Legendary Ukrainian heavyweight Wladimir Klitschko (64-5, 54 KOs), who announced his retirement from boxing 13 months ago, recently came back to the sparrings. And now he spars with his countryman, the only undisputed champion of the world in current boxing, cruiserweight king Oleksandr Usyk (15-0, 11 KOs). Usyk, who will likely face former WBC cruiserweighht champion of the world Tony Bellew (30-2-1, 20 KOs) on November 10 in London, UK, had posted a photo with Wladimir after their sparring session on his official Instagram page. "Great sparring with a big champion", - wrote Oleksandr Usyk. Source and photo are here - http://boxingnews.com.ua/en/photos/21772-foto-dnja-klichko-i-usik-posle-sovmestnogo-sparringa
For me it's a clear answer on the question why these guys are such great boxers - because they LOVE boxing! I don't think Wlad is going to come back and Usyk doesn't need to spar with Wlad, why would he? But they are just enjoying it, they ENJOY boxing.
If Usyk plans on moving to HW why would he fight Bellew first? He will have to adjust to bigger and stronger guys at HW. And Bellew is a former CW champ and not really a natural HW. It would seem better for Usyk to take on a real HW sized guy and get accustomed to the bigger guys before fighting a top HW.
Pretty sure Wlad has been sparring with him for a few years. There were a few rumours before he fought Joshua that Wlad had been embarassed in sparring by Usyk.
No, he definitely didn't spar with Usyk before Joshua fight. Probably before he fought Fury, because Fury often boxes as a southpaw.
He wants o get big money fight against Bellew, but Bellew wants all Usyk's belt to be on the line. Usyk will move to thhe HW division after beating Bellew.