Certified Trainers Say You Should Never Waste Your Gym Time On These Exercises

woman in workout outfit
woman in workout outfit

This article has been updated since its original publish date of 10/20/2023 to include more expert insight.

You may think that just working out means that you’ll get fit and lose weight in no time, right? Not exactly. Not every move or machine at the gym is going to make you stronger or fitter. Some are not that helpful at all, no matter how many reps you do. To learn more about exercises that just waste your time, we spoke with certified fitness trainer Bishnu Pada Das; Cara D’Orazio, a certified personal trainer, group fitness instructor, and specialist in sports conditioning; Andrew White, CPT and co-founder of garagegympro.com; and Matt Haas, certified fitness trainer. They said bicep curls, leg pressescrunches, and Smith machine squats, end up doing more harm to your muscles than good or just don’t provide any improvement. Read more below!

Bicep curls with a straight barbell

Biceps curls are a very popular weight-training exercise that works the muscles of the upper arm and, to a lesser extent, muscles on the lower arm. Different equipment and grips can be used for this exercise including those using dumbbells, kettlebells, resistance bands, cable machines, or straight barbells. Although this exercise is common in a lot of workout plans, bicep curls with a straight barbell are not recommended by certified trainers like Haas.

"The standing bicep curl is an exercise that only targets your biceps, and is easy to do incorrectly," he stresses. "When you're standing up it's easy to cheat and swing the weights up with momentum when you get tired. If you want to train your arms more effectively, choose compound exercises that work your arms more functionally, such as chin-ups. If your goal is defined arms, then you are better off working the triceps which make up 70% of the arm's total mass." To maximize time in an arm workout routine, focus on exercises that use additional weight and resistance. This will help actually challenge the muscles, build strength, and achieve your fitness goals!

Leg press and leg extension

The leg press is a weight training exercise where the person pushes a weight or resistance away from them using their legs. The leg press can be used to improve someone's overall lower body strength. Unfortunately, this exercise can actually aggravate and even damage the leg muscles rather than build up strength.

"These exercises may be less effective at building overall leg strength and size of the leg because they only target a single muscle group (the quadriceps in the case of leg extensions and the quadriceps and hamstrings with leg presses)," Das says. "Compound exercises that involve multiple muscle groups, such as squats and lunges, may be more effective at building overall leg strength and size because they require the muscles to work together to perform the movement."

Because the exercise targets only one specific muscle group, it doesn't work on developing muscular balance or stability, which forms an important part of overall leg health. Also, putting too much stress on the isolated muscle may lead to muscle imbalances and overuse injuries. Haas has better workout ideas. He recommends, "a squat, which targets more leg muscles and stabilizer muscles and can be done with no weight or at the gym with as much weight as you can handle safely." Will do!

Sit-ups and crunches

Crunches are a workout that targets the abdominal muscles to build "six-pack" abs and flatten the stomach. Das says, "These ab exercises only target the rectus abdominis (the six-pack muscle) and [do] not effectively work the other core muscles, such as the obliques and transverse abdominis. These muscles are important for stability and support and should be included in any comprehensive core training program." Crunches don't require much force to be activated and are unlikely to cause appreciable muscle size or strength increases. If you're sick of crunches and looking to improve the size, strength, and definition of your abs, it is far more effective to focus on heavy compound movements, like squats and deadlifts, that require large amounts of force to be exerted by the core.

D'Orazio agrees and says, "While crunches target the abdominal muscles, they only burn a minimum amount of calories and fat. They will certainly not be enough for weight loss."

Smith machine squats

Smith machine squats, while seemingly convenient in the gym, might not be the most efficient use of your time and effort. Unlike free-weight squats, the Smith machine guides the barbell along a fixed vertical path, limiting the natural range of motion and stabilization required for a proper squat. This restricted movement pattern may hinder muscle engagement and development, potentially leading to muscle imbalances.

White elaborates and says, "While they can be good for beginners to learn squat mechanics, the guided path of the Smith machine doesn't engage stabilizing muscles like free-weight squats do."

He says that workouts that fail to involve multiple muscle groups simultaneously often result in lower calorie burn and prove less effective for both weight loss and overall fitness.

"Many machine-based exercises don't mimic real-life movements, limiting their effectiveness in building functional strength that benefits daily activities," he notes.

Instead he recommends free-weight squats and lunges, "These exercises engage the entire lower body, core, and even the upper body, leading to more calories burned and a greater increase in muscle mass."