3. Upright row. Pulling weights, a barbell, or a weighted cabled bar up under your chin is a big no-no, says Saremi, a podiatrist and editorial staff member of the Aerobic and Fitness Association of America's American Fitness magazine.



"When people pull their hands (carrying the weight) up to their chin, they are going to compress the nerves in the shoulder area, impinging the shoulder," Saremi says.



A safer alternative: Instead, do a front or lateral shoulder raise, lifting weights out to the front or side of the body. Even better, try the bent-over row: Bending forward at the hips, hold weights down beneath your shoulders, then lift toward sides of your body. This exercise is much safer, and targets all the muscles of the upper back as well as the biceps.

4. Lying leg press with knees bent too deeply. Lying on your back with your feet on a weighted plate, you push the plate up and bring it down, with the aim of working the quadriceps, hamstrings, and glutes. The problem with this exercise comes when you bend your legs too far.



"This can be very dangerous if you come down too deep," says Warpeha.



That's mainly because form falls apart. Your spine cannot maintain proper alignment when your legs come back too far, so the pelvis tilts and the lower back begins to take over. And the weight used is usually heavy enough to injure the back, causing strain to muscles or damage to disks. In addition, he says, bending your knees too deeply can injure or damage your knees.



If you want to do this exercise, Warpeha suggests a good rule of thumb: Keep your butt from rotating off the back of the machine, and don't bend past 90 degrees at the knee and hip.

A safer alternative: Try squats or lunges to work the same muscle groups while resisting your own body weight.

5. Squats on the Smith machine. This is a squat you do standing at a machine that has a barbell on a sliding track. The barbell rests on your shoulders, behind your head.



In a true squat -- done as you hold a barbell at your shoulders -- the bar doesn't go straight up and down as it does with the Smith machine, Warpeha says: "Looking from the side, the bar has some sway."



"On the machine, the bar doesn't give, so it forces the body into disadvantageous biomechanical positions," he says. People also tend to put their feet further in front of their bodies when doing squats on the machine, which adds to the problem.



Considering that today's adult population is wrought with knee and back problems, says Danberg, the last thing you want to do is an exercise that might aggravate weakness and injury.

