Injury Prevention for Runners

What raises your risk

No single factor decides who gets hurt. A 2024 umbrella review of 13 systematic reviews, covering 148 primary studies, concluded that injury risk is multifactorial and advised cautious interpretation of individual findings, since the included reviews were of low or critically low quality¹. Two factors have the most behind them, and Runsense builds around both.

A previous injury is the best-supported risk factor. A 2021 review of 29 prospective cohorts found a previous running injury the strongest risk factor in long-distance runners (moderate-quality evidence), while rating the evidence across risk factors as limited². In a 2021 study of 224 recreational runners followed for a year, those with a previous injury were injured at about twice the rate of those without one³. So the weeks after an injury are the ones to protect, and the guide on returning to running sets the order.

A session much longer than your recent runs is the jump to watch. In 5,205 adult runners followed for 18 months, injuries were more common when a session was more than 10% longer than the longest run of the previous 30 days: about 1.6 times as often for a session 10% to 30% longer, 1.5 times for 30% to 100% longer and 2.3 times for more than double. The week-to-week change in distance showed no relationship. It is an observational study, so it shows an association and not a cause⁴. Its runners were adults at middle mileages, so its limit is a rough guide for runners like them.

A weekly percentage does not protect on its own. In a 2008 randomized trial of 532 novices, a 13-week program built on the 10% rule had the same injury rate as a standard 8-week program (20.8% against 20.3%)⁵. A 2022 review of 36 articles and 23,047 runners found the evidence linking weekly distance, duration, frequency, intensity or recent changes in them to injury conflicting, and advised caution when recommending optimal progressions⁶. The guide on progressive overload covers how Runsense builds.

What prevention trials found

Strength work does not make you injury-proof. A 2024 meta-analysis of nine randomized trials in 1,904 endurance runners found no significant difference in injury risk or rate between runners who added exercise programs and those who did not. A post hoc analysis of supervised programs alone found significantly lower risk, and seven of the nine studies were of low quality⁷.

The best result so far is a supervised hip and core program in novices. In 325 novice runners randomized over 24 weeks, a hip and core program guided by a physical therapist led to about a third fewer lower-limb injuries than static stretching, and the average weekly prevalence of overuse injuries was 39% lower. An ankle and foot program did not reduce overuse injuries, and acute injuries were more frequent in that group⁸. In a 2020 trial, a self-directed 10-minute quadriceps, hip abductor and core program done three times a week for 12 weeks did not reduce overuse injuries that stopped 720 first-time marathon runners from finishing (7.1% against 7.3%). Injuries were self-reported⁹. So if injury is your reason, see a physical therapist first, and once you are cleared, build the weakness work for that problem into your strength sessions, as the coach Scozzaro does. The guides on core work for runners and strength training for runners cover the work itself.

Stretching did not lower injury risk. A 2011 Cochrane review of 25 trials (30,252 participants, 19 of the trials in military recruits and 3 in runners from the general population) found no evidence that stretching reduces lower limb soft-tissue injuries, with results compatible with either a small reduction or an increase, and it called the evidence base very weak¹⁰. Stretch if you like it, and do not count it as injury prevention.

The common injuries

A 2021 review put Achilles tendinopathy, shin splints (medial tibial stress syndrome), patellofemoral pain (runner's knee), plantar fasciitis and ankle sprains at the top by how many runners get them in a year, and patellofemoral pain, shin splints, plantar fasciitis, IT band syndrome and Achilles tendinopathy at the top by how many runners have them at a given time¹¹. Among ultramarathoners the ankle, knee and lower leg were the three most frequently injured sites¹¹. In a 2022 living review of trail-running injuries, the lower limb was the most reported region, specifically blisters of the foot and toe¹². These guides cover them:

• Achilles tendinopathy
• Shin splints
• Runner's knee
• Plantar fasciitis
• IT band syndrome
• Stress fractures, where running stops until a clinician clears it
• Foot care and blisters

Warning signs to back off

For the pain you run with, Runsense uses physical therapist Vikash Sharma's rule. Your clinician may set a different limit, and for a diagnosed injury theirs comes first:

• Pain stays at 3 out of 10 or lower (4 at most) while you run, and is stable or improving over the weeks.
• Stop the run if it climbs above that.
• It is back to its usual level within 24 hours of finishing. If it is not, the run was too much for now.
• A limp, or any change in how you move, is a stop at any pain level.
• Sharp or pinpoint bone pain, pain at rest or at night, and pain that gets worse the longer you run are stops at any number. Stop and have it assessed. The guides on pain versus soreness and stress fractures cover the signs.

