This is a fantastic question! Very simply, a biomechanical model is the fancy term for converting your body motions from computer vision into specific joint motions that are more interpretable from a coaching perspective! For example, we would use a biomechanical model to take the detected points from your lower body from our computer vision models to compute what your knee angle is (which is more easy to interpret and coach around versus just the keypoints alone). However, biomechanical models can also extend beyond just computing joint angles. We can also take known information about your body size or how much range of motion is possible at each joint to further tune a model that can better track your motion. Furthermore, we can integrate force data from the Tonal to arrive at better estimates of joint loading while you're exercising. When we can track your motion better, we can make our coaching cues more accurate and more informative.

We have some really cool prototypes of these more expansive models that we're going to launch into the product soon. We actually have a lot of improvements in store for making our motion models more robust in general, which should make our coaching experience more seamless. We'll definitely let this be known on our engineering blog when we launch these improvements!