How close to failure should you train?
Key Points You Need To Know!
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The Study: Influence of Varying Proximity-to-Failure on Muscular Adaptations and Repetitions-in-Reserve Estimation Accuracy in Resistance-Trained Individuals (2025)
A recent study published in The Journal of Sports and Exercise examined whether training close to failure is necessary during a 10-week resistance program (Martikainen et al.). To test this, researchers assigned two groups the same training program, but varied how close each group trained to failure.
The ultimate question they asked was: “Do you need to train to failure every session to get results?”
It turns out, you don’t.
Who Were The Participants?
The study used 39 trainees consisting of men and women aged 20–35 years old. Further, each participant had 2–9 years of continuous resistance experience with at least two training sessions per week.
Researchers went a little further than most studies and had a requirement for strength lifts for men and women.
- Bench Press: (M) 1.15–2 × body mass and (F) 0.7–1.2 × body mass
- Back Squat: (M) 1.35–2.3 × body mass and (F) 1.1–1.7 × body mass
Having these requirements ensured the lifters were trained sufficiently, which eliminated any interference with “newbie gains”. Newbie gains refer to the phenomenon when untrained individuals see results easily, seemingly regardless of what they do.
By using this strength requirement, researchers had greater confidence that any differences seen in the results were a result of the training.
What Training Program Did The Participants Use?
The trainees followed the same 10-week training program using an upper-lower split training four times a week. It was a typical, professional resistance training program that used a mixture of;
- Compound exercises (i.e., bench press, back squat)
- Accessory work (i.e., lat pulldown, face pull, dumbbell press)
- Isolations (i.e., curls, tricep extension, core)
The 10 weeks were then divided into two 5-week blocks that simply altered the rep scheme used, for example;
- Block 1: 3X7-9
- Block 2: 4X4-6
Now here’s the important part. While both groups followed the same workout plan, they trained with different reps in reserve (RIR). One group pushed closer to failure throughout the study, while the other stopped further away.
Reps in Reserve (RIR) is a method of autoregulation that helps trainees adjust training intensity based on how many reps they feel they could still complete at the end of a set. Instead of following a fixed rep scheme (like 3 sets of 10), the number of reps performed is guided by perceived effort:
- RIR 1: Stop when you believe you could do only 1 more rep → very intense, close to failure.
- RIR 3: Stop with about 3 reps left in the tank → moderately intense.
- RIR 5: Stop when you could still perform around 5 more reps → lower intensity, further from failure.
In this study, two groups were used.
- Group RIR1: This group used RIR1 for the entire program, bringing every set close to failure.
- Group RIR1-4: This group decreased the RIR every week during each 5-week block. They altered how close they trained to failure and only used the same intensity as the RIR1 twice.
Both groups also used a deload every 5th week.
A 5-week block looked like this;
- Groups: RIR1 // RIR1-4
- Week 1: RIR1 // RIR4
- Week 2: RIR1 // RIR3
- Week 3: RIR1 // RIR2
- Week 4: RIR1 // RIR1
- Week 5: Deload
As you see, the training of the RIR1-4 group decreased in intensity for 5 weeks. They then restarted for the second block.
*We put the entire training program below, so feel free to check that out!*
4 Important Results To Know About Training To Failure
At the end of the study, the researchers made several important observations.
1. Training Close To Failure Did Not Improve Muscle Growth
At the end of the 10 weeks, researchers found that both groups had relatively similar increases in strength and hypertrophy. This means that continuously training close to failure had no benefits for resistance-trained individuals.
However, the RIR1-4 group did experience lower levels of RPE, or ratings of perceived exertion. This basically means they saw the same amount of benefits without the stress and discomfort.
This makes sense as we would expect training close to failure every session to build a lot of fatigue.
It’s also important to note that even though the groups brought each set to varying degrees of failure, the total weekly volume was statistically similar. This is an important detail as it’s pretty well established that total volume is a primary indicator of muscle growth (Figueiredo et. al, 2018)
2. Not Training To Failure May Produce Bigger Arms
While not statistically significant, muscle growth in the biceps and triceps actually had greater trends that favored the RIR1-4 group. This suggests that if any group produced greater muscle growth in the arms, it was the RIR1-4 group.
This is a bit surprising.
Since the arms are smaller muscles, the general thought is that they can handle greater stress and require less time to recover. It’s also the opposite of what we usually see in the gym, with things like drop sets and forced reps to improve muscle growth.
However, this is not what occurred. What’s interesting is that the researchers didn’t really have any theories as to why this might be.
3. Mitigating Fatigue Is Likely Better For Squat Strength
Researchers noted something interesting in terms of strength. When it came to bench press, the RIR1 group appeared to produce slightly greater results.
However, when it comes to the lower body, the RIR1-4 group provided a significant advantage.
- RIR1 Group: Only 5 of 15 participants increased squat strength by more than 5kg, while 2 participants showed no improvements.
- RIR1-4 Group: All participants had a significant increase in strength, while 13 of 16 participants added 5kg+
Researchers theorize this likely comes down to fatigue. The bench press uses smaller muscle groups and smaller loads when compared to the back squat.
