In one of the greatest moments in Canadian sports history, Simon Whitfield won the gold medal in the triathlon at the 2000 Summer Olympics in Sydney, Australia and a silver medal at the 2008 Summer Olympics in Bejing, China. The triathlon is a gruelling combination of swimming, cycling, and running and is the ultimate test of speed, strength, and endurance.

As Whitfield propelled himself around the triathlon course, he used a variety of muscles and converted the stored chemical energy in their cells into kinetic energy. During this conversion, a tremendous amount of oxygen was required by his respiratory system. Remember that your body systems work together to provide homeostasis. The motor system is vital to your survival and your overall health, wellness, and performance.

In this lesson, you will explore the following essential questions:

• How are the roles of cardiac, smooth, and striated muscles different?

• How do specialized structures in muscles cause muscle contraction?

• What is the relationship between energy use by muscle cells and heat production?