5 x 3 or 8 x 3 for Isolation Exercises?

Hi! Coach Thibaudeau
Can 5x3 or 8x3 1 min rest work with isolation exercises with loads of 0.5 kg or 1 kg? Thanx

One more question what do you think about wrist curls isometric/static hold 10 sec, 3 sets, 3 min rest, 3 times a week adding 0.25 kg or 0.5 kg every sessone if it is possibile, what precentage of 1 rm or beyond is best for static hold?


Well, first of all, your question leaves many unknown, not the least being how heavy is 0.5 - 1kg compared to your max? I mean, that is supremely light, even for isolation exercises. So unless your max is barely more than that (which is not likely), it will likely not do anything.

I honestly don’t understand what you want to achieve with this. There is nothing that would lead to significant hypertrophy or strength there, unless you are phenomenally weak and 0.5 - 1kg is actually a challenging load.

And if it IS a challenging load, 1 min is too short of a rest period.

Again, what do you want to accomplish or get from this?

I personally don’t see you getting much out of this.

10 sec isometrics would be a strength method, you would get basically no muscle growth from that. First because isometrics, by themselves, are already a lot less effective than normal reps to promote muscle growth. And that 10 seconds would not be a sufficient duration to get the potential hypertrophy isometrics may provide. To get some muscle growth from isometrics, your sets should last 30-60 seconds.

6-10 seconds can work for strength BUT:

  1. The gains would be position-specific (increasing strength mostly at the angle trained +/- 15 degrees)

  2. It would have to be a maximal effort for those 6-10 seconds. That’s why “holding weights” (yielding isometrics) are not the best option for this. Overcoming isometrics, where you are pushing or pulling against a fixed resistance is a better option.

Here is an an example of an overcoming isometric:

Are you just trying to come up with some novel training approaches or have you heard those somewhere because they sound … well… and don’t take this the wrong way… kinda stupid.

And why are you trying to come up with a complex methodology to strengthen something as unimportant as wrist curl???

It depends…

Why are you doing the hold? For strength? For size? As an activation tool? For technical learning?

You can’t use a % of your max on a full range lift to select the weight you use for your holds because not all angles in the movement are the same strength!

For example, maybe using 90% of your max for a hold in the mid-range position might be too hard whereas doing the same 90% at the top 1/4 of the range might be too easy.

If you want to get anything from isometrics, the level of effort for the selected duration and position must be very high. Meaning that it should be hard to complete the selected duration with the load you picked.

Is it possible forever? No.

Is it possible for a week? Yeah, probably

Is it possible for many weeks? Maybe, maybe not.

Strength gains:

  1. Decrease over time (you can’t keep adding the same amount of weight every week, at some point your strength will progress at a slower pace).

  2. Get smaller the more you repeat the same stimulus, as your body becomes adapted to that specific demand.

So at first, yeah, adding 0.5 - 1kg per session (1.5 - 3 kg per week) might be doable and maybe you can keep that up for a few weeks. But eventually, no, you can’t keep adding more resistance.

Think about it… let’s say that your starting maximum for a 10 seconds hold is 40kg and that you add 2kg per week (you are talking about 1.5 to 3kg per week, so I averaged it to 2kg). Well, in a year you will go from 40kg to 90kg. After 2 years you’d do 140kg. After 3 years you’d do 190kg… see where I’m going with this? There is a limit to how much “rapid strength gains” you can get, even with proper training,

I’m going to use a powerlifting example, Ed Coan, widely recognized as the best powerlifter of all time. Who also tested positive for steroids. Had the following improvements on his 3 lifts over a 15 years period:

Squat: Gained 20kg in 15 years
Bench: Gained 8kg in 15 years
Deadlift: Lost 3kg in 15 years

During that time he also went up a weight class, gaining 10kg.

Even if we only look at the squat, which had the biggest improvement:

A man that:

  • Was a genetic freak, built to be super strong
  • Was using steroids
  • Gained 10kg (mostly muscle)

Reached a point where the best he can do was adding around 1.3kg/year on squats,

And adding weight on a movement like squats is A LOT easier than adding weight on wrist curls because of the amount of muscle involved.

Ed was squatting 418 to 438kg … 1.3kg out of 418kg is 0.3%

1.3kg out of a 40kg (for example) wrist curl is 3.2%… which is a 10x faster rate of improvement.

My point is simply that you cannot sustain a specific rate of gain forever, or even for a long time.

Thank for answer, for forearms my goal is strenght, i heard about that what i wrote.

Well all I can tell you that might help is that if you want to gain strength, the loads you have to lift much be heavy or hard for the duration you select.

10 sec holds are fine for strength, but the load you use for those 10 secs must be challenging.

As for reps (the 5 x 3 or 8 x 3 that you mentioned), the same principle applies for strength, meaning that the weight you select must be challenging for those 3 reps. That’s why your original question doesn’t make much sense… 0.5 to 1kg would be too light (again, unless you are super weak and doing 1kg x 3 reps on wrist curls is hard for you).

And if you select the load properly, and that 3 reps is heavy and hard, then 1 min of rest is too short. You’ll build up central fatigue which will make each set less effective that the one before.

Also, if you are specifically talking about 3 reps on wrist curls, that is too low considering how short the range of motion is. That is too little mechanical work to get much out of it.

Finally, getting stronger is both neurological and muscular. I don’t see you gaining much muscle from sets of 3 reps on wrist curls (again, because the amount of mechanical work is too small considering the range of motion). Which means that all of the strength gains would come from neurological adaptations, which are limited.

I’ve known a lot of guys with super strong grip and forearms (strongman competitors, arm wrestlers, guys who could close the #3 and 4 captain of crush) and none of them did wrist curls, NONE. They did lots of heavy deadlifts, farmer’s walks, thick bar lifting, hammer curls, reverse curls and when they did grip work it was holding huge weights with a thick bar, captain of crush gripper work or pinch grip work, Thor’s hammer and stuff like that.

I personally do wrist curls and extensions from time to time. But mostly for high reps to build muscle or a a warm-up (I have elbow issues)

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