Runners are notorious for tight hamstrings that can cause lower back problems and lead to pulled muscles. Tight hamstrings also limit your range of motion, which can affect running stride, form and speed. To improve hamstring flexibility, try this lying hamstring stretch, which keeps the spine neutral whereas basic toe touches (forward bends) do not, thereby reducing risk of low back pain.

Stretching the quads forces your hamstrings to contract, helping them get stronger. It's important to have strong and flexible quads since these muscles help lift your knees and increase your speed. This standing quad stretch is into to incorporate after a run, and once you master this, you can carefully pull your thigh and knee slightly behind your body (not pictured) for a greater hip flexor stretch at the same time.

Your piriformis muscle is responsible for the rotation of the hip. Although it's very important in activities that frequently change direction, it tends to tighten up in runners. If the piriformis becomes too tight or spasms, it can irritate the sciatic nerve, which causes pain in the glutes, lower back and thighs. To prevent these issues, try these two stretches:

Flexible calf muscles can improve your ability to increase the length of your stride, which results in increased speed. Loose calf muscles also take some of the burden away from your shins as you bring your trailing leg forward when running, helping prevent shin pain or shin splints. This basic calf stretch is an easy one to incorporate. Check out this video for more calf stretching demonstrations.

The illiotibial band is part of a muscle that runs along the outside of the knee and can create pain when it starts to rub on the kneecap. This is typically an overuse injury (trying to do too much too soon or not giving your body adequate time for rest and recovery). Stretches that target the IT band, like the example below, can reduce pain and prevent future knee problems.