Pre-patch, the block was a wall. Post 1.02, the block became a shield with durability.
To understand the 1.02 patch, you must understand the chaos of Fight Night Champion version 1.00 (the launch version). fight night champion 1.02 patch
Upon release in March 2011, reviewers praised the new "Full Spectrum Punch Control" and the devastating "Champions Mode" (where you break opponents’ jaws and ribs). But online, the game was a warzone of exploits. Pre-patch, the block was a wall
If you are returning to the game or just installing the patch, you must adjust your playstyle to match the 1.02 meta. fight night champion 1.02 patch
In the vanilla (1.00) version, stamina depletion was inconsistent. Fighters could spam power punches without tiring out quickly enough.