New research shows that training with a couple of reps in reserve can be just as effective
I was recently a guest on For The Real Bodybuilders podcast, a show focused on women’s health and wellness. When asked what the ideal resistance training approach looks like for healthy aging, I offered something simple but practical: train hard, but keep “two in the bank.” In other words, lift with enough intensity to stimulate the muscle, but stop a couple reps short of failure.
It’s the kind of advice that lands well because it solves a familiar dilemma. Resistance training is no longer niche, it’s widely recognized as essential for maintaining healthspan, preserving muscle, and supporting long-term function. But with that awareness comes confusion. Do too little, and you don’t send a strong enough signal to the body to adapt. Do too much, pushing to failure every set, and you risk excessive fatigue, compromised recovery, or even injury.
A recent study in Medicine & Science in Sports & Exercise offers timely insight. It tested whether stopping just short of failure, leaving a couple of reps in reserve, can be as effective for strength and muscle gains as training to the limit. The results support the advice: effective training isn’t about breaking down the body, it’s about challenging it consistently, and recovering well enough to do it again.
Rethinking Maximum Effort
Lifting to failure, the point where you can no longer complete a rep, is a time-honored standard in strength training. It’s long been assumed that the harder you push, the more you gain. But the idea that every set must end in complete exhaustion is starting to give way to a more practical and sustainable approach. Recent evidence suggests that similar strength and muscle gains can be achieved without going all the way to failure. The new study compared training to failure with a method called “reps in reserve” (RIR), where lifters stop each set when they feel they could do one or two more reps with good form. The results showed that strength improvements were nearly identical, and the difference in muscle growth was modest at best.
This finding reinforces an important shift in training philosophy. The goal isn’t to train until the wheels fall off—it’s to apply enough stress to drive adaptation, consistently, over time. Most lifters can get the same benefit by working hard and stopping just shy of total fatigue. That means less soreness, faster recovery, and fewer disruptions to the rest of your training or daily life.
What the Study Actually Tested
The study tracked 42 experienced lifters, including 8 women and 43 men, over eight weeks. Each participant followed a streamlined program of just two full-body sessions per week, each lasting about 30 minutes. Each workout consisted of one set of nine compound movements: think squats, presses, and rows.
Participants were split into two groups. One group trained to muscular failure. The other used the RIR approach, stopping each set when they estimated they had two reps left. These were trained individuals, not beginners, so their progress wasn't due to novelty. And yet, even with minimal volume and frequency, both groups made significant gains. This is key. Many lifters assume that progress requires multi-hour sessions or four-day splits. But this study shows that even a minimalist routine, done with effort and consistency, can deliver meaningful results. For busy professionals, endurance athletes, or anyone looking to lift smarter, not just harder, this is a valuable reminder. It also affirms the principle of the “minimum effective dose” in strength training. You don’t always need more. Sometimes, you just need better execution of less.
Strength Gains vs. Muscle Growth
Both groups in the study got stronger. Bench press, squat, and muscular endurance all improved to a similar degree. For instance, squat one-rep max increased by 13.2% in the failure group and 12.4% in the RIR group, functionally indistinguishable. Muscular endurance, measured by how many leg extensions participants could perform at a set weight, also showed no meaningful difference. Power output, however, measured by countermovement jump, was slightly higher in the failure group. This may matter for athletes who rely on explosive strength. But for most lifters, the marginal gain doesn’t justify the added fatigue.
The only clear edge for failure training was in muscle size. The failure group experienced slightly greater hypertrophy, especially in the quadriceps and arms. Ultrasound scans confirmed it. But the differences were modest, and the practical benefit depends on your goal. If you’re training primarily for physique, those extra few percentage points may matter. If you’re training for function, health, or performance, they likely don’t.
In short: you can build nearly the same strength, and almost the same muscle, by stopping just short of failure. That makes RIR a smart choice for most lifters, especially those balancing other training or recovery needs.
When to Stop, When to Push
Reps in reserve works best when you’re honest with yourself. Estimating how many reps you have left takes awareness and experience. In this study, researchers occasionally had participants continue lifting past their estimated stopping point, and found that their estimates improved over time. This supports a simple approach: newer lifters may need to occasionally train near to failure to calibrate their internal sense of effort. Once that’s established, RIR becomes a practical, flexible way to train.
It also offers protection against the variables that affect training quality like stress, sleep, nutrition, or fatigue from other sessions. On days when you feel under-recovered, you can still train productively. On days when you feel fresh, you can push harder. RIR lets effort scale with readiness while still promoting progress. That doesn’t mean failure is off-limits. It can still be used strategically, especially on single-joint movements like curls or leg extensions, where the recovery cost is low. But pushing to failure on every compound lift, in every session, is neither necessary nor wise for most lifters.
Effective strength training isn’t about proving something to the barbell. It’s about creating consistent challenge with room to recover and adapt. Most of the time, leaving one or two quality reps in the tank is a great template to keep your progress sustainable.