What Does Science Say about Ideal Half- and Full Marathon Training Program Lengths and Volume to avoid Running-Related Injury
** To recertify my UESCA certification every two years I have to write a research paper on a training topic of interest, I figured I would post them here as well**
As running has increased in popularity in recent years, more individuals have looked to coaches (or coaching apps/the internet) for guidance with their training. Training programs for half and full marathons vary in length and volume to accommodate runners’ experience levels and their initial fitness. However, I have found it quite common for potential clients to view these programs as “couch-to…” plans. For example, I have had many individuals ask to be trained for a marathon only 16 weeks away while currently running just three to six miles per week, or running only once or twice per week. I have also been asked to prepare an athlete for a 50-miler on the basis of three runs per week. These experiences have made me curious about what research says regarding training program length and volume as they relate to both marathon completion and injury prevention.
A cohort study published in 2020 in the Scandinavian Journal of Medicine and Science in Sports by Fokkema et al. stated that “finish time is determined by a combination of training volume and training pace.” They found that “in half‐marathon runners, a higher training volume, longer longest endurance run, and higher training pace were related to a faster finish time, while a higher training volume and longer longest endurance run were also related to less decline during the race.” In this study, “higher training volume” was defined as greater than 32 km per week (19.9 miles), and a “longer longest endurance run” was defined as 21 km (13 miles) for half marathon participants. For marathon participants, a training volume greater than 65 km per week (40 miles) and an average training pace of 5:15 min/km (~8:30 min/mile) were correlated with faster finish times and reduced late-race pace decline. This study provides a rough picture of what peak mileage should look like leading up to a half or full marathon.
A 2022 study by Toresdahl et al. in The Physician and Sportsmedicine followed 720 runners training for the New York City Marathon. It found that “runners who averaged <4 training runs per week during the study were less likely to report getting injured compared to those who averaged ≥4 per week [relative risk 1.36, (1.13-1.63), p=0.001],” and that “longest training run distance during the study was inversely associated with race-day injury incidence [OR 0.87 (0.81, 0.94), p<0.001].” The full text is not freely available, but given the notoriety of the research group, I found the study important to include—though I would have liked more details on their findings regarding the ideal longest training run distance.
A 2025 study published in the Scandinavian Journal of Medicine and Science in Sports by Abrahamson et al. reviewed the Garmin-RUNSAFE Running Health Study. This cohort study prospectively followed 7,391 runners over 18 months to assess who was most likely to sustain a running-related injury. It found that “those running >105 km (cRD = -31.6, 95% CI -23.1; -40.1), 7 times per week (cRD = -47.1, 95% CI -35.9; -58.3), and who followed a structured running program (cRD = 4.4; 95% CI 0.9; 7.8) had the fewest new RRIs.” It also found that “those with few (<1 year) or many years (>40 years) of experience had the most RRIs. Runners were more prone to injury if they had few (<1) or many (>40) years of running experience, lower total weekly frequency (<2 times/week), shorter weekly distance (<25 km), or did not use a structured program.” With respect to my initial question, I am especially struck by the importance of running experience in injury avoidance. In my practice, it is often individuals who have never run a marathon who reach out with unrealistic expectations of training program length and volume. This study reinforces that newer runners with low frequency and low weekly mileage are most vulnerable to injury—something that must be considered carefully when designing novice training programs.
A 2014 observational study by Nielsen et al. in the Journal of Orthopaedic & Sports Physical Therapy followed 827 volunteers, of whom 202 sustained running-related injuries. Those who increased their weekly mileage by 10% over two weeks were less likely to be injured than those who increased by 30% over two weeks.The “10% rule” is a commonly cited guideline in marathon training, but it can be limiting at lower mileage levels. Using ChatGPT for help with the math, I combined principles from these studies. To never exceed a 10% increase in weekly mileage over two weeks, and to peak at more than 65 km per week (45 miles in this example), an individual would need 44 weeks to progress from 6 to 45 miles per week. To progress from 6 to 25 miles per week (greater than 32 km), the individual would need 22 weeks.
