1. Biomechanics of throwing a frisbee Daniel Kim Biology 438-301 Professor Rome

2. Once upon a time… Wham-O Toys
Bridgeport, CT – William Russell Frisbie opened Frisbie’s Pie Company
Cotroneo analysed biomechanic and aerodynamic aspects of disc flight from throw observations. Release velocities were correlated with range to confclude that initial velocity is the most important factor affecting the maximum distance thrown

3. Frisbee Throws Backhand Forehand Overhead
Standard
Skipping
Hover
Curve Pass
Forehand
Overhead
All work under a similar principle

4. 3 Stages of a Frisbee Throw
Wind-up
Acceleration
Follow through

5. Range of Motion
Cotroneo (1980) compared the force contribution of body segments in backhand versus forehand Frisbee throws while
The segments of the torso and throwing arm act as a kinetic chain to maximize the speed
of the final segment.
Cotroneo concluded that there is a relationships between initial velocity and maximum distance thrown
Controneo analysed biomechanic and aerodynamic aspects of disc flight from throw observations. Release velocities were correlated with range to conclude that initial elocity is the most important factor affecting the maximum distance thrown.

6. The Backhand Throw

7. Backhand Throw

8. Wind Up (backhand) Torso twists (winding up)
Weight of thrower shifts to left foot
Arm horizontally adducts towards torso
Forearm flexes
Wrist curls
Analysis of 57% maximal effort throws reveals that the largest power contribution results
from horizontal adduction of the shoulder providing nearly all the work done to increase
translational velocity of the Frisbee.

9. Acceleration Continues from maximum rotation of torso
Sequential uncoiling of torso and arm
Torso twists right and bends forward
Weight shifts to right foot
Humerus and torso are aligned
Forearm pronates
All-important wrist flick

10. Follow Through Arm continues to extend at shoulder, elbow, and wrist
Finished when torso twists maximally to the right

11. Second Look at the Backhand

12. Second Look at the Backhand

13. X-Displacement vs. Time

14. Force Generated and Work Performed
Assuming that mass of a human arm is about 6.5% of total body weight:
marm= 73 kg*.065 = 4.75 kg
Acceleration prior to release was m/s^2
Force = Mass * Acceleration
4.75 kg * m/s^2 = N
Work = Force * Distance
Distance traveled: m
107.6 N * m = 152 J
Velocity from logger pro (calculated in quadrature): 13.1 m/s

15. The Forehand Throw

16. Forehand Throw

17. Wind Up Feet facing receiver Knees slightly bent
Weight shifted to right foot
Torso turns right (winding up)
Shoulder horizontally abducts away from torso
Elbow pointing forward
saFeet facing receiver
Knees slightly bend
Weight shifted to right foot
Disc brought back
Elbow pointing forward
Shoulder begins snap
Torso unwinds first
Then Shoulders
Then Elbows
Then WRist df

18. Acceleration and Follow Through
Torso unwinds
Shoulders rotate giving speed
Elbows straighten
Wrist snaps
Throw completed when torso is facing forward

19. Second Look at the Forearm Throw

20. Second Look at the Forearm Throw

21. X-Displacement vs. Time

22. Force Generated and Work Performed
Assuming that mass of a human arm is about 6.5% of total body weight:
marm= 73 kg*.065 = 4.75 kg
Acceleration prior to release was m/s^2
Force = Mass * Acceleration4.75 kg * m/s^2 = 114 N
Work = Force * Distance
Distance traveled: m
114 N * m = J
Velocity from logger pro (calculated in quadrature): 12.3 m/s

23. Conclusions
Compare energy inputted to the velocity of the frisbee to see which throw is more energy efficient
Backhand Throw:
152 J / 13.1m/s = 11.60
Forehand Throw:
100 J / 12.3 m/s = 8.13
Given this single trial, the backhand form requires more energy than the forehand form.

24. Future Investigation
Using different camera angles, calculate the energy inputted as rotational energy. Which throw puts more spin into the frisbee?
Investigate the specific backhand throws (skipping, hover, curve pass) and analyze how the body inputs the proper energy to manipulate the trajectory of the frisbee.

25. Resources
melthesis.pdf