In your case you are in very good general condition and your times show it. So what remains is DOWNHILL conditioning. Downhill running is not a passive thing… it isn’t some natural activity that we all do well or fast. If it isn’t practiced you will suffer for it.

Cure:
Run repeats downhill at top and near speed (this will also serve as overspeed training which is excellent).
Focus on relaxing your upper body – don’t flail your arms all over the place.
Run erect and do not lean backwards giving a sort of braking effect to your running.
Allow gravity to take you. You should be able to run quite fast without the effort. But, it requires very fast leg turnover to become smooth.
Don’t take huge overstriding strides… strive for faster moderate length strides (though certainly they will be longer than on flat ground).

A couple weeks of practicing downhills 2-3 times per week should greatly reduce your incidence of cramping.

I seem to only get side aches after or during the down hills when in races. It is significantly making my times really bad on these hilly courses. Do you know why this is and what i can do?

Claudia was in her early 40s; 5-4 115 pounds soaking wet; no risk factors; no history of heart disease in her family; a highly competitive runner since high school – almost 30 years running experience; represented the US in the World Duathlon championships only 10 years ago; is a masters All-American in multiple events… had a heart attack.

So, I am not an alarmist, but I did want to share that the pain you experience is not typical. That does not mean that it is anything other than deferred pain from the diaphragm. But, I would be remiss if i didn’t introduce other possibilities.

I wouldn’t want to drop dead in the middle of a run, but I am only 25 and not overweight. Do you think at this age I might still need to see a cardiologist?

Given that one thought, in the interim it would appear that conditioning is the most likely cause since you are just beginning. Since it does go away after warming up and moving along a bit I would try to do longer warm-ups that include both stretching and strengthening your diaphragm/abs/core. Side to side stretches, sit-ups or crunches, core (the plank) exercises might be things to work into that warm-up. The goal is to get all those muscles warmed up similarly to after the 5 minutes you usually find relief.

I don’t think I’ve ever come across a medical term for this deferred pain. Maybe we could coin a phrase for it!

Now that I’ve read from your site (and a few others) that it could be messed up nerve connections, and that the pain is actually my diaphragm, my question is do you have any suggestions on alleviating it in the short term? I completely understand that with training/conditioning my muscles should get used to this work, but I don’t have any cramp near my diaphragm to press on at the moment, and I don’t think I want to try the aspirin/advil route. Such a weird phenomenon, but I’m so glad to find out it’s sort of normal! Is there any term to describe it so that I can go read more technical details, just to satisfy my own curiosity =)

Thank you so much for your site, it’s so very appreciated!