If you're training for a marathon, you don't necessarily need to log a long run every single weekend leading up to race day. According to running coaches and exercise physiologists, intermediate and advanced runners can complete a marathon successfully with as few as four to seven long runs during a 12- to 16-week training block, rather than the 10 to 16 that traditional training plans often prescribe.

What Counts as a Long Run, and Why Does It Matter?

The definition of a "long run" isn't about hitting a specific distance; it's about duration and what happens to your body during that time. Will Baldwin, a USATF and VDOT-certified running coach, explains that the threshold for a true long run is around 90 minutes. "I quantify it as anything longer than 90 minutes," Baldwin stated. "That's when we really should be fuelling. [Ninety minutes] is when it makes a big difference. We're going to feel our glycogen [stored carbohydrates] running out, and it gets mentally harder".

At the 90-minute mark, your body shifts from burning stored carbohydrates to burning fat for energy, which is a much less efficient process. This is why long runs serve multiple critical purposes in marathon training.

Why Do Long Runs Matter for Race Day Performance?

Long runs accomplish several things that shorter workouts cannot. They help you practice fueling strategies, develop cardiovascular fitness, build muscular endurance, and strengthen the bones and connective tissues in your legs. Todd Buckingham, PhD, an exercise physiologist at PTSportsPRO in Michigan, emphasized the importance of adaptation: "The stomach is just like any other part of the training that you do in that it can adapt and change and learn how to better absorb fuel".

Todd Buckingham, PhD, an exercise physiologist at PTSportsPRO in Michigan

Beyond nutrition practice, long runs prepare your legs for the pounding they'll endure during the actual race. Buckingham noted that "it gets your legs used to the pounding they're going to take for the entire duration of the race," which is probably the most important benefit of long-run training.

Buckingham

How to Determine Your Ideal Long-Run Strategy

• Experience Level: Beginner runners benefit from the traditional approach of one long run per week, as they need more time on their feet to develop both mental toughness and physical capacity. Intermediate and advanced runners with a solid fitness base can get away with fewer long runs and may benefit more from pace-based workouts, strength training, and mobility work.
• Quality Over Quantity: Rather than eking out a standing weekly long run, focus on hitting a minimum number of high-quality runs on a customized schedule. A good long run finishes relatively strong, allowing you to pick up the pace even though the distance is long, rather than fading toward the end.
• Complementary High-Mileage Days: Most training plans should include other long days beyond the traditional weekend long run. These might include longer threshold runs or tempo runs that add up to significant mileage but incorporate specific workout structures, allowing you to practice fueling strategies while building fitness in a more targeted way.

Molly Huddle, a two-time Olympian who previously held the American 10,000-meter record, has seen runners aim for six long runs, miss one or two, and still perform well in their events. However, she emphasized that this strategy only works for seasoned runners with a solid fitness base. "I think that if you're a novice, it would be a different situation," Huddle noted.

Milica McDowell, DPT, a physical therapist and exercise physiologist at US Physical Therapy, explained the reasoning behind reducing volume for experienced athletes: "You're trying to sharpen the sword. You're trying not to break them down from a physiology standpoint," she said, noting that too much volume can impede recovery and lead to burnout and injuries.

The Risk of Diminishing Returns

One of the key insights from running experts is that there's a point where additional long runs stop providing meaningful benefits. Baldwin pointed out that "we're spending this huge portion of time practicing a skill that isn't very specific. There are a lot of general aerobic benefits, but once you've been running for a while, those just don't move the needle that much anymore. You're just getting really good at running 20 miles two minutes slower than what you're hoping for".

This doesn't mean that every long run needs to feel easy or perfect. Even "junky" long runs that feel borderline miserable have value, primarily from a mental perspective. Baldwin explained: "Being able to get through on a bad day is such a skill. That's a big part of fitness, too. Your basement kind of rises up a bit. Your bad days are just a little bit better".

Baldwin

The bottom line is that there's significant flexibility in how you approach long-run training. If traditional weekly long runs work for you and keep you motivated, there's no need to cut back. But if you've been feeling depleted, burnt out, or injured, reducing your long-run frequency while maintaining quality and incorporating other types of workouts may be a smarter path to race day success.