It’s true that most gyms have a lot of fancy equipment and a lot of free weights. It’s also true that most gyms have too much fancy equipment and not enough free weights.

Generally we have two primary objectives when working out: (i) Enhance our personal health and wellness, and (ii) look good (or at least better). However, somewhere on that list is "avoid injury". No one wants to hurt themselves, we don’t want to feel pain or discomfort. Although it’s nearly impossible to avoid the occasional pulled muscle or overuse injury, you can make your exercise routine safer by avoiding some of that "fancy equipment".

The following includes a handful of machines/equipment to avoid. This list is not exhaustive, but rather includes the equipment I see most often used. Note: The lists of alternative movements are not exhaustive either.

1. Smith Machine Anything (with an occasional exception): The Smith Machine consists of a barbell that is fixed within steel rails allowing for vertical movement only. That last part "vertical movement only", that’s why this machine is no good.

First, a quick physiology primer: When the body moves, it rarely follows a fixed plane of motion. In other words, if you were to tape a marker to your shoulder, squat near a wall, and then look at the drawn line, you would not see a straight line, more likely an arc. This is referred to as the "arc of power". The body follows these arcs for movements such as squats, dead lifts, bench presses, and rows.

The design flaw with the Smith Machine is the fixed vertical plane of motion, forcing your body out of the arc of power. The result is (i) reduced force and power production, and (ii) compromised joint positioning.

There are only two exercises I recommend you use the Smith Machine for. The first is Australian Rows. These are an exception because the bar doesn’t move, and you’re really only using the Machine as a glorified pull-up bar.

The second is supervised light weight box squats. Only a very specific movement pattern is safe when squatting on the Machine. Weight should be relatively light (higher reps) and strict form adhered to.

Easy Alternatives: Body weight squats, barbell squats (front or back), dumbbell goblet squats, lunges, split squats, step-ups, barbell bench, dumbbell bench, dips, pushups, dumbbell row, barbell row, chin ups, pull ups, cable row, military press, shoulder press, deadlift, and any possible variation of these movements.

Bottom line:  Whatever you think about doing with the Smith Machine - use dumbbells or barbells instead.

2. Behind the Neck Pulldown & Shoulder Press. Lat Pulldowns and Shoulder Presses - powerful, effective movements when done properly. Done improperly, one of the most dangerous movements for your rotator cuff.

The rotator cuff is a group of muscles and associated tendons that stabilize the shoulder. As strong as the rotator cuff is, improper movement can result in gradual micro-tears, leading to macro-pain. Performing these activities behind the neck places an inordinate amount of stress on the rotator cuff,  pinning it back against the joint. A safer alternative is to perform them in front of the head.

Also, everyone has "physiological and postural anomalies" caused by genetics, repetitive movement, and posture; all of which can be addressed by slightly altering the movements. If you feel discomfort in your shoulders when performing either of these activities, try shifting your hand position into "neutral" (palms facing each other) or "supine" (palms facing you). 

3. Leg Extension: The Leg Extension is "designed" to target the Quadriceps (the big muscle on the top of your leg). Mayo Clinic physiologists determined the Leg Extension abnormally, and unnecessarily, stresses the knee. This is likely caused by the resistance being applied low on the leg (around the ankle).

Additionally, exercisers squat rather than use the leg extension have stronger ligaments and connective tissues around the joint. This leads to a increased joint stability and decreased risk of injury.

Alternatives include squats, lunges, and split-squats.

4. Pec Dec, Hip Add- / Abductor, Seated Twist, Most Selectorized Machines: Each of these machines locks your body into a plane of motion, defying the bodies arc of power . In an effort to avoid reiterating what’s already been said, read "1" above.

A note on the Add- / Abductor - The hip joint is not capable of the same movement complexity as the shoulder. The hip is generally designed to go forward and backward with limited lateral (side-to-side) movement. Adding weight to this lateral movement won’t slim your buns or shape your hips, it will wear down the joint, causing pain and stiffness over time.

Alternatives to these movements:

a. Pec Dec: pushups, dumbbell flyes, cable flyes, chest press, bench press, and pullovers;

b. Hip Add- / Abductor: Lying side leg raises, flutter kicks, scissor kicks, donkey kicks, and bird-dogs;

c. Seated Twist: Cable chop, dumbbell chop, Russian twist, side-plank; and

d. Selectorized Machines: The same movement with dumbbells, barbells, or body weight.

These machines are popular because they’re easy to use and require little attention to form. However, with limited exception, avoid them. You’ll get a better workout in 30 minutes with free weights then you will in 60 minutes with machines.