If you can plank, crunch, and twist like a champ, start adding some weight to your workouts and ... A good rule of thumb when it comes to strength training is that the last 2-3 reps should be a ...
Sit on the floor with your knees bent and feet lifted off the ground, holding a dumbbell or kettlebell with both hands. Lean back slightly and rotate your torso to one side, bringing the dumbbell ...