He was also retooling Brianna Rollins , the US champion in the 100 meter hurdles , and Kristi Castlin , the US runner - up in the 100 meter hurdles .
And Muhammad was not the only runner training with Johnson at the CSUN track .
Muhammad was also retooling Brianna Rollins , the US champion in the 100 meter hurdles , and Kristi Castlin , the US runner - up in the 100 meter hurdles .
And Muhammad was not the only runner training with Johnson at the CSUN track .