LOS ANGELES — In the weeks before Los Angeles Rams training camp was set to start, Blake Corum was on the opposite side of the country, challenging his body in ways he never had before.The third-year running back was inside the Team Ascension Sports Academy in Fredericksburg, Va., where he used to drive an hour before middle school and high school at 4 a.m. Six years later, he found himself trying new movements for the first time.In one of them, he explodes through one leg against a resistance band attached to a squat rack. In another, he props up one foot on a bench behind him with two dumbbells in each hand, then launches the planted leg.He will also leap up from two knees to land his right foot on a foam pad, then back to an overturned BOSU ball on his left while catching a rubber weight in one hand.These have appeared in videos that have gone viral, shared on Instagram more than 80,000 times and reaching NFL Network. And they have Rams players and coaches dreaming of what they and Corum might be able to build.“I did see a couple of those videos,” coach Sean McVay said, “and they look cool as s—. It’s impressive. I want to see him make people miss like that in the hole.”Corum’s inspiration to take his training to this level was about blending the old with something new. His throw-back journey began with a number change, back to his childhood 24. It continued with buying a house near his hometown of Marshall, Va., to start raising his baby daughter Zara, who was born in May.“I just needed to go back to my roots,” Corum said.