A typical modern gym houses hundreds of individual pieces of exercise equipment, some of which appear purposefully designed to injure as many trainees as possible.
Here are ten of the most dangerous exercise machines. Avoid these, and avoid any so-called personal trainer who recommends them.
1. Smith Machine
A smith machine is just a bar built into an apparatus that restricts the bar to a vertical path, and sometimes prevents it from tipping sideways. Smith machines are dangerous because they lock the lifter into a vertical or near-vertical straight-line bar path. The smith machine can be safely used for short range-of-motion exercises such as shrugs and calf raises, where the natural bar path is close to vertical. However, for any compound lift such as a bench press, overhead press, squat or deadlift, the natural bar path is not a straight line. By interfering with your natural (and optimal!) movement, the smith machine increases the stress on your joints and stabilizer muscles. I tore ligaments in both my shoulders using a smith machine for overhead presses.
2. Leg Extension
As you extend your leg into the locked-knee position, your shin bone rotates slightly. Leg extension machines interfere with this rotation. This puts unnecessary stress on the knee joint and can cause the knee cap to grind against the femur. Moreover, the quadriceps evolved to assist in running and jumping movements, not to provide torque against a rotating force.
3. Bent-arm Laterals Machine
Doing dumbbell laterals with your arms straight (but not locked) is reasonably safe and beneficial exercise. However, bending your arms, as this machine forces you to do, dramatically increases the stress on your rotator cuff and can lead to tears. The small muscles and tendons comprising the rotator cuff heal slowly and are difficult to rehabilitate.
4. Cable Row
Rows are a great exercise; however, rowing machines almost always suffer from the same problem. At the beginning of the exercise, you have to reach so far forward to grasp the handles that you inevitably overextend your lower back. This can damage your spine, the nerve cluster in your lower back, and your spinal erectors (the small muscles that hold your lower back straight. These are the sorts of injuries that don’t get better.
Suggestion: use a piece of chain and carabiners to bring the handles closer to you, or get someone to pull down on the cable so you can get into position safely.
5. “Ergonomic” Benches
The thing about ergonomics is that it has to be personalized to your body. These so-called ergonomic benches make assumptions about your height, weight, proportions, limb length, etc. Unless your body happens to fit these (often restrictive) assumptions, you’re out of luck. I can feel the benches in the above picture interfering with my shoulder movement. They also encourage taller people to move too close to the uprights (thus press to linearly) and encourage shorter people to move too far away from the uprights (thus endangering the shoulder in the initial lift). All of this serves to corrupt one’s pressing motion and endanger the shoulders, elbows and wrists.
6. The Pec Deck
This type of pec deck puts your shoulders in the inner dislocation position and can tear the shoulder ligaments or the rotator cuff.
7. Ab Twisters
The spine is not meant to twist. Twisting the spine can damage the disks between your vertebrae. The kind of spinal twists they do in Yoga (slow, controlled stretches) are probably ok, but twisting against resistance encourages a faster and more violent movement that’s significantly more dangerous.
8. Ab Crunch Machines
Crunches do stimulate growth in the rectus abdominis (the six-pack); however, the full crunching your abs also full flexes your spinal erectors, putting maximum pressure on your lower back. Over time, this damages the disks in your back. Besides, most people’s abs are invisible not because they’re ill-developed but because their percentage body fat is too high. If you want your abs to show, hit the treadmill, not the crunch machine.
Suggestion: Composite exercises such as squats and pushups work your abs the way they were intended to work – as stabilizers. If you must do an ab-specific exercise, try the plank position.
9. Standing Calf Raise
The calf is a very strong muscle. Working both calves at the same time on a standing calf raise can involve hundreds of pounds in a normal person, and over 1000 lbs. in a very strong person. This kind of weight compresses the spine, breaks blood vessels in the shoulders, and generally puts a lot of strain on joints. Standing calf raise machines often encourage this sort of practice because they often come with signs showing a two-leg movement.
Suggestion: Do calf raises one leg at a time. Hold a dumbbell in one hand and a post to keep you steady in the other.
10. The Decline Bench
The decline bench is a shoulder-wrecker if there ever was one. Pressing on a decline bench puts extreme pressure on the shoulder joint and surrounding stabilizer muscles, meanwhile making it nearly impossible to press the weight in the natural back-toward-your-head arc. The slant of the board encourages the lifter to push from the shoulder instead of the chest, and to let the shoulders ride “up” (toward the head) when they should be rotating “down” and back (toward the feet). The decline bench is just an exercise clusterfuck. It’s biomechanical voodoo. Don’t use it.
Suggestion: If you must work specifically on your lower pecs, try a parallel bar dip. However, avoid an extreme range of motion (dropping past the point where your upper arms are parallel to the ground) or this too will put exaggerated stresses on the shoulder. (Note: never do dips behind your back – these endanger the rotator cuff.)
If you’ve used one of the machines profiled above for years without injury, consider yourself lucky it hasn’t hurt you yet and quit now! Yes, smoking hasn’t killed you yet either, but that doesn’t mean you should keep doing it. I am not a doctor; check with yours before starting a new workout program. Don’t just switch to free weights if you have no idea what you’re doing. Find a good book on weight training (The Insider’s Tell-All Handbook on Weight Training Technique, for example) and read it before you beat yourself up.