Arm day, leg day, ab day—these are the familiar pillars of strength training. But what about lower back day? Our lower backs are often overlooked, yet they're a crucial part of fitness. Many of us ...

Start on all fours. Extend your right arm in front of you and your left leg behind, actively reaching in opposite directions.

Brad: There you go. It's very simple. Mike: So the three common motions to help with centralisation are first spinal flexion going forward. Mike: Extension, or going backwards. Mike: And then you have ...