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

The Snatch is 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 on same gender but different sport level (beginner and professional) crossfitters 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 Snatch with 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 difference on the reaction forces supported by the knee joint of the beginner of 6.11% higher in contrast to the professional crossfitter. However, power generation along the complete motion of the Snatch is 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.