Rounded shoulders, hunched back, pulling as hard as possible: This is how most people think they should use the rowing machine, and it makes trained rowers cringe. "I always see people using this machine as an arms-and-back workout," says Esther Lofgren, current World Champion rower who is training for a spot on the U.S. Olympic Team. "They usually conk out a minute or so later." It's a blessing that these amateur rowers don't last long, because, as Matthews says, misusing the machine this way puts a lot of force on back and spine muscles, which can lead to herniated disks.
Be safe: Push back with power from the legs, and let the arms and back follow. Instead of hunching your shoulders up to your ears, keep a long neck and straight back throughout the stroke. If you feel any pain in your back, lighten the resistance.