Bicycle Twist Crunch

The bicycle twist crunch combines two actions that most abdominal exercises keep separate: flexing the trunk and rotating it. Bringing one elbow toward the opposite knee while the other leg extends works the rectus abdominis and the obliques at the same time, and that crossed pattern reproduces the job the obliques actually perform when you walk, throw or change direction. It is one of the few floor movements that needs no equipment and still stays demanding long after a plank has stopped being difficult. The most widespread mistake is the tempo: performed quickly, momentum does most of the work and the hands end up pulling on the neck. Rest the fingers lightly against the sides of the head without lacing them, move the torso slowly, and let the rotation come from the ribs rather than from the elbow reaching across.