Face it: You’ve got a lot on your plate and you really have to cut the fat these days. Productivity and efficiency are key.

“You’re wasting a lot of time and energy on things that don’t give you the desired effect when you could be putting that time and energy into much more productive exercises,” says Wayne Westcott, Ph.D., exercise science director at Quincy College in Massachusetts, who estimates that nearly half the people in the gym could substitute better exercises to achieve their goals.

Fitness experts are quick to point out that there are very few exercises that are completely useless across the board, but here are the ones they deem less worthy of your valuable time.

1. Smith machine squats

“The primary reason I would deem this move fairly useless for most people is the fact that the Smith machine in general locks you into a guided bar path, which will reduce the co-contraction of the quads and hamstrings. That decreases hamstring activation because they don’t have to counteract the quads as much and the bar is already being stabilized.” - Craig Rasmussen, C.S.C.S., training director at Results Fitness in Newhall, CA.

2. Abductor/adductor machine

“Most people do this exercise because they’re trying to reduce fat inside or outside their legs, and there’s much better alternatives for that. Exercising the muscle below the fat doesn’t do anything directly to the fat above it. You can get the same stabilizing muscles and the main prime mover muscles involved when doing things like stepups. Doing a lunge also recruits your adductors and abductors very strongly.”- Rasmussen

3. Standing chest flye (for chest)

“It doesn’t work the chest at all, because the chest isn’t working against gravity. What it is working are your shoulders, holding the weights against gravity in a lateral raise position. So I’m not saying it’s a bad exercise, but people think it works your chest and it doesn’t.” - Westcott

4. Triceps extensions or dumbbell kickbacks

“Triceps extensions or dumbbell kickbacks is a classic one that most people will waste a lot of time on. You can create a whole lot more of a training effect from doing things like pushups and any kind of presses. So that’s where you’re better off spending your time.” - Rasmussen

5. Dumbbell-loaded side bends

“Unfortunately, when you’re holding two dumbbells—one in each hand—the one dumbbell counterbalances the other dumbbell. There’s not much muscle effort when they balance each other out, so the dumbbell-loaded side bend is a fairly useless exercise. People think they’re getting a workout, but they’re really not.” - Westcott

6. Leg extensions or leg press

“The hamstrings are not very active at all during leg extensions or leg presses, so there’s a lot of sheer force and compressive forces created on the knee. If you're trying to build strength in your legs and have no knee or hip limitations, it’s better to do something like a lunge or a squat where that knee extension motion is involved, but you’re also just utilizing a whole lot more muscle mass around that joint.” - Rasmussen

7. Training on plate-loaded machines

“Training on machines can be very intense and developmental of some qualities. However, in terms of efficient use of time, machines allow us to train in one plane of motion, but we move in three planes. Machines allow a primary motion in one plane, while the other two planes are stabilized by the motion or apparatus. If we train with free weights, we have to control all three planes. Using this thought process, training on machines is 33% as useful as training with free weights.” - Charlie Weingroff, D.P.T., physical therapist and performance coach in New York City

8. Russian twists

“If there are two motions that yield negative adaptations in the structures of the spine, they are loaded and repeated motions of trunk flexion and rotation. While these exercises, like forms of crunches and Russian twists, can be very intense, there are dozens of other options to train those spinal muscles for the same fitness without the wear and tear of the spinal structures.”- Weingroff

9. Curls

“For curls, you are better off doing chinups, pullups, or various pull-down exercises because you’ve got multiple joints involved so you can use a whole lot more weight and put more stress on the target muscles. Stress is a good thing because that is what causes adaptations. There’s a time and place for those single-joint exercises, but it’s primarily for kind of putting the icing on the cake when you’ve already got the cake baked. People make the mistake of putting the frosting on before they really have any cake there.” - Rasmussen

10. Pilates to build flexibility

“While not impossible, very few people improve in Pilates when they are already inflexible. Pilates happens to be a useful warmup or cooldown if coached properly, but it is a terrible waste of time for improving strength or movement in already limited individuals.”  - Weingroff