How to Safely Increase Your Running Mileage

One of the primary causes of running injury is increasing mileage too quickly. Although it's not even February, some folks are beginning to think about ramping up mileage whether it's training for Boston Marathon or an early season 50k (anyone else signed up for Chuckanut 50k on March 19th?). I am sharing a useful, evidence-based guideline for safely increasing your running mileage. Feel free to email me with any questions regarding this article at

Sorry about the small print. I have re-typed the smaller print below if you are having difficulty reading.

New insights

Although runners, coaches, and health care providers commonly use the 10% rule, more science is needed to understand its role in injury prevention. Researchers followed 873 new runners for 1 year; during this period, 202 runners had a running-related injury. The researchers compared runner injuries based on each participant’s weekly increase in running distance: less than 10%, 10% to 30%, and more than 30% in the

2 weeks prior to injury. Runners who increased their mileage by more than 30% had a higher injury rate than those who increased their mileage by less than 10%. Runners who ran farther faster were at higher risk for patellofemoral pain (runner’s knee), iliotibial band syndrome, medial tibial stress syndrome (shin splints), patellar tendinopathy (jumper’s knee), greater trochanteric bursitis, and injury to the gluteus medius or tensor fascia latae (see illustration). However, other types of injuries were not linked to the 10% rule, such as plantar fasciitis, Achilles tendinopathy, calf injuries, hamstring injuries, tibial stress fractures, and hip flexor strains. The authors suggest that these injuries may be related to other training errors. 

Practical advice

A sudden increase in weekly running distance by more than 30% over a 2-week period may put runners at increased risk for developing running-related injuries. The lowest injury rates were found in new runners who increased their weekly mileage by less than 10% over 2 weeks. However, other running injuries may be linked to running pace, increasing running speed, sprint training, or other training errors. If you are starting a running program, your physical therapist can help customize a safe running progression to meet your needs. For more information on a personalized running program, contact your physical therapist specializing in musculoskeletal disorders and running-related injuries.