The Marathon Training Mistakes That Send New Runners to Physical Therapy—and How to Avoid Them

Marathon season can be especially exciting for first-timers. The thrill of making it through a full training block and hitting the starting line brings a serious sense of accomplishment—not to mention the pride of making it across the finish line.But marathon newbies should take note: The risk of injury during your first 26.2 training cycle is high.A study published in Physician and Sports Medicine in 2021 found that just under half of study participants (all new to the 26.2-mile distance) who were training for the New York City Marathon experienced minor injuries, affecting training and performance, while just under 10 percent had major injuries, preventing them from hitting the starting or finish line. (However, previously running a half marathon and clocking less than four runs per week was associated with lower risk of injury.)Injuries—minor and sideline-inducing—are common in newer runners because of the demands running has on the body, and an increase in mileage and intensity, says Robert Maschi, DPT, a board-certified orthopedic specialist and associate clinical professor at Drexel University. “The marathon is a completely different process,” he says, compared with shorter race distances and their training programs.This is compounded by the idea that the more we do, the better position we’ll be in, and the better our results will be, says Vikash Sharma, DPT, a physical therapist with Perfect Stride Physical Therapy.“People think if they take rest days or modify their workouts they’ll fall behind,” he says. “People cram workouts in and push through niggles because the training plan says to do it.”And that’s how first-time marathoners end up in a physical therapist’s office. PTs have seen it all when it comes to running injuries, and their goal is to keep their patients moving and headed toward their race-day goals.If you’re considering your first marathon or are already in the throes of training and want to stay pain-free, physical therapists explain the mistakes new marathoners often make in training that land them in the PT office—and how to avoid them for a more successful build.Skipping a Gradual BuildAt some point the running community placed the marathon on a pedestal that determines who real runners are (even though anyone who runs is a runner). And when that happened, people seemed to skip over the gradual build of distance races and jumped straight into marathon training and then straight into an IT band injury.“There are different requirements to run a marathon,” Maschi tells Runner’s World. Often, “people don’t understand the amount of time it takes to really build that sort of cardiovascular [or musculoskeletal] fitness to run 26.2 miles.”When runners start to add mileage or intensity to their workouts too quickly, their bodies aren’t ready for that increased load, Maschi says.“People don’t have the structural support and mechanics to withstand the [increased] load [of marathon training],” says Chloe Costigan, DPT, co-owner of Mobility Doc, a physical therapy office. She notes that runners who have completed a half marathon think the marathon is the next logical step, but doubling that race distance (and the required training) takes time.“People might work out for an hour, and then they’re jumping to two- and three-hour training runs,” she tells Runner’s World. “That’s a lot of time to be exercising.”And the adaptation from shorter distances to 26.2 miles can take months for your bones, muscles, tendons, and other tissues to get stronger.For first-timers, Costigan says, “you’ve never done this before. You’re just experiencing so much novelty, and the body is not used to it all.”Avoid It: When developing a marathon training plan for your first marathon, it should increase weekly mileage by just 10 percent (or at most, 20 percent)—also known as the 10 percent rule, Maschi says. This increase walks the line between improving performance and avoiding injury.Costigan suggests something a little unorthodox, too: Train for a marathon but don’t run a marathon in your first cycle. “You’re adding more novelty on race day with expectations and logistics,” she says. “I really wish there were a distance between a half marathon and a marathon, like 20 miles, to help people get used to [the marathon].”FIND YOUR MARATHON PLANIgnoring MechanicsYour running biomechanics are how you move when you’re running, and that movement affects how your body handles the force running has on your body. While you can improve your running form to help sidestep injury and become a more efficient runner, Maschi says running shoes have a significant effect on your biomechanics.He recommends prospective marathoners visit a local specialty running store for a gait assessment. This will inform the type of shoe that is best for their stride.Shoes aside, it’s important to address any biomechanical or gait issues—such as overstriding, crossover gait, or medial collapse (when your knees knock inward)—because they can lead to injury, especially over the course of high-mileage weeks. “That repetitive movement, thousands of steps per mile, add up and can lead to overuse injuries,” Maschi says.Costigan agrees: “You’re more likely to see overuse injuries related to a breakdown in mechanics because you’re experiencing more cumulative fatigue. IT band syndrome is a perfect example; your glutes are getting tired and if you don’t have a chance to fully recover, it'll expose more of that [fatigue].”Avoid It: “We can tweak [biomechanical issues] early on so the tissues don’t get overloaded,” Maschi says. Working with a physical therapist is the best way to address running mechanics, including modifying cadence and knee positioning.OUR GUIDE TO RUNNING FORMBeing Inflexible With Your Training Program Perhaps one of the biggest traps to catch first-time marathoners is rigidity. And, related, a strict finish time goal. In these cases, runners don’t give themselves room for life outside of running, like travel, illness, or family obligations.