This weekend I watched a lot of football. Watching it this week made me realize how bad it must hurt to get hit by a 240+ pound linebacker. The average running back runs about 4.72 m/sec and has a mass of about 97.5 kg. If the linebacker stops the running back in 1 second, the force on the running back is about 460 newtons. Due to newtons third law, that same force is thrown onto the linebacker as well. A linebacker that is famous for his powerful tackles is James Harrison for the Pittsburgh Steelers. He is 125 kg... Sometimes football is better to be watched then played.