An experiment is performed in which a muscle–tendon unit is fixed at some (unknown) length , the muscle is activated to a specified level, and the tendon force is measured once the muscle and tendon have reached equilibrium (steady state). The muscle has the following active and passive force–length relationships:

The tendon has the following force–strain relationship:

The muscle and tendon parameters are , , , and pennation .

For each of the following experimental conditions (specified activation and measured tendon force), calculate the length of the muscle and the length of the tendon .

(a) , 

(b) , 

(c) , 

(d) ,