Build endurance and core muscle simultaneously with this three-move ab workout — without crunches ... work well with a medicine ball or cable machine with the pulley set to the highest point.

The study looked at the results of a number of different ab exercises ... that by analysing muscle activity in the abdominals, the best of the bunch is the bicycle crunch. To complete a bicycle ...

“When holding a plank, the work is constant,” says Emma. “In a crunch, you give the abdominal muscles a slight respite as you reach the floor, but in the plank you are just holding continuously.