Light or Heavy Weights, Which One is Better?

The other day, I was surfing the internet and typed in “building muscle” into the Google search box.

I took a look at the results on the first page and noticed something very peculiar. About 7 places down, there was a title that stated:

“Light Weights Better Than Heavy For Building Muscle?”

This immediately got my attention. It’s not because I think light weights are better than heavy, what I wanted to find out was how they came to this conclusion.

For those of use who’ve been in the iron game for any length of time, know that using heavy weights is one of the primary methods used to build muscle mass.

This type of training has been around for decades and one that has been proven time and time again, both in science and the weight room, as a working model for promoting positive muscle growth.

There is no question that this method works. However, using heavy weights is not the only method that can be used to build muscle mass.

There are literally, hundreds of varying combinations of weight and exercises that can be used to improve muscle mass and tone.

I’ve personally tried using light and heavy weight and have come to the conclusion that both can be effective at promoting muscle growth. However, I have noticed varying degrees of muscle growth with both methods, which I will get into shortly.

The real question is whether light weight is better at building muscle than heavy weight. According to the article, light weights are in fact better at promoting muscle growth. You can read the article here. Here’s an excerpt:

“Fear not. For sports experts say that when it comes to building muscle, light weights could be more effective than heavy.

Researchers at McMaster University in Hamilton, Canada, found that carrying out more repetitions of light weights could build muscle mass just as effectively, if not more so, than lower reps of heavy weights.”

If you want to read the summary of the actual study, you can find it here. The study was aimed at determining the effect of resistance exercise (varying weight and volume) on muscle protein synthesis, anabolic signalling, and myogenic gene expression. The actual study involved 15 men aged 21 years of age. Each performed 4 sets of leg extensions at varying degrees of exercise loads and/or volume. Given as follows:

  • 90% of one max output until failure;
  • 30% of one max output to 90% work-matched failure;
  • 30% of one max output until failure

The study concluded low load, high volume training is more effective at building muscle than high load, low volume training.

As I mentioned before, this is really no secret. However, what I find unsettling about this article, and the study, is the fact that weights are very subjective and to say that light weight is “better” than heavy is rather ignorant. In fact, I find this article very misleading and adds to the general confusion that is already out there when it comes to building muscle.

Firstly, it has been shown that using 90% of one repetition maximum is NOT conducive to building muscle. This is old news. Using this type of weight and volume is meant to improve strength levels. There is simply not enough volume to stimulate the necessary amount of muscle fibers for muscle growth – Especially the larger muscle groups such as the quadriceps.

At 90% of your maximum one repetition maximum, your repetition range will probably be in the range of 3 to 4. At this weight and range, your going to be using much more tendon strength. It is for this reason that I don’t recommend using 90% to 95% of your one repetition maximum for extended periods of time. It is simply too hard on your joints and tendons and if your body doesn’t have the genetics for it, chances are, your going to sustain an injury.

However, this type of training is used in strength sports such as power lifting and Olympic lifting where maximal repetitions are necessary. Please keep in mind that most of these athletes know that they can’t sustain 90% to 95% maximal effort for extended periods of time so they incorporate varying types of pyramid progressions.

That aside, the information in this study has been around for decades and is certainly not cutting edge news.

Secondly, this article (And the study) use weight as a subject measure to muscle growth. That is, it doesn’t take into account the most important element to muscle improvement. This element being consistent and improved levels of exercise intensity. Simply stating light weights will build muscle mass is hugely exaggerated. To me, its absolute rubbish.

According to the study:

“Rather than grunting and straining to lift heavy weights, you can grab something much lighter but you have to lift it until you can’t lift it anymore,” says Stuart Phillips, associate professor of kinesiology at McMaster University. “We’re convinced that growing muscle means stimulating your muscle to make new muscle proteins, a process in the body that over time accumulates into bigger muscles.”

