No pain, no gain is a myth—if you know this one simple strength training technique

Training to failure features prominently in the resistance exercise playbook. The theory goes that by stressing your muscles to near breaking point when lifting weights, you'll cause micro-tears in the tissue that, once repaired, grow back bigger.

This process, called muscular hypertrophy, underpins strength training and muscle building, and it's essential if you want to keep your body strong, fit and impervious to injury as you age.

The problem is, training to failure hurts. Stressing every sinew can flood your working muscles with painful lactic acid, while it can also overload your central nervous system, leaving you feeling wiped out for hours after your workout.

Fortunately, there is another way.

Study finds failure is not an option

A new study suggests lifting weights well within the bounds of failure can elicit the same strength and muscular endurance gains. Better still, the research found just two 30-minute sessions of resistance training per week is plenty to build size and strength.

The winning formula, researchers found, is to stop within two reps of the point of failure. Known as working up to two reps in reserve (RiR), the study's authors believe these findings could remove two of resistance training's major hurdles: time and discomfort.

"The largest barrier to resistance training adherence is time," lead author Tom Hermann tells me. "For many, especially those who don't find resistance training to be a major priority, taking the time to train is a challenge. Similarly, discomfort is a barrier for many."

These results, however, "provide evidence that a) you can make gains when only performing one set per exercise, and b) you can make gains even a couple of reps away from failure."

Due to the nature of the protocol—fewer reps and just one set per exercise—Hermann says the discomfort levels experienced by participants was "incredibly low compared with other resistance training programs".

Why reps in reserve beats failure

In the study, 42 young, resistance-trained men and women were randomly assigned to one of two parallel groups: a group that trained to failure on all exercises and a 'submaximal effort group' that trained with two repetitions in reserve for the same exercises.

With this second group, that meant stopping at the point that they felt they could perform two more reps before hitting failure.

The participants performed a single set of nine exercises designed to target all the major muscle groups per session, including the bench press and barbell squat, two times a week for eight weeks.

"We assessed pre-post study changes in muscle thickness for the biceps brachii, triceps brachii and quadriceps femoris, along with measures of muscular strength, power and endurance," says Hermann, who worked alongside renowned fitness expert Brad Schoenfeld PhD on the research.

Results indicated that while several measures of muscle growth tended to favor the fail protocol, both groups saw "appreciable gains in most of the assessed outcomes" and improvements in strength and muscular endurance were virtually neck and neck.

RiR gains for beginners likely to be even more pronounced

"These findings suggest that single-set routines can be a time-efficient strategy for promoting muscular adaptations in resistance-trained individuals," the study concluded.

"Training to failure in single-set routines may modestly enhance some measures of muscle hypertrophy and power, but not strength or local muscle endurance."

Hermann adds that while the study focused on resistance-trained individuals, he would expect the results to be even more favorable for lesser-trained or untrained individuals. "You can probably get away with even less than this and still make great progress," says Hermann.

Ready to put this newfound knowledge to the test? Use the 2 RiR protocol with this full-body dumbbell workout. Do one set instead of the recommended three, but choose a dumbbell weight that challenges you in that one set, leaving you with two reps in reserve at the end of the first and only set.