Far too often when we evaluate athletes, the first thing that we notice is complete lack of flexibility in the hamstrings. For a lot of high school coaches who also double as head strength and conditioning coaches, it's a challenge to closely monitor athletes for muscle imbalances. That being said, we see a lot of athletes with an imbalance between their quads and their hamstrings. Squatting can help build speed and explosiveness so it's a no brainer for any weights coach that he should squat his athletes. The issues that arises is the strength coach may not be aware that he is making a kid quad dominant. What I mean by quad dominant is the athlete fires their quadricep when squatting (or doing any other explosive movement) while their hamstrings are under firing. What happens over time is quad domination where the quads take over the movements like sprinting and jumping and the hamstrings cannot quite keep up. When that happens we end up with pulled hamstrings or even torn hamstrings. We had an athlete this past year who had many leg injuries, that all stemmed from an under performing hamstring. This athlete tore his hamstring one season, then came out the next season and tore his ACL. Now I am not saying that either of these injuries could have been completely prevented simply by building up the hamstring but most orthopedic sports medicine doctors will agree that an underdevelopment in either the hamstring, quads, or glutes increases your odds of having a knee injury. It's important for us to focus on hamstring exercises such as a dead lift or a hamstring curl so that the muscle is individually targeted and can learn to fire quickly on its own. Doing exercises as simple as laying on your stomach and firing your heel as quick as you can to your rear will over time, improve the hamstrings ability to fire quickly which is exactly what we need when sprinting or jumping. Along with exercises like hamstring curls and RDL's, stretching is equally as important. Yoga was seen as "uncool" to a lot of athletes for some time but we are quickly seeing a rise now that everyone is catching on. You must stretch to keep the muscle group loose. If it's too tight it can cause many injuries such as the obvious hamstring tear or pull, to something like an achilles rupture or a torn knee ligament. The human body is designed to perform squatting movements using equal parts quads, hamstrings, and glutes. If either one of those muscle groups are underdeveloped or under firing, there is sure to be trouble. It is very important as a strength and conditioning coach to insure that all of your athletes are taking the proper steps to gain flexibility as well as maintain symbiosis between the major muscle groups.