Open Sim 

Day 1: I had to open Open Sim and they had to modify the coordinates of specific joints to complete the assignment seen below. 

Questions

1. Degrees of Freedom

a. Use the Coordinates panel to view the degrees of freedom of the model. How many degrees of freedom, in total, does the model have? List the degrees of freedom of the right leg.

In total the model has 23 degrees of freedom. the right legs has 7 degrees of freedom. 

b. All models are approximations. Compare the degrees of freedom in the model to the degrees of freedom in your lower limbs. Give an example of a joint motion in the model that has been simplified. Give an example of a motion that is not included in this model.

I cannot move my leg side ways completely up like so. Ankle rotation in a circular movement. 

2. Muscles

a. How many muscles are in the model? How does this compare to the number of degrees of freedom in the model? What is the minimum number of muscles required to fully actuate the model?
Hint: Full actuation of the knee, for example, means both knee flexion and knee extension.

93 muscles 

b. Name two muscles, other than the gluteus medius, in the model that are represented by multiple lines of action. Why do you think these muscles are represented in this way?
Hint: Other muscles with multiple lines of action use the same naming convention as the gluteus medius.

c. Which knee extensor muscles have wrapping points? At what knee angles do the wrapping points appear for each of those knee extensors? A muscle may have more than one wrapping point.

3. Modeling Limitations

a. Zoom in on the right hip, and display only the glut_max3_r muscle (right hip extensors group). Examine this muscle for the full range of hip flexion angles. What problems do you see with the path of glut_max3_r through the range of motion? In what ways are point-to-point representations of muscle paths a simplification of musculoskeletal geometry?

Sometimes, the muscle itself goes through bones and gets stretched unimaginably through different ranges of motion. The point-to-point simplification of the musculoskeletal geometry has its problems, such as the fact that it does not represent the many different ways that it stretches  and changes around the bones and how ligament keep the two connected.

4. Muscle Fiber Length vs. Joint Angle

a. Study the plot of muscle fiber length vs. knee angle. For each of the rectus femoris and vastus intermedius, do you expect the fiber-length curve be different if the right hip was flexed? Why or why not? 

Yes, because the flexing of the right hip will change the fiber-lengths curve as it is affected and stretched by the hip. 

b. In the Coordinates window, adjust the model's right hip flexion to 45 degrees (save the pose as r_hip_flex_45), add rectus femoris and vastus intermedius fiber-length curves for 45º hip flexion. Compare the muscle curves for the model with an unflexed hip you plotted previously to the curves for the model that you just plotted. How have the curves changed? Explain your findings. How can bi-articular muscles complicate analysis?
Note: To select multiple curve names, hold down Ctrl (PC) or Command (Mac) while selecting. To print or save a plot, right-click on the plot and select Print or Export Image. 

The rectus femoris now has a smaller curve for the fiber length, while the vastus intermedius stays the same. This is because the rectus femoris is affected by the changing of the right hip degree while it does not affect the vastus intermedius, which rests and is affected by the knee angle. It can complicate it because their locations severely affect how they interact with different types of movement. 

6. Range of Motion

a. Synchronize and play the normal gait and crouch gait. Be sure to loop the animation, adjust the play speed, and rotate the models. Visually compare the two motions. From your observations, qualitatively describe the general differences in kinematics (joint coordinates) between the normal and crouch gait motions. 

Now quantitatively compare knee flexion angles over the crouch and normal gait cycles.

• • • Open a new Plot window.

    • Make the Normal model current by double-clicking its name, Normal, in the Navigator. It should become bold-faced.

    • In the plot window, click Y-Quantity, select normal_gait, and select knee_angle_r. Click OK.

    • Click X-Quantity and select normal_gait. Click OK.

    • Edit the text in the Curve Name textbox to read Normal Gait.

    • To add the curve of right knee angle vs. gait cycle, click Add.

    • Make the Crouch model current by selecting it (double-click) in the Navigator. It should become bold-faced.

    • In the same plotter window, click Y-Quantity, select crouch1_gait, and select knee_angle_r. Click OK.

    • Click X-Quantity and select crouch1_gait. Click OK.

    • In the Curve Name textbox edit the text to read Crouch Gait, then click Add.
      
      
      
      

    • b. Draw the plot of the knee angle curve for a normal gait cycle. Label the times at which heel strike and toe-off occur, and the stance and swing intervals.   0.6 seconds

    • c. What is the range of motion for knee flexion during stance phase for normal gait?

    • -60 to 0

    • d. How does knee flexion range of motion for crouch gait compare to that of normal gait?

    • It has a much smaller range

1. Which motion is expressed in positive angles: wrist flexion or wrist extension?

Wrist Flexion

2. Which motion is expressed in positive angles: radial deviation or ulnar deviation?

Radical Deviation

3. What are the functions of the Extensor Carpi Ulnaris (ECU) muscle? Check or circle all that apply.

    Ο wrist extension   Ο ulnar deviation 

4. What are the functions of the Extensor Carpi Radialis Brevis (ECRB)? Check or circle all that apply.

     Ο wrist flexion  Ο radial deviation   

Testing 

We essentially tested by moving each slider to the max and min of each slider to try and find the best arrangement that creates the most speed. We found that using a minimal  Tibial Anterior, and a moderate to low Rec Fem and Hamstring Muscle force, and finally with a slight turn to the left of around 10 we achieved our optimal value of 13.89 max speed. 

My max speed for the soccer ball challenge is 13.89 

From this OpenSim project, I learned how muscles and bones work together to create movement, and how computer models can help us process that. I saw that even small changes in how we model muscles, like point-to-point, can make the simulation less accurate. This helped me realize how detailed and careful you have to be when studying the human body.

This kind of modeling is really helpful in real life, especially in medicine. It can be used to design better prosthetics, plan surgeries, or help people recover from injuries by showing how their body moves. Using these tools can lead to better treatments and help people move more comfortably and safely.