Probably a muscle cramp as a result of dehydration and other nutrients from sweating on a long bike ride. 140 km is not an uncommon distance for experienced riders to go on a weekend ride. At a steady 30 KM per hour thats a 5 hour ride. Many bike clubs commonly do 100-200 (160-320 kilometer) mile bike rides on the weekends, with nutjobs in competitive events like race across america.....