Myo Reps & Rest-Pause Training: The Science of Efficient Hypertrophy

Most lifters face the same problem: limited time in the gym but wanting maximum muscle growth. Traditional sets with long rest periods work—but they take time. What if you could get the same (or better) results in less than half the time?

Enter Myo reps and rest-pause training—two intensity techniques that have gained traction in the fitness community over the past few years. Developed by Norwegian strength coach Borge Fagerli, Myo reps (short for "muscular rep" or "myotatic reps") represent a different approach to structuring your sets. Rather than multiple long sets with extended rest periods, you're doing one "activation set" followed by short, sharp micro-sets with minimal rest between.

The science behind these techniques is intriguing—and the results from research are compelling.

What Are Myo Reps?

Myo reps are a training technique designed to maximize "effective reps"—the reps that actually stimulate muscle growth. The idea is simple: instead of doing 3-4 sets of 8-12 reps with 2-3 minute rest periods, you perform one longer "activation set" followed by several brief "Myo-rep sets" with only 5-15 seconds of rest between them.

Here's how it works:

Step 1: The Activation Set Perform 15-30 reps with a weight around 30-50% of your one-rep max. This should take you to roughly 1-2 reps shy of failure. Step 2: The Myo-Rep Sets Rest just 5-15 seconds (about 3-5 deep breaths), then knock out 3-5 more reps. Repeat this cycle for 3-5 Myo-rep sets, or until your reps drop below 3 per micro-set.

A typical session might look like this: 20 reps → 5 → 5 → 5 or 25 reps → 5 → 4 → 4 → 4 → 3

The key is that you're hitting failure multiple times in rapid succession, which theoretically maximizes the "effective reps" in each set.

The Science: How It Works

Henneman's Size Principle

Myo reps are grounded in Henneman's Size Principle, which describes how your body recruits muscle fibers:

• Your muscles recruit slow-twitch (Type I) fibers first—these are fatigue-resistant but produce less force
• As you fatigue or increase load, your body progressively recruits fast-twitch (Type II) fibers—these are more powerful and have the greatest growth potential
• In traditional training, you need multiple sets to repeatedly tap into these fast-twitch fibers

Myo reps keep rest periods so short that your fast-twitch fibers stay "activated," allowing you to hit them multiple times without completely resetting between sets.

Research Findings

A 2019 study published in the Journal of Strength and Conditioning Research compared rest-pause training (essentially Myo reps) against traditional multiple-set training in trained subjects over 6 weeks [1].

Results:

| Metric | Rest-Pause | Traditional Sets | |--------|-----------|------------------| | 1RM Strength | Similar gains | Similar gains | | Localized Muscular Endurance | +27% (leg press)* | +8% | | Thigh Hypertrophy | +11%* | +1% |

\*Statistically significant difference (p < 0.05)

The rest-pause group showed significantly greater hypertrophy in the thigh musculature and much better muscular endurance—while likely spending less total time training.

Another study from the Research Quarterly for Exercise and Sport found that high-volume training with restricted rest periods produced the largest acute growth hormone (GH) response [2]. While GH spikes alone don't guarantee muscle growth, they do indicate a potent metabolic stimulus.

Benefits of Myo Reps

1. Time Efficiency

This is the big one. You can achieve similar or better muscle growth in significantly less time. For busy lifters, this is a game-changer.

2. Joint-Friendly

Because you're using lighter loads (30-50% of 1RM instead of 70-80%), Myo reps place less stress on your joints, tendons, and ligaments. This makes them especially useful for:

• Lifters recovering from injury
• Older trainees
• Anyone dealing with joint issues

3. Breaking Plateaus

If you've stalled on traditional training, Myo reps introduce a novel stimulus that can help break through sticking points. The increased time under tension and repeated approaches to failure create new growth signals.

4. Mental Freshness

Fewer sets mean more mental energy for quality reps. You're not just going through the motions—you're attacking fresh reps each micro-set.

Practical Application

How to Implement Myo Reps

• Choose Your Weight: 30-50% of your 1RM (30% for beginners, 40% for intermediates, 50% for advanced)
• Start with Isolation Exercises: Most people find Myo reps work best on isolation movements like lateral raises, curls, tricep extensions, leg extensions, and calf raises
• Do Your Activation Set: 15-30 reps to near-failure
• Rest 5-15 Seconds: Take 3-5 deep breaths
• Hit 3-5 More Reps: Go to failure again
• Repeat: For 3-5 Myo-rep sets total

Sample Workout (Push Day with Myo Reps)

• Barbell Bench Press: 3 sets × 6-8 reps (traditional, 3 min rest)
• Overhead Press: 3 sets × 6-8 reps (traditional, 3 min rest)
• Incline Dumbbell Press: 3 sets × 8-10 reps (traditional, 2 min rest)
• Lateral Raises: 1 × 20 (activation) + 4 × 5 (Myo-reps)
• Cable Flyes: 1 × 15 (activation) + 4 × 5 (Myo-reps)
• Tricep Pushdowns: 1 × 20 (activation) + 4 × 5 (Myo-reps)

Important Guidelines

• Limit to 5 Myo-rep sets max: More isn't better—it just increases fatigue without adding benefit
• Use for isolation exercises primarily: While you can use Myo reps on compounds, most lifters find it too taxing
• Don't ego lift: The lighter weight is intentional. Trust the process
• Match volume if comparing: If you're testing Myo reps against traditional sets, keep total volume similar for fair comparison

Myo Reps vs. Rest-Pause: What's the Difference?

These terms get used interchangeably, but there are subtle differences:

Rest-Pause: Typically involves taking a brief rest (10-30 seconds) within a set, then continuing with the same weight. You might do 8 reps, rest 15 seconds, do 4 more, rest 15 seconds, do 3 more. Myo Reps: Uses a lighter weight (30-50% 1RM) for the activation set, then continues with that same light weight for all subsequent micro-sets. The rest periods are slightly shorter (5-15 seconds), and the entire structure is more regimented.

Both work on the same principle—repeated approaches to failure with minimal rest—but Myo reps are more structured and use percentages of 1RM for programming.

Who Should Try Myo Reps?

Great for:

• Busy professionals with limited gym time
• Lifters with joint issues who want to reduce load
• Intermediate-advanced lifters looking for new stimuli
• Anyone wanting to increase training density without extending gym time

Maybe not ideal for:

• Complete beginners (focus on learning movements first)
• Powerlifters focused purely on 1RM strength
• Those who genuinely enjoy longer rest periods between sets

The Bottom Line

Myo reps and rest-pause training offer a scientifically-grounded way to build muscle more efficiently. The research shows comparable (and sometimes superior) hypertrophy compared to traditional sets, with the added benefits of reduced joint stress and significantly less time in the gym.

If you've been stuck in a hypertrophy plateau or simply want to maximize your gains per minute in the gym, Myo reps deserve a spot in your training toolkit.

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References

• Prestes J, et al. Strength and Muscular Adaptations After 6 Weeks of Rest-Pause vs. Traditional Multiple-Sets Resistance Training in Trained Subjects. J Strength Cond Res. 2019 Jul;33(7S):S113-S121.

• Research on acute growth hormone responses to high-volume, short-rest training. Research Quarterly for Exercise and Sport.