Footwork Study (Page 2)

Adding muscles to the skeleton would be a big job. The principal investigator, Dr. Jani Macari Pallis, wanted a model with a smoother more realistic motion then the team's previous models. In addition to skeletal motion, muscles "flex". Jani decided that a "proof of concept" would be developed. Instead of creating a new model for the entire human body, the team would start with a smaller test case. A general rule in research - if a technique doesn't work for a simple case, it typically will not work for a more complicated situation. Once the technique works for a simpler case you can extend it to a more complicated one.

Jani felt the leg, from the knee cap to the foot, would be ideal. Compared to other parts of the body, leg motion is fairly limited in direction and range of motion.

In The New Model Muscles Can be Cutaway To See The Underlying Muscles And Skeleton

Compare the motion of your knee to the range of motion of your wrist or your shoulder. The knee, wrist and shoulder act as different types of joints. Your knee acts like a hinge. Think of a door or cabinet hinge. The door can open and close, but doesn't operate in any other direction.

There are also different types of muscles. Bend your leg at the knee and then straighten your leg to its original position. Bending a joint is referred to as flexion; straightening that bent limb is called extension. Muscles operate with a pulling motion. Muscles to not push. In general there is a muscle (or set of muscles) that are used to bend joints and limbs - these are called flexors. Different muscles, called extensors, are used to straighten the limb.

Unlike the knee joint, the wrist acts like a universal joint (a combination of two hinges). While the door hinge can move in one direction, the universal joint moves back and forth in two directions. The shoulder has one of the most complicated motions. It acts like a ball-and-socket joint and can move and rotate in multiple directions.

There would be two major tasks in this part of the footwork project: 1) create the new 3-dimensional model and 2) capture a player's motion from the US Open footage and then apply that motion to the 3D model.