion
The illusion of “floating” through the air or linear translating while airborne could be achieved but required that the arms elevate above horizontal
In some dance traditions this is not a permissible motion
The illusion could be extended further by lowering the arms and legs after the jump apex, however, this may result in a hazardous landing

15. References
Lemaire, E.D. & Robertson, D.G.E. (1990) Validation of a computer simulation for planar airborne human motions. Journal of Human Movement Studies, 18:
Laws, K. (2002) Physics and the Art of Dance. New York: Oxford Press.

16. Wow! Questions?