This move, Johanna told us, is very fluid and challenges your balance and ability to contract your core. "It can also do a lot for toning the legs as they are moving in a bicycle-like motion," she said.
- Start in a traditional plank — shoulders over hands and weight on just your toes.
- With your core engaged, bring your right knee forward under your chest, with the toes just off the ground. Return to your basic plank. Switch legs, bringing the left knee forward.
- Keep switching legs and begin to pick up the pace until it feels a little like running in place in a plank position. Continue "running" in your plank.
- If you're doing these for reps and sets, Johanna suggests doing 3 sets of 15 per side.