The term D.O.M.S. is used frequently within the world of endurance, it represents the ‘Delayed Onset of Muscle Soreness’. The name refers to the fact that sometimes you don’t actually feel the effects of a training session or race until the following day when you step out of bed. Those who have ran a marathon will understand the sensation. You cross the line and undoubtedly you’re tired but there isn’t a great deal of physical pain. However, the next morning, or perhaps even the morning after that, your attempts to walk downstairs backwards provide the family with the highest level of entertainment they have ever experienced.

The same may be said of the inexperienced cyclist who decides to enter a 100 miles hilly cycle sportive, despite a poor training background. Aside from the embarrassment of being unable to sit down for a week, the morning after generally requires a family member to assist their descent to breakfast. So what’s happened? Has someone been repeatedly battering your tired legs throughout the night whilst you failed to wake from your exercise induced, coma like sleep? The answer lies with D.O.M.S. and the inflammation process.

The inflammation process

During a marathon running event the muscle tissue is damaged due to repeated stress and this triggers the inflammation process. The damage occurs ‘during’ the marathon but the inflammation process takes 24-48 hours to reach its peak, so the pain you feel the following morning was actually happening ‘real time’ during the second half of the race.

An important note to make here is that when people slow down in the final 6 miles of the marathon, we generally assume it is caused by low carbohydrate stores, often termed ‘hitting the wall’. However, there is likely to be a significant amount of muscle tissue damage by this stage in the race which will undoubtedly have an impact upon performance. Due to the D.O.M.S. effect, we rarely discuss the significance of tissue damage during the event. It’s important to recognise that the pain you experience 24-48 hours after the race is caused by damage which happened ‘real time’ in the second half of the marathon. That’s why you were getting slower!!

*Part of the inflammatory process involves fluid build up in the damaged area, due to this fluid build up you may weigh more 24-48 hours after the marathon that you did before, perhaps even 1-2kg extra in weight! Don’t worry.. it’s just water and it will pass.

How do I know if I’ve got tissue damage as opposed to simply having tight muscles?

1. It’ll be very ‘tender, warm and swollen’ and if someone squeezes your leg you’ll instinctively want to punch them (NB: they never see the funny side of your response).
2. When you stretch, it makes no difference to the tenderness, the pain still exists (it’s not tight, its damaged) and its probably better if you actually don’t stretch!

*Myth explosion – the pain and tenderness the day after the event has absolutely nothing to do with lactic acid in the muscles. It’s an old wife’s tail and I’m not even open to discussion on the matter.

How does damage affect performance?

You don’t have to be a rocket scientist to understand that a damaged muscle will not work as effectively as a healthy muscle. However, aside from the actual physical damage directly affecting performance, it’s possible that the inflammation process is acting on a much higher plane and going straight to the governor.

The central governor

There are various theories regarding ‘why we slow down’ and one of the most prominent in recent years has been the ‘central governor’. This theory suggests that fatigue is controlled by the brain (which can effectively switch off nerve signals to muscles) rather than fatigue being controlled by ‘peripheral factors’ such as the ‘actual muscle damage’.

Okay, here is a simple example:

1. The muscles is damaged and therefore doesn’t work well, as a result you slow down. That is ‘peripheral control’, the muscle is damaged and the muscle doesn’t work, at no point is the brain involved.
2. The muscle is damaged and somehow the brain’s monitoring system detects this. As a result the brain blocks nerve signals to the muscle so it can’t function fully and you are forced to slow down, that’s central governor control.

Why are we talking about central governor and gone off track from inflammation?

Yep, I was hoping you’d ask that. When we damage a muscle we kick start the ‘inflammatory process’ which is a chain of events involving a series of chemicals, each having a different purpose and action. One of the most widely researched in a chemical known as Interleukin-6 (IL-6) which is released into the blood stream during early stages of muscle damage and inflammation. Research suggests that IL-6 is detected by the brain and as a consequence, the brain then acts to slow you down in some way. In an old study (completed by Tim Noakes 2004) runners completed 2 separate 10k runs a week apart. They were healthy during both but prior to the second run they were injected with IL-6 and ran almost a minute slower.

