If I wanted to get my arms as big as I could possibly get them… I would keep the reps between 6 and 8, and I would do all basic movements where I’d handle as heavy a weight as possible.
– Bill Pearl
Yet the practical advantages of using 8 reps, beyond pure analysis of the growth stimulus, may allow for better results in the long run.
8 reps per set have a firm place in both physical culture & exercise science.
Classic bodybuilders like Arnold, Sergio, and Frank Zane often used pyramid training for major exercises. This meant increasing the weight with each set, crossing 8 reps along the way.
In early studies, 8 reps have long been included in the so-called hypertrophy range for the repetition maximum continuum. This starts as low as 6 and often proceeds to 12-15 reps depending on the source.
Modern findings show that performing sets close to failure is the essential factor. This aligns with my knowledge & experience as well. Sets of 8 reps just allow this to occur without some disadvantages when going higher or lower.
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I have a definite preference for the 8×8 system of sets and reps… your muscle fibre will plump out, giving you a solid mass of muscle density as a result.
– Vince Gironda
- Limits the burn from glycolysis.
- Achieves the minimum set duration for maximizing full motor unit recruitment.
- Reduces absolute joint stress.
- Moderates reps to develop a mind-muscle connection.
- Seems no worse, or better, than variety (probably).
Limits the burn from glycolysis.
Our bodies draw upon energy systems to power movement, with the proportion depending on intensity.
At 30 seconds or lower, the ATP-PC system dominates.
Once you exceed this rough limit, while maintaining a high level of effort, glycolysis takes over. This causes a burning sensation in the muscles due to the accumulation of hydrogen ions, making the environment acidic.
In the end, whatever causes fatigue only varies the time to reach inevitability within a bodybuilding context: high-threshold motor unit recruitment, which mostly involve the most powerful Type II fibers.
Yet metabolic stress can feel uncomfortable, making it possible that you apply less effort. Sets of 8 are more tolerable, as even with the utmost effort you terminate the set before it gets unbearable, given reasonable interset rest lengths (2-3 min).
Some experts, both within the bodybuilding & scientific communities, feel that metabolic stress increases sarcoplasmic hypertrophy more so than mechanical tension for myofibrillar hypertrophy.
Similarly in the past, some defended higher reps for increased glycogen storage that is no longer in vogue.
Despite one great study, this remains largely unproven. It’s hard to differentiate between sarcoplasmic growth and inflammation, plus if it means a new proportion instead of an intermediate stage.
Achieves the minimum set duration for maximizing full motor unit recruitment.
For many large muscles, full motor unit recruitment occurs at 80-90% of a maximum voluntary contraction. This is somewhere between 5-8 reps on a set to positive failure.
Once you have full motor unit recruitment, the nervous system uses rate coding to increase force. This generates additional pulses that rapidly activate the motor unit’s fibers.
In my view, successful bodybuilding means generating enough pulses to stimulate growth in the high-threshold motor units. These pulses should occur under relatively slow contractions so that the most cross-bridges form due to the force-velocity relationship.
This explains why lifting beats explosive activity like sprinting for building muscle. This doesn’t mean slower is better in bodybuilding. Very slow reps likely reduce effort.
Many in the industry now summarize it as ensuring sufficient weekly volume to progress within these conditions.
Furthermore, I don’t feel more tension from a high pulse rate is required: it’s the total number of pulses needed that occur below a maximum speed.
If you accept this, you realize that we can achieve enough pulses through a diversity of training methods, some more efficient than others.
You’d require fewer sets than 1-4 reps, since those achieve less mechanical work under full motor unit recruitment.
You’d also need less volume than the same number of sets for more reps, which though possibly leading to a bit extra growth, seems about the same due to similar effects on the vital muscle fibers.
You get to full recruitment faster as you fatigue with each set. For sets of 8, you may also not even need warm-up sets. Finally, you exert less perceived effort since the weight alone quickly involves all motor units.
Many argue 5 reps are most efficient. Being in the lower range of full motor unit recruitment for many muscles, they are likely right. Reg Park thrived on 5×5.
