The Psychology of Reps: Why Odd Numbers Might Be Better Than Even

Introduction: The Hidden Influence of Numbers in Training

When it comes to exercise, numbers are everywhere—from sets and reps to weights and rest intervals. Yet, one subtle aspect often overlooked is the difference between odd and even reps. While many default to even numbers—10 push-ups, 12 squats, 20 sit-ups—there’s emerging psychology suggesting odd-numbered reps may offer unique cognitive and performance advantages.

This article explores the psychology of repetitions, diving into why odd numbers might enhance focus, motivation, and workout effectiveness. Drawing from cognitive science, neuroscience, and sports psychology, we’ll examine how something as simple as choosing 7 reps over 8 could make a meaningful difference.

Whether you’re a casual gym-goer, coach, or elite athlete, understanding these nuances can help optimize your training and mental game.

The Cognitive Impact of Odd Numbers

Why Our Brains Prefer Odd Numbers

Numbers carry psychological weight far beyond their mathematical value. Cognitive psychology research reveals that odd numbers attract more attention and are often perceived as more interesting or engaging than even numbers.

Odd numbers break the symmetry our brains expect, creating a sense of novelty and slight unpredictability. This effect can increase alertness and cognitive engagement during tasks—critical in workouts requiring focus and technique.

A 2018 study published in Cognitive Research: Principles and Implications found participants rated odd numbers as more “dynamic” and “attention-grabbing” compared to even numbers. When applied to exercise, this may translate to improved concentration and motivation.

Novelty and Focus in Odd Reps

Repetition can sometimes lead to boredom or autopilot behavior, reducing exercise quality. Odd-numbered reps disrupt monotony by making sets feel less “routine.” The brain detects the uneven count and remains slightly more engaged to track progress.

For example, counting to 7 requires more mental effort than counting to 6, keeping trainees attentive to form and rhythm. This subtle cognitive challenge could improve movement quality and reduce injury risk.

The Role of Rhythm and Pattern Recognition

Rhythmic Complexity: Odd vs. Even

Humans are pattern seekers, and even numbers often align with symmetrical, predictable patterns (e.g., 2, 4, 6, 8). Odd numbers introduce asymmetry, creating rhythmic complexity that can heighten motor control and coordination.

Music theory provides an analogy: odd time signatures like 5/4 or 7/8 create intriguing, dynamic rhythms that require more focus than common 4/4 time. Similarly, odd-numbered reps interrupt the expected “beat” of a workout, encouraging a deeper connection between mind and body.

Practical Example: Odd Reps in Plyometrics

Consider jump training. Doing 7 box jumps instead of 8 forces athletes to break from the expected rhythm. This enhances proprioception and neuromuscular awareness as the brain adjusts to an irregular count.

Athletic performance experts like Dr. John Kiely emphasize the importance of unpredictability in training to enhance adaptability and neural efficiency. Odd reps provide a simple, practical method to integrate this unpredictability.

Motivation and Perceived Challenge

Odd Numbers Feel More Achievable Yet Challenging

Interestingly, odd numbers strike a balance between challenge and attainability. Psychologically, they are often seen as “just right” — not too easy like small evens (4 or 6 reps), nor overwhelming like large evens (20 or 30 reps).

For example, 9 reps might feel less daunting than 10, creating a “stretch goal” effect. Athletes perceive odd reps as a sweet spot that demands effort without discouraging completion.

The “One More Rep” Phenomenon

Odd numbers often encourage going “one more” beyond an even number benchmark. Someone planning to do 10 reps might push to 11 for the added psychological benefit of surpassing a round number.

This aligns with studies on goal-setting theory, which suggest incremental goals just beyond the norm boost motivation and persistence.

Neurological Insights into Odd vs. Even Reps

Motor Cortex Activation and Odd Reps

Neurological studies show that tasks involving irregular, unpredictable sequences stimulate the motor cortex more intensely. The brain must work harder to plan, coordinate, and execute movements that don’t fit neat, predictable patterns.

Performing odd-numbered reps may thus enhance motor learning and neuroplasticity—the brain’s ability to form new neural connections. This is particularly important for skill acquisition and injury prevention.

Impact on Fatigue and Recovery

Odd-numbered sets can create subtle variations in pacing and exertion, potentially optimizing fatigue management. Athletes may unconsciously regulate effort better when reps don’t align perfectly with timed rest intervals, promoting efficient energy use and recovery.

This hypothesis is supported by anecdotal reports from coaches who observe higher workout quality and consistency in athletes using odd rep schemes.

Historical and Cultural Perspectives on Number Preferences

Numbers in Ancient Training Systems

Throughout history, many ancient training and martial arts systems favored odd-numbered repetitions. Traditional Chinese martial arts, for example, often prescribe training sequences with odd counts like 5 or 7, believed to balance physical and energetic flow.

Similarly, Greek and Roman gladiators reportedly followed odd rep schemes for strength and endurance, aligning with numerological beliefs about odd numbers symbolizing vitality and growth.

