“Slow-twitch muscle fibers are mostly used for long endurance exercises...” — David Kirsch Quote

“Slow-twitch muscle fibers are mostly used for long endurance exercises like aerobics, swimming, and distance running. Fast-twitch muscle fibers are generally more powerful and are activated during maximum exertion exercises like heavy weightlifting and intensive, short bursts of sprints.”

“Eating is not a bad thing; it's not a curse. And I think to have long, sexy, lean, tight muscles, you need to feed them with good quality proteins and make sure you stay hydrated.”

“With enough lunges and squats, your butt will stay firm till you're 80.”

“If you're totally sedentary and eat 2,500 calories a day, don't instantly go to 1,200 calories and hours of aerobics - your weight loss will be sudden and violent, but also fleeting.”

“The way I use to develop an aerobic condition is three against three, man to man, in a square 20 metres by 20.”

“It's a question of spreading the available energy, aerobic and anaerobic, evenly over four minutes. If you run one part too fast, you pay a price. If you run another part more slowly your overall time is slower.”