PDA

View Full Version : Analyzing running performance with the spring-mass model.

tandresen
08-06-2008, 09:25 AM
Hello Colleagues,

Is anyone else using the spring-mass model to understand their running
performance?

I modified my home treadmill (1) to capture my step-frequency and
duty-factor.

>From my running-in-place step-frequency I can calculate my leg-stiffness.
When I use this value in the model, its output (2) closely follows the
step-frequency and duty-factor I measure over the speed range (3).

I am especially interested in the mass specific power (watts/kg) expenditure
due to spring compression (4). The values shown in the PowerSpring/mass
curve (2 to 4.5 watts/kg) are close to the power expended by a mid-pack cyclist.

Does anyone else use the spring mass model in this way?

Ted Andresen
Math Department
St. Petersburg College
St. Petersburg, Florida

(1) A graph of the data from the model is at:
_http://members.aol.com/MathPhysicsModel/TMDetector.jpg_
(http://members.aol.com/MathPhysicsModel/TMDetector.jpg)

(2) A graph of the data from the model is at:
_http://members.aol.com/MathPhysicsModel/SMvsExp.gif_
(http://members.aol.com/MathPhysicsModel/SMvsExp.gif)

(3) The output tabulation from the model is at:
_http://members.aol.com/MathPhysicsModel/SMvsExpData.gif_
(http://members.aol.com/MathPhysicsModel/SMvsExpData.gif)

(4) How the model calculates the mass specific power:
_http://members.aol.com/MathPhysicsModel/SM/SM.html#EnergyPower_
(http://members.aol.com/MathPhysicsModel/SM/SM.html#EnergyPower)

**************Looking for a car that's sporty, fun and fits in your budget?
Read reviews on AOL Autos.
(http://autos.aol.com/cars-BMW-128-2008/expert-review?ncid=aolaut00050000000017 )