Why do runners get so many injuries? And does strength training really make a difference?

For many of us, running is one of the most accessible forms of exercise. It’s free and you don’t need equipment. But it is also one of the more likely to lead to injury.

Studies of novice runners report around 18 injuries per 1,000 hours of running, which is more than double the rate experienced by more advanced runners. Most injuries seem to occur to the knee, ankle and lower leg, and are more likely to be “overuse” injuries, rather than acute muscle sprains.

Read more: My shins hurt after running. Could it be shin splints?

Overuse injuries tend to occur when a tissue is repeatedly loaded more than it can tolerate, without enough time to adapt.

This might happen because running starts to feel easier before your body is actually ready to do more.

So, what’s going on? And does improving strength alongside fitness help prevent injuries?

Fitness increases faster than muscle and bones adapt

When you start running, your cardiovascular system adapts quite fast. Blood volume increases within days, your cells’ mitochondria (which generate energy for exercise) can adapt in as little as two weeks, and the number of blood vessels in your muscle increases in around four weeks.

As a result, aerobic fitness measurably improves within as little as two weeks, and runs that felt hard in week one can feel manageable by week four. This can make it very tempting to go further and faster.

However, tendons and bones adapt on different scales and different timelines.

Tendon adaptations, such as becoming stiffer and stronger, typically take at least 12 weeks of consistent (and fairly heavy) loading.

Similarly, bone remodelling – which can make bones denser and able to withstand more impact – can take months, if not years.

Read more: Does weightlifting improve bone density?

Muscles sit somewhere in between. They can grow fairly quickly (within three to four weeks), but running on its own doesn’t do much to improve muscle strength or size.

This is important because, when you run, the calf muscles and Achilles tendon handle forces of several times your body weight with every stride – but running may not actually strengthen these tissues.

Basically, your heart and lungs adapt to running before your tendons and bones have caught up. This might explain why we see so many overuse injuries in runners.

Strength training and running injuries

Across sport, the evidence that strength training can help prevent injury is encouraging.

A large meta-analysis – which combined the findings of 25 studies, involving 26,610 participants – found strength training programs reduced sports injuries by more than 60%.

For runners specifically, however, the evidence is a little more mixed.

Another recent meta-analysis found that, on average, strength training programs don’t reduce injuries in runners.

However, they did note many interventions in their review had low adherence, meaning people didn’t stick to the strength training exercises. Those that were supervised did actually have a positive effect on injury outcomes, likely because of better adherence.

So strength training exercises might be effective – but only if you actually stick to them (funny, that…).

Read more: Strength training has a range of benefits for women. Here are 4 ways to get into weights

What the evidence does make clear is that strength training makes you a more economical runner, meaning you use less energy for every step you take.

So even if strength training only has a small impact on injury risk, it will make you better at running.

How to strength train for running

If you do want to sneak in some strength training to help prevent injuries and improve performance, you should prioritise the muscles and tendons that do the most work in running.

This means doing calf raises, split squats, squats, and deadlifts, with relatively heavy loads, for fairly low reps (5–6). This improves your maximum force output and strengthens tendons, which has been shown to improve running performance.

You might also want to do some plyometric exercises, such as pogo hops, tuck jumps, and single leg hops. These teach your body how to absorb and use force quickly.

Other ways to reduce running injuries

While some people advocate stretching as a way to prevent injuries, there is no strong evidence to suggest it will help.

However, there are a couple of things that do have some evidence behind them.

First, big spikes in how much and how often you run have been shown to lead to injuries. So, try not to increase your running distance by more than a couple of kilometres per week.

Second, running burns a lot of energy, and you need to have enough energy available to help recover after you run. As a result, eating enough carbohydrates and protein to meet your needs might help prevent overuse injuries such as stress fractures. Some research also suggests consuming more calcium and vitamin D might do the same.

Finally, there is some research indicating that running on grass reduces impact, compared to running on harder surfaces, like the road. So doing a couple of your weekly runs on grass might be a good way to give your body more time to adapt and recover between runs.

Read more: Running on a treadmill is easier than running outside. Does that matter?