Begin with a basic plank: in a push-up position, form a straight line from your head to your toes.
Keep your pelvis tucked, your spine and neck neutral and shoulders relaxed and away from your neck.
With elbows bent (softended) reach one knee towards the same-side elbow. Repeat one side after the other. Perform 10 touches per side with quick switches from side to side.
NEXT: Side plank
Workout by Holly Barker (pictured), images by James Patrick