Can’t Build Muscle? Here are 3 Reasons That Are Easy To Fix

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Have you been consistent with your weight training program and aren’t seeing the muscle growth you’re expecting?

This article highlights the common issues that cause lackluster muscle building results in women & men, and offers suggestions on how to fix them.


Typical reasons you can’t build muscle

Problems building muscle are often found in these three areas: 

1. Training habits – too much cardio, not being on a proper muscle-building program, not enough effort

2. Diet habits – not eating the right foods in the right quantities 

3. Rest & recovery habits – poor sleep patterns, not enough muscle recovery, & overtraining


What’s next

Ahead we’ll break down these three sections – training, diet, & recovery – in detail.

We’ll identify what mistakes commonly occur so you can take care of them and generate success with your muscle-building plans.

If you’re interested in more specific info on training & diet routines focused on muscle-building, my article How To Build Muscle & Gain Weight If You’re An Ectomorph may be helpful to you.

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Science resources included

As is my custom here on heydayDo, I will provide links to all of the relevant sports science & medical resources, clinical studies, and nutritional data used in this article.


Training & poor muscle growth

Here are a few places in someone’s strength training program where a mistake could get in the way of their muscle building.


Too much cardio

Cardio exercise provides a host of health & fitness benefits for sure (1).

But do too much of it or do it at the wrong time and you will hurt your muscle building efforts, as sports science has shown.


Don’t do cardio before you lift

If you do your cardio workout before you lift weights, you’ll have less energy for a heavy weightlifting workout, and that leads to less muscle building.

Less energy means less effort, and less effort means less work for the muscle groups you’re training that day.

Less muscle work means a less effective workout which means less muscle-building results.

A recent study on cardio exercise & weightlifting found that the cardio workout beforehand reduced the quality of the strength training (2).

The researchers concluded that

“acute resistance exercise performance is significantly compromised..after aerobic exercise exercise.”


Young woman exhausted at gym doing too much cardio, too tired to lift weights - heydayDo image

Cardio uses up calories needed for growth

As you’ll see in the next section on diet, not providing your lifting program with enough calories is a sure way to prevent muscle building.

Cardio burns calories which is cool for weight loss purposes no doubt, and the American Council on Fitness recommends three 30-minute cardio sessions per week for those looking to add muscle (3).

But too much cardio during your weekly fitness routine can burn up calories your body needs to repair, feed, & grow your muscles.


Cardio reduces muscle building & strength results

A research review published in the Journal of Strength & Conditioning looked at over 20 cardio + strength training research studies.

They determined that having a regular cardio routine interfered quite a bit with the effectiveness of weightlifting programs (4).

Cardio significantly slowed both strength & muscle gains for the participants, compared to the people who only lifted weights.


Again, this isn’t cardio done before the lifting like in my previous example. These are people who were doing regular cardio workouts and strength training concurrently in the same week.


Bowflex SelectTech 552 Adjustable Dumbbells

More muscle = more calories burned too

Keep in mind that strength training provides great weight loss benefits too, if you’re concerned about being able to lose fat and gain muscle at the same time (5):

* More muscle on your body means more calories are being burned, and your muscle burns a lot more calories than your fat does (6).

* Strength training burns more calories after your workout than cardio does. And it can boost metabolism for up to 72 hours post-workout (7).


Bottom line: Cardio’s a great way to burn calories if you’re trying to shed pounds, but science has proven it can really hurt muscle building if done at the wrong time or in excess.

Avoid doing it before workouts or even on workout days, except for use as a brief warmup.


Using the wrong lifting routine

Just because someone’s doing lots of sets, reps, & weightlifting exercises doesn’t mean they’re going to get bigger.

Building muscle mass as quickly as you can is dependent on you choosing the right exercises and the right training volume.


Not focusing on compound exercises

The common mistake here is spending too much of the workout doing sets of isolation exercises instead of compound exercises.

Compound exercises work more than one muscle group at a time, and are essential for building overall strength and muscle mass.

Before steroids, the bodybuilders with the most muscle mass concentrated on compound exercises, not isolation exercises.

If you’re unfamiliar with the term or are wondering which exercises are compound exercises, here’s a list of most of the essential ones:

  • Squats
  • Bench Presses
  • Deadlifts
  • Overhead Presses
  • Bent-over rows
  • Pull Ups
  • Dips
  • Pullovers

Isolation exercises on the other hand include things like:

  • barbell curls
  • triceps kickbacks
  • leg extension machine
  • calf raises
  • other gym machines where you sit & isolate a muscle

Isolation exercises have their place, especially in the case of curls & calf raises, since there’s no other primary exercise for those muscle groups.

