YouTube Viewer's comment:
Why did you ask her to stop when she started to substitute?
Dr Blake's response:
When isolating a muscle/tendon while strengthening, it is important to strengthen that one muscle and not allow for substitution. Substitution means that the patient will use another group of stronger muscles to do the activity, and not use the weaker muscle (it will go along for the ride). By isolating a muscle/tendon, you can increase its strength rather quickly and correct muscle imbalances produced by strong vs weak muscles. Dr Rich Blake