Higher loads are best for strength, or increasing your 1 rep max, due to neural factors as well but otherwise don’t matter for hypertrophy.
However, this small improvement may be offset by other issues.
Reduces absolute joint stress.
Unlike muscles, bones & connective tissue handle resistance in absolute terms.
This can become problematic when performing sets of 5 on exercises like skull crushers, which already place tremendous shearing forces on the elbows.
Nonetheless, they are required to develop multi-joint muscles.
Moderates reps to develop a mind-muscle connection.
The perception of handling very heavy weights, often starting as high as 5 reps, may create fear or a compulsion to move “at all costs.” Your concentration draws toward stabilization and getting the weights up.
Ultimately, 1-5 reps is not required for bodybuilding, and heavier weights invite more risk.
8 reps subjectively allows the right duration. You can focus on working the muscle over just performing the movement or fighting through discomfort.
Seems no worse, or better, than variety (probably).
Everything works, but nothing works forever.
This has been said by diverse proponents like Charles Poliquin, Jack LaLanne, Arthur Jones and countless others esteemed within athletic & fitness circles.
Still, bodybuilding hasn’t developed rich support from centuries of successful practitioners. We are still figuring it out.
Yet I wonder if they are right.
The worst-case scenario from variety seems to be that it all does the same thing anyway. At the least, it refreshes your program mentally. You could possibly have all the potential upside, even if slight physically, with no real downside.
Periodization, while starting to break down in the literature on the specifics of why it works, nonetheless has been highly successful.
This way of thinking doesn’t suit me though.
Consistency seems to limit neural & physiological resets when changing it up. I don’t mind constancy when something works, and progressive overload is still pursued. Perhaps variety just compensates for excessive training.
Maybe periodization just shows the value of not going “all-out” all the time. Training to failure could overstress the body in what could otherwise be attained with a little extra volume.
Is 8 Reps Per Set Perfect?
Take a simple idea and take it seriously.
– Charlie Munger
We must overcome the allure of the quick fix over consistently following good principles.
Nutrition comes to mind, whereas so many try to shortcut the ironclad rule that “a calorie is a calorie.”
Just like in politics, extremists occupy their niches in bodybuilding. You have the ultra-high volume trainees representing the Silver & Golden Eras. You have High Intensity Training (HIT) devotees like Casey Viator, Dorian Yates, and Clarence Bass.
Yet no one can deny these polar opposites have created successes!
Working hard is efficient. Advanced techniques, like drop sets, will hammer those fast-twitch muscle fibers quickly. HIT can work, even if it doesn’t suit everyone.
We have flexibility in how we achieve our goals, but you must put in the work. Higher intensity must balance out lower volume. You must train progressively, doing enough to disrupt homeostasis.
Most old-school training styles had very short rest periods, partially explaining the ridiculous volume. This runs from Steve Reeves to Arthur Jones. For his honest 8×8 system, meant to limit the burn, Vince still rested between sets for well under a minute.
But longer rest periods allow higher strength output, leading to more growth set-for-set. If workout length doesn’t matter (and knowing it won’t turn catabolic), then longer rest periods actually improve results.
Though I love to work hard during my sets while advancing toward ever-heavier weights, I hate rushing through my workout. I also like simplicity & ease of measurement so rely on straight sets.
Therefore, for most of my life, I’ve performed 3-5 working sets of 8 reps, done once weekly per exercise. On some isolation movements I do 10-12 reps, especially when purely extending the elbows & knees. I rest 3-5 minutes between sets.
I like the single progressive system, usually increasing weight slightly versus trying for more reps. Training to failure sometimes happens but isn’t the goal.
This has led to good results, and I enjoy doing it. I’ve been consistent over the decades. My approach closely mirrors bodybuilding routines in the 90s, with less volume than popular today, supported by Chris Aceto or Wilfried Dubbels.
Most of us, if being honest, prefer the moderate path. We can apply nothing close to the volume of Bill Pearl or the intensity of Mike Mentzer. Don’t blindly follow what works for them… what works for you?
So, are 8 reps per set perfect for bodybuilding? Not exactly. However, the practical advantages should aid you throughout your long training career!