It has become common for people to foam-roll their muscles before weights or calisthenics nowadays. Generally-speaking, before their warm-ups and stretches. It's a brief massage, "myofascial release" as it is termed but that sounds dubious to me. Sometimes it hurts, but in a good way. Sometimes people do it after a workout.
I have no idea whether it does any good, but I do it anyway: back, butt, quads, hammies, sides of upper legs, and calves. I don't do my arms. Takes less than 5 minutes, feels good.
Amazon sells them but all gyms have stacks of them.
Using foam rollers