Volume Volume Volume

Many runners are familiar with the 10% rule – don’t increase your weekly mileage by 10% of the previous week’s mileage. This rule of thumb has been around for ages, but you can see how an umbrella rule like this won’t apply to everyone with a few examples like:

• Runners at 0 miles in week 1 should be running 0 miles in week 2
• Runners at 3 miles in week 1 should be running 3.3 miles in week 2
• Runners at 100 miles in week 1 should be running 110 miles in week 2

There’s a floor and ceiling effect, clearly. Somewhere in between this inverted U-shaped curve, there’s probably a fair amount that the 10% rule works well enough for. But how well is well enough? How much is too much? Is there any research to back this up (okay, only I care about this one)?

Although it’s likely been around longer than 2003, a group of physicians gave the recommendation of the 10% rule based on level III evidence. That is, based on evidence such as case-controlled or retrospective studies. While this isn’t terrible, it isn’t on the same level as a randomized controlled trial, prospective study, or diagnostic study. Buist et al. conducted an RCT and found that the 10% rule didn’t hold up in novice runners (no significant difference in injury rate increasing weekly running distance by 24% over an 8-week period compared to a group progressing their weekly running distance by 10% over a 12-week period). Nielsen et al. then conducted a 1-year prospective cohort study that looked at 873 novice runners and the incidence of injury with increases in <10%, 10-30%, and >30% weekly mileage over 2 weeks. Interestingly, 30% appeared to be the significant cut-off point where injury incidence (patellofemoral pain, iliotibial band syndrome, medial tibial stress syndrome, patellar tendinopathy, greater trochanteric pain, and injury to the gluteus medius or TFL) significantly increased over the 10% mark. Not to say that everyone should start increasing their weekly mileage by 29% to maximize their training, but know that 10% can be a bit conservative in some cases.

As of the date of this post (10/17/18) it’s notable that the RUNSAFE research group based out of Denmark is conducting a 1 year prospective running injury study (the SPRING study) to investigate the effects of the modified acute:chronic workload ratio on injury. Acute:chronic workload ratio is another way of looking at overall load management for athletes; we’ll dive into this deeper in a future post, but this will be the first study to specifically examine it in running.

So what does this all mean? 10% is fine. Not 10% can also be fine. Use a healthy amount of good judgement and common sense.

Questions? I will field at least 10% of them.

Dr. Jason Tuori, PT, DPT, CSCS

References/cool running readings:

1. 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; 44(10): 739-47.
2. Running: how to safely increase your mileage. J Orthop Sports Phys Ther. 2014; 44(10): 748.
3. Buist I, Bredeweg SW, Van mechelen W, Lemmink KA, Pepping GJ, Diercks RL. No effect of a graded training program on the number of running-related injuries in novice runners: a randomized controlled trial. Am J Sports Med. 2008; 36(1): 33-9.
4. Johnston CA, Taunton JE, Lloyd-smith DR, Mckenzie DC. Preventing running injuries. Practical approach for family doctors. Can Fam Physician. 2003; 49: 1101-9.
5. Jungmalm J, Grau S, Desai P, Karlsson J, Nielsen RØ. Study protocol of a 52-week Prospective Running INjury study in Gothenburg (SPRING). BMJ Open Sport Exerc Med. 2018; 4(1): e000394.