I was very young for most of the Robinson Spurs and the lack of supporting cast was more of an issue than Robinson's post game, that said other High end bigs of the Era were better at back to the basket backing people down. Robinson wasn't bad at it, but he wasn't an all time great at that either. What he had was great speed for his size pretty good handles, (for his size and era very good) and good strength. His back issues were a major limiting factor in his later career. It would have been really interesting seeing a different era Robinson, but in a lot of ways game wise Robinson was very comparable to Garnett in that he would and could be effective in the post and backing people down but his natural preference was to face up.