Ahh yes, Bill. This is a common issue/problem/goal in Lifetime Athletes. Ankle dorsiflexion can be viewed functionally as the ability of the shin to move forward while the heel is on the ground. When the shin is vertical with respect to the foot (or perpendicular to the ground) we can term that a roughly 90 degree angle at the ankle. As the ankle dorsiflexes, the shin comes downward, the knee drives forward, and the angle lessens toward, say, 45 degrees. This is valuable for both injury prevention and performance. Most of us have some stiffness in this area and can benefit from improving ankle DF.
Kati is correct in that there are some band moves that can be applied. The most basic is the old “pull your foot up against the band” setup. This mainly works the muscles in the front of the shin and isn’t super powerful to stretch the joint, but it can still be helpful. Next up is using a strap or heavy band to pull down and back on the top foot bone, the talus, while the foot is in weight-bearing, as we drive the knee forward. Putting your foot on a chair, bench or stool is key.
Another trick is simply to work in some of your exercises to keep the heels down as you do squats and lunges. However, during ballistic movements like jumping and hill sprints you should avoid doing this.
I’ve got a good resource for you. It’s a video I did last year on Plantar Fasciitis and it has a number of exercise progressions for enhanced foot and ankle function.
Also, we can always have a foot mobility MasterClass session if you like. Thanks for the great question.