An ongoing question we all face during racing in long distance endurance events is the compromise of lightweight shoes, bikes, etc. vs. maybe a bit more weight and less aerodynamics but more comfort. Of course in shorter events comfort becomes less of an issue (to some degree!) and it's all about speed via no socks while running in a triathlon, no change of clothes in the transition area, etc.
As the race becomes significantly longer, comfort becomes more of issue for many of us. Being comfortable can counter balance some of the intense fatigue that occurs in ultra distance events. Here are few items to consider for your next ultra distance events:
1. If your competing in an Ultra Distance Triathlon (Double, Triple, Quintuple, DECA Ironmans) the key is to stay on the bike and aerodynamics especially races over the Double Ironman distance become less of a factor. Many athletes use lightweight road bike geometry frames with aero bars and aero rims. The key is to STAY on the bike for as long as possible.
2. If your racing in a long distance trail running race consider using just a larger somewhat heavier shoe to protect those toes during the later stages of the race when many athletes are suffering with feet problems.
3. Consider using a two piece wetsuit while competing in an ultra distance open water swim or ultra distance triathlon. The advantage of the two piece suit is that if chafing occurs or overheating it's very easy to take off the top and keep the bottoms on and still have significant buoyancy from the legs which tend to sink!
4. Absolutely a must in long distance running, triathlons, adventure racing events - make sure there are no seam problems in shorts, pants, shirts that will cause ongoing chafing.
5. Carry small container of Glide, Bag Balm, or other anti-friction creme in cycling shirt pocket, or running pack during very long races.
6. For a race that entails a very long bike section or bike race (300 + miles) consider using a fuel pack attached to top tube as it's very difficult after 20 hours or so to reach back to the pocket in your cycling jersey - I know this one well!
7. Fix the feet early before the "hot spots" become serious problems.
Of course there are plenty others, let me know your thoughts or idea's on what works for you in the ultra distance events to remain as comfortable as possible.