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10 Mistakes People Make in the Gym

Man lifting barbell

Kent Probst, BS, MEd

Kent Probst is the owner of Long Healthy Life Blog

Most of us know the health and fitness benefits of strength training related to health and longevity.  But many don’t know the 10 mistakes people make in the gym that prevent us from getting all the benefits.

You’ve decided to incorporate strength training into your health and fitness regimen.  Or maybe you’re already off to the races.

There’s a lot you need to know when it comes to strength training.

You’re bound to make mistakes starting out. Even people at an intermediate level make mistakes.

Most likely you’re making some mistakes.  That’s okay.  It happens to the best of us.

Maybe someone in the gym, or a friend told you to work out a certain way.  It could be that you read something on the Internet.

If you’re making the effort, you should get as much benefit as possible from your strength training workout.

Spend enough time in the gym and you begin to notice certain behaviors regarding how people perform strength training.

I’ve pulled together a group of mistakes that a lot of people make in the gym.


What Are 10 Mistakes People Make in the Gym?

1. Performing repetitions too fast or too slowly

A significant body of research demonstrates that the optimal speed for repetitions is 0.5 to 6 seconds.

This includes the concentric contraction (shortening), the isometric contraction (static) and the eccentric contraction (lengthening).

The isometric contraction occurs between the concentric and eccentric contractions.

Performing your repetitions significantly faster than 6 seconds doesn’t allow you to get the potential benefits (increased hypertrophy or muscle mass) of the eccentric contraction when done slowly.

A good ratio is to do the concentric contraction (lifting) 2 seconds and the eccentric contraction (lowering) 4 seconds.


2. Not using full range of motion

If you look around the gym, you’re sure to find people not doing full range of motion (ROM).

While there may be some benefits to using partial-ROM, not exploiting full ROM neglects the benefits of full ROM, particularly increased muscle mass.

The stretched position elicited by full ROM is important for increasing muscle mass.


3. Not timing yourself between sets

If your goal is to increase strength and muscle mass, then you should be paying attention to the rest time between your sets.

While you can get some benefit from resting 60 to 90 seconds between sets, resting 2 minutes or more will yield greater increases in muscle mass.

Resting 2 minutes or more allows you to handle a larger load volume.


4. Strength training at sub-optimal times

Many of us lead busy lives, and can only work out in the morning or mid day.

But did you know the best time to do strength training is between 4pm and 6pm?

Your body temperature peaks between 4pm and 6pm, and it’s believed to be the reason pliability, speed, and strength peak during this time frame.

Therefore, the optimal time for resistance training is 4pm to 6pm.


5. Doing cardiovascular exercise and strength training too close together

You may be surprised to know that cardiovascular exercise and resistance training conflict with each other at the molecular level.

When they are done in the same session, gains in muscle mass and strength are adversely affected.

This is why you should do cardiovascular exercise and resistance training at least 3 hours apart.

Additional research has shown that you need between 6 hours and 24 hours to avoid having cardiovascular exercise interfere with gains in strength and muscle mass.


6. Doing exercises in the wrong order

It’s commonly believed that you should train the largest muscles first.

This is based on the belief that the large muscles used in multi-joint exercises are impaired when smaller, secondary muscles are fatigued first.

The research is equivocal on this. Whether you’re working large muscles or small muscles first, it doesn’t seem to matter.

What’s important is that you work muscles that are lagging behind first.


7. Training too intensely

The old adage, no pain, no gain is not necessarily true.

Always training to failure can lead to overtraining, which is a decline in performance, or a lack of improvement.

While there can be some benefit to training to failure, it should be implemented in the last set of an exercise.

Most of your sets should be done to subfailure, allowing for 1 or 2 repetitions in reserve.


8. Not using a log or journal

It seems easier just go in and do your workout, and not worry about keeping a record of what you’re doing.

But if you want to maximize progress, it’s important to keep an electronic or written record of what you’re doing.

Almost no one can remember how many reps you did and how much weight was used on the bench press two months ago.

Being able to go back and look at your workouts a month or two ago, will tell you how much weight you should be using today.

250 x 250 Evergreen


9. Not stretching properly

Some people don’t stretch after their workouts, or they stretch improperly.

Stretching increases pliability and reduces tight muscles. Muscles look for pliability as a cue, and use it as a stimulus for power and strength outcomes.

Pliable muscles, or muscles that are stretched, contract more forcefully than muscles that are tight.

Flexibility training, or stretching, should be done after an exercise session. Static stretching should be held for 30 seconds without pain.

Stretching longer than 60 seconds is detrimental to power, strength, and speed-dependent skills.

Each stretch should be done 3-5 times.


10. Combining dissimilar exercises

Sometimes you see people in the gym combining two biomechanically different exercises, such as knee extensions and bicep curls.

This type of exercise pairing confuses the muscles, which look for consistency.

For your workout to have positive strength outcomes, your muscles need consistency to make the necessary physiological adaptations.

Pairing biomechanically similar exercises is one way to accomplish this.

It’s more effective to do a tricep extension immediately followed by tricep dips.


Don’t make the 10 mistakes people make in the gym

You now have a leg up (pun intended) on a lot of people in the gym.

By incorporating these recommendations you’ll be on your way to more effective strength training workouts.

You can expect to reach your goals of increased strength and muscle mass in less time.

You can smile knowing you’re not wasting your time in the gym.


Disclaimer: This post includes affiliate links, and I will earn a commission if you purchase through these links. Please note that I’ve linked to these products purely because I recommend them and they are from companies I trust. There is no additional cost to you.



Science and Development of Muscle Hypertrophy, Second Edition, Brad Schoenfeld, (Human Kinetics Publishers, 2021).

Timing Resistance Training, Amy Ashmore, (Human Kinetics Publishers, 2020).

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Hi, I'm Kent

As a personal trainer, exercise physiologist, and bodybuilder, I’ve dedicated my life to optimal nutrition, fitness and natural remedies. And putting it all into practice. Now I’m taking my experience and knowledge to the next level by helping others through blogging.


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