Last week one of our clients asked me the following question:

If you’re natural with average genetics, your goal is muscle building, and you could only do one rep range for the rest of your life, what would it be?

I like to apply to 80/20 with everything in life, and training is no different. Just like you should be spending 80% of your time doing the big compound lifts, I believe you’ll get 80% of your results from being progressive in the 5 to 8 rep range.

For the natural guy with average genetics, this really is the sweet spot for muscle growth.

If you take a look at scientific research and years of anecdotal evidence, the main factor driving muscle growth is progressive overload (i.e. heavier weights lifted over time), with some fatigue accumulation added into the mix too. (i.e. the pump)

In order to facilitate the strength gains required to apply overload in the muscle, we need maximum recruitment of muscle fibres. This typically occurs when we increase force production up to 80-85% of maximum force output. After this level, the body relies on neurological pathways to create more force output.

For most people, this 80-85% of maximum force output is roughly 5 to 8 reps.

This will vary between individuals and muscle groups depending on your fast / slow twitch fibre make up. For example, some people will be able to get 15 reps at 85% of maximum during certain leg exercises, whereas others will only manage 5 reps on a bench press at 80%.

As a general rule though, it works well.

Besides the scientific basis behind 5-8 reps, I’d argue that spending time in the 5-8 rep zone can be safer, due to your ability to maintain maximal tension and tightness at all times.

This is particularly true for more beginner lifters, and when doing the compound exercises like the squat and deadlift.

Trying to maintain perfect technique while staying tight for 12 reps is a lot harder than executing a clean set of 6 reps. And so I’d save high rep, free weight movements for advanced individuals only.

What About Low Reps?

If you train in low rep ranges, i.e. 1-4 reps, you may get the recruitment, but you won’t get the fatigue, volume or overall workload necessary for growth. Which partly explains why bodybuilders are bigger than powerlifters.

Another reason I’m not a huge fan of spending too much time below 5 reps is that technique often begins to falter, joints become compromised, and burnout is more likely.

I’d only train using lower rep ranges periodically in order to develop extra strength to be able to lift more in higher rep ranges. I would rarely make this the focus though if muscle growth is your goal.

What About High Reps?

If you train only in high rep ranges (12+), you’d need to take it to failure in order to recruit all muscle fibres. The second problem here is that the high threshold, fast twitch muscle fibres – the ones with most potential for growth – won’t be recruited until the very end. Which means they won’t be exposed to overload or metabolic stress for very long.

Now, I’m not discounting the value of lower or higher rep work here. I’ve always said that progressive overload in a wide variety of rep ranges is what’s critical to accumulating muscle mass.

My point instead is to keep you focused on what matters, and that the foundation of your training should be based in the 5-8 rep range. This rep range works so well because it gives you the perfect blend of maximal muscle recruitment as well as metabolic stimulus.

What About 8-12 Reps – The Remainder Of The ‘Hypertrophy Zone’?

After you’ve built a foundation in the 5-8 rep range, that’s when doing slightly more reps can provide benefits.

If you’re skinny and weak, working excessively in the 8 to 12 rep range will provide little muscle recruitment and tension.

But once you become stronger and more advanced, adding in days where you spend time in this rep range works well.

This is where utilising split such as the heavy/light method, where you vary the rep ranges through the week can really accelerate your muscle building results.

For example, one of my favourite 4-day splits for intermediate muscle building clients is:

Day 1: Chest/Back/Delts – 5-6 exercises in the 5-8 rep range

Day 2: Legs/Arms – 5-6 exercises in the 5-8 rep range

Day 3: Chest/Back/Delts – 5-6 exercises in the 8-12 rep range

Day 4: Legs/Arms – 5-6 exercises in the 8-20 rep range (higher reps for legs)

The other situation I may start some guys on 8-12 reps is if they’re in the beginner-early intermediate stage, and have a reasonable foundation of ‘mass’. They’re not skinny or ‘weak’, and more ‘thick set’.

For these people, I typically start with a full body approach training three days a week and working in the 8-12 rep range.

After 4 to 6 weeks, I’d typically move them into an approach that allows them to vary their rep ranges.

What If You're Over 40? 

The common advice is that if you’re over 40, you should lift lighter to help protect your joints. I agree with this, as there’s usually a lot more wear and tear as you get older.

However, it entirely depends on your training age, injury history and strength levels.

A guy who’s been training seriously for25 years will need a completely different approach to someone who’s only been working out properly for 3 years.

If we take the case of the former, I’d keep the majority of the work in the 8 to 12 rep range, and throw in a fair amount of higher rep sets too. If you’re strong with a great mind muscle connection, this approach will be both safer and beneficial to make progress.

What About Women?

I like to program women in a slightly higher rep range than men. Women will always be able to perform more reps with a given weight. This comes from their proportionally larger size and percentage of type 1 fibres that are more fatigue resilient in nature. Instead of focusing most of your time in the 5-8 rep range, you’ll want to bump this up to 8-10 in many cases.

What About Isolation Exercises?

Once you pass the beginner phase of training, there will be certain exercises and body parts that aren’t suited well to lower rep ranges. You’d be better off adding higher rep sets to train these muscle groups. For example:

• Lateral raise variations (10-15 reps)
• Rear delt fly variations (10-30 reps)
• Face pulls (10-20 reps)
• Biceps curls (8-15 reps)
• Triceps extensions and pushdowns (10-15 reps)
• Back extensions (10-20 reps)

What About Highly Slow Twitch Muscle Groups Like The Quads?

While the majority of your work should still be in the 6-12 rep range, there is merit for adding in some very high rep sets for quads.

50 rep leg presses and breathing squats have been around for decades for a reason – they work.

But you need to earn the right to do them, and if you’re still weak and squatting one plate a side, these won’t be of any benefit to you just yet. You need to get strong first before you train with high reps.

Putting It Altogether

To build muscle most effectively for the natural trainee with average genetics, 80% of your time and focus should be spent in the 5-8 rep range.

Once you get strong, you can start adding in more sets in the 8-12 rep range. At this stage, your focus will be shifted to the commonly touted ‘hypertrophy’ zone of 5-12 reps.

This is where heavy/light splits work great where you focus on 5-8 reps one day, and 8-12 on the other day.

Another favourite of mine is to focus on 5-8 reps on each day, but add in slightly higher rep back off sets after those main sets. This gives you the best of both worlds in one day.

Outside of this, you can add a little bit of extra work in rep ranges above and below. Just remember to always keep the goal the goal, and focus on what matters and produces real results.