What it means when Lenny Kravitz does high reps with low weights

The Question

Hi! Was wondering your opinion on this Lenny Kravitz workout routine revealed in his What Lenny Kravitz Can’t Live Without interview in The Strategist today.
75 reps seems kinda nuts to me but who knows?! Thanks again for what you do! --Millie

The Answer

Earlier this week, I got many urgent and distressed inquiries begging me to explain Lenny Kravitz’s sixth favorite thing from Lenny Kravitz’s The Strategist list of his 12 favorite things:

The objects themselves (a pair of 15lb dumbbells) were less confusing than: This man goes around with 30 pounds of weights in his bag?? But more to the point, he does sets of 50 to 75??? We’ve heard of 20 reps in a set; by God, we’ve heard of 30 reps in a set. But 50… to be honest, I can’t exert myself and count that high. Why would anyone?

I think I can help here. Even though we are not talking about myths of bodyweight training, we are going to touch on a lot of the points that come up in that series. To clarify, I have not personally spoken to Lenny Kravitz. Everything in here is broad science-based information on how muscle size and strength come to be, and how they stay. But Lenny Kravitz and his li’l 15 pound dumbbells, have at least one important thing to teach us:

Sustained periods of progress matter way more than keeping up the highest amount of pressure all the time for eternity.

But we are going to work up to that. First, let’s break down what we are looking at, and then how we can process this information in a way that will let us sleep at night.

Read the series:

• The myths of bodyweight training, part one
• The myths of bodyweight training, part two
• The myths of bodyweight training, part three

Thing to know #1: Lenny Kravitz is already jacked.

Lenny Kravitz is an aesthetically muscular guy. He is extremely conventionally attractive, and he is famous and rich, and the first part likely played a role in enabling the second and third part. I’m saying this not to invalidate any of the other elements that follow, but it’s important to keep in mind that someone like Lenny Kravitz has very little to offer us, the rabble, in terms of practical advice. It is important to not to misinterpret his born hotness as special dispensation to teach the rest of us how to become hot in general.

Thing to know #2: Lenny Kravitz probably has a little-acknowledged but significant training history, and that matters a lot.

This has been a topic of discussion in “The myths of bodyweight training” series, parts 1, 2, and 3. But it bears repeating: Having a significant and long-running foundation in muscle- and strength-building activities affects what you need to do to maintain muscle and strength, both in the long and short run.* We will get into that more in a minute.

But what do I mean when I say training history? I mean at some point, this person undertook a trajectory that involved something like the following:

• 0.5-1 years of linear progression using heavy weights and low reps to lay a solid strength base
• 2-9 years of bulking, maintaining, cutting, maintaining, bulking, maintaining, cutting again, usually in cycles of 1-3 months but sometimes as long as 6 months (depending on personal tolerance, genetic capacity for building muscle, etc.), pursuing usually either an entirely hypertrophy-focused routine or one that mixes strength and hypertrophy, until the desired look and/or strength level is achieved

Lots of people don’t literally do the above. But it’s the most straightforward way to go about putting the building blocks in place for doing a wild-sounding thing like “maintaining your hot body with nothing but a pair of 15lb dumbbells.”

Lenny Kravitz very likely already put in work of a whole other type than what he is describing to you now, doing probably years of a lot of low-rep heavy-weight intensity and hypertrophy work, before he got to a point that he could maintain his washboard abs for any period of time with his little 15lb dumbbells.

A less direct but important point: It’s also tough to get really, really lean without having a nice foundation of muscle that will keep your body in good working order and keep your metabolism high. Many people think they have Kravitz-esque muscles down there, if only they could shed enough body fat. If you’ve never lifted weights: almost certainly not! (Unless you are that 1% of the 1% of the genetic elite.)

Thing to know #3: Taking breaks or scaling down periodically is not only not ruinous, but kinda encouraged.

I see plenty of embarrassment and anxiety out there when people have to “take time off” and “go back to the gym.” But in reality, this is one of the more satisfying ways to live—“periodized” into what we call macrocycles. You train toward a goal for a set period of time; you attempt or even achieve the goal; you re-evaluate and design the next macrocycle accordingly. You ratchet down and take a little time to rest and diversify your training before you go back in again. If the training losses were too great to bear when anyone ever took time off or cross-trained, we would not have macrocycles. But we do.

There is a certain amount of sub-peak-threshold goosing you can do that will really extend the strength and/or size dropoff. Put another way: Doing whatever you can helps a lot more than doing nothing at all, and you probably have to do less than you think—please listen closely—once you build that foundational strength and muscle. The higher strength-y and muscle-y heights you have reached, the more you can maintain with relatively little work.