A 2023 study in the British Journal of Sports Medicine found that the acute:chronic workload ratio (ACWR) is a stronger predictor of running injury risk. In this study, Toresdahl et al. calculated the ACWR for 735 runners training for the New York City Marathon over the 16 weeks prior to the race, defining it as the current week’s mileage divided by the average mileage of the past four weeks. They found that an ACWR ≥1.5 was associated with more running injuries.
When I applied these findings to the ChatGPT-generated training models, the result was a 32-week marathon plan (peaking at 65 km per week) and a 22-week half marathon plan. While I would never consider using AI to write individualized training programs for athletes, in this case I found it helpful for calculating mileage progressions and adjusting variables quickly and accurately.
A quick review of popular static training plans shows that Hal Higdon’s Novice 1 program spans 12 weeks for a half marathon and 18 weeks for a marathon. Runner’s World offers half marathon programs lasting 10–14 weeks and marathon programs lasting 16 weeks. Nike’s plans run 14 weeks for the half marathon and 18 weeks for the marathon.
All in all, I am not suggesting that these programs are irresponsible, but I do believe they can be misleading to novice runners, who may assume it is safe to start training only 12 weeks before a half marathon or 18 weeks before a marathon simply because they see such programs online. Reputable coaches and coaching groups should consider offering “readiness programs” that help runners build a foundation before starting an official half or full marathon plan. This is not about making more money from clients but about ensuring they can tolerate training load while reducing injury risk.
Special attention should be paid to novice runners, those running fewer than once per week, and those with very low weekly mileage prior to starting a structured training program. Collectively, these studies highlight the importance of gradual mileage progression, while also ensuring the athlete builds sufficient resilience to handle the demands of half and full marathons. We do not need all of our runners to be fast, but we have seen that “fast” often correlates with “fit” and “resilient,” which can in turn increase the likelihood of completing a race uninjured.
As coaches, we face the choice of either appeasing clients by rushing their training or educating them honestly about their risks given the timelines they prefer. Each case deserves personalized analysis and feedback, but the studies above provide useful guidance for making sound decisions that keep athletes both healthy and realistic.
References:
Fokkema T, van Damme AADN, Fornerod MWJ, de Vos RJ, Bierma-Zeinstra SMA, van Middelkoop M. Training for a (half-)marathon: Training volume and longest endurance run related to performance and running injuries. Scand J Med Sci Sports. 2020 Sep;30(9):1692-1704. doi: 10.1111/sms.13725. Epub 2020 Jun 3. PMID: 32421886; PMCID: PMC7496388.
Toresdahl B, McElheny K, Metzl J, Kinderknecht J, Quijano B, Ammerman B, Fontana MA. Factors associated with injuries in first-time marathon runners from the New York City marathon. Phys Sportsmed. 2022 Jun;50(3):227-232. doi: 10.1080/00913847.2021.1907257. Epub 2021 Mar 31. PMID: 33750264.
Abrahamson J, Lindman I, Eriksen MB, Kibsgaard A, Nielsen RO. Using Self-Reported Training Characteristics to Better Understand Who Is More Likely to Sustain Running-Related Injuries Than Others: The Garmin-RUNSAFE Running Health Study. Scand J Med Sci Sports. 2025 Jan;35(1):e70004. doi: 10.1111/sms.70004. PMID: 39713859; PMCID: PMC11664494.
Nielsen RØ, Parner ET, Nohr EA, Sørensen H, Lind M, Rasmussen S. Excessive progression in weekly running distance and risk of running-related injuries: an association which varies according to type of injury. J Orthop Sports Phys Ther. 2014 Oct;44(10):739-47. doi: 10.2519/jospt.2014.5164. Epub 2014 Aug 25. PMID: 25155475.
Toresdahl BG, Metzl JD, Kinderknecht J, McElheny K, de Mille P, Quijano B, Fontana MA. Training patterns associated with injury in New York City Marathon runners. Br J Sports Med. 2023 Feb;57(3):146-152. doi: 10.1136/bjsports-2022-105670. Epub 2022 Sep 16. PMID: 36113976.
