Why Did Wladimir Collapse after 4 rounds and Vitaliy did not ?

Larry Merchant claimed that Wladimir had merely outpunched himself in the Brewster fight. Larry also said that Vitaliy is a smarter and more resourcefull fighter than Wladimir is, and that Vitaliy knows how to conserve his energy. The following Compubox numbers prove Larry Merchant's theory WRONG. The numbers show that Vitaliy boxed Danny at a substantially HIGHER TEMPO than Wladimir did against Lemon. Moreover, Vitaliy was able to easily maintain that HIGH TEMPO through round 8. These Compubox numbers raise a worrisome question: Why did Wlad collapse to the floor at the end of Round 4? (He then barely made it to round 5 and lost by a TKO.) I believed and now even stronger believe that there WAS something really wrong with Wlad's health that night (whatever the reasons were). I also think that there should be a W.Kltschko-Brewster rematch. Table 1. COMPUBOX PUNCH STATS for Vitaliy-Danny Fight: Vitaliy Klitschko 53/94 41/75 33/59 35/71 37/81 30/70 33/56 22/33 (mid-round stoppage) Danny Williams 4/21 4/22 9/30 4/26 4/20 10/32 6/28 3/14 Table 2. COMPUBOX PUNCH STATS for Wladimir-Lemon Fight: Wladimir Klitschko 33/78 32/77 24/59 20/58 11/39 Lemon Brewster 7/34 6/28 9/31 6/27 15/38