Model input

Muscle activation

At least three inputs, such as: activation intensity, activation frequency, joint angle, joint angular velocity, and musculotendon path length.

Model output

Muscle moment applied to the corresponding joint

Muscle force, length, velocity, and moment arm.

Basic principle

Using experimental input-output data to identify the model

Based on physiological experimental observations of the muscle, such as force-length and force-velocity relations.

Model parameters

Few

Large number

Parameter adjustment

Adjusted for each subject

Adjusted for each subject

Simplicity

Depending on the complexity of the used modeling method

Complex, but it is available as a software with GUI [36] .

Training data sets

Essential

None

Muscle physiological behavior

Does not take it into account.

It gives a clear idea about intramuscular behavior.

Used to calculate muscle energy expenditure

No

Yes