A recent study challenged the commonly held belief that you have to lift to failure to gain muscle size and strength. Should you pay attention to it?
If you're a bit of a gym rat, interested in putting on muscle, or you've been reading my articles for a while, you've likely encountered the term “lift to failure.” But just in case it's new to you, let me explain.
For years now, it has been a bit of a 'known fact' that if you want to gain strength and muscle size, you need to lift to failure
Close your eyes and pretend you're lying on a weight lifting bench about to do a set of bench presses. If you have enough weight on the bar and you do enough reps, you will eventually not be able to complete the movement. Panic will set in, your eyes might bug out, and you might have to grunt, groan, and contort your body to get the bar safely back on the rack.
That's lifting to failure.
For years now, it has been a bit of a “known fact” that if you want to gain strength and muscle size, you need to lift to failure. No matter how much weight is involved or how many reps you want to do, you must reach that point where you can’t successfully do another rep, if your goal is to get the maximum benefit from that workout.
This is an important point that I don’t want you to miss. The weight doesn’t have to be heavy for this protocol to be effective. You can reach failure by lifting big heavy weights or you can reach failure by doing a whole lot of reps. Either way is effective.
In fact, Dr. David Behm, a Memorial University of Newfoundland researcher who studies resistance-training protocols, told the Globe and Mail a few years ago:
Well, hold on to your sweatband because a new study has thrown a bit of a monkey wrench in this long-held belief. East Tennessee State University published research in Sports that has shown that backing off—just a little bit—from failure (at least some of the time) may actually give you greater gains.
The "lift to failure" study
The stated purpose of this study was to compare the physiological responses of skeletal muscle to a resistance training program using repetition maximum (RM) or relative intensity (RISR). Which, in plain English, means they wanted to compare the muscle gains between lifting to failure and lifting just below failure.
To make this comparison, fifteen well-trained males did ten weeks of strength training three times a week. The RM group achieved a relative maximum each day, while the RISR group trained based on percentages. That is, the RM group exercised until failure on each exercise, while the RISR group did not reach muscular failure.
I already explained what training to failure means, but what is relative intensity? Well, let’s say that I can consistently do three sets of eight reps with 100 kg on the bar for a particular exercise before I reach failure. If I were in the relative intensity group, I would lift 80 percent of that to avoid reaching failure. If you do the math, that means that I would lift three sets of eight reps at 80 kg instead of 100. Make sense?
In a nutshell, the two groups were doing basically the same amount of training, but one was going to failure, and one was just skirting failure by a slightly more comfortable 20 percent.
After the ten weeks were over, two papers were published from this study. In the first paper, the researchers showed that the RISR training yielded “greater improvements in vertical jump, rate of force development, and maximal strength compared to RM training.” Then, the second paper added more detail and filled in some blanks.
That more thorough paper included results of muscle biopsies and ultrasounds which showed a greater increase in overall muscle size, the size of individual muscle fibers, and several molecular signals of muscle growth in the RISR or relative intensity group.
The problem with training to failure
You may be thinking, Well, okay, Brock—that's that! I'll never lift to failure again.
But I think the message is more nuanced. I mean, we can’t just throw all the previous evidence out the window because of one study. Especially one that only involved only 15 participants (there were 18 at the start of the study. but one dropped out, and two got injured).
What I have done for the last few years, for myself and my clients, is to have one challenging workout per week and two or three easier ones. This sort of workout program is not only an easier pill to swallow, week after week, but it ensured that the one hard workout was executed properly. This strategy all comes down to recovery, both mental and physical.
If you do every workout to failure, you have to recover for longer. The truth is, it takes more time to recover from a workout when you go to failure. The negative neuromuscular effects of a killer workout like that can last for about 24 hours at best, and more like 72 at worst. That takes a chunk out of your workout time. But if you back off the intensity—say 20 percent off, like in the study—you can return to the gym fresh and ready to hit it in less time and with more joie de lifte.
And that's what I think the researchers missed in this study. The execution and consistency of your workouts is more important than whether you went to failure or not.
The real point
Let’s go back to 2010, when a McMaster University exercise scientist named Dr. Stuart Phillips published a paper that compared lifting to failure with either five reps of a heavy load or 24 reps of a lighter load. In that study, muscle biopsies showed that both workouts stimulate similar levels of muscle protein synthesis, a molecular measure of how quickly new muscle was growing. Was that complete malarkey? Does Dr. Phillips need to retire in shame?
Who's right? I have a radical answer to that question: All of them! And none of them. And who cares, anyway?
The point I am making is that all the workouts work.
Splitting hairs and getting hung up on all the science can make you crazy and potentially cause you to spend more time at the library researching than getting a good workout in.
Here's my takeaway. If you're feeling good and lifting to failure gives you the happy and accomplished feeling of having crushed a workout, that's your choice for today. If you aren’t feeling completely awesome—maybe you haven’t slept well or you have a lot on your mind—back off a little and enjoy a slightly easier lift. The difference between the two is negligible physiologically but can make all the difference psychologically. And as science has proved, whether you lift to failure or not doesn't seem to make a difference.
Remember that unless you're making a living from lifting weights, your exercise time is supposed to be fun or at least satisfying. So don’t get hung up on the details. You're moving your body, challenging your muscles and mobility, and pushing to be a better version of yourself tomorrow than you were yesterday. And that is all that matters.