Comparative dynamic analysis of the effect of a well-performed technique of the snatchon the knee joint

The Snatchis part of the sport of weightlifting currently used in recreational strength training workouts,and it has shown a high potential of musculoskeletal injury risk of lower limbs due to poor executions of the exercise. The main purpose of this study is to present a comparative dynamic analysis of motion oncross fitters ofthe same gender butofdifferent sport level (beginner and professional),based on position and force data obtained from a capture motion analysis using the “Helen Hayes” protocol. The dynamic reactions on the knee joint of two women performing the Snatchwith and without a weighted bar are presented for the three phases of a well-performed technique. Subjects were instrumented with “Moticon” force sensors (Sensing Foot Dynamics) operating at 50 Hz; four cameras “OptiTrack Prime 13” at 100 Hz with passive markers were used to provide the input parameters of the dynamic analysis. Information found indicates that there is a 6.11% increasein the reaction forces supported by the knee joint of the beginner comparedto the one of the professional crossfitter. However, power generationalong the complete motion of the Snatchis 171.81% higher for the beginner during the catching phase when using a not weighted bar and 5.08% higher for the professional women during the second pull when using the bar.