Just stop and think about this for one second

Look at the 2 examples given at the top of this page for ‘peripheral control’ and ‘central control’. These 10k runners did not have muscle damage prior to either 10k, they were healthy, fuelled and ready to go until injected with IL-6. Their slower time cannot be explained by muscle damage, low fuel or any other form of peripheral control. The only possible explanation is the circulating chemicals. The chemical IL-6 has even been suggested as a possible cause for the lethargy associated with ‘chronic fatigue’ or ‘chronic overtraining’. We know that all general illnesses and all forms of stress kick start the inflammation process and that in turn creates IL-6.

How does energy and nutrition relate to tissue damage?

VERY IMPORTANT: In previous blogs we have talked a great deal about carbohydrate and fat use during exercise and how to refuel. There is a presumption that if you refuel correctly and use fat as a fuel source, you will be successful in endurance events. As a consequence, when people fail to hit their target times, the first thing they turn to as an excuse is ‘failing to get the nutrition correct’. We treat nutrition as some kind of magic wand and if it’s done correctly, you can cycle and run forever, but the reality is very different. It doesn’t matter how much fuel you pour into a broken car, it isn’t going to drive anywhere fast. Without the conditioning which comes from running long miles on hard surfaces, even the most fuel efficient athletes will break down due to tissue damage. CONSIDER THIS: The energy used when cycling and running at a steady pace are not significantly different (slightly higher for running). However, many people who can cycle for 6 hours with little issue, will find themselves in pretty bad shape after as little as 2 hours of running. So ask yourself this question, is it fuel intake or is it damage causing the issue?

What causes the damage?

1. Damage will be far greater if you’re not conditioned to the distance and terrain. In simple terms you need to spend time on your feet and do the longer sessions.
2. Harder surfaces are more likely to cause damage, although this isn’t always strictly true as runners do become accustomed to the surface they train on.
3. Running down hill is the real killer as the muscles contract eccentrically, braking your speed, thereby causing much greater damage.
4. This isn’t limited just to running. Cycling for several hours and repeatedly performing the same pedal action will lead to muscle tissue stress and damage.

How can you avoid the damage?

1. As above, you need to complete longer sessions, including downhill running if relevant.
2. It’s possible that damage may be reduced, by using compression clothing. Research is very poor but ‘subjective’ feedback suggests that it certainly helps.
3. Your weight will have an impact upon damage, if you have a few KGs to lose, it will help!
4. Whilst this is a subjective / commercial / controversial addition to the list, specific shoes such as HOKA which are specifically designed to reduce impact can reduce damage and associated DOMS.

What should I do if I have tissue damage?

1. Rest and let your legs recover for a few days.
2. Avoid very deep post event massage or stretching, sticking fingers into or stretching damaged tissue is never a good idea, wait a few days at least.
3. After a few days do some light exercise such as cycling to encourage blood flow to the area and assist the repair process.

If you found this article useful, it would help us a great deal if you share on Facebook, Twitter and social media.

Until then, limit the damage…

About Marc:

Sports Science lecturer for 10 years at St Helens HE College.

2004 established The Endurance Coach LTD sports science and coaching business. Worked with British Cycling as physiology support 2008-2008. Previous Triathlon England Regional Academy Head Coach, North West.

In 2006 established Epic Events Management LTD. Now one of the largest event companies in the NW, organising a range of triathlon, swimming and cycling events. EPIC EVENTS also encompasses Montane Trail 26 and Petzl Night Runner events.

In 2010 established Montane Lakeland 50 & 100 LTD. This has now become the UKs leading ultra distance trail running event.

In 2010 established The Endurance Store triathlon, trail running and open water swimming store. Based in Appley Bridge, Wigan, we are the North West’s community store, organising and supporting local athletes and local events.

Check out the endurance store HERE