The 24-year-old, who has joined the Italian outfit on a loan agreement, fell out of favour at the Emirates and spent last season at Sunderland on a temporary deal.
"At Juventus, the training has been different to and much harder than anything I've done before," ESPN quotes Bendtner as saying.
"Because of that, my form is at a peak. I'm much sharper. Without playing, I'm down to fighting weight and that's never happened before."
Meanwhile, the Denmark international has claimed that he hopes to make a permanent move to Turin.