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Nikolaos Zaras, Angeliki-Nikoletta Stasinaki, Polyxeni Spiliopoulou, Giannis Arnaoutis, Marios Hadjicharalambous, and Gerasimos Terzis

Elite weightlifting performance depends on both biological 1 , 2 and biomechanical factors. 3 , 4 The snatch (S) and the clean and jerk (C&J) are multijoint movement patterns where the activation of the entire neuromuscular system dictates a successful lift. 2 Considering that the second pull in

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Stephen J. Rossi, Thomas W. Buford, Douglas B. Smith, Robin Kennel, Erin E. Haff, and G. Gregory Haff

Purpose:

The primary purpose of this study was to simultaneously analyze both ends of the barbell with 19 weightlifters (age 18.0 ± 3.2 years, body mass 84.0 ± 14.2 kg, height 167.3 ± 8.7 cm) participating in a weightlifting competition to determine whether there were asymmetries in barbell kinematics and kinetics between the right and left sides of the barbell. The second purpose was to compare barbell-trajectory classification of the snatch and clean lifts between the right and left sides of the barbell.

Methods:

Barbell kinematic and kinetic data were collected and analyzed with 2 VS-120 weightlifting-analysis systems (Lipman Electronic Engineering Ltd, Ramat Hahayal, Israel). Barbell trajectories (A, B, and C) for the right and left sides were analyzed for each lift.

Results:

No significant difference was found in trajectory classification between sides of the barbell for either lift. The frequencies analysis revealed that type C barbell trajectories were the most prevalent in each lift. When the right and left sides of the barbell were compared during the snatch and clean, no significant differences were determined for any kinematic or kinetic variables.

Conclusions:

The V-scope system appears to facilitate analysis of barbell kinematics, kinetics, and trajectories during weightlifting competition regardless of which side of the barbell is analyzed.

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Yung-Hui Lee, Chin-Yang Huwang, and Yang-Hwei Tsuang

The biomechanical characteristics of 13 snatch lifts performed by 4 elite athletes were analyzed. Electromyographic data, ground reaction force index (GRFI), knee angular velocities, barbell velocities, and lifting time were obtained 0.2 s before the lift, for the first pulling phase (FP), and for the second pulling phase (SP). The preactivation, normalized electromyographic values correlated negatively with GRFI (p < .01). In the FP and SP, all of the parameters correlated positively with each other except lifting time. GRFI in the FP also correlated positively with GRFI, maximum knee angular velocities, and maximum barbell velocities of the SP (p < .01). In the SP, the ground reaction force reached its maximum first, followed by knee angular velocity and then barbell velocity. Barbell velocity reached its maximum before the knee and the hip joint were fully extended. When the correlation of parameters between the consecutive phases of snatch weight lifting was analyzed, it was demonstrated that the preactivation of trunk and leg muscles is important in the activation of the reflectory system in order to fully utilize the forces for generating lifting speed in the pulling phase.

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Loren Z.F. Chiu and George J. Salem

Potentiation has been reported in power tasks immediately following a strength stimulus; however, only whole-body performance has been assessed. To determine the acute effects of weightlifting on vertical jump joint kinetics, performance was assessed before, during, and after snatch pull exercise in male athletes. Jumping was assessed using 3D motion analysis and inverse dynamics. Jump height was enhanced at the midpoint (5.77%; p = .001) and end (5.90%; p < .001) of the exercise session, indicating a greater powergenerating ability. At the midpoint, knee extensor net joint work was increased (p = .05) and associated with increased jump height (r = .57; p = .02). Following exercise, ankle plantar flexor net joint work was increased (p = .02) and associated with increased jump height (r = .67; p = .006). Snatch pull exercise elicited acute enhancements in vertical jump performance. At the midpoint of the exercise session, greater work at the knee joint contributed to enhanced performance. At the end of the exercise session, greater work at the ankle contributed to enhanced performance. Consequently, potentiation is not elicited uniformly across joints during multijoint exercise.

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Tadao Isaka, Junichi Okada, and Kazuo Funato

The purpose of this study was to describe the kinematic characteristics of the snatch technique from the viewpoint of barbell trajectory. Subjects included 6 elite male Asian weight lifters who