Muscle Failure: It’s not dichotomous (and what that means for your next workout)

For twenty-three years, I’ve taught the importance of training to momentary muscle failure; the point in which another rep can no longer be completed with perfect form.  The benefits include maximal muscle fiber recruitment (which is the stimulus for stronger muscles) and significantly more calorie expenditure during and after the workout.  I’ve coached tens of thousands of workouts with NFL football players, high school and college athletes, and personal training clients in which muscle failure has been the focal point of each set. 

To be clear, our understanding of muscle failure has evolved over the years. 

In the late ’90s, we treated muscle failure like a light switch.  If you reach muscle failure you had, “flipped the switch” and stimulated your muscles to receive an optimal response.  If you didn’t reach muscle failure, the switch was un-flipped (and to stick with the analogy, the light stayed off).  Once you reached failure, the switch was flipped and you could stop because the lights were on and couldn’t be MORE on. 

Today, we have more research on the benefits of muscle failure than we did two decades ago.  Although failure has shown to be even more important than we thought in the late 1990s, our understanding of failure has evolved. 

Rather than flipping a switch, failure acts more like a continuum.  The further you move down that continuum, the better results you get. 

Picture your next workout: You are performing leg extensions and you are deep into the set.  You’ve performed nine repetitions and the discomfort is extreme.  Your quads are burning, and your heart rate is still elevated from the leg press you did just two minutes earlier.  Every part of you wants to stop.  You set the weight down and stop before attempting your next rep and wait for your trainer to help you lift the tenth rep.  This is muscle failure. 

But could you have done more?  Did you stop because of the burn?  Did you stop because of the elevated heart rate?  If you were offered $100 at that moment to complete the tenth rep without assistance, would you have been able to?  Perhaps.  Could you have completed half, or 75% of the rep before needing help?  If you weren’t stressed about the rest of your workday ahead, would you have been able to perform two to three more reps? 

Back to your workout.  Just at that moment, your trainer helps you lift the weight and instructs you to lower it in 30-seconds; “30 seconds!” you think to yourself, and you impressively muster 25 of those 30 seconds.  This represents moving further down the continuum of muscle failure. 

Take home message:  Momentary muscle failure is not a switch to be flipped.  Instead, muscle failure is probably a continuum and it’s up to us to channel the mental and physical preparedness needed in the moment to move us further down that continuum.  A few practical ways we can do this:

Don’t let your trainer help you until you REALLY need it; with perfect form, try another rep.  From a mental standpoint, toward the end of the set, focus on just one rep at a time.
When your trainer does start helping you lift the weight, don’t rely on the trainer; your focus should still be on lifting as much of it as possible with your trainer barely picking up the slack.
Focus on really giving your best effort during the eccentric contractions (a 10, 20, or 30 second “negative”).

Perhaps most important: Keep in mind that getting to any of these points of failure is valuable. Much more valuable than simply stopping at 12 reps when you could have easily completed 15 or 20.