Since power equals force times speed if the athlete learns to make faster movements he increases h

“Since power equals force times speed, if the athlete learns to make faster movements he increases his power, even though the contractile pulling strength of his muscles remains unchanged. Thus, a smaller man who can swing faster may hit as hard or as far as the heavier man who swings slowly.”

Lee, Bruce. Tao of Jeet Kune Do. Black Belt Communications, 2011, loc. 40.