How much force does the body absorb when running?

The force from the surface can be two to three times body weight with each step. How large it is depends, among other things, on speed and running technique.

When should running pain be examined?

Pain that returns in the same spot, increases while running, or continues after the session may be a sign of an overuse injury. If the pain persists or worsens, you should reduce your running and have the cause examined.

Do You Run a Lot? Here's Why Recovery is Important | Hardworkout Magazine

Key takeaways

- The ground reaction force in running can reach two to three times body weight with every step, depending on speed and running technique.

- Beginners generally benefit from a non-running day between sessions, while experienced runners can often handle consecutive days provided they adjust for how hard the previous sessions were.

- Prolonged energy deficiency can weaken bone health and increase the risk of stress fractures, which makes adequate carbohydrate and protein intake part of recovery.

When your fitness improves, it can be tempting to increase both the pace and the number of kilometers. Perhaps the usual runs feel easier, and you want to add more sessions during the week. But even if you have the energy to run more, it doesn't mean your legs are ready for it.

How quickly you increase your training volume, and how much time you allocate for recovery, can affect both your progress and the risk of injuries.

How much force do your legs absorb with every stride?

With each running step, muscles, tendons, and bones must handle the forces that arise when the foot strikes the ground. The force from the surface can be two to three times body weight. How large it is depends, among other things, on speed and running technique.

The calf muscles, particularly the gastrocnemius and soleus, work together with the Achilles tendon to control movement in the ankle joint and create propulsion. The thigh and gluteal muscles stabilize the body and control movements in the knees and hips.

Tendons store and release elastic energy, while the bones are subjected to repeated bending and compressive forces. Particularly the calves and feet must withstand large forces when you run.

A run of 10 kilometers can involve around 5000-6000 landings on each leg, depending on the stride length. Therefore, both the number of kilometers, intensity, and how often you run matter for how much the legs are subjected to.

Why does fitness improve faster than tendons and bones?

Endurance can improve faster than tendons and bones can adapt. Therefore, you may have the capacity to run longer and faster, even if your legs are not yet able to handle the increased training load.

The cardiovascular system can show clear improvements already after a few weeks of training. Adaptations in tendons and bones usually take longer.

When you run regularly, the tendons are stimulated to produce and reorganize collagen. This protein is an important part of tendon tissue. Over time, the tendons can become stronger and withstand greater forces.

In the bones, old bone tissue is continuously broken down and replaced with new. If the training volume increases too quickly, the breakdown can temporarily exceed the buildup.

If you continue to run a lot without sufficient recovery, small injuries in the bone tissue can occur. These can eventually develop into a stress reaction or a fatigue fracture.

Tendons can also develop pain if the training volume increases faster than they can adapt. Pain in the Achilles tendon is among the most common overuse injuries in runners.

![](https://hardworkout.no/wp-content/uploads/2024/10/AdobeStock65042676.jpeg)

How much recovery do you need?

The need for recovery depends on how far and hard you run, how often you train, and how accustomed your body is to running.

After a long run or a hard interval session, the muscles may have a reduced ability to generate power. At the same time, glycogen stores may be partially depleted. How long it takes to recover depends, among other things, on how demanding the session has been.

You do not need to be fully recovered before each run. Easy sessions between the hard ones can work well, but even if the heart rate is low, the legs are still subjected to repeated impacts.

For beginners, it may be sensible to have a day without running between sessions. Experienced runners can often handle several days of running in a row. However, they should still adjust their training based on how demanding the previous sessions have been.

Can cycling or swimming replace some of your runs?

If the legs need relief, cycling or swimming can be good alternatives. Both activities provide an opportunity to train endurance without the same impacts as running.

How to Improve Your Recovery

How well you recover is also influenced by how you distribute your training, how much you sleep, and what you eat.

- Distribute the hard sessions: Include easy days or rest between demanding interval sessions and long runs. This gives you time to recover before the next hard session.

- Increase training volume gradually: Avoid large jumps in distance for individual sessions. [A study from 2025](https://bjsm.bmj.com/content/bjsports/59/17/1203.full.pdf) with over 5200 runners found a higher risk of overuse injuries when a run was more than 10% longer than the longest run in the past 30 days. This does not mean that 10% is an absolute limit, but the findings show why you should be cautious about increasing the length of your runs too quickly.

- Prioritize sleep: Most adults need 7-9 hours per night. Too little sleep can reduce performance and make it harder to recover after demanding sessions.

- Eat enough food: Carbohydrates replenish glycogen stores after exercise, while protein helps repair and maintain muscles. Prolonged energy deficiency can also weaken bone health and increase the risk of stress fractures.

- Use alternative training if needed: Cycling and swimming can replace some running sessions when you want to reduce the number of kilometers. This way, you can still train your endurance.

- Monitor pain: Pain that returns in the same spot, increases while running, or continues after the session may be a sign of an overuse injury.

When is leg pain a sign of an overuse injury?

It is normal to feel sore or tired in the legs after a hard run. More localized pain, especially in the calves or feet, may, however, be early signs of an overuse injury. If the pain persists or worsens, you should reduce your running and have the cause examined.

![running](https://hardworkout.no/wp-content/uploads/2021/04/l2.jpg)

Sources:

How much running is too much? Identifying high-risk – [British Journal of Sports Medicine](https://bjsm.bmj.com/content/bjsports/59/17/1203.full.pdf)

International Delphi consensus on bone stress injuries in athletes – [British Journal of Sports Medicine](https://bjsm.bmj.com/content/bjsports/59/2/78.full.pdf)