This is a commonly asked question. I find that most people train either too hard for too long OR they don’t train enough (or hard enough) to see results and eventually quit lifting. What is recommended for most people who just want to gain strength, gain muscle, and function better in their daily lives and recreational sports?
Training to Failure Does Come with Negative Effects
Lifting to failure does cause excessive muscle damage and extends the amount of time you need for recovery. When someone trains to failure often and it is done for long periods of time, this is called overtraining. Overtaining can lead to overuse injuries. Folks in this situation typically do this until they have pain serious enough that keeps them from training, then they come to see me. Obviously, this is not ideal and is not a sustainable way to strength train.
Research does tell us that training to failure is not necessary to create significant neural and structure changes to muscle. You can lift close enough to failure and get the same benefits, and maybe even better benefits (see below).
This 2019 paper looked at single leg extensions to failure on one leg compared to stopping 1-3 reps from failure on the other. After 14 weeks, the non-failure leg actually showed better strength and muscle growth gains than the failure leg.
So should I ever lift to failure? If so, how often?
This depends on your goals and the type of strength training that you are following. In regard to compound lifts like a deadlift or a barbell back squat, I typically recommend that you train to failure or test some version of your max effort every 8-12 weeks or longer. Most of us do not need to be training to failure with our compound lifts any more frequently than that. There are other ways to track progress than performing a set to failure. So ultimately, if your goals do not include max effort lifts (ex. you are not a competitive powerlifter or strongman competitor), then you can spread out your max days or skip them altogether.
If we are talking about single joint accessory exercises like a bicep curl, then you can train to failure much more often.
So where is the sweet spot for everyday strength training?
You will get the same benefits in maximizing your muscle growth without the negative side effects if you consistently train within 1-3 reps of failure.
Note 1: Focus on this with compound lifts especially as you are more at risk of injury as they are more fatiguing and more complicated movements. Single joint accessory lifts are arguably safer to go to failure with more often.
Note 2: You definitely don't want to consistently train at an intensity that is less than a 5 or 6/10 effort though. This is not enough stimulus to create muscle growth.
Focus each set on going within 1-3 reps of failure. You should be able to maintain good form for all of the reps, and start to feel some fatigue or struggle by the last few reps.
Hope this was helpful in keeping you strength training and injury free!
Let's talk soon,
Physical Therapist, Certified Strength and Conditioning Specialist, Cert. in Dry Needling