Personally, simply picking up a weight and lifting it until your muscles fatigue is not conducive to building muscle. Let me state that right now. Lifting a 30 pound dumbbell and performing umpteen arm curls until they give out is a poor way to try and build muscle. The fact of the matter is that lifting weights for the sake of lifting weight is counterproductive, regardless of how much weight is used.

Here’s what the researchers missed.

In order to build muscle mass, one has to keep adding more and more intensity into their exercise regiment with each passing week. This is called, “performance improvement” and is integral to any successful weight training program. It doesn’t matter if you use a heavy weight and low repetitions or light weight and high repetitions, in order to build muscle mass, one needs to be constantly improving. This my friends, means incorporating additional intensity levels with each passing workout. Simply performing 30 pound dumbbell curls until failure, day in and day out, will not produce any desirable muscle building effect. Why? Your body is not forced to adapt (muscle strength and growth) to higher and higher work levels (intensity). However, let’s say on the next workout you perform;

• The same amount of repetitions but use 40 pounds is used instead of 30 pounds using the same rest periods;

• Additional repetitions with the same 30 pounds within the same time frame and rest periods;

• Using the same weight and repetitions but performing the workout in a much faster manner using little rest times.

If one can improve using the above methods, one can expect an improvement in muscular development, provided rest and nutritional needs are met. Regardless if your lifting light or heavy weight, one cannot expect to build muscle without making additional improvements in performance.

However, I have had success using both methods. At my current age of 41, I’ve had to adjust my training style because of injuries, so I now have to avoid using heavy weight and train with light weights and high repetitions. I’ve been using this method for about a year and it has yielded some great results.

However, if there is one thing I can say about using heavy weights is that my body doesn’t possess that same dense, muscular look that I had when I was using heavy weight. I seem to be missing that “thick” look that I once had, when I was using heavy weight. The use of heavy weight incorporated more fast twitch muscle fibers as opposed to slow twitch which may be responsible for muscular density. I can’t say for certain but I know for a fact my body looks different now than when I was training with heavier weights. Of course, this is all dependant on one of the most important elements in weight training which is genetics and body type.

Body Types and Weight Training

Each one of us is built differently. Depending on various factors such as age, gender, metabolism, and body type will determine which type of training method is best suited for our bodies. I remember back in high school, we were very adventurous bunch and would try all types of methods to improve our muscularity. We tried using various types of training methods including light and heavy weights.

I remember two friends who had two totally different body types. My one buddy was super skinny and frail with tiny joints and frame. He must have weighted about 110 pounds soaking wet. My other buddy was thickly built with huge joints and a super wide, natural frame. He weighted a solid 210 pounds. In our experiments, I found that my skinny buddy couldn’t handle the heavier weight and would take days to recover from the sessions. His joints ached and his muscles were tired all the time. He simply couldn’t handle the heavy weight.

My big buddy on the other hand, couldn’t get enough heavy weight. His muscles seemed to explode with each heavy session and let me tell you, he lifted heavy whenever he got the chance. I remember spotting him on the shoulder press one time and his elbow joints were so big I could barely get my hands around them. This guy was 19 years of age and he had 19 and a half inch arms! This guy was built for using heavy weight.

However, when we tried using light weights and higher volume, my smaller buddy started to put on more muscle. He seemed to excel with this type of training and started to gain body weight. My other buddy (The bigger one) actually started to lose weight and strength. His body was starting to “reject” the light weight training. It was a strange phenomenon.

My body type is in between and I get results from both types of training but my joints are small so super heavy training is not for me. Moderately heavy weight with a repetition range of 12 to 15 is a perfect fit for me.

There are three main body types. They are as follows:


An endomorph usually have larger frames including wider shoulders and hips. They are naturally heavier with generally larger joints. This type of body can carry a lot more muscle mass, bone and body fat. Endomorphs have an easy time putting on muscle mass but also have a tendency to easily add more body fat, and keep it on.

This type of body can handle heavier loads because of the larger joints and body frame. Generally speaking, endomorphs are built to lift heavy weights and can generally add a huge amount of strength and muscle mass using low repetitions and heavy weight.


