Here is a little background about myself. 6'0 165 lbs, 25 years old. worked out 4-5 times a wk for 5 yrs up until about septemeber of '05. Most if not all of those workouts were focused on strength training, pretty safe to say there was little to no cardio / abs being done, out of fear of losing weight. my upper body strength has always been above average, but i fear my conditioning has been seriously lacking. I had recently taken a civil service exam for a police dept, and did the requisite push ups w/ zero difficulty. but w/ in 15 seconds was told to proceed to the sit ups where I was required to do 38 sit ups w/ in a minutes time. when i got to about 15-20 my form started to decrease and by 30 i had 15 seconds remaning and could not physically lift my body any longer. after this process I was extremely fatigued & had extreme dry mouth. I have till march 19th to complete the requsite training & would really appreciate any insight as to what could have caused this serious lack of energy / failure on my part. as well as any recomendations based on my weight / age as to what exercises could be done to seriously increase my level of cardio / abdominal endurance. thank you so much in advance