John Hughes has some interesting articles on his site.
Recently he discussed physical ailments that can lead to a DNF (Did Not Finish).
Of course most of these relate to riding upright bikes.
Since I started riding recumbents in 2002 I have only ever experienced the last two conditions.
Cramping has rarely bothered me, especially since I have been using topical magnesium.
Hot feet is something I have experienced on some hot rides.
Shoes with metatarsal supports seem to help me.
Saddle Discomfort / Saddle Sores afflicted 21% of the respondents. Riders’ butts are as different as riders’ faces. This column discusses the general types of problems, causes and solutions. If you suffer from pain in the nether regions, hopefully you can use or adapt one of these suggestions to help.
Upper Back, Shoulder, Neck Pain / Discomfort was a problem for 17% of the respondents. The column illustrates with photos the common causes and how to correct them.
Numb / Painful Hands was a problem for 16% of the respondents. The column describes the physiological causes and the changes you can make to your riding equipment and technique.
Low Back Pain / Discomfort, caused by muscles tightening as you ride, was a problem for 15% of the respondents. Using a personal example, I describe what I do and how you can deal with it.
Cramping Pt 1 and Cramping pt. 2 are a case study of this quite painful problem for 11% of the riders surveyed. It describes what causes cramps and what you can do to prevent them, including whether advertised supplements actually work.
Hot / Painful Feet hurt 9% of the respondents. The column describes in detail the causes and then the remedies, starting with the simplest.