The tip-toe crunch is a variation on the crunch exercise that involves placing the toes on or near the ground. This can help isolate the abs from the hip flexors. The tip-toe crunch can be performed for time or for reps as part of the core-focused component of any workout.
Activates and strengthens the abs, the rectus abdominis or “six-pack” muscles in particular
Pulling the toes into the ground can help turn off the hip flexors and isolate the core muscles
Simple way to progress sit-ups when they become easy to do for high reps