Telling the kinds of pain apart

"Pain" covers several different things, and each gets a different response. The intensity number (a 4 or a 7 out of 10) does not tell you which one you have. What tells you is where it is, what it feels like, when it started, and how it behaves when you move. This is Runsense's way of sorting, not a diagnosis. Five common types:

• The under-conditioning burn. A diffuse muscular or tendon burn in both legs that builds while you run, common when you are returning or newer. It settles when you walk for a bit. The response is run-walk rather than days off: take walk breaks to let the burn settle, run again, and grow the running stretches gradually.
• Delayed-onset muscle soreness (DOMS). Both legs, roughly symmetric, achy and stiff after something new or hard, such as a downhill run or a new strength routine. It starts within about a day, peaks between 24 and 72 hours and fades over 5 to 7 days. It fades before the muscle has regained its full function, as a 2019 review shows¹³, so the next run stays easy, and nothing about it needs a stop.
• Acute post-effort soreness. A beat-up, heavy feeling in your legs and feet right after a hard, long or hilly effort, once you are already conditioned, with nothing sharp or one-sided. It is felt the same day, where DOMS comes a day or two later. The response is ordinary recovery: easy movement, food, fluids and sleep, with no change to the plan.
• A cramp. A sudden, involuntary clench of one muscle. Stop briefly and stretch it gently until it eases, which a 2022 review of cramps in athletes and the physically active gives as the usual treatment. The review calls the cause controversial, says recent evidence points to a confluence of intrinsic and extrinsic factors rather than one cause, and says individualized prevention will likely be more effective than general advice such as drinking more fluids¹⁴. So a cramp that keeps coming back is worth raising with a clinician.
• An injury. This is the one to respect. The tells are sharp or pinpoint pain, pain on one side only, pain that gets worse the longer you run, pain that is still there the next day or at rest, and any sharp bone pain. A pain that eases once you are warm can still be an injury: in Achilles tendinopathy, a 2023 review reports runners feel the pain at the start and end of a run with less in between¹⁵. The response is to end the run, replace running with aerobic work, and come back on a clear signal that it has improved instead of on a date (see "If something hurts" below).

When the signal is mixed

When it is genuinely unclear, pin down one detail before you change anything: one side or both, sharp or a diffuse ache, and does a walk break settle it or does it keep getting worse. Both legs, a diffuse ache or burn, and settling with easy movement point toward conditioning or soreness, which you train through with walk breaks and gradual building. One side, sharp or pinpoint, worsening as you go, or present at rest points toward injury, which you respect by backing off.

Do not guess in either direction. Parking a returning runner on rest for a conditioning burn is a mistake, and so is running through a real strain. Ask the one question that best separates the possibilities, and until it is answered, the pain rule above decides whether the run continues.

Flat legs with no pain

A slump can be a signal without any ache. A few flat days after hard training are expected and pass. If heavy legs, falling performance and low mood last for days, ease the load and see a clinician. A 2013 joint consensus statement of two sports-science colleges names fatigue, performance decline and mood disturbance as symptoms of overtraining syndrome, says an athlete will often show the same signs in nonfunctional overreaching, and says telling the two apart is very difficult¹⁶. The guide on overtraining covers what to change.

If something hurts

A first report of pain gets this order:

• Match the response to the kind of pain. The injury picture (sharp or pinpoint, one side only, or worsening the longer you run) means end the run and do not run again until the pain has improved. The other four types do not mean stopping your running, so respond to each as described above.
• Replace the running you cut with aerobic work that adds no lower-body impact, such as cycling, swimming or pool running, at an easy conversational effort, which is zone 2 in a five-zone model. The guide on returning to running covers what happens to fitness while you are off.
• Come back on a clear signal and not a date. The checks in the return to running guide come first, then a starting dose below your pain-free baseline, with hills and fast running last.
• Do not diagnose it yourself. A pain on one side that stays and gets worse at the same load is a building injury, and McClung's answer is to see a provider: a credentialed physical therapist, in person or a good virtual consult, because where it hurts may not be where it comes from (Scozzaro). See one right away for sharp bone pain, significant swelling, or trouble bearing weight.