Guide
How do you build running back up after an injury, towards a race?
Have your injury assessed by a physiotherapist or doctor first. Meanwhile, keep your fitness with cycling, rowing or aqua jogging at the same heart rate; in studies, 3.2 km run time stayed the same after 6 weeks this way. Once walking, calf raises and single-leg hops are pain-free, build up over about 3 weeks: first alternating walking and running, then easy continuous running, and only after that threshold work again.
In short
- Always have an injury assessed by a physiotherapist or doctor first.
- Cycling or aqua jogging holds your fitness for up to 6 weeks.
- Use a pain limit, for example at most 5 out of 10 and no worse the next morning.
- Build up over about 3 weeks, with threshold work as the last step.
- A previous injury is a risk factor; keep training strength.
This is not medical advice. If you have pain or an injury, or you are unsure, have it assessed by a physiotherapist or doctor. If you felt a "shot" or "kick" in your calf, have an Achilles tendon rupture ruled out first.
How common are injuries in HYROX athletes?
Common, and mostly from overuse. Chittenden and colleagues (2026) followed 89 HYROX athletes for 12 weeks. On average, 30% had a health problem in a given week. 73% of injuries came from overuse. The knee was hit most often, and the knee and lower leg together gave the biggest burden. Those who had been injured before seemed to run more risk, although that result was uncertain.
How do you keep your fitness if you cannot run?
Keep training in a way that does not load your injury, at the same heart rate as your running training.
| Study | What runners did | Result after 6 weeks |
|---|---|---|
| Eyestone et al. (1993) | Cycling or aqua jogging instead of running | 3.2 km run time unchanged |
| Wilber et al. (1996) | Aqua jogging, 5 days a week, hard and easy | VO₂max, threshold and running economy unchanged |
Tanaka (1994) warns that other sports never give you more than your own sport, but does call cross-training suitable during recovery. You can replace a threshold session this way with blocks of 4 minutes at your threshold heart rate on the bike or rower. How to find that heart rate is in finding your threshold pace.
Can you keep training through pain?
Sometimes, with a clear pain limit and in consultation with your physiotherapist. For Achilles tendon problems, Silbernagel and colleagues (2007) let one group keep running and jumping following a pain-monitoring model. After 12 months they did as well as the group that took 6 weeks of rest. Beyer and colleagues (2015) found that heavy, slow calf exercises and eccentric exercises worked equally well for Achilles tendon problems. People did stick with the heavy, slow version better: 92% against 78% of the sessions.
Benchmrk uses this pain limit: at most 5 out of 10 during the exercise, and no worse the next morning. If not, you take a step back.
When are you ready to run again?
When walking, calf raises and hopping are pain-free. Benchmrk uses this return test:
| Test | Goal |
|---|---|
| Walking | Pain-free |
| Single-leg calf raises | 20 to 25 times, pain-free |
| Single-leg hops | 10 times, pain-free |
For comparison: in a study of 566 adults, men reached a median of 24 and women 21 single-leg calf raises, on a 10° slanted board. Your physiotherapist can compare your result with your other leg and with your own age group.
How do you build running back up?
Step by step, over about 3 weeks. This is the build-up Benchmrk uses after a passed return test.
| Week | Running |
|---|---|
| 1 | 10 × (1 min easy running + 1 min walking); later 8 × (2 min + 1 min) |
| 2 | 5 × (4 min easy + 1 min walking); later 20 to 30 min continuous easy |
| 3 | 30 to 40 min easy + 4 relaxed strides; threshold back with half the reps |
In week 3 you still run the runs in your sim at easy pace. Race pace comes only after that. With a calf or Achilles injury, Benchmrk leaves out calf-heavy stations such as the sled push, lunges, burpees and wall balls for as long as the injury is active. Also read a faster sled push for the substitutes.
What does an injury mean for your race?
That your goal may have to shift. While you cannot run, your fitness grows less. Benchmrk then calculates less progress in your prediction and builds your volume up more slowly. If you have a season with several races, you can mark a race as a B or C race. How many weeks you have left and what that means is in how many weeks to train for HYROX and the HYROX taper.
How do you prevent a new injury?
With strength training. Lauersen and colleagues (2014) analysed 25 studies with 26,610 participants. Strength training lowered sports injuries to less than a third, and overuse injuries by almost half. Stretching had no effect. A previous injury is a risk: in a study of professional Australian football players, a previous calf injury raised the risk of a new one within 2 seasons 6.7 times. So build your volume up gradually, see the HYROX training plan.
How Benchmrk does it
If you report an injury that affects running, your runs become cross-training at the same heart rate and stations that load the injury drop out. With calf or Achilles problems, every session gets a rehab block: first isometric, then heavy and slow, then jumps. After the return test, a 3-week build-up of walking and running follows. Your volume grows more slowly and your prediction takes the injury into account.
Frequently asked questions
How long before you can run again after an injury?
That depends on the injury, and a physiotherapist or doctor assesses it. In a study of professional Australian football players with a calf injury, return took an average of 19 days without and 31 days with severe damage to the aponeurosis.
Do you lose your fitness if you do not run for a few weeks?
Not if you keep training another way. In two studies, runners who cycled or aqua jogged for 6 weeks kept their VO₂max or their 3.2 km run time.
Can you keep running with a painful Achilles tendon?
Sometimes, with a pain limit and under guidance. In a randomised study, continuing to run and jump following a pain-monitoring model did as well as 6 weeks of rest.
When are you ready to run again?
Benchmrk uses as a return test that walking, 20 to 25 single-leg calf raises and 10 single-leg hops are pain-free. Always discuss this with your physiotherapist.
How do you stop the injury coming back?
Keep training strength. In a meta-analysis, strength training almost halved the number of overuse injuries. In another study, a previous calf injury raised the risk of a new one considerably.
Sources
- Chittenden et al. (2026), Health problems in HYROX athletes – 12-week prospective cohort, Front Sports Act Living (accessed on 22 October 2026)
- Eyestone et al. (1993), Water running and cycling and 2-mile run performance, Am J Sports Med (accessed on 22 October 2026)
- Wilber et al. (1996), Water run training and maintenance of aerobic performance, Med Sci Sports Exerc (accessed on 22 October 2026)
- Tanaka (1994), Effects of cross-training, Sports Med (accessed on 22 October 2026)
- Silbernagel et al. (2007), Continued sports activity using a pain-monitoring model in Achilles tendinopathy, Am J Sports Med (accessed on 22 October 2026)
- Beyer et al. (2015), Heavy slow resistance versus eccentric training for Achilles tendinopathy, Am J Sports Med (accessed on 22 October 2026)
- Green et al. (2020), Return to play and recurrence after calf muscle strain injuries, Am J Sports Med (accessed on 22 October 2026)
- Hébert-Losier et al. (2017), Reliability and normative values for the standing heel-rise test, Physiotherapy (accessed on 22 October 2026)
- Lauersen et al. (2014), Exercise interventions to prevent sports injuries, Br J Sports Med (accessed on 22 October 2026)