dumbbell lawnmower rows
Here's another exercise which works multiple muscle groups at the same time - your legs, core, and back will all feel this one.
Start by holding one dumbbell, medium weight. Stand with your feet staggered - back foot points sideways and front foot points at a 45 degree angle. Hold the dumbbell in the hand on your back foot's side. Lean forward, putting all your weight on your front foot, with the dumbbell hanging at your side, near the floor. Pull the dumbbell up, quickly and smoothly, to shoulder height, as you simultaneously pivot your body weight over your back foot. Reverse the motion and lower yourself back to the starting position.
Video - this exercise is much easier to explain by watching a video; check out this one published by Mens Health Magazine.
Legal Disclaimer (don't blame me).
Warning - I am NOT a licensed physical trainer, therapist, nutritionist, or a doctor. I am a regular guy who just happens to love exercise and fitness.
Exercise can be dangerous if done incorrectly or in excess. I can't see you, and you can't see me, to know if you're doing an exercise incorrectly, which could lead to injury.
Please Please Please seek help / advice / counsel from a local professional before starting a new program, or before doing an exercise you're unfamiliar with. This information is intended as a guide to point you in the right direction. If you aren't familiar with the exercises described herein, I highly recommend seeking professional advice before trying them.