Any biomechanics people here - help needed

Underground S&C Underground
1

  I was wondering if you could help me out. I need help on how to calculate joint reaction forces, ground reaction force and torques.



Basically I'm doing a mini project on runners with a forefoot strike vs. heel strike for my biomechanics class. I have two pictures of the same runner one doing a heel strike, and one doing a foot strike. I've made free body diagrams of them, (two link models, separating the foot and the lower leg).



And I have an anthropometric table, so that I can measure the segments and use the table to figure out the Center of Mass for the segment.



I guess I'm just not getting where the angles come into play . And I have to put in my own numbers/data cause there is none available. So I am gonna go by the assumption that this runner is 150 lbs.





Here are the pictures:



Heel Strike







Forefoot Strike



2

Hey ground,

I can't send PMs since I'm not a pro member, so I am responding to your message here.

I haven't done research in years so I don't know how much help I would be. I'm not sure how much using the angles would help with data as most foot/running ground reaction force studies use force plates, etc.

If anything, I'd think you would be best to use a triangle to create the angle, using the point of impact on the foot, center of gravity, and force of gravity in your calculations. If I come across anything from my schooling I will pass it along.

Not sure if any of these links will help, but I figured I'd send regardless.
http://www.bsu.edu/web/ykwon/pep294/lab8/grf_lab.html
http://www.jssm.org/vol9/n1/21/v9n1-21pdf.pdf
http://www.umass.edu/locomotion/pdfs/jbme-2009.pdf

3

thanks matt!