To quote from my previous post, “The strength you build is yours, even if you don’t do it forever: the evidence for ‘muscle memory’”:

First, the preserved-strength-gains bit. In a 2019 study, researchers compared the effect of strength training on trained vs. “naive” muscles by having nine men and ten women strength train for 10 weeks and then take 20 weeks off. They found that, during that detraining period, muscle size and thickness went down, but strength stayed elevated by 60%. In another 2019 study on 53 adults who strength trained for 6 months, their gains were “partly preserved” even a year later. And in a small 1991 study of six women, scientists found that when the women strength-trained for 20 weeks and then stopped for 30-32 weeks, “maximal dynamic strength decreased but not to pretraining levels.” The overall point being here: If we build strength once, we’re never as weak again as we were in the first place.

So that’s if you do nothing at all. What if you do even a little? How little can you do?

I’m tapping the “It Depends” sign again. It depends on you (genetically, attitudinally, etc.), it depends what you have done before and what you will do now. If you normally carry construction equipment around for eight hours a day and then go down to doing 15lb dumbbell curls and things for 10 minutes a day while you are starting a new job, you will lose a good amount of strength and/or size. If your norm is half an hour of strength work three times a week and you go down to twice a week, you will lose relatively less, but you probably had less to begin with. Whatever you can do is going to help. But here’s how to think about it: If your goal is to grow or get stronger, it matters more that you get these deliberate and significant periods of progress in, way more than that you keep the highest amount of pressure up, all the time, for eternity.

Thing to know #4: Muscle endurance falls off faster than strength or power.

This is a minor element, and I’d be surprised if it’s actually on Lenny Kravitz’s mind. But per a Stronger By Science research review on detraining, people lose muscle endurance (how long before your muscle gets tired) somewhat faster than raw strength or power (your max squat or power-clean poundage).

The whys are a bit murky. But the relevant takeaway is that, if someone had to take a few weeks away from the gym, their work capacity needs a little bit more protecting than their raw strength. It’s not likely that Lenny Kravitz is doing this part of it all on purpose. But if you are trying not to lose too much fitness during an off-period, that doesn’t require finding a fully-equipped gym.

Thing to know #5: The 15lb dumbbells chose the 50-75 reps, not Lenny Kravitz.

Let’s bring it back to the dumbbells. Are they sentient?? No. Let me explain:

We tend to look at a Lenny Kravitz type doing this sort of thing in the wrong way. He says he does that many reps and that he’s “going for tone, not bulk,” and everyone gets extremely nervous that sets of less than 50-75 reps will turn them into the Hulk. “Lenny says he doesn’t want bulk, and neither do I,” they say. So they go around doing hundreds and hundreds of reps, thinking that their fat will melt away, revealing Lenny-Kravitz-type muscles underneath. Not only is this miserable to do, it is probably not how this works.

However, it feels pretty clear here to the trained eye that Lenny Kravitz is not choosing the number of reps he wants to do and then choosing the weight to go with it. He is choosing the weight first—in this case, a set of dumbbells that are not too heavy to carry in his luggage—and then doing whatever amount of work needs to be done to match it.

He does trot out the classic saw of “tone not bulk.” But that could be accomplished with as few as 15 reps per set, 20 on the outside. The fact that he goes well beyond this number suggests it’s what he needs to feel anything out of a pair of 15lb dumbbells.

What he’s doing is firmly in the realm of cardio (or “muscle endurance,” as above), as opposed to muscle-building. “I’m not trying to put on bulk, I’m trying to tighten up,” he says. Here, we can take “tighten up” to mean “get leaner by burning calories, losing body fat, and preserving muscle.” But as I’ve painstakingly laid out here, to the extent that “what celebrities do” is at all relevant to us, almost certainly what some lighter weights would do for someone like Lenny Kravitz is down to the years and hours and calories and, very likely, genetics that came well before the little 15-pound dumbbells. The 15-pound dumbbells have not much to do with the Lenny Kravitz we see before us; they are probably just a best -possible -scenario sometimes for him.

It may be, too, that Lenny Kravitz’s usual, non-travel workout involves a full complement of weights and machines and tools you’d expect to find in the lavish private gym he may train in. The dumbbells may be in case hein can’t find, or doesn’t have time for, anything else.

That is, unless he were to come back around and clarify that he really does work, and only has ever worked, with 15-pound dumbbells; then he is truly the supreme genetic elite and therefore not at all relevant to emulate, or, he is lying. I can tell you, categorically, no one will ever become muscular like Lenny Kravitz by only ever doing sets of 50 to 75 reps, unless they are the 1% of the 1% of the genetically blessed, musculoskeletally.