What Do The Greatest Sportsman of All-Time Have In Common? Answer: Speedwork
Muhammad Ali, Roger Federer, Michael Jordan and Wayne Gretzky, all trained with speed work at some point in their lives.
To improve endurance, power, stamina, and quickness, each one - the very best of all-time in their individual sport trained by doing short bouts of high-intensity running. If it’s good enough for them, then it’s good enough for us.