Back in November I posted on here that I was planning to start training for a triathlon. That day, May 18th(Encinitas triathlon of recent shark attack fame), is coming quickly. I know that I am not near where I should be but since it is my first I am ok with that as my goal is finishing, not a fast time. My problems though have not been laziness or lack of trying. Since November I have suffered 2 sprained ankles, knee problems, 2 respiratory infections and 3 colds. That is more medical problems in 6 months than I have faced in the last 5 years. The ankles were caused once by drunken shenanigans, and the 2nd in a slip down the stairs when my biking cleats didnt grip too well on the wood surface. The knee problems were caused by wearing my orthotics with my skate shoes. The sicknesses were a different story, however. Both respiratory infections began within 6 hours after a ride as did 1 of the colds.

This has left me unable to train for weeks at a time. Over the last 6 months I have had no choice but to do on again/off again training. My conditioning is to a point where I can swim and bike for a long time but running... well lets just say I am going to have to walk most of the 5k. What can I do to prevent this from happening in the future? I am setting a goal to do the Mission Bay Triathlon in October as my 2nd tri. I don't want the same thing to happen. Should I be taking supplements? Should I look into changing my diet? What else can I do to help my immune system?

I have a couple suggestions:
1. Focus on building up your aerobic base - not on speed - but only on endurance. In other words, go slow as you build yourself up over time. Don't worry about your pace at all.
2.

Sorry about that...
2. After you've built up your distance work on speed with interval training. At first go fast for a minute then slow, and gradually build it up to 2 minutes, 3 minutes, etc, with time in between.
3. Eat healthy - review your diet, maybe with a dietician, but in any case with somebody who can give you helpful, factual feedback - don't go the supplement route, it has too many unknowns.
4. Make sure you get enough sleep - that is very important.

Hope that helps.