You may be learning that the more stress you put on a bone, the larger it gets (Wolff’s law). This is readily seen when you find and learn all those bumps and ridges on the bones in your lab. Many of the structures (or ‘growths’) you learn about are created by the stresses/forces a muscle applies when it pulls on the bone it’s attached to. The bone responds by getting bigger in areas of increased stress, so it will be able to withstand more stress in the future. The more you exercise, the more stress you put on your bones. Your body responds by increasing bone density or bone mass. The average person starts to lose bone mass at around 35 years of age. So, the more you exercise when you are younger, the more bone mass you develop and the more bone tissue you will have to lose when you are older. In other words, your bones will be stronger for longer. The prevalence of osteoporosis (porous, weakened bones) in children has been increasing in recent years. There could be many reasons for this alarming trend. It could be that children are watching more TV, playing more video games, and/or avoiding more strenuous types of physical activities like sports and physical labor (work). There could also be other explanations for this trend, such as dietary factors. We’ll explore those next time. So, get your exercise and stay tuned! 🙂