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|Posté le: Mer 28 Juin 2017 - 08:48 Sujet du message: Weightlifting Strength And Velocity Jim Napier
Sir Isaac Newtonʼs 2nd law of motion (F = ma) is a reflexion of how a weightlifter should go about training their squats and pulls. Where force (F) is the result of a change in acceleration (a), generated against a mass (m) or the weight of the barbell. Since generally all snatches and cleans from the platform to receiving the weight are achieved in about 1 second, then acceleration (a) is constant, and force (F) will be in equilibrium with that mass (m) or the weight on the barbell. Since the snatch and clean must be achieved in about 1 second, regardless of the increase in that weight, then the accelerated mass will always be in equilibrium to the force. When a lift is missed due to the lifter being unable to overcome the forces placed on their body, and therefore the inability to achieve the correct velocity, then the change in velocity is slower, which then decreases the force production (F), and the lifter and the weight are out of equilibrium.
It has always been a well known and accepted fact that the snatch and clean & jerk are considered speed lifts, but this description has never been used with the squats and pulls. The problem with not viewing those squats and pulls as speed lifts, at least from the perspective of the weightlifter, is that those same forces produced during a snatch or clean & jerk will not be in equilibrium if the squats and pulls are not also executed in 1 second. Specifically 1 second in the ascension of the squats and .67 seconds in the pull from the platform to full extension.
The above paradox and other problems associated with deceleration during training are thoroughly discussed in this book as well as my other books: The Sport of Weightlifting Series: Book One on conscious and unconscious lifting, and The Sport of Weightlifting Series: Book Two on programming basics.
Jim Napier has competed in the sport of weightlifting for 38 years as both an open and master lifter. He was National Champion in 1977 and placed 2nd in 3 other National Championships. He set 4 American records in the snatch with a best of 155k at 82.5k. As a master lifter he has recently established a National record and one WR in the M70 age group. He has a degree from TCU in Physical Education, with studies in physics, statistics, anatomy and kinesiology.
bound: 226 pages
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