moment arm of quadriceps muscle force

[Nor Fadhillah]

Hi,

I am doing some calculation to determine quadriceps muscle force. Later I
am going to use this value to calculate the tibiofemoral joint reaction
force. My question is:-

1- How to determine the value of moment arm of the quadriceps muscle
force. Most of the mathematical problems from a biomechanics textbook use
" 0.05m" as the value of the moment arm.

2- I understand that the moment arm of the quadriceps muscle force differs
from one person to another. Is it possible to assume a certain value for
moment arm throughout the calculation?

Thank you.
Fadhillah
Biomechanical Engineering
International Islamic University Malaysia
Kuala Lumpur, Malaysia.