I went on a metric century today with about 3700+ feet of climbing. According to my Polar 720i, that's about 1800 more feet than I normally do on 65 miles. Well, the ride as going great. Finally we got to this one longish climb...some guy came past me....I decided to follow....I finally pasted him back....HR hit 173 (my theoretical max) and stayed there a while...I was huffing and puffing...only going about 5 mph or so...but I got that hill. My buddy who was with me at the beginning said I was out of sight by the time he got to the top of that hill. He must weigh some 60 lbs less than me. Well, the next time a major hill came...I started having cramps in my left quad...the muscle to the left of the knee cap (inner front thigh)...got off and massaged it for a bit...it felt better. Went on...another hill...this time it started locking up. Got off...I couldn't bend my leg....it was stuck straight....that muscle as hard as a rock...it took about 3 minutes before it relaxed. That was at 46 miles. I rode to 50 miles (3400ft of ascent) where the next rest stop was. I got in the sag wagon. Dammit. I must learn to respect the climb. I must find some better climbing material, too.