High rep or low rep for building muscle

High rep or low rep for building muscle

On this week's blog I would like to discuss whether to use a high rep - light weight protocol for building muscle or whether a low rep - high weight protocol is more effective in achieving an increase in muscle size.  This topic has been discussed on the gym floor for years and has hugely divided opinions. 

Many people believe that to build muscle most effectively you need to be lifting between 8-12 reps for around 4 sets and this classic bodybuilding method has been the staple for many people for a number of years.  But some recent studies have brought to light new information that could turn that on its head. So what is best? 

Well as usual there is no simple answer and a lot of it comes down to personal choice and lifestyle as usual but a little exploration may help you make up your own mind. 

In 2016 a study at McMaster University in Ontario, USA found that lifting relatively light weights (about 50% of your one-rep max) for about 20–25 reps is just as efficient at building both strength and muscle size as lifting heavier weights (up to 90% of one-rep max) for 8-12 reps.

"Fatigue is the great equaliser here," says Stuart Phillips, senior author on the study and professor in the Department of Kinesiology.  "Lift to the point of exhaustion and it doesn't matter whether the weights are heavy or light."

To complete their research they took 2 groups of men, all of whom were experienced weight lifters.  They all followed a full body protocol for 12 weeks with the same exercises.  One group lifted lighter weights (up to 50 per cent of maximum strength) for sets ranging from 20-25 repetitions. 

The other group lifted heavier weights (up to 90 percent of maximum strength) for 8-12 repetitions.  Both groups lifted to the point of failure.

Researchers analysed muscle and blood samples and found that the gains in muscle mass and muscle fibre size, a key measure of strength, were virtually identical.

"At the point of fatigue, both groups would have been trying to maximally activate their muscle fibres to generate force," says Phillips, who conducted the work with graduate students and co-authors Rob Morton and Sara Oikawa.

So this would suggest that it's about the total volume of work rather than how heavy your weight is. Reps x weight = muscle growth. 

So both styles of lifting are as effective as each other as long as you get enough volume on the muscle group and work to the point of exhaustion.  Essentially it's up to you which method you choose. 

Here are a few benefits of each to help you make the right decision for you:

Benefits of High rep training on building muscle - 

  • Easier on joints and can be better for those who have injuries. 
  • Using lighter weights is much safer for a less-experienced lifter.
  • You can workout alone as you don’t always need a spotter with a lighter weight. 
  • Many body weight exercises would be enough making it great for home workouts. Perfect while many are still working from home.

Benefits of Low rep training on building muscle - 

  • Builds more strength.
  • Less exhausting than a higher rep range especially for certain lifts.
  • Form is likely to be less compromised as less time on the lifts. If you are doing it wrong it's not for as many reps as the high rep training.

With my clients I often recommend a combination of both training modalities to keep the body from plateauing.  As a beginner or someone coming back from injury an idea would be to periodise your programs into 4-6 weeks of high rep, low weight, followed by 4-6 weeks of low rep, high weight. 

This first block helps get the body used to lifting weights again in a safe way and helps to take some pressure off the joints, improve movement patterns and prepare the body for lifting heavier.

In the second block you will lift heavier and less reps in order to continue to build muscle but to now increase muscle strength also. 

Aaron Collins-Thomas

Founder of TONIQ


What method are you going to use? Let us know in the comments below. Share this with someone who you know would benefit from reading this. The U Perform Family loves sharing ideas and encouraging each other.