But a muscle builder won’t want to build her workout on a bunch of isolation exercises.


Bottom line: A workout built to build muscle & strength will require 80-90% of your energy & effort be focused on compound movements.


Not using progressive resistance training rules

The mistake here is doing the same weight with the same number of reps for the same number of sets over a period of weeks & weeks.

In order to stimulate your muscles to grow, it’s important that they be continually challenged.

Progressive resistance training means that as you get stronger, you very gradually increase the intensity of your workout over time.

You can do this by increasing the number of reps to one of your sets, or by increasing the weight by a very small amount.


Progressive resistance primer

Let’s say that in one of your exercises you’re doing 3 sets of 8-12 reps.

Say you start off with a weight you can do 8, 8, & 8 with.

Next workout (or next week) shoot for 8, 8, & 9.

Then 8, 9, & 9, and so on, trying to get an extra rep either every workout or every new week.

You keep working within that same “3 sets of 8-12” range, but you’re progressively getting stronger within it as well.


Increasing the weight very gradually

And once you can easily do 3 sets of 12, it’s time to bump up the weight.

Only increase it a little so that you’re back to having to work hard just to get to 8 reps.

The reason you only increase the weight a little is because there are human limitations on how much you can keep increasing the workout intensity.

By moving up your weights slowly, your body is less likely to “plateau”, or stall, with that particular exercise.


By constantly challenging your muscles using progressive resistance principles they will continue to grow.


Not doing the right # of reps for muscle hypertrophy

The mistake here is usually doing far too many reps per set.

If you’re doing 15, 20, or 25 reps – the weight is obviously too light for it to challenge your muscles to grow.

A less common error is when someone has patterned their set & rep regime like a powerlifting routine.

Here, there are too few reps (usually from 1-4) per set and long rest periods between sets.

This format is great for building strength but not so much for building aesthetic muscle in the style of bodybuilders & muscular fitness models.


No magic rep number

First off, there’s no magic number of reps that will always cause muscle hypertrophy (the science term for muscle cell growth).

However, there are some general guidelines I can pass along.

These are based on boatloads of sports science research, as well as real-world proof courtesy of some of the greatest non-steroid bodybuilders.

The ACSM (American College of Sports Medicine) recommend 8-12 reps per set for beginners & intermediate lifters looking for muscle hypertrophy, and offer the full gauntlet of 1-12 reps for what they call advanced trainees (8).

But again, performing under 5 reps isn’t the most common territory for the type of muscle size + definition you’re used to seeing on fitness models & bodybuilders.


How the original great ones built muscle

Reg Park (Arnold Schwarzenegger’s early idol & later his mentor) is the one who made the classic 5×5 workout classic (9).

It consisted of 5 sets of 5 reps per exercise.

By the way, the first 2 sets were light & easy; the last 3 were what he called his “work sets”.

In Arnold’s very early days he did his own versions of Reg’s routines, and sometimes would go to 10 reps on the main exercises (10).

In that same article I just provided the link for, notice that Larry Scott – the inventor of the preacher curl/preacher bench – used a 6-8 rep routine for most of his main muscle group exercises.

All three of these guys enjoyed a lot of muscle growth using these rep ranges in between 5 & 10, so the odds are good your sweet spot for building your muscle lies somewhere in that range as well.

I wrote up my own version of the 5×5 here on heydayDo, adapting it to my older “ectomorph” body. It’s going real well for me – I see strength & muscle gains. Check it out if you’re interested.


Lifting without enough intensity

Out of shape skinny guy making fun of his too light dumbbell - heydayDo image

The mistake here is simply that the person isn’t working hard enough. 

They could be doing the right exercises for the right number of reps, but since the weight’s too light there’s not a lot of effort.

Your muscles have to be stressed while you’re lifting in order to trigger growth.

One way to do that is to make sure your last few reps on every set are hard for you to complete.

So if you’ve settled in on an 8-12 reps per set regimen, you’ll want the last few reps to be difficult to complete, whether you’re stopping at 8, 10, 12, or even 6 on a day you’re weaker than usual.

The tail end of every set should present a challenge for you; that’s what intensity means in this case.

