When taking a movement oriented approach towards rehabilitation, one quickly realizes how important the ankle and hips are to movement. A significant degree of ankle and hip mobility is needed to squat and lunge.
And while mobility is needed to assume these fundamental positions, strength is needed to maneuver in and out of those positions.
Glute activation is paramount in rehabilitation. There are many bridge variations (see here, here, and here) that can be done to activate the glutes. However, activating muscles in isolation does not always translate to normal human function.
In order to activate the glutes during the normal gait cycle, the hips need to move into at least 10 degrees extension. However, in order to move into hip extension when standing or taking a stride, ankle mobility is a prerequisite.
Without sufficient ankle mobility, the hips cannot move into extension and the glutes cannot fully activate. This can lead to a calf and quad dominant gait, which perpetuates the vicious cycle of stiff ankles and hips.
The amount of ankle dorsiflexion needed for a normal gait cycle is about 20 degrees. A good place to start improve ankle mobility is foam rolling the calves and performing a simple stride stretch.
If you finding yourself frustrated with not getting anywhere with improving hip mobility through foam rolling and glute activation, you may want to look further down the kinetic chain. A locked up ankle can be a driving force of movement dysfunction.