There are couple of exercise handouts frequently coming to my office that I wish I could add to the burn pile - a very big burn pile. 1 of those is the simple calf stretch that most people do for heel heel pain and diagnosed plantar fasciitis. Not that it's never appropriate, but that its very often inadequate to address the problem.
The posterior leg muscles, wether hamstrings, calves, are connected via an overarching fascia layers that starts in the lumbar spine (technically the fascia layers connect all the way to the skull, but for the lower extremity sake, you can do a very effective stretch from the waist down), extends through the buttock muscles, hamstrings, deep and superficial calf muscles, to the plantar fascia layers of the foot all the way to the under surface of the toes. In some people, myofascial tightness will be limited to one muscle group and doing a calf stretch will be effective, but in my experience of chronic leg tightness, recurrent injuries, chronic foot pain, the dysfunction spreads along the fascial chain. And as such, you cannot effectively release a local muscular area without doing a stretch that involves all of the parts of that chain together.
The "leg up the wall" stretch aims to do just that. It requires to wiggle your buttocks all the way to a wall, try to straighten out the knees as much as possible, and apply some gentle downward pressure on the toes using a strap or a long towel. It's incredibly intense. It's also incredibly effective. The connective tissue of the fascia does not release in 30 seconds, it needs at least a minute of slow steady hold without bouncing, with some deep breathing, in order for those connective tissues to start to lengthen. I tell people to have patience. Often it will feel intense, and not releasing for a couple of weeks before the patient can get in that position and feel some normal flexibility. The rewards are worth it.