What's Limiting Your Performance? The 3-1 Test That Reveals Your Training Blind Spots

Most athletes train hard but wonder why progress stalls. What if a simple 30-minute test could reveal exactly what's holding you back? The 3-1 limiter assessment does just that – and the results might surprise you.

Why Do Most Athletes Train the Wrong Way?

Here's the problem: most training plans assume everyone has the same limitations. Runners pile on more miles. Cyclists chase higher FTP numbers. But what if your real limitation isn't what you think?

Some athletes need more cardiovascular fitness. Others need better muscular efficiency. Training the wrong system wastes months of effort and leaves performance gains on the table. The solution? Complete a 3-1 Limiter Assessment.

What is the 3-1 Limiter Assessment?

The 3-1 protocol is deceptively simple:

• 3-minute work intervals at increasing intensities
• 1-minute rest between each interval
• Continue until you can't maintain the required power/pace
• Monitor muscle oxygen levels throughout using Moxy

But here's what makes it powerful: those 1-minute rest periods reveal A TON about your physiology. How your muscle oxygen responds tells you exactly where your body's bottleneck lies.

How Does Muscle Oxygen Reveal Your Limitations?

During exercise, your muscles need oxygen to produce energy. The 3-1 test tracks this oxygen in real-time, revealing two distinct limitation patterns:

Is Your Heart the Problem?

• Muscle oxygen stays low during rest periods
• Your cardiovascular system can't deliver enough oxygen
• Common in athletes who need more aerobic base training

Are Your Muscles the Problem?

• Muscle oxygen recovers quickly but doesn’t drop during harder work intervals
• Your muscles can't effectively use available oxygen
• Often seen in strength-trained athletes new to endurance sports or sedentary individuals

What Should You Do If You Have Oxygen Delivery Limitations?

If your test shows delivery limitations, your training should focus on:

• Build Your Aerobic Engine: Long, steady-state sessions at comfortable intensities
• Increase Training Volume Gradually: Your heart and lungs need time to adapt
• Use Heart Rate Zones: Target Zone 2 training for maximum aerobic development 
  • Note: you can determine your zone 2 with this test as well!
• Be Patient: Cardiovascular adaptations take 6-12 weeks to show significant improvement
• Heat Train: Heat training is a very powerful way of improving your cardioavascular system, follow the 5, 50, 5 rule. Exercise in the heat at a rating of perceived exertion of 5, 50 minutes a day, for 5 weeks.

What Should You Do If You Have Oxygen Utilization Limitations?

If your muscles can't use oxygen efficiently, try:

• High-Intensity Intervals: Short, intense efforts improve muscular oxygen extraction
• Muscular Endurance Work: Sustained efforts at threshold intensities
• Sprint Training: Brief all-out efforts enhance mitochondrial function
• Focus on Recovery: Proper rest allows muscular adaptations to occur

Why Does This Matter More Than Traditional Testing?

Standard fitness tests measure what you can do, not why you're limited. VO2 max tells you your ceiling but not how to raise it. Lactate testing shows when you fatigue but not the root cause.

The 3-1 limiter assessment reveals the "why" behind your performance:

• Saves Training Time: No more wasted months on irrelevant training
• Accelerates Progress: Target your actual limitation for faster gains
• Prevents Plateaus: Address bottlenecks before they stall progress
• Personalizes Your Plan: Train your physiology, not generic recommendations

When Should You Retest Your Limitations?

Your limitations change as you adapt to training. Retest every 8-12 weeks to:

• Track improvements in your limited
• Identify new bottlenecks as they emerge
• Adjust your training focus accordingly
• Ensure you're always targeting the right system

Is Limiter Assessment Worth the Investment?

Consider this: most athletes spend thousands on equipment and coaching but never identify their actual limitations. A single limiter assessment can redirect months of training toward what actually matters for your performance.

The cost of testing pales compared to the time and effort saved by training the right systems. Plus, the motivation boost from finally seeing targeted improvements is invaluable.

What's Your Next Step?

Stop guessing what's limiting your performance. The 3-1 limiter assessment takes 30 minutes but could transform how you train forever.

Whether you're stuck at a performance plateau or want to maximize your training efficiency, discovering your true limitations is the first step toward breakthrough results. Your body has been trying to tell you what it needs – now you have a way to listen. 

Want a more detailed guide to completing your first limiter assessment? Download the Training and Racing with Moxy eBook below!