Performing the back squat puts stress on just about every muscle in the human body. Further, the loads are greater and the working muscles (legs) are bigger. As such, this creates greater fatigue and requires greater recovery time between sessions.
4. Using Repetitions In Reserve (RIR) To Estimate Intensity Is Accurate
A secondary goal of the study was to also determine the accuracy of trainees using repetitions in reserve (RIR).
Researchers made two important findings:
- Trained individuals can accurately use RIR from the start
- The accuracy of RIR can be improved further after use
This suggests that trained individuals have enough experience with resistance training to use RIR accurately. Better yet, using RIR regularly can help improve your ability.
How Does This Compare to Other Studies?
The importance of training to failure has always been a point of interest, both in the gym and with researchers. In the past, training to failure was believed to be mandatory and seen in common sayings such as;
- “No pain, no gain”
- “The last rep is the most important”
While training with intensity is definitely an important factor, other research has made similar conclusions; training to failure is not mandatory for muscle growth or strength.
This is seen in a large meta-analysis from Dr. Brad Schoenfeld published in The Journal of Sport & Health Science (Grgic et. al, 2022). They formed a straightforward conclusion: “Training to muscle failure does not seem to be required for gains in strength and muscle size.”
Interestingly, the above study also found evidence that not training to failure may be superior for strength gains, stating “In studies that did not equate training volume between the groups, the analysis showed significant favoring of non-failure training on strength gains.”
This makes sense as strength is generated through your neuromuscular system. If you’re constantly fatiguing your body with heavy loads, it will fry your system, resulting in lower performance.
One thing to point out in terms of strength is that the total load likely plays a role as well. Benching 135lbs is very different from 315lbs and will likely have differing effects on your neuromuscular system.
Final Takeaway
We don’t want people to confuse this with saying you don’t need to train hard. You need to train hard, but also need to train smart. Pushing our bodies to the extreme won’t automatically mean we’ll see benefits.
However, we also understand that many people simply like the rush you get; in this case, there doesn’t seem to be any massive cons of training close to failure.
The best practice is likely to alter your intensity, as seen in the RIR1-4 group. It’s a good mix of pushing it to the brink while also giving time to let the body recover.
However, there are a few caveats;
- Training to failure likely becomes more important when using lighter loads. The above advice is true when using loads of 60-85% 1RM.
- Progressive overload is still a must. You
- Total volume still plays a significant role in overall growth.
Full Summary And Details Of The Study
- Participants: 39 healthy men and women (20–35 years old), all resistance-trained.
- Groups:
- RIR1 group: Trained with ~1 rep in reserve (very close to failure) every set.
- RIR1-4 group: Started with ~4 reps in reserve and gradually worked closer to failure over 4 weeks (ending at 1 RIR).
- Duration: 10 weeks (two 5-week blocks, partly supervised).
- Measurements: Squat and bench press 1RM, Muscle growth (quadriceps, biceps, triceps), and session RPE (perceived exertion).
Key Findings
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The Study Training Program
Lower #1
- Back squat - 3x7−9 // 4×4−6
- Leg press - 3×7−9 // 3×7−9
- RDL - 3×7−9 // 4×4−6
- Standing calf raise - 3×7−9 // 3×7−9
- Lying leg raise - 3×7−9 // 3×7−9
Upper #1
- Bench press - 3×7–9 // 4×4–6
- Skull crusher - 3×7–9 // 3×7–9
- Incline DB press - 3×8–10 // 3×8–10
- Lat pulldown / Pull-up - 4×7–9 // 4×7–9
- Standing BB curl - 4×7–9 // 4×7–9
- Incline DB lateral raise - 4×7–9 // 4×7–9
Lower #2
- Back squat w/ 2s pause - 3×7–9 // 4×4–6
- Bulgarian split squat - 3×8–10 // 3×8–10
- Leg curl - 3×8–10 // 3×8–10
- Seated calf raises - 3×8–10 // 3×8–10
- Sit-up - 3×8–10 // 3×8–10
Upper #2
- Bench press w/ 2s pause - 3×7–9 // 4×4–6
- Pec deck fly - 3×8–10 // 3×8–10
- Cable triceps pushdown - 3×8–10 // 3×8–10
- Incline DB row - 4×8–10 // 4×8–10
- Incline DB curl - 4×8–10 // 4×8–10
- Cable rope face pull - 4×8–10 // 4×8–10
References
- Figueiredo, V.C., de Salles, B.F. & Trajano, G.S. Volume for Muscle Hypertrophy and Health Outcomes: The Most Effective Variable in Resistance Training. Sports Med 48, 499–505 (2018). https://doi.org/10.1007/s40279-017-0793-0
- Grgic J, Schoenfeld BJ, Orazem J, Sabol F. Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: A systematic review and meta-analysis. J Sport Health Sci. 2022;11(2):202-211. doi:10.1016/j.jshs.2021.01.007
- Martikainen, O., Niiranen, H., Rytkönen, T. et al. Influence of Varying Proximity-to-Failure on Muscular Adaptations and Repetitions-in-Reserve Estimation Accuracy in Resistance-Trained Individuals. J. of SCI. IN SPORT AND EXERCISE (2025). https://doi.org/10.1007/s42978-025-00338-8
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