Why is the Backyard Ultra Distance 4.167 Miles? Explained

Why is the Backyard Ultra Distance 4.167 Miles? Explained

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The Magic Number: Why is the Backyard Ultra Loop Exactly 4.167 Miles?

Anyone new to the fascinating world of the Backyard Ultra often encounters the same initial question: why the incredibly specific loop distance? 4.167 miles (or 6.706 kilometers) seems arbitrary, almost comically precise. Unlike standard race distances (5k, 10k, marathon, 50k, 100 miles), this number doesn’t immediately resonate. But rest assured, like most things designed by Backyard Ultra creator Lazarus Lake,, there’s a deliberate method behind the apparent madness.

As we explored in the Backyard ultra format explained, pillar and detailed in the Official backyard ultra rules,, this distance isn’t random guesswork. It’s a calculated figure deeply rooted in ultrarunning history and purposefully designed to contribute to the unique challenge and structure of the Last Person Standing format. This article unravels the Backyard ultra distance origin, and explains exactly why backyard ultra distance 4.167 miles, is the magic number.

The Core Reason: The 100-Mile / 24-Hour Connection

The fundamental reason behind the 4.167-mile loop lies in its direct relationship to one of the most iconic benchmarks in all of ultrarunning: completing 100 miles within 24 hours.

Here’s the simple math:

  • 4.167 miles/loop * 24 loops (one per hour for 24 hours) = 100.008 miles

Laz designed the loop distance specifically so that a runner completing exactly one loop every hour for a full day would achieve the legendary 100-mile mark almost perfectly within the standard 24-hour timeframe.

Why is the 100-Mile / 24-Hour Mark Significant?

In the culture of ultrarunning, covering 100 miles is a monumental achievement. For decades, finishing a 100-mile race, especially within the common 24-hour cutoff often required for prestigious awards like the Western States 100 silver buckle, has been a benchmark of exceptional endurance. It represents a formidable physical and mental barrier. (See our Backyard ultra vs 100-miler comparison, for more on how these challenges differ).

By embedding this calculation into the very fabric of the Backyard Ultra format, Laz achieved several things:

  1. Linked BYU to Ultrarunning Heritage: It immediately connected his new, quirky format to a universally understood and respected endurance goal, lending it credibility and context within the wider sport.
  2. Created a Built-In Milestone: For participants in the potentially indefinite BYU, reaching the 24-hour mark and completing the 24th loop (achieving 100 miles) becomes a huge psychological milestone. It’s a tangible achievement within a race that otherwise lacks a defined finish line for most competitors.
  3. Established a Pacing Framework: The distance inherently sets up the unique pacing demands of the race.

Implications of the 4.167-Mile Distance

This specific distance has several crucial consequences for how the race unfolds:

  • The “Relentless but Runnable” Pace: To complete 4.167 miles in exactly 60 minutes requires an average pace of approximately 14 minutes and 24 seconds per mile (or about 8 minutes and 57 seconds per kilometer). This pace, in isolation, is well within the capabilities of most runners who would attempt an ultra. However, the challenge lies not in the speed, but in the relentless repetition and the limited recovery. To get any meaningful rest (e.g., 10 minutes), runners must average closer to 12 minutes per mile (around 7:27 min/km) for 50 minutes. This dictates the core Backyard ultra pacing strategy,: finding a sustainable, efficient pace that allows just enough rest without burning unnecessary energy. It makes the race less about raw speed and more about meticulous energy management and durability.
  • Global Standardization and Comparison: Using this precise distance is critical for the integrity of the official Backyard Ultra system worldwide. It ensures that:
    • Performances at different affiliated events are comparable.
    • Backyard ultra world records, have a consistent basis.
    • The Silver Ticket races, qualification system for Big’s Backyard Ultra, functions fairly, as results from different events can be directly compared based on the number of loops completed.
  • Mental Framing: Knowing the math provides structure. Runners can think in terms of “How many loops to 50 miles?” (12 loops), “How many to 100k?” (15 loops), “How many to 100 miles?” (24 loops). These become intermediate goals within the larger, indefinite challenge.

Evolution to the Standard

While the 4.167-mile distance linked to the 100-mile/24-hour goal seems to have been the core concept from early on, it’s worth noting that the execution at the very first Big’s Backyard Ultras involved slight variations (like separate day trail loops and night road loops) before Laz and the global affiliated system standardized on using a single, consistent 4.167-mile loop throughout the entire event for simplicity and consistency. This standardization further solidified the importance of this specific distance as central to the official format. What does yard mean backyard ultra context, became synonymous with this exact measure.

Conclusion: A Deliberate Design Choice

So, the answer to Why backyard ultra distance 4.167 miles, or Why is backyard ultra loop 6.706 km, is clear: it’s not random. It is a deliberate, calculated choice by Lazarus Lake, directly linking the Backyard Ultra format to the iconic Backyard ultra 100 miles 24 hours connection,. This “magic number” dictates the unique pacing requirements, enables global standardization for records and qualification, provides crucial mental milestones for competitors navigating the indefinite challenge, and grounds the format within the rich history of ultrarunning achievements. It’s a key element that makes the Backyard Ultra the unique test of relentless persistence that it is, demanding precise execution of the Official backyard ultra rules, from the Starting corral, to the final Loop completion.

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