The Raised Leg Hip Thrust works the entire lower body with a particular focus on the gluteus maximus and gluteus medius as well as the hamstrings. This is a great exercise to build posterior chain strength which is important for reducing the risk of many running related injuries.
Set yourself up with a platform for the feet - you can use a step or pile a few weights on top of each other. Lie on the floor with your feet on the raised platform with your feet and knees approximately hip width apart. Extend your arms forwards pushing the bar into your hips. At this point you may need to shuffle your body towards the raised platform so that your bum is relatively close to your feet. From here drive your hips up into the sky, squeezing your glutes and core before coming back down.
If you are doing the weighted version with a Barbell, when you come back down you want the bar to hit the ground at the same time on both sides to ensure you are working evenly across our body.
When driving your hips up, only bring them as high as they go without your back beginning to arch - if you do begin to arch your back you will realise fairly quickly as you will begin to have a sore back.
The raised feet rather than raised shoulders in this exercise allows for an increased range of motion as well as greater glute activation.