<p>Casey Hayes rides Shaft during the Professional Bull Riding Tour stop at the Denny Sanford Premier Center on March in Sioux Falls, S.D.</p>
May 23, 2015
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May 23, 2015 9 p.m.
Not even helmets prevent bull riders' concussions
SIOUX FALLS, S.D. - Kasey Hayes hopped on the bovine beast trapped in the narrow holding pen like he'd done hundreds of times. He adjusted a tight rope on his left hand, found his balance and signaled he was ready to dominate the bull for the next eight seconds - or, at least, hoped to.