You are probably not learning or progressing if you’re not making mistakes. When you make mistakes, then you know better and then do better. If you make the same mistake twice, you will learn better the third time.

In the weight room, when striving for progress, mistakes are going to be made and are usually a combination of ego, impatience, or a lack of knowledge. The ego and impatience are something for you to work on, but I can help with the knowledge part.

Nearly 99% of lifters who touch a weight want either big, well-defined arms or both. The other 1% are lying to themselves. There’s a reason why people clamber for mirror space by the dumbbell rack with busting out curls because a pair of muscular arms is a status symbol of hard work.

Unfortunately, due to ego, impatience, and a lack of general muscle-building knowledge, mistakes can be made when lifters are trying to add size to their arms. Here, we’ll focus on three big and common mistakes lifters make when trying to add size to their arms.

Bodybuilder doing a workout for biceps with dumbbell curls exercise
Srdjan Randjelovic

Reliance on Either Compound or Isolation Exercises

There are two schools of thought regarding adding size and strength to your arms. The compound exercise school where the students say all you need are big compound exercises like chin-ups and bench presses to build big arms. Then there is the isolation exercise school, where students think you need to hammer your arms with every bicep curl and triceps exercise known to man to make them grow.

The truth is you don’t need one or the other; you need both.

Your biceps and triceps will be heavily involved with big compound movement for the chest and back, but that’s not all you need. This 2021 study compared the biceps growth of doing dumbbell rows versus dumbbell curls. After eight weeks, although performing only dumbbell rows led to biceps growth, adding biceps curls to the mix was shown to lead to more gains.

Although only the biceps were studied, these findings mean two things for those interested in getting bigger arms.

  1. You will still gain arm muscle by performing compound exercises and should never overlook their importance. Your arms should follow suit the bigger and stronger your chest, back, and shoulders get.
  2. Isolating your biceps and triceps with one or two isolation exercises after your compound exercise is essential to add size to your arms.

Never do just one or the other; always do both.

Fit bald man doing arm workouts with a incline dumbbell curl exercise
Jasminko Ibrakovic

Don’t Cut Short Your Range of Motion

It seems so obvious that it shouldn’t be said, but many lifters still make this mistake when adding muscle and strength. Granted, there is a time and a place for partial range of motion lifts like rack pulls and floor and board presses because they will strengthen you and help you break through plateaus.

But it’s the goal to size your arms or any body part; there is a better muscle-building stimulus when your arm muscles are stretched under load, for instance, the bottom of a biceps curl, chin up, or when your hands are behind your head during an overhead triceps extension. Here’s a research study that backs up this very point.

There’s no need to dazzle you with scientific facts and knowledge, but this is as close to reality when it comes to building muscle as there is. The more time you put a muscle under tension, the better the chances it will grow, and a surefire way to achieve this is by performing compound and isolation exercises with a full ROM.

To improve your arm’s muscle-building potential, maximize the stretch they go through and don’t shorten the range of motion. Both will lead to better flex times.

Man lifting a heavy single dumbbell off the dumbbell rack
tool2530 / Shutterstock

Forget to Focus On Progressive Overload

There was a long-held thought that eight to 12 reps was the best range for building muscle. But the truth is you will build muscle in many reps ranges with light to moderate weight because you don’t always need to go hard and heavy to build muscle. But there is one thing that will never change, and that is to build muscle; focusing on progressive overload is paramount.

You know, sometimes, it is easy to overlook the obvious.

But in the social media age of chasing the muscle pump for the best selfie or constantly shifting between the coolest exercises, there is a lack of focus on consistency and progressive overload.

Instead, pick two or three biceps and triceps exercises and record your sets, reps, and weight used. Focus on increasing your volume (total reps x weight lifted) or time under tension each workout and stick with them for four to six weeks. Then, switch up your exercises to prevent training boredom and encourage muscle-building stimulus, then watch your arms grow.