To Fail or Not to Fail: The Surprising Truth About Muscle Gains and Training to Failure


In the world of fitness and bodybuilding, the quest for muscle hypertrophy—increasing muscle size—is a central goal for many athletes and coaches. Recent research sheds light on the nuanced relationship between resistance training (RT) intensity, specifically proximity-to-failure, and muscle hypertrophy. This article delves into these insights, offering practical advice for optimizing your training regimen.

Understanding Proximity-to-Failure

Proximity-to-failure refers to how close an athlete gets to the point where no more repetitions can be completed in a set with good form. Historically, training to momentary muscular failure (when you can't perform another rep) has been seen as essential for maximizing muscle growth. However, recent studies suggest a more nuanced approach may be just as effective, if not more so, for promoting hypertrophy.

The Role of Repetitions-in-Reserve (RIR)

The concept of Repetitions-in-Reserve (RIR) has emerged as a crucial tool in resistance training. RIR is an estimate of how many reps you could still perform before reaching failure. Training with an RIR approach means you stop your set when you think you could do a few more reps, rather than pushing to failure. This strategy balances intensity and the risk of excessive fatigue and muscle damage, which could otherwise impair muscle growth and recovery.

Key Insights from Recent Research

1. Effectiveness of Training Close to Failure

Research indicates that terminating sets close to, but not at, muscular failure can stimulate muscle hypertrophy effectively. This approach reduces the risk of unnecessary fatigue and muscle damage, suggesting a strategic balance is key.

2. RIR as a Practical Training Guide

Implementing an RIR scale helps athletes manage their training intensity wisely. It allows for high-intensity training less likely to result in overtraining or excessive muscle damage.

3. Comparative Results of Different Training Intensities

Studies comparing training to failure versus using an RIR approach show similar increases in muscle size. This challenges the notion that pushing to absolute failure is always necessary for growth.

4. Individualized Training Protocols

The research underscores the importance of tailoring training protocols to individual athletes. Factors such as training experience, recovery capacity, and specific fitness goals should inform how close to failure one should train.

5. The Importance of Accurate RIR Estimation

Developing the skill to estimate RIR is crucial for this approach's success accurately. Coaches and athletes should focus on refining this skill to ensure training sessions are both effective and safe.

Practical Applications

For athletes and coaches, these insights offer a roadmap to more effective and sustainable muscle growth. Here are some practical tips:

  • Start with RIR: Begin incorporating RIR into your training sessions, adjusting the intensity of your workouts to end sets with a few reps left in the tank.
  • Personalize Your Approach: Tailor your proximity-to-failure based on your current fitness level, goals, and how you're recovering from workouts.
  • Monitor and Adjust: Use your response to the training—such as progress in muscle size and feelings of fatigue—as feedback to adjust your training intensity.


The journey to muscle hypertrophy is both a science and an art, requiring a deep understanding of how the body responds to different training stimuli. The latest research offers valuable insights into optimizing training intensity for muscle growth, emphasizing the importance of strategic planning and individualization. By balancing the drive for intensity with the need for recovery, athletes and coaches can foster sustainable progress towards their hypertrophy goals.

Embrace the nuanced training approach with RIR, personalize your training protocol, and remember that the best results come from a balanced, informed approach to resistance training.

Refalo, M. C., Helms, E. R., Robinson, Z. P., Hamilton, D. L., & Fyfe, J. J. (2024). Similar muscle hypertrophy following eight weeks of resistance training to momentary muscular failure or with repetitions-in-reserve in resistance-trained individuals. Journal of Sports Sciences, 1-17.