“People think if they miss a workout then everything will fall apart,” says Sharma, who also owns the education program, Running for Life. That might mean if they miss a couple of long runs, they’ll jump to the next long run to coincide with that week’s plan. “But those previous weeks had a purpose and your body may not be adapted to hit that [long run],” Sharma says.Costigan has seen patients who are so married to a time goal in their first marathon that they push themselves over the edge to try to reach it. When you’re so attached to a time goal, she says, “you’re sometimes projecting the best version of yourself without taking into account how the training or race are going to go—especially for your first.”Avoid It: Because this is your first marathon, you’ll want ample base-building time to help your body adapt for what’s to come. There isn’t necessarily a list of boxes to check to be able to run a marathon, Sharma says, but you have to understand your current fitness first, before starting a build.That said, Alysha Flynn, founder of What Runs You and an RRCA-certified run coach, previously told Runner’s World that being able to run six to eight miles in one go is a reasonable baseline for recreational runners.Maschi emphasizes that missing a few easy runs here and there won’t totally derail your training if you’re sick, injured, or just can’t swing it one week. So don’t try to force the miles, say by making your long run even longer.When it comes to goal-setting, be flexible. If you’re eyeing a sub-four marathon as an A goal, for example, think about B and C goals, in case that time gets out of reach. Then you’ll still have a successful training journey and race day.Fueling InadequatelyHow you fuel during your training cycle is going to play a big role in how you perform and recover. Sharma routinely asks his patients, particularly the marathoners, what their nutrition looks like.“As your activity ramps up, including mileage and strength training, is your nutrition also increasing? A lot of times the answer is no,” Sharma says. “Or runners are fueling for their long run but their overall nutrition hasn’t changed.”Although physical therapists like Sharma likely won’t see a patient coming in to address fueling needs, it might be evident in their performance, or if they have an injury and comment about increased fatigue that won’t go away.“If your nutrition isn’t ramping up with your training, you’ll feel sluggish, fatigued, you’re not adapting or performing well, and you don’t feel recovered,” he says.Ultimately, poor nutrition—not enough calories or not the right mix of nutrients like protein, fat, and carbohydrates—can lead to injury because your body doesn’t have what it needs to recover and then perform again.Avoid It: In a perfect world, marathoners would work with registered dietitians to flesh out a meal plan for a marathon training cycle, including the week leading up to the race and on race day. There is a calculator to help determine how many calories you’ll need during marathon training, but good rules of thumb for fueling include:Carbohydrates: Consume about 2.3 grams to 5.5 grams of carbohydrates per pound of bodyweight per day. Aim for the lower end on days you have runs just an hour or less and the higher amount for days with longer runs. Protein: Experts recommend athletes consume 0.5 grams to 0.8 grams of protein per pound of bodyweight per day. In 2019, the International Association of Athletics Federations proposed even more protein for athletes, up to 1.1 grams per pound of bodyweight. Fat: The recommended daily intake for fat is about 60 grams per day or about 20 to 35 percent of your daily calories. THE FULL GUIDE TO MARATHON NUTRITIONSkimping on Sleep Similar to not fueling enough, if you’re not getting adequate sleep you might be at higher risk of injury, Sharma says. A 2025 paper published in the Scandinavian Journal of Medicine & Science in Sports reported an association between poor sleep quality and injury in runners. And Sharma references a 2025 study published in Applied Sciences that found that runners who slept fewer than seven hours per night for two weeks doubled their risk of injury.Those authors of the second paper wrote: “Recreational runners may require as much, if not more, sleep than professionals. Unlike professional athletes, recreational runners often balance training with work, school, home, social, and personal responsibilities, increasing their need for restorative sleep.”First-time marathoners, Costigan says, may underappreciate how much their weekly routine will have to change. “And that’s not just because you’re training more,” she says. “You’re going to need more sleep…you’ll need more time to recover.”Avoid It: Aim for seven to nine hours of sleep per night, particularly during high-mileage weeks. This might mean shaving a mile or two off of an easy run to sneak in extra sleep.When possible, naps are an excellent way to add more sleep; the authors of the Applied Sciences paper recommend naps of 20 to 90 minutes. A brief nap, just 20 minutes, is effective rest and can prevent naptime grogginess, while a longer nap can protect against muscle damage.Heather is the former food and nutrition editor for Runner’s World, the author of The Runner’s World Vegetarian Cookbook, and a nine-time marathoner with a best of 3:23. She’s also proud of her 19:40 5K and 5:33 mile. Heather is an RRCA certified run coach.