At and weighing at the time, Lee was renowned for his physical fitness and vigor, achieved by using a dedicated fitness regimen to become as strong as possible. After his match with Wong Jack Man in 1965, Lee changed his approach toward martial arts training. Lee felt that many martial artists of his time did not spend enough time on physical conditioning. Lee included all elements of total fitness—muscular strength, muscular endurance, cardiovascular endurance, and flexibility. He used traditional bodybuilding techniques to build some muscle mass, though not overdone, as that could decrease speed or flexibility. At the same time, with respect to balance, Lee maintained that mental and spiritual preparation are fundamental to the success of physical training in martial arts skills. In "Tao of Jeet Kune Do" he wrote: