Back extensions are a great strengthening exercise, and you don't need any special equipment to do them.
Here I use a stability ball as it makes your core work harder throughout the exercise.
Main muscles: Lower and middle back muscles (mainly Erector Spinae). Also deep back muscles (multifidus and semispinalis)
Secondary muscles: Glutes, hamstrings and neck muscles
1. Lie facedown on a stability ball, hands behind your head, feet against a sturdy object.
2. For the beginner verion, keep your knees on the ground.
3. Squeeze your glutes and lift your torso up until your body forms a straight line. Hold for one or two seconds.
4. Slowly return to start.
For the next stage, perform the same movement but with your knees off the ground
To add more of a core element, you can include twists (this can be done in both the beginner and progressed version).
This exercise targets the lower back but also incorporates the obliques (the muscles on the outside of your torso).
You can also add a weight by holding a disc across your chest.
Why I like it
The lower back is a really important area of the core that can sometimes be forgotten when doing core work.
This stability ball version is great for all fitness levels, and you can feel those back muscles work as you do it.