Mesomorphs generally have muscular bodies with a stocky build. Their body types are athletic with a fairly large bone structure and have a fairly easy time adding muscle. Mesomorphs generally have narrow hips and wide shoulders with muscular arms and lower body. This type of body generally has an easier time losing body fat than Endomorphs.

Moderate to light heavy workloads and higher repetitions work quite well for Mesomorphs. Because of their larger joints and upper body frames, they can handle heavier workloads using high repetitions.

Generally very skinny with a small bone structure, Ectomorphs are the classic hard gainers. This body type has a thin build with narrow waists, shoulders and small joints. Ectomorphs generally have a very fast metabolism and because of this, they have a hard time adding body weight and muscle mass. Ectomorphs have very little body fat.

Because of their small body structure and small joints, Ectomorphs are very susceptible to injury when training with heavy weights and low repetitions. Light to moderate weights using medium to high repetitions seem to work for Ectomorphs. Compound movements seem to work best for Ectomorphs.

It is quite rare that one person possess a Mesomorph, Endomorph, or Ectomorph body type. These are extreme body types and usually, a person contains a combination body type such as an Ecto-Mesomorph which is a combination of Ectomorph and Mesomorph characteristics. Myself, I am an Ecto-Mesomorph but have more Ectomorph characteristics than Mesomorph. I naturally have wide shoulders and narrow waist but I have very small joints. It is because of this that I can’t handle super heavy weight and low repetitions. I respond best to moderate weight and high repetitions.

In reviewing the study, there is no mention of this fact. It is probably one of the most important elements in weight training in determining the effectiveness of a particular regiment. Ambiguous statements such as “Light weights ‘better than heavy’ for building muscle” does nothing to help the weight training community without further investigation. Each of us if build differently and we will all respond differently to varying types of weight, set, and repetitions schemes.

I’ve actually written a report on body type training and it’s something I strongly suggest you investigate further. You can read about it here.

Honestly, light weight has been used for years as an effective method to build lean muscle mass. This is old news and back in the day, Arnold used this method as one of his primary muscle builders. To tell you the truth, using super heavy weight and performing 2 to 3 repetitions will do literally, nothing for building muscle mass. So comparing super heavy weight for low repetitions and light weight and high repetitions is pretty useless.

This study also fails to take into account the absolute need for body improvement and body types into account, which in my opinion are needed for building muscle.

Don’t get me wrong, light weight and high repetitions can build muscle mass, but to say it is better than using heavy weight is totally misleading and ignorant.

As a side note, I also find it disturbing that Google would display this short, flimsy article in the 8th position on it’s first page for the popular search term “building muscle”. This article is under 500 words and is basically a poor summation of a totally misleading study on building muscle (In my opinion, of course). I would assume people searching for information on “building muscle” would want accurate and informative reports and articles. This is why I really don’t use Google anymore – The results have been very poor. There are other search engines, which in my opinion, are much better at providing relevant and accurate results. Google isn’t google anymore, their results are that of a second rate search engine who place making money over relevant results.

Anyways, that aside, take the study and article with a grain of salt because there is a hell of a lot more to building muscle than “light weights better than heavy weights at building muscle”. Personally, the study is very misleading and adds to more confusion when it comes to building a lean, strong body.

There is a resource that in my opinion is simply fantastic. It’s the first of it’s kind because it uses your body type to customize a personalized weight training routine. It was developed by Kyle Leon and a team of fitness experts. I’ve used it and it works. Here’s what I like about it, it comes up with a custom plan that includes weight training routines and diet. It takes out all the guess work. You simply punch in your numbers and it spits out a complete program. Check it out today here.

You can also read my personal review of this program here.

Please keep in mind that this is my personal opinion.

All the best,


Blake Bissaillion

Blake has been weight lifting for about 28 years now. He's 45 years of age and started seriously training when he was 18 years old.

Blake is the founder of, a successful fitness website that has been around for more than 15 years.