Las Vegas: Manny Pacquiao’s knockout power went absent for nine years, but his boxing intellect never stopped expanding.

So as he steps towards his first fight as a 40-year-old in Saturday’s WBA secondary welterweight title defence against former four-division champion Adrien Broner at MGM Grand, Pacquiao expects to flex his cerebral muscles to dissect his 29-year-old foe.

“Not only do I train my physical body, I train my mind,” Pacquiao said on Wednesday. “I’m a senator [in the Philippines], so my mind is always busy. Also, I play chess, billiards and darts — sports that [require] mind work. I’m always reading — the Bible, books and learning English words.”

Pacquiao (60-7-2, 39 KOs) has credited the addition of rest between his patented intense workouts for helping to maximise his physical performance in the ring, and both his trainer Freddie Roach and conditioning coach Justin Fortune insist they’ve seen no slippage in the quality of power punches Pacquiao has delivered in training camp.

His knockout slump that dated to a 12th-round stoppage of four-division champion Miguel Cotto in late 2009 ended in July when he knocked down Lucas Matthysse three times en route to a seventh-round stoppage.

“My secret of this camp is I’m throwing strong punches,” Pacquiao said. “I keep on working out. Age is just a number ... it depends on how you prepare and discipline yourself. Sometimes at that age, you become lazy and tired, but I’m addicted to exercise. Even without a fight scheduled, I’m doing basketball almost every day, like four hours.”