Personal Fitness Professional - January 2008 - (Page 29) Here is a look at some of the finer points of machine training: • Seated vertical pressing machines place a great deal of stress on the lumbar spine, more so than standing vertical pressing exercises. In order to press as much weight as possible, athletes will actively hyper-extend the lower lumbar to gain extra leverage. • Seated leg press machines do not afford backrests that equal the spine’s natural curvatures. Additionally, many young athletes tend to overload seated leg presses with extreme amounts of weight. At increased loads during the eccentric or lowering phase, the lower lumbar will go through a forced flexion, a terribly unstable position for one’s lower back to be in. • Hack-squat machines can place a great deal of anterior shearing forces on the knee joint. They tend to primarily work the quadricep muscles and are less effective at training the critical hip extensor muscles of the posterior chain. • Hip abduction and abduction machines allow minor to excessive spinal rotation. As you try to isolate a hip abduction exercise, you will naturally “shift” away from the leg in motion and experience spinal rotation. Due to the body’s natural habits of motion, it is impossible to isolate a movement or muscle without experiencing stabilization dynamics in other parts of the body. • Smith machines allow for vertical motion only, which is contraindicated in exercises such as the squat, an exercise that many young athletes perform on the Smith machine. In good squatting form, there should be a natural forward lean while the hips are pushing back. This allows one to maintain a sound neutral lumbar spine position and actively generate force from the powerful hip extensor muscles. With Smith machines, this motion is eliminated completely, and lumbar flexion is promoted. • In many cases, coaches and trainers use machines in a circuit type fashion and route several young athletes at a time through a machine-to-machine type routine. Whenever young athletes are working on timed events (i.e. the coach allows for 20-40 seconds at each station), you can be assured that the athlete is attempting to get as many “high intensity” reps out of his/her set as possible, often at the complete disregard of their execution. With machine or free-weight strength training, perfect execution is a must — in a sense, that makes machines and free weights equal in this argument. Having said that, the very unnatural nature of machines make them even more of a concern from a biomechanical safety perspective with respect to “timed” training sessions or sets. Brian Grasso currently serves as CEO for the International Youth Conditioning Association and is a sought-after expert in the realm of young athlete development and youth fitness worldwide. He presents educational seminars to personal trainers and coaches throughout North America, Europe and the Pacific Rim. For more information, check out Brian’s ground-breaking Free Resource Center at www.DevelopingAthletics.com. ● « ENJOYING BRIAN’S ARTICLE? CONTINUE READING IT ONLINE AT WWW.FIT-PRO.COM JAN-FEB2008 · WWW.FIT-PRO.COM 27 29 http://WWW.FIT-PRO.COM http://www.DevelopingAthletics.com http://WWW.FIT-PRO.COM
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