I would like to compare the metabolic power consumption of my target muscles under different conditions.
As shown in the Inverse Dynamics settings of my model (Fig. 1), is the default muscle model in the AnyBody Modeling System used to predict metabolic power consumption? If not, which muscle model is recommended for this purpose, and how can I change it to a different model?
Within the InverseDynamicStudy, the outputs include Pmet and Pmet2. Do these values represent the overall metabolic power consumption of the entire musculoskeletal model during the trial (as shown in Fig. 2)?
Also under InverseDynamicStudy, each muscle has a Pmet value for each band. I summed all the corresponding Pmet values to calculate the total metabolic power consumption of my target muscle. Is this the correct approach to determine the metabolic power consumption of a specific muscle? Please see below for an example.
The metabolic power can be computed for all types of muscles and their combinations. For example, it can be 3 element Hill muscles for the legs and simple muscles for the spine. Depending on the region of interest you can choose the muscle type.
Pmet - yes. According to the ref. manual: "Pmet - The total metabolic power of all muscles in the study.". For Pmet2 is a bit different: "Alternative quantification of metabolic power useful for comparison. It comprises the metabolic power of the muscles specified in ‘MetabolicMuscles2’ using the metabolsim model specified in ‘MetabolicModel2’."
So if you specified something in MetabolicMuscle2 - then it will not be the total power.
That looks reasonable. Do you have a problem with this code? You can always check it my comparing values for 1 or 2 muscles. You can also do it like in a class example for metabolic models using Pmet2. You can find the example in your installation folder, mine is in:
C:\Program Files\AnyBody Technology\AnyBody.8.1\anyscript-demos\ClassExamples\AnyMetabModel.any
Thank you for your helpful response. I have a few follow-up questions regarding muscle modeling and metabolic power calculations:
As shown in the screenshot of my model settings, the "3-element Hill muscle model" has been implemented for both legs. I would like to confirm whether this is the recommended model for estimating metabolic power (Pmet), especially for lower extremity muscles, which are my primary areas of interest. I am interested in the lower body and a couple of back muscles.
I’m still exploring the muscle model settings to gain a deeper understanding. Could you please guide me on how to navigate through different muscle models in my simulation and how to modify or switch models if needed? I've come across different metabolic models such as: MetMdlUmberger2010, MetMdlBhargava2004, 3-element Hill muscle model, etc.
Which of these is typically set as the default or recommended model for accurate Pmet calculations? What are the steps to select or change the metabolic/muscle model if necessary?
Currently, I haven’t specified any custom settings in the MetabolicMuscle2 object. As a result, I assume the model is computing Pmet and PmetRate based on default parameters. Both outputs appear to be very similar in my case. Could you clarify if this behavior is expected under default conditions?
I don’t have any issues with the code itself. I’ve been using it to sum the Pmet values across my target muscles (from the individual muscle bands), and then exporting the overall values. So far, the results make sense when compared with the corresponding muscle force patterns and different assistance conditions. I’ll also take a look at the class example you mentioned for further reference.
Thank you again for your valuable guidance and feedback—I truly appreciate your support.
The 3-element Hill muscle is supposed to be more accurate and provide more detailed output. As far as I remember this is our default choice for the body parts where detailed information was available for this muscle model type. Whereas different metabolic models have their own pros and cons and underlying assumptions. That said the class-demo example I suggested in my previous post shows how you can use several of them at the same time for comparison:
And regarding the point number 2: It is quite likely the case. Please note MetabolicMuscle2 array is for specifying muscle objects, whereas MetabolicModel2 is to specify alternative metabolic model. And to be certain you can always provide some value to the MetabolicModel2 parameter.
I would also very much recommend to read the ref. manual (the F1 button on relevant keywords such as Pmet, Pmet2) - the description should be quite accurate.
