squats model

I want to analyse the muscle forces in the hamstrings (semitendinosus, semimembranosus and biceps femoris long head) during cycling and squatting trough inverse dynamics. The cycling model in the AMMR is quite usefull. Which model should I use for simulating the squat movement? Is the StandingHuman a good starting point or this only a static model?

Another question is about saving the output. The most important output parameter is the fm muscle force of the three muscles. Is there a class to automatically save the charts of the muscles forces into the output folder? (I know about the AnyOperationMacro and AnyOutputFile commands, but i want to automatically save my results as a figure like .bmp without having to manually search for these charts every time)

Hi Jan,

Unfortunately it is not really possible to make an automated screenshot of the chart view yet. But it is possible to draw a 2D/3D plot in the Model View and take a screenshot of that one (please look for AnyChart inserted into a fixed ref. frame):

Link to example of drawing

For saving it automatically please look at the camera object creation code:

It is a bit of workaround - it might also be easier to make an output and process result in Matlab/Python, etc.

Kind regards,

Ok Pavel, thanks!

I am having trouble using the drivers in the StandingModel. For instance: if i want the pelvis to go up an down along the y-axis. Therefore I need to activate the PELVIS_POS_Y_DRIVER. In order to do that, I define the global driver as 1 in the frist line of Mannequin.any


When loading the program, I always get the error:

ERROR(SCR.SCN6) : C:/P…s/A…y/A…0/AMMR/Body/A…n/B…s/i…e/MannequinDrivers.any(22) : ‘TRUNK’ : Unexpected character.

Of course TRUNK is defined already, so I don’t understand what is meant by this. Is my methodoly wrong, or did I overlook something?

Thanks for telling us, it seems that there is an error in the Model. What is your final goal? What motion do you want to achieve?
I do not recommend to use this driver.

I want to simulate a squat movement. For the basic beginning step, I just want to move the pelvis along the vertical axis. Then I want to do a inverse dynamic analysis because I need to know the quadriceps and hamstrings forces.

But recently I discovered that the standingmodel doesn’t take inertia forces into account, so I don’t think this model is ideal for my problem. Is there another model that I can use?

The StandingModel will use inertia! But if it’s a static posture, inertia will of course not affect anything. As soon as you make it a motion, inertia will affect the model.

If a basic knee bend is enough, you could start a new model from the templates: Standing Man

and just edit the Manequin.any:

  AnyVar HipFlexion = 45.0; 
  AnyVar HipAbduction = 0.0; 
  AnyVar HipExternalRotation = 0.0;
  AnyVar KneeFlexion = 90.0; 
  AnyVar AnklePlantarFlexion =45.0; 
  AnyVar SubTalarEversion =0.0;


If the standingmodel accounts for inertia forces, then I cannot understand the charts shown in the attachment. These charts show fm from rectusfemoris1 during 2 different setups.

First one:
duration time: 1 second
AnyVar HipFlexion = 45.0;
AnyVar KneeFlexion = 45.0;
AnyVar AnklePlantarFlexion =45.0;

Second setup:
duration time: 4 seconds
AnyVar HipFlexion = 11.25;
AnyVar KneeFlexion = 11.25;
AnyVar AnklePlantarFlexion =11.25;

As you can see, in both situations the three joints change with 45 degrees (4*11.25=45).
Because the first situation only lasts 1 second, the body undergoes higher accelerations, so i would expect a higher muscle force.
But as you can see in the picture, fm has the same variation in situation 1 as it has in situation 2.

Therefore I thought inertia forces were not accounted for and the muscle forces were calculated static… Did I miss something with this reasoning?

Thanks for the support
(These charts were maid with a trial license, but i can also use the license from my university)

Look at some of the other muscles and the overall work:


1sec 4sec
1.31E-01 1.38E-01
1.32E-01 1.39E-01
1.32E-01 1.39E-01
1.33E-01 1.39E-01
1.33E-01 1.40E-01
1.34E-01 1.40E-01
1.34E-01 1.40E-01
1.36E-01 1.41E-01
1.64E-01 1.69E-01
1.95E-01 2.01E-01
2.22E-01 2.29E-01


1sec 4sec
3.54E+00 9.45E-01
-2.69E+01 -7.03E+00
-5.72E+01 -1.49E+01
-8.69E+01 -2.27E+01
-1.16E+02 -3.02E+01
-1.44E+02 -3.74E+01
-1.71E+02 -4.43E+01
-1.96E+02 -5.08E+01
-2.20E+02 -5.68E+01
-2.42E+02 -6.25E+01
-2.63E+02 -6.76E+01