It comes from Bruce Lee's saying that a boxer should not have too many muscles. It should be said that this statement is correct to some extent, but that is the case of extremely developed muscles. For most people, we should not worry about muscular underdevelopment, but only about muscular underdevelopment. It is unthinkable to have speed, or to rely on muscles and a small amount of muscles to drive bones and tissues that cannot lose weight to achieve high speed.
In other words, Bruce Lee suggested that the muscles should not be too big, but his own muscles are excellent.
Of course, muscles do affect speed, mainly transformation. Tai Sen can't reach the speed of Bruce Lee. But Tai Sen's strength is unmatched by Bruce Lee. And fighting, in fact, in most cases, strength is still the most important factor.