I LOVE the foam roller or a good trigger ball for myofascial release.
Your goal this week is to give your back side a good roll out...from the glutes to the feet, spend a couple minutes in each area, find those knots and roll baby roll.
Knots in the muscles, aka trigger points, affect the fluidity of movement, can cause muscle imbalances, weaknesses, referral pain (pain to other areas in the body) and increased your risk of injury.
Trigger points in the glutes can cause back pain as well as referred pain down the leg (some people mistake it for "sciatica")
Tight hamstrings and calves will affect the way you walk which can then cause injuries like hip and back pain, plantar fasciitis, shin splints, muscle cramping, etc.
Tight quadriceps have the potential to cause hyperextension of the low back and inhibition of the glutes which produces back pain!
Moral of the story...keeping the fascia healthy and mobility, keeps the body healthy and mobile.