Yasso 800s: The Creator, How They Work, and Training Considerations

Who Created Yasso?

The Yasso 800s, a popular running workout and marathon pace predictor, were created by Bart Yasso, the former Chief Running Officer for Runner's World magazine.

What Are Yasso 800s?

Yasso 800s are a specific interval training workout widely used by marathon runners. The core concept involves running 800-meter repeats (approximately half a mile) at a consistent, challenging pace, followed by an equal amount of recovery time. The workout's unique appeal lies in its alleged ability to predict a runner's marathon finish time.

• The Workout Structure: A typical Yasso 800s session might involve running 800 meters fast, followed by 800 meters of easy jogging or walking for recovery. Runners progressively increase the number of repeats, often building up to 10 repetitions.
• The "Magic" of Yasso: The predictive element comes from converting your average time for the 800-meter repeats (in minutes and seconds) directly into a marathon finish time (in hours and minutes). For example, if you consistently run your 800s in 3 minutes and 30 seconds, the Yasso predictor suggests you could run a marathon in 3 hours and 30 minutes.

The Creator: Bart Yasso

The origin of the Yasso 800s is intrinsically linked to Bart Yasso, a prominent figure in the running community and a long-time editor and Chief Running Officer at Runner's World magazine.

• Bart Yasso's Background: Yasso spent over three decades at Runner's World, becoming a beloved and influential personality. He completed numerous marathons, ultra-marathons, and triathlons, including the iconic Badwater Ultramarathon. His approachable demeanor and wealth of experience made him a trusted voice for runners worldwide.
• The Genesis of the Workout: Yasso began experimenting with 800-meter repeats in the late 1980s. He noticed a consistent correlation between his average time for these intervals and his subsequent marathon finish times. This observation, initially anecdotal, became a widely shared training method after being popularized in Runner's World magazine. He never intended it to be a scientific formula but rather a simple, accessible benchmark for runners.

How Yasso 800s Work (The Underlying Physiology)

While not a precise scientific formula, Yasso 800s tap into several physiological adaptations crucial for marathon performance.

• Aerobic Capacity (VO2 Max): Running 800-meter intervals at a high intensity significantly challenges the cardiovascular system, improving the body's ability to utilize oxygen efficiently. This enhances VO2 max, a key determinant of endurance performance.
• Lactate Threshold: The structured nature of interval training, with periods of high intensity followed by recovery, helps to raise a runner's lactate threshold. This means the body can sustain a faster pace for longer before accumulating excessive lactic acid and experiencing fatigue.
• Pacing and Mental Toughness: Consistently hitting target times for 800-meter repeats trains a runner's sense of pace and builds mental fortitude. This ability to maintain focus and effort through discomfort is invaluable during a marathon.
• Muscular Endurance: Repeated bursts of speed followed by active recovery contribute to improved muscular endurance in the legs, preparing them for the sustained effort of a marathon.

Implementing Yasso 800s into Training

For runners considering incorporating Yasso 800s into their marathon preparation, a structured approach is recommended.

• Gradual Progression: Start with a lower number of repeats (e.g., 4-5) and gradually increase the volume each week, aiming for 8-10 repeats as race day approaches.
• Warm-up and Cool-down: Always begin with a thorough warm-up of easy jogging and dynamic stretches, and conclude with a cool-down jog and static stretching.
• Frequency: Typically, runners might include Yasso 800s once a week or every other week during an 8-12 week marathon training block. It should not replace your long runs or other essential workouts.
• Listen to Your Body: While the goal is to hit consistent times, it's crucial to adjust based on how you feel. Overtraining can lead to injury or burnout.
• Surface: Perform these on a track or a flat, measured course to ensure accurate distances and times.

Limitations and Criticisms of Yasso 800s

Despite their popularity, Yasso 800s have limitations and are often the subject of debate among coaches and exercise scientists.

• Predictive Accuracy Varies: The correlation isn't universally accurate. Factors like running economy, age, gender, training history, and the specific demands of a marathon course (e.g., hills) can significantly influence actual race performance.
• Not a Scientific Formula: It's an empirical observation, not a physiologically derived equation. There's no robust scientific evidence directly linking 800-meter interval times to marathon performance in a predictive manner across all individuals.
• Focus on Speed, Not Endurance: While it builds speed and VO2 max, it doesn't fully replicate the specific demands of sustained aerobic endurance required for a marathon. Long runs remain paramount for building endurance and practicing race-day fueling.
• Risk of Overtraining: Pushing too hard on these intense intervals, especially without adequate recovery, can increase the risk of injury or lead to fatigue.
• Individual Variability: What works for one runner may not work for another. Elite runners, for example, often have a much larger differential between their 800m interval pace and their marathon pace.

Conclusion: The Legacy of Bart Yasso

Bart Yasso's contribution to the running world goes far beyond the workout that bears his name. The Yasso 800s stand as a testament to his practical, experience-based approach to training and his desire to provide accessible tools for runners. While it should be viewed as one tool among many in a comprehensive training plan, rather than a definitive predictor, Yasso 800s have undoubtedly motivated and guided countless runners in their marathon journeys, cementing Bart Yasso's legacy as an enduring icon in the sport.