"Chris is looking lean and hungry and, after all the injuries over the past couple of years, it's almost like him starting from scratch again," said Herd senior to the Birmingham Mail.
"He obviously had an issue with the club last year but that has been sorted and he is looking forward, rather than back.
"Villa gave us the run of their facilities and we worked on a lot of things, from general fitness to ball work.
"I've kept up with the coaching side of things since quitting the game as a player and I wanted to do my bit to pass on what I know to help Chris hit the ground running in what is a big season for his career.
"We started off training at just a local park in Birmingham and then headed to Villa's training base. He also did gym work and pool work.
"Football is a marathon and not a sprint and for Chris it will now all be about maturity kicking in.
"In the past he's sometimes been a bit over eager to impress and has been playing at a 100 miles an hour.
"My message has been about pacing himself more and channelling his aggression a little bit. Maybe a case of using his head as much as his body to make things happen on the pitch."
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