Is Lifting Heavy Still Worth It?

Hi coach,
I’ve been training for more than a decade, started “powerlifting” at a young age (15yo) and was very ego-driven. Although I hit some decent numbers, my joints really paid the price over the years. At the moment my shoulder hurts pretty much all the time and my back and knees are very fragile. I’m only 27.
Right now, I train mostly to look good (I prefer lifting heavy but don’t really have a choice anymore).
My question is: Do I really leave anything on the table hypertrophy-wise if I only train with light to moderate weights, high reps and short rest periods ? Or do I still need to include a minimum of heavy lifting. I’ll also add that I’m drug-free.

If you reach the same fatigue level in your sets (e.g. stopping 1 rep short of failure), strictly for hypertrophy purposes it doesn’t matter if you get anywhere between 6 and around 20 reps.

If you reach a point of 1 rep short of failure you will get 5 reps per set, regardless of the weight, that are effective at stimulating hypertrophy.

Lifting heavy (less than 6 reps per set) is actually less effective strictly from a muscle growth perspective because you get fewer effective reps per set. So you need to do more sets to get the same amount of growth.

The limitation of light weights (let’s say more than 12 reps) is that you have to do a lot of ineffective reps to get to the 5 money reps in your set.

For example, if you do sets of 6-8 reps to 1 rep short of failure, you’ll have 5 money reps and 1-3 ineffective reps that are there just to cause enough peripheral fatigue to force the body to recruit the growth-prone fast-twitch fibers.

If you do 15 reps to 1 rep short of failure, you also get 5 money reps but now you have 10 ineffective reps.

Why does that matter? Because central fatigue (fatigue of the CNS which decreases your capacity to recruit the fast-twitch fibers) is more closely related to volume than intensity.

So by doing high reps, you will likely achieve a state of central fatigue (which makes the whole workout less effective at stimulating growth once it’s there) after fewer sets. Which might reduce the effectiveness of your workout.

That’s why I prefer sets of 6-8 (maybe up to 10) for hypertrophy.

You can do higher reps (12 maybe up to 15) but I would suggest only using them on single-joint exercises which cause less central fatigue than multi-joint movements.



Don’t the same rules apply here? If you use sets of 5 aren’t you already maximally recruiting the fast-twitch muscle fibers from rep 1? Staying one rep short of failure means 4 maximally effective reps per set. So yes, you have to do more sets but each set also contains less garbage reps.

The only other thing I can think of why reps below 6 are less effective for stimulating growth is inadequate fatigue of the FT muscle fibers due to limited time under tension. But once again, if you change the rep tempo to something like 6010 for example and you perform 5 reps, that’s 35 seconds, which in theory should be enough to stimulate hypertrophy.

Am I overlooking something important here?

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Glad the ‘ineffective reps’ of a set was brought up which always bugged me . In a set of 8-12 I always figured the first half of the set were really warm ups for the last, effective reps.

To make as many reps in a set effective I love using breakdowns , a drop at about the third or forth rep which makes each rep in an 8 -12 rep set difficult.

As long as sets like this are kept at a minimum of one or two ‘sets’ per exercise , is there is problem of doing so ? The volume is low , intensity high … and of course it wouldn’t be done on every exercise but more than one in the workout. Also, these would be machine movements using Performance Pins or with dumbbells for immediate drops in resistance.

I love doing these and think of them as ’ cluster set break downs '. Do you see a problem with this method , as long as you were properly warmed up and volume was kept down ?

Hi Christian. Do you see any difference between upper body and legs in regard to the ideal 6 - 8 range?

There isn’t. Some people think that the legs need higher reps to grow, and that is absolutely unsupported by science and logic. Heck, I personally always progressed better from lowish reps on lower body.

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So, three sets of 6 to 8, all over, leaving one rep spare, with specialisation on one primary lift from month to month, and with an occasional maintenence deload. I like simple.


Where do you proceed when strength progression has stalled on rep range 6-8? Isn’t strength progression the foundation for further hypertrophy? Do you shift excercises? Applying a period of deload or metabolic conditioning, meaning higher reps? This bearing in mind the OP couldn’t train heavier.

Not directly.

Provided that you train at the proper level of effort on each set and have a solid plan, strength gains don’t really stall until you reach your potential. What actually happens is that strength gains from a workout are too small to allow you to add more weight to the bar immediately.

For example, after a productive session, your strength improves by 0.5 to 2.5% depending on your development level and other individual factors.

That amount of strength gain is not always sufficient to add more weight right away, especially on smaller exercises in which the smallest amount of weight you can add represent a large increase in relative load. For example, on lateral raises, most gyms have DBs in 5lbs increment. If you did 20lbs x 6 reps on lateral raises, going up to the 25lbs represents essentially a 20% increase in load. So even if you have a solid 2.5% strength gain from your workout, you are still far off of the 20% increase in load.

Sometimes you can do it, either because you left a lot in reserve in the previous workout so you have more room to add weight. Or maybe you compensate or even cheat just enough to move the heavier weight, but it’s not the target muscle moving the extra load.

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The first thing I do is trying to get more reps in with the same load, within reason.

For example, maybe you didn’t gain enough strength to go from 20lbs x 6 to 25lbs x 6. But Maybe you gained enough strength to get to 7 reps with 20lbs, or even 8 reps.

So if your find yourself unable to add more weight, you can shift your focus to adding more reps (I wouldn’t go higher than 10-12, personally). And when you reach the top of the range, then you can add weight.

If you reach a point where you can’t even add reps with a certain load, yeah, I would change the exercise. But I’d need to stagnate for at least 3 workouts as 1-2 might simply be due to fatigue or other factors.

I also want to mention that when stagnation occurs, you should first and foremost look at your diet and sleep to see if they are optimal. Failure to progress could simply mean that you are not consuming enough energy and nutrients to positively adapt to the session. And lack of sleep can also create central fatigue, which reduces the strength of the neural drive, leading to less muscle fiber actvation and force production.


Metabolic conditioning would not help him get stronger, quite the contrary.

A deload might be in order but only if the lack of progression is due to central fatigue. The thing is that central fatigue is NOT a feeling. You don’t necessarily feel tired or burned out. It’s just a reduction in the strength of the excitatory drive from the nervous system to the muscles.

A good way to assess it is to measure either your vertical jump or grip strength.

First establish a baseline (e.g. after a few days off, when you feel good) and measure it prior to every workout. If it is significantly down it indicates a higher level of central fatigue. If that stays with you for several days, then yeah, a deload can help.

Higher reps can be a good strategy but in the context mentioned above: NOT lowering the weight to be able to do high reps but focusing on adding reps with the same weight rather than on adding weight.


Thank you very much, coach Thibaudeau!
Now that is what I call a complete response. I believe everyone reading it must’ve learned something! Much appreciated.