Side step push-ups
Why? This move challenges your posture in a few ways and also works on shoulder stability.
How? Place a 30cm hurdle (such as a rolled-up towel) lengthways in front of you. Assume a push-up position parallel to the hurdle. Perform a slow and controlled push-up, then step laterally with your hands and feet to the other side of the hurdle. Perform another push-up and step back over to where you started.
Sets and reps: 3 sets of 6-15.