How Far Should You Push Yourself to Build Strength?

You’re drenched in sweat and sore, and even lifting your gym bag onto your shoulder feels like a struggle. The workout was grueling, but was it truly effective?

For years, many trainers and athletes believed that lifting to failure—the point at which you cannot complete another repetition—was the most effective way to build muscle. However, recent research challenges this notion, indicating that training at slightly less than maximum intensity can yield comparable results.

“The question I ask people is: ‘Are we improving or just getting tired?’” said David Frost, associate professor of kinesiology at the University of Toronto.

If you’re new to weightlifting, it can be difficult to gauge how intense your workouts should be. Learning how it feels to reach failure—and knowing when to push that far—can help you develop a sustainable strength training routine and progress safely as you get stronger.

There are two types of failure in strength training. “Technical failure” happens when you can’t complete another rep with proper form and control, forcing other muscles and joints to compensate. “Muscular failure” occurs when your muscles are so fatigued that you simply cannot lift the weight anymore.

While training to failure can increase muscle mass, some experts warn that the risks may outweigh the benefits. “If you push yourself to failure and damage your muscles to an extreme degree in one session, it will negatively affect your performance the next day and beyond,” Frost explained. Additionally, attempting to lift with poor form increases injury risk.

The key is to put in effort every time you hit the gym. Challenging your muscles causes tiny tears in the tissue, which then repair, grow, and strengthen during rest.

“You don’t necessarily have to train to failure, but a consistently high level of effort over time is essential,” noted Brad Schoenfeld, professor of exercise science at Lehman College in New York, who researches the effects of resistance training on muscle growth.

When starting out, perform new exercises using just your body weight to master proper form, advised Elizabeth Davies, a strength coach based in Kent, England, who primarily works with women new to weightlifting.

Once ready to add weight, begin with a light load and focus on maintaining good form rather than maximizing repetitions.

You can use the Repetitions in Reserve (RIR) scale to determine how much weight to use. This method involves estimating how many more reps you could perform at the end of a set before reaching failure. Ideally, choose a weight that leaves you with a few reps in reserve.

RIR allows you to adjust your workouts based on how you feel that day—which can vary due to factors like sleep, nutrition, hormones, and stress—instead of sticking rigidly to a fixed weight.

As a beginner, your muscles tend to adapt quickly, so stopping when you still have five or six reps left can still lead to progress, Davies said.

Research suggests that as you advance, stopping two or three reps before failure may be optimal for maximizing muscle growth. When you can perform the same number of reps for two or three consecutive weeks, increase the weight slightly and observe how your perceived effort changes, Frost recommended.

Once you’re comfortable with an exercise and can perform it consistently with good form, occasionally training to failure can help fine-tune your understanding of the effort needed. After all, “if you never train to failure, you don’t know how close you are to it,” Schoenfeld remarked.

When your body is pushed beyond its limits, it adapts to better handle that challenge next time, explained Schoenfeld.

If you enjoy the feeling of reaching your maximum effort, failure training can have a place in your regimen on occasion. Davies allows her clients to use this approach for single-joint movements, such as bicep curls, which won’t exhaust them excessively or hinder progress.

Ultimately, the most important factor in strength training is accumulating consistent hard work over time, Frost concluded. Most days, that means pushing yourself a bit more than the day before.