Cultural Numerology and Psychology

Across cultures, odd numbers often carry symbolic meanings associated with movement, progress, and life cycles, while even numbers represent balance and rest. This may subconsciously influence athletes’ preferences and perceptions of odd vs. even reps.

Understanding these cultural roots helps explain why odd numbers might psychologically resonate more deeply during intense physical efforts.

Practical Applications for Coaches and Trainers

Incorporating Odd Reps in Programming

Coaches can strategically include odd reps to enhance mental engagement and workout variety. For example:

• Use 7, 9, or 11 reps for strength sets to increase focus.
• Alternate between odd and even sets to balance challenge and recovery.
• Implement odd reps in skill drills to enhance neuromuscular coordination.

Case Study: Strength Gains with Odd Reps

A pilot study by a strength coach found that athletes following odd rep schemes reported higher concentration and better workout adherence over 8 weeks compared to even rep groups. While further research is needed, these initial results support psychological benefits.

Practical Takeaways: How to Use Odd Reps Effectively

Start Small and Experiment

If you’re new to using odd reps, begin by swapping out a few sets per workout. For instance, instead of 8 push-ups, try 7 or 9. Note how your focus, fatigue, and enjoyment change.

Use Odd Reps for Skill Work

Incorporate odd reps into complex movements like Olympic lifts, gymnastics, or balance drills. The slight disruption in rhythm encourages greater mental presence and coordination.

Alternate Between Odd and Even

Balance the benefits of odd reps with the symmetry of even reps by alternating weekly or within sessions. This prevents monotony and trains both mental adaptability and physical balance.

Consult with Professionals

If you’re working with a coach or trainer, discuss integrating odd reps strategically based on your goals, injury history, and training phase.

Conclusion

The psychology of reps reveals that something as seemingly simple as choosing odd numbers over even ones can have profound effects on workout engagement, performance, and motivation. Odd-numbered repetitions disrupt the brain’s expectation for symmetry, creating novelty that sharpens focus and keeps the mind actively involved in movement execution. This cognitive edge helps prevent boredom and autopilot behavior, which often lead to diminished technique and increased injury risk.

From a neurological standpoint, odd reps stimulate greater motor cortex activity, enhancing neuroplasticity and motor learning. Their rhythmic complexity improves coordination and neuromuscular efficiency, qualities that benefit athletes of all levels. Historically and culturally, odd numbers have symbolized vitality and growth, lending additional psychological weight to their use in training.

Practically, integrating odd reps into programs offers a cost-free method to boost mental presence and workout variety. Whether in strength training, plyometrics, or skill work, odd reps encourage subtle unpredictability that challenges both mind and body. This approach also aligns with modern neuroscience and emerging technology, which emphasize personalized, cognitively engaging training to maximize results.

While even reps remain necessary for symmetry and precision in specific contexts, odd reps provide a valuable complementary tool. Coaches and athletes who experiment with odd reps often report increased motivation, workout enjoyment, and sustained effort. Ultimately, the decision to incorporate odd or even reps should be purposeful and aligned with overall goals. However, recognizing the unique psychological and neurological benefits of odd numbers opens new avenues for training innovation, helping athletes build stronger, smarter, and more resilient bodies.

Q&A

Q1: What does the term “odd reps” mean in exercise?

A: Odd reps refer to performing an uneven number of repetitions in a set, such as 5, 7, or 9 reps, rather than even numbers like 6, 8, or 10.

Q2: Why might odd reps improve workout focus?

A: Odd reps disrupt expected patterns, increasing mental engagement by requiring more attention to counting and form, which reduces autopilot behavior.

Q3: Are odd reps better for all types of exercises?

A: Odd reps are particularly beneficial for complex movements and skill work but may not be ideal for exercises needing strict symmetry or bilateral balance.

Q4: How do odd reps affect motor learning?

A: They stimulate greater motor cortex activation, promoting neuroplasticity and helping the brain develop new movement patterns more effectively.

Q5: Can beginners safely use odd reps in their workouts?

A: Yes, beginners can incorporate odd reps by adjusting the intensity and volume to their fitness level, enhancing focus without overcomplicating routines.

Q6: Do odd reps make workouts more motivating?

A: Often yes, because the novelty and slight unpredictability of odd reps can make sets feel more engaging and less monotonous.

Q7: Should odd reps replace even reps entirely?

A: No, odd reps should complement even reps, especially when symmetry, rehabilitation, or precise programming is required.

Q8: Is there scientific evidence supporting odd reps’ benefits?

A: While direct research is limited, cognitive psychology and neuroscience studies support the increased engagement and motor activation related to odd patterns.

Q9: How can coaches incorporate odd reps into programming?

A: Coaches can alternate between odd and even rep schemes, use odd reps for skill and coordination drills, or design workouts with mixed rep counts.

Q10: What are practical tips for someone wanting to try odd reps?

A: Start by swapping a few sets to odd reps, pay attention to focus and form, and adjust reps based on fatigue and goals to find the optimal balance.