Wladimir Klitschko has fought in the least heavyweight title fights than any heavyweight champion in the sport's history.
Overall , he became the second-longest reigning heavyweight champion of all time , and has the second-most successful title defenses total of any heavyweight boxer with 23 -LRB- including his initial reign as WBO champion -RRB- , behind Joe Louis -LRB- 25 -RRB- and ahead of Larry Holmes -LRB- 20 -RRB- and Muhammad Ali -LRB- 19 -RRB- .	heavyweight	heavyweight	WBO	World Boxing Organization	second-longest reigning heavyweight champion of all time	longest reigning heavyweight champions	Joe Louis	Joe Louis	Larry Holmes	Larry Holmes	Muhammad Ali	Muhammad Ali
