Walking into the gym and expecting a great workout is like walking into the supermarket and expecting a gourmet meal. The basic ingredients are there, but like they say in the infomercials, results may vary. With working out, as with cooking, a little bit of smarts, dedication, creativity and knowledge will make all the difference between perfect pasta and a gelatinous ball of mush.
For this list of no-no exercises, we consulted Stuart McGill, PhD, professor of spine biomechanics at the University of Waterloo, in Ontario; Nicholas DiNubile, MD, author of FrameWork: Your 7-Step Program for Healthy Muscles, Bones, and Joints; and trainer Vern Gambetta, author of Athletic Development: The Art & Science of Functional Sports Conditioning.
1. Seated Leg Extension
What it's supposed to do: Train the quadriceps.
What it actually does: It strengthens a motion your legs aren't actually designed to do, and can put undue strain on the ligaments and tendons surrounding the kneecaps.
A better exercise: One-legged body-weight squats. Lift one leg up and bend the opposite knee, dipping as far as you can, with control, while flexing at the hip, knee, and ankle. Use a rail for support until you develop requisite leg strength and balance. Aim for five to 10 reps on each leg. (If you are susceptible to knee pain, do the Bulgarian split squat instead, resting the top of one foot on a bench positioned two to three feet behind you. Descend until your thigh is parallel to the ground and then stand back up. Do five to 10 reps per leg.)
2. Seated Lat Pull-Down (Behind the Neck)
What it's supposed to do: Train lats, upper back, and biceps.
What it actually does: Unless you have very flexible shoulders, it's difficult to do correctly, so it can cause pinching in the shoulder joint and damage the rotator cuff.
A better exercise: Incline pull-ups. Place a bar in the squat rack at waist height, grab the bar with both hands, and hang from the bar with your feet stretched out in front of you. Keep your torso stiff, and pull your chest to the bar 10 to 15 times. To make it harder, lower the bar; to make it easier, raise the bar.
3. Seated Hip Abductor Machine
What it's supposed to do: Train outer thighs.
What it actually does: Because you are seated, it trains a movement that has no functional use. If done with excessive weight and jerky technique, it can put undue pressure on the spine.
A better exercise: Place a heavy, short, looped resistance band around your legs (at your ankles); sidestep out 20 paces and back with control. This is much harder than it sounds.
4. Seated Leg Press
What it's supposed to do: Train quadriceps, glutes, and hamstrings.
What it actually does: It often forces the spine to flex without engaging any of the necessary stabilization muscles of the hips, glutes, shoulders, and lower back.
A better exercise: Body-weight squats. Focus on descending with control as far as you can without rounding your lower back. Aim for 15 to 20 for a set and increase sets as you develop strength.
5. Squats Using Smith Machine
What it's supposed to do: Train chest, biceps, and legs.
What it actually does: The alignment of the machine—the bar is attached to a vertical sliding track—makes for linear, not natural, arched movements. This puts stress on the knees, shoulders, and lower back.
A better exercise: Body-weight or weighted squats. See "Seated Leg Press" above.
6. Roman Chair Back Extension
What it's supposed to do: Train spinal erectors.
What it actually does: Repeatedly flexing the back while it's supporting weight places pressure on the spine and increases the risk of damaging your disks.
A better exercise: The bird-dog. Crouch on all fours, extend your right arm forward, and extend left leg backward. Do 10 seven-second reps, and then switch to the opposite side.