Marathons are gruelling events, and for many runners the hard work of training starts early. The goal is to build fitness slowly and steadily without getting injured. But some runners pick up an injury just as they ramp up their training, weeks or months before the big event. In some cases, a steroid injection can help a runner keep training. So, is running after cortisone injections safe? When should you have a cortisone shot during training, and what should you do afterwards? Here are the answers to the most common questions.
What injuries respond to a cortisone shot?
Common marathon injuries that respond to cortisone include joint swelling and tendon-related pain from overload. Conditions that tend to do well include patellofemoral pain (runner’s knee), IT band syndrome, knee arthritis, and greater trochanteric pain syndrome (hip bursitis).
Because of the risks, a steroid injection isn’t recommended for some injuries — particularly any large weight-bearing tendon, such as the Achilles or patellar tendon. And a cortisone shot should only ever be one small part of managing an injury, alongside physiotherapy, medication, and activity modification.
Running after a cortisone injection: is it safe?
It can be, provided we choose the injury carefully. While you’re ramping up training, we wouldn’t inject a large weight-bearing tendon such as the Achilles or patellar tendon because of the risk of tendon damage or rupture. But some common marathon injuries — hip bursitis and IT band friction syndrome — are safe to inject. Even then, we advise resting from running for at least a week afterwards. So the timing of the injection is essential.
How long before a marathon should I have a cortisone shot?
A steroid injection can take up to a week to work, sometimes a little longer — and we advise up to a week of rest afterwards. So timing is everything.
We usually recommend an injection just before the final phase of intense training (4–6 weeks before a marathon). Alternatively, you could have it at the start of the taper (1–2 weeks beforehand). Because a cortisone shot typically lasts only 2–3 months, we’d advise against getting one more than 2 months before the race, as it may wear off before you get to the start line.
How long after a cortisone injection can I exercise?
We suggest resting the injected joint or tendon for at least three days. You can then resume non-impact activities such as swimming or cycling. Wait a week before returning to impact activities such as running. And if you develop a cortisone flare, wait until it settles before returning to exercise.
How long does a cortisone shot last?
A cortisone shot lasts about 2–3 months, though in some cases the effect is longer or shorter. This is why we’d advise against having a shot more than two months before a marathon.
What are the potential side effects of a cortisone injection?
Most runners tolerate a cortisone injection well when it’s used safely. But it’s worth knowing the more common side effects that can affect your training:
- A cortisone flare. Flares start about 12 hours after the injection and typically last 3–5 days, occasionally up to a week. Ice and oral NSAIDs immediately after the injection help settle them.
- Skin changes, such as fat atrophy and skin depigmentation.
- Tendon weakening. There’s evidence from animal studies that cortisone can temporarily weaken tendon structure, which is why we avoid injecting large weight-bearing tendons — and why you must rest from running for at least a week after any injection.
- The infection rate is estimated at 1 in 10,000.
For more details, see our guide to the side effects of cortisone injections.
Are there injection options other than a cortisone shot?
Hyaluronic acid occurs naturally in tendons, ligaments, and bone. Injected into a joint, it improves the pain and function of arthritis. These injections take 2–4 weeks to start working and suit mild arthritis discomfort — and, unlike cortisone, they need minimal rest from running.
Platelet-rich plasma (PRP) is made by spinning whole blood in a centrifuge, then injecting the concentrated platelets into a joint or tendon to reduce pain.
That said, both hyaluronic acid and PRP are less useful in the short window just before a marathon.
What about a local anaesthetic on the day of the marathon?
A long-acting local anaesthetic can be injected on the morning of the marathon. It starts working within 30 minutes and lasts about 12 hours. Conditions that may respond include IT band syndrome, patellar tendonitis, Achilles tendonitis, greater trochanteric pain syndrome, and foot tendonitis.
This is purely for symptom relief on the day — it doesn’t treat the injury, and it must be performed under ultrasound guidance to improve accuracy and avoid leakage into nearby nerves or blood vessels. It should only be considered after weighing the risk of running through a painful injury.
Frequently asked questions about running after cortisone injections
How long after a cortisone injection can I run?
Rest the injected area for at least three days, then resume non-impact exercise (swimming, cycling). Wait at least a week before returning to running — and longer if you get a cortisone flare, until it settles.
How long before a marathon should I get a cortisone injection?
Ideally, 4–6 weeks before (at the end of hard training), or 1–2 weeks before (at the start of tapering). Because cortisone lasts only 2–3 months, don’t have it for more than about 2 months, or it may wear off before race day.
Which running injuries can be treated safely with injections?
Conditions such as hip bursitis (greater trochanteric pain syndrome), IT band syndrome, runner’s knee, and knee arthritis respond well to treatment. We avoid injecting large weight-bearing tendons — the Achilles and patellar tendons — because of the risk of tendon weakening or rupture.
Can I have a cortisone injection directly into my Achilles or patellar tendon before a race?
No, we specifically avoid cortisone in these large weight-bearing tendons, as it can weaken them and increase the risk of rupture. Other treatments are safer for these tendons.
Is it safe to numb an injury with local anaesthetic to run a marathon?
It can relieve symptoms on the day, but it doesn’t treat the injury and masking pain carries a risk of making things worse. It’s a decision to make carefully with a sports doctor, under ultrasound, weighing the risks for your specific injury. Moreover, I would not have a cortisone injection before a marathon unless I had discussed the timing of the injection as outlined above.
Final word from Sport Doctor London on running after cortisone injections
Cortisone injections play only a small role in managing most running injuries — we combine them with therapy and rehab for the best outcome. Running after cortisone injections is safe with a common-sense, cautious approach, and in marathon running, timing is everything.
To discuss whether an injection suits your injury — and when to time it around your race — Dr Masci can assess you in London. Contact the team here or call +44 (0) 203 488 0350.
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