You've captured the speed aspect well. Client likes your choice of blue, and your highlight of the brain area. He doesn't like the male figure or use of orange though.
Client added these reference sites whose logo he admires: FastGym: I like that they have a logo to left that is immediately recognizable and simple. http://www.fastgympa.com/personal-training.php
VelocitySports: this is what I'd like but that incorporates Brain. - See also on one of middle pictures the BIG V that has motion to it for Velocity Gym - http://www.velocitysp.com/