Oh, no, my nemesis - stairs!

So, today is the day after the London Triathlon. The day after Karina and I swam 1.5km, cycled 40km and ran 10km and pushed our bodies to their limits for 2 hours and 24 minutes (in Karina's case) and 2 hours and 51 minutes (in mine). That was good enough to earn Karina a silver medal in her age group, and a personal best for me.

And today is the day that I declare stairs to be the most evil invention in the history of mankind.

Why?

DOMS - Delayed Onset Muscle Soreness. That sore feeling you get 24-48 hours after intense exercise. And in my case, specifically in my quadriceps - those big thigh muscles that push us up stairs, or steady us as we go down them. They were used hard on the bike, and were already in a bit of pain during the run.

Scientists aren't quite sure what causes DOMS, although they've come up with many theories over the years: muscle spasms, build up of lactic acid, etc. The best theory anyone has at the moment was actually proposed over 100 years ago: that when you do intense exercise, you cause microscopic tears in the fibres that make up your muscles.

But that doesn't explain why the pain starts 24-48 hours AFTER you tear the muscles. Studies have shown that it's not just the intensity of the exercise, but how your muscles have been used in the process. Researchers in Sweden showed that volunteers running downhill on a treadmill got far worse DOMS than those running uphill.

This seems to point towards DOMS being caused by eccentric muscle contractions - the motion where a muscle shortens but an external force (e.g. a weight or gravity) is forcing it to lengthen. For example, when running downhill, quadriceps have to act as a brake against gravity. Eccentric contractions push muscles to their limits (which is also why you should focus just as much on lowering a weight as you do on lifting it) and sometimes beyond. This causes tears, requiring more muscle repair.

It's the process of repairing our muscles that most likely cause that soreness as damaged tissue is cleared out and new cells are built. As fluid rushes into the affected area it makes the muscle fibres swell causing inflammation. At the same time there is an increase in 'nerve growth factor' that lasts for up to 2 days, making nerves more sensitive to pain. Swollen muscles + increased pain sensitivity could = DOMS, although it's not been conclusively proven yet.

The bottom line is that DOMS is a natural consequence of a hard workout or race, as part of the muscle damage/repair cycle. But without this cycle, you would never get any benefit from training. However, it's worth noting that DOMS is necessary to improve - so the old "no pain no gain" just isn't true. Pain during exercise is a bad idea.

Hopefully my quads will be recovered in time for our little ride from London to Paris on Wednesday. See you next week.</