These barbell and dumbbell exercises are the best way to build muscle ... Lift your right leg off the floor by pressing your weight into your left foot and squeezing through your left glute.
Maybe you’re just bored of sit-ups or they’re off ... To progress the exercise, hold a weight between your thighs or feet. While performing any core exercise, the key is to really feel it.
Sit down slowly while tightening ... so that all your weight is on your arms. March in place, keeping your feet flat on the ground as you alternate. Repeat this exercise 15 times on each leg.