Remember back when I described progressive resistance training earlier.

Once all the reps for that set are too easy, increase the weight.

That injects a fresh intensity level, and that’s how you can keep your muscles growing.


Wasting time between sets

Keeping a close watch on how much time to rest between sets is a good idea, as it’ll help keep the workout intensity up.

Use your watch or your phone to time your rests.

In general, limit total rest time between sets to 60 seconds for most of your workout.

If you’re doing a lower rep routine (5-6) with heavy weights, a 90-second to 2 minute rest is definitely appropriate.

This way cardiovascular fatigue isn’t as much of a factor influencing your results.

You catch your breath & recover enough to go strong again in a couple of minutes.

But anything up in the 8-12 range, you want to be starting that next set on the 61st second.



2. Diet habits that hurt muscle growth

What we choose to eat & drink while we’re trying to build muscle has a big say on how successful our weightlifting plans are.

Put another way, a crappy diet can slow or flat-out derail muscle building.

Here are the most common diet mistakes people make that hurt their training goals.


Not eating enough calories

The mistake here is self-explanatory.

Training hard to build muscle requires a lot of energy. Energy for our bodies is expressed as the word calories.

When building muscle is our goal it’s important to eat a lot more calories than we normally would.

And normal here includes whatever level of physical activity we usually have, whether it’s a maintenance-type of lifting program or other weekly fitness routine.

The body needs the extra energy (via more food) to manage all sorts of system processes to help the muscle building process along.


My weight gain smoothie recipes

Want a lot of great-tasting & good-for-you-too calories?

In my article Protein Shake Recipes For Weight Gain here on heydayDo, I show how I put together my high-calorie protein smoothies when I want to gain weight by building muscle.

I also provide all the nutritional information: calories, protein, carbs, fats, & fiber.


How many more calories per day above normal?

An analysis of existing sports nutrition research recommends that athletic individuals involved in intense resistance training geared towards muscle hypertrophy consume between 375-500 calories per day above their normal BMR, a.k.a. their Basal Metabolic Rate (11).


If you’re unfamiliar with the term, your basal metabolic rate – also known as your TDEE (total daily energy expenditure) – is the number of calories your body burns per day. It takes into account your level of physical activity as well as a few personal attributes like age, sex, height, & weight.

It’s calculated using a complicated equation, but you can use free ones online to calculate yours, like this one here.


Bodybuilders need up to 15% more calories

And a research study specifically focused on the nutritional needs of bodybuilders recommends that during the off-season while they’re adding muscle that their caloric intake could be as much as 15% higher than their normal BMR (14).


Determine your BMR, and aim for 110% of it

Mere mortals like us who are looking to build muscle can aim a little lower than those advanced athletes & bodybuilders, and so 10% or so above our basal metabolic rate is a good target.

For example, my BMR is roughly 2700 calories a day. 110% of that would be 2700 + 270 = 2970.

So when I’m on a muscle-building campaign like I am nowadays, I’ll shoot for about 3000 calories per day.


These extra calories are important

Regarding recreational muscle builders, the International Sports Sciences Association (ISSA) simply states that if someone is

“not meeting his/her caloric needs for growth and repair, they will not get bigger, stronger muscles.” (13)


Not eating the right kind of calories

If the type of calories you’re ingesting aren’t what your body needs to build muscle, it won’t build it for you.

We just discussed creating a caloric surplus so that there’s enough energy to build muscle.

But the right nutrients have to be in that food too – it can’t be a bunch of junk.

That’s called dirty bulking, and it just creates the added burden of having to manage a weight loss program later.

I humbly suggest just eating a lot of clean, nutritious food instead.


Not getting enough daily protein

Protein is king when it comes to building muscle. After all, the process to build & repair your worked-out muscles is called muscle protein synthesis.

So you need enough protein daily to provide for all the building & repairing you got going on with your muscles.

The ISSN (International Society of Sports Nutrition) recommends that intense trainees get in the neighborhood of 0.7 – 1 gram of protein per lb. of bodyweight per day (15).

It’s possible to get all of your daily protein need from the food you eat, but it’s not easy for many of us, yours truly included.


Consider protein supplements

For example, my daily protein requirement is between 180-200 grams per day.

That amount’s equal to roughly 6 cans of tuna, or 30 eggs, or 2 lb. of lean beef or chicken.

Ever since I started strength training back in 1982, I had a hard time eating enough of that stuff to hit my protein number every day.

So I started drinking protein powder in between my big meals, instead of trying to chow down on another chicken leg or hardboiled egg.

Whey digests quickly and doesn’t leave you with a “too full” or bloated feeling, so that has worked for me for decades now.

I also drink a collagen shake nowadays too. It’s sourced from beef but has absolutely no taste to it, so I can mix it with whatever.


Bottom line: It’s important to get the right amount of lean protein into your body every day when you’re working out with weights. Get most of your protein from quality food sources, and consider a protein powder supplement if it’s hard to eat enough meat, chicken, fish, & eggs every day.


Get the right % of other macros too

Carbohydrates are essential for intense training energy too, and the ISSN goes further and states that athletes will need a lot more carbs & protein than the average person (16).

Their recommendations for “regular adults” includes up to 35% fat.

But muscle builders & athletes will consume much less fat than that since their daily requirement for protein & carbs is higher.

A sports science research review recommends the following macronutrient ranges for muscle builders (17):

  • carbs 55-60% of total daily calories
  • protein 25-30%
  • fats 15-20%


3. Not enough rest & recovery

The third & final area where muscle building can be negatively affected has to do with rest (particularly sleep), & proper workout recovery.

A lack of either of these things in a person’s life will hurt their chances for effective muscle growth.

As I said earlier, muscle building is an intense experience for our bodies.

It is necessary that they have the time to recover, restore, & rejuvenate themselves & to repair the muscles that have been worked.


Not enough sleep hurts muscle growth

Medical research has shown that our bodies release most of their growth hormone when we’re in deep sleep (18).

This growth hormone is an important part of how our muscles grow while we’re strength training.

Poor sleep habits – sleeping less than 7 to 8 hours a day – not only reduces the amount of growth hormone production, but also prevents our bodies from getting the quality rest needed to properly recover from our workouts.


Not enough recovery between workouts

If you’re working out hard 5-6 times a week while you’re attempting to build muscle, you run the risk of not letting your body (& certain muscle groups) have the time they need to recover properly.


You definitely want to avoid overtraining

If you’re working out too much you can run your body into the ground and end up in the unpleasant catabolic state known as overtraining.

The American Council on Exercise states that if you overtrain, your body will start increasing its release of stress hormones adrenaline & cortisol, which cause their own sets of problems for you (19).

And any muscle gaining you hope to do will be derailed.

You won’t have productive workouts until you’ve healed from the various symptoms of fatigue, decreased performance, insomnia, etc.

This could take weeks for some people.

Here’s a helpful video from Jeff Nippard, someone who is an expert at building muscle:

Some of the biggest (clean) muscle builders lifted 3x a week

Earlier in the article I mentioned one of the greatest muscle builders of all time, Reg Park (20).

Now’s a good time to mention that he gained pounds & pounds of muscle early in his career while only lifting 3 days a week.

Without steroids.

He knew that muscles grow after you’ve done all the weightlifting, on your off days.

And when he was doing that famous 5×5 workout of his, he had 4 off days a week.

Laura Efrikian and Reg Park

Reg Park starring in one of his 5 Hercules movies


The ACSM (American College of Sports Medicine) recommends 48 hours between workouts of the same muscle group, which you might’ve known already (21).

They also go on to recommend things like

  • dynamic & static stretching,
  • hydration,
  • post-workout nutrition,
  • foam rolling &
  • massage

as options to enhance the recovery process, along with at least 8 hours of quality sleep.

I’ll vote that sleep is THE most important one in the bunch.


Wrapping Up

I hope this article highlighting the common reasons some people can’t build muscle will be helpful to you.

Making the right choices regarding your training, your diet, & your recovery can make all the difference in the world.

I wish you well on your fitness journey; let’s go.

– greg

About The Author

heydayDo author Greg Simon

Hi, I’m Greg Simon. Fitness training & nutrition researching since 1982. ISSN (International Society of Sports Nutrition) Pro Member. MBA, B.Sc.

Author. Surfer. Organic food grower. Congenital heart disease survivor (so far). is my wellness blog that’s about encouraging a healthy lifestyle as we age. 

I share my fitness training experience as well as the sports science research I’ve done on the many benefits strength building, exercise, & good eating habits offer us. 

I also write review articles after product testing and evaluating home gym equipment & fitness supplements.

My hope is that you’ll find useful or encouraging information here on my website that will benefit your unique fitness journey.

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