Acute Variables: Performing Sets to Failure

Definitions

• Sets to Failure (reps-to-failure/set): Sets-to-failure is a resistance training strategy in which an individual performs repetitions of an exercise until they can no longer complete a repetition. The word "failure" in this context may include:
  • Mechanical failure is performing repetitions until another repetition cannot be performed through a full range of motion (ROM), regardless of effort.
  • Volitional failure is an exerciser performing repetitions until they choose to stop, depsite encouragement to continue (presumably due to fatigue).
  • Form failure is performing repetitions until another repetition cannot be performed with optimal posture/form. Note that form failure is not included in any of the methodologies of the studies included in this review.
• Reps-in-reserve (RIR, normal sets, or reps-NOT-to-failure/set): Reps-in-reserve is a training strategy intended to approximate effort while performing fewer reps than sets to failure. The number of reps-in-reserve is an exerciser's estimate of how many more reps they could have performed before reaching failure.
  • For example, if an exerciser performed 8 repetitions but feels they could have performed 2 more reps before failing, then the intensity is 2 reps-in-reserve, and they are presumably using a 10-repetition maximum load (10-RM load). Common strategies include 1-2 reps-in-reserve, 3 reps-in-reserve, and half-reps/set. Note, "feeling half-reps" is likely unreliable and assumes that the exerciser has some experience with the exercise and the load and can estimate the total number of reps they would perform for a set. RIR can be used in conjunction with a 10-point Rate of Perceived Exertion (RPE) scale. For example, an RPE of 8/10 corresponds to 2 RIR ("2 reps left in the tank").

Evidence-based Summary Statement on Sets to Failure:

Based on a systematic review of all available peer-reviewed and published research, the Brookbush Institute recommends performing repetitions to failure per set (reps-to-failure/set) for optimal improvements in hypertrophy, strength endurance, and maximal strength. However, repetitions in reserve per set (reps-in-reserve/set) are recommended for enhancing power outcomes and for athletes engaging in high-frequency training with the intent of improving sports performance, hypertrophy, strength, or power. Performing 1–2 reps-in-reserve/set, along with 1 additional set per exercise, maintains exercise volume (an influential acute variable), sustains rep velocity and force across multiple sets, and reduces post-exercise performance decreases and long recovery periods associated with reps-to-failure/set.

It is also important to note that for most training goals, reps-to-failure/set is not the most influential variable. For example, performing 1 set to failure is less effective than performing 3 sets with reps-in-reserve for improving hypertrophy, strength, or power, as total training volume has a larger influence on outcomes. Similarly, training load is a more influential variable for improving strength, and contraction velocity is more influential for power development.

• Reps-to-failure/set recommended for:
  • Hypertrophy
  • Strength Endurance
  • Max Strength
• 1-2 Reps-in-reserve/set and an additional set/exercise is recommended for:
  • Power
  • Athletes performing high-frequency training (with hypertrophy, strength, or power goals).
• Acute variables that are likely more influential than sets to failure:
  • Volume: 1 set-to-failure is less effective than 3 sets-not-to-failure.
  • Load: Load is more influential than reps-to-failure/set for strength goals.
  • Velocity/force (repetition tempo): Concentric velocity and force production are likely to have a larger influence on strength and power (and potentially hypertrophy) than reps-to-failure.

Course Summary

Based on the research available and carefully developed conclusions, this course answers many of the questions regarding performing sets to failure for improving strength, hypertrophy (muscle growth), muscle endurance, and power. Additionally, training experience, age, and athletic performance are also addressed. Additional topics include the effects of set-to-failure on blood chemistry, hormones, markers of muscle growth, body composition (body fat), electromyography, and post-exercise force production.

This course reviews all of the available research comparing "sets to failure" and "sets not to failure" (e.g., reps-in-reserve). Although the definition of failure most often included mechanical failure and the inability to perform another repetition (reps), some studies included volitional failure in which a participant chose to stop. Sets not performed to failure included a range from 1-rep-in-reserve to an estimated half-of-the-reps that could be performed for a load. Unfortunately, most of the research on this topic is plagued by methodological issues, including studies that altered multiple variables, making determining the most influential variable challenging, and studies that compared protocols on each limb of an individual despite known cross-over effects. Despite these challenges, the conclusions in the statement above are well supported and are likely to be congruent with any additional research published.

Some findings from the included systematic research review resulted in counterintuitive, or at least unconventional, recommendations. For example, it may be beneficial to use an athlete's perception of intensity (similar to a BORG scale) to perform reps-in-reserve/set to maintain or improve bar velocity/power throughout a high-frequency training program, to optimize improvements for power, as well as strength and hypertrophy.

Movement professionals, including personal trainers, fitness instructors, strength coaches, physical therapists, athletic trainers, massage therapists, chiropractors, and occupational therapists, should consider acute variables essential knowledge for optimal exercise programming. Sets to failure is one of these critical acute variables. This course is part of our ongoing effort to optimize acute variable recommendations.

Pre-approved credits for:

• Certified Personal Trainer (CPT) Certification

Pre-approved for Continuing Education Credits (CECs)for:

• Athletic Trainers
• Chiropractors
• Group Exercise Instructors
• Occupational Therapists - Intermediate
• Personal Trainers
• Physical Therapists
• Physical Therapy Assistants
• Physiotherapists

This course includes:

• AI Tutor
• Course Summary Webinar
• Study Guide
• Text and Illustrations
• Audio Voice-over
• Research Review
• Technique Videos
• Case Study and Sample Routine
• Practice Exam
• Pre-approved 3 Credit Final Exam

Additional Acute Variables Courses:

• Acute Variables: Repetition Tempo
• Acute Variables: Repetition Range
• Acute Variables: Rest Between Sets
• Acute Variables: Circuit Training
• Acute Variables: Sets per Muscle Group
• Acute Variables: Training Frequency and Recovery Between Sessions
• Acute Variables: Training Load (Weight and Resistance)

Sample Program:

• Case: Basketball Athlete
• Goal: Performance
• Split: Upper/Lower
• Frequency: 4 sessions/week (not including practice)
• Routine Construction: Circuit Training
• Periodization: In-season training

Phase 1

Acute Variables

• Load: Moderate (75-85% of 1 RM load, light loads for power) 
• Reps/set: 6-8 (2 reps-in-reserve)/set
• Sets/exercise (circuits): 3-4 sets/muscle group. Note that when performing reps-in-reserve, adding an extra set will maintain exercise volume.
• Rest between exercises: Circuit training, 1- 2 min rest between exercises
• Training Time: 25 minutes (excluding warm-up).

Routine: Upper Body

• Back:
  • Rope Row
• Chest:
  • Asymmetrical Dumbbell Press
• Power
  • Single-leg Medicine Ball Chop
• Shoulders/Corrective (Active Rest)
  • Single-leg Alternating Horizontal Abduction

Routine: Lower Body

• Legs Strength
  • Front Rack Frontal Plane Lunge
• Core
  
  • Side-plank with bottom leg on knee and top leg straight and abducted
• Power
  
  • Single-leg depth jump to balance
• Corrective (Active Rest)
  • Heel walks