From ACE’s website, some foam rolling advice for the lower body:
While the process does not look immediately appealing, foam rolling—also referred to as trigger point or self-myofascial release—has become an important part of any fitness program. It’s an excellent method of melting away muscle tension to make your general stretch routine more effective. Other results include improving your overall performance in the activities you love and keeping you moving pain-free through your workouts.
There are many ways to approach foam rolling, but I have found the safest and best results by following these guidelines:
Roll over the muscle slowly, feeling for areas that are tight or “hot.” When you find a “hot spot” your instinct will be to roll away from it. Instead, support more of your body weight with your arms or opposite leg and breathe deeply as you gently apply pressure.
Focus on small areas. Move incrementally rather than in large repetitive movements that cover the entire muscle, which can lead to greater inflammation.
Stay on one spot for one to two breaths and then move an inch higher, lower, right or left. If you do not find anything in that direction, move an inch in another direction and repeat this process.
Avoid rolling over the joints. Keep the foam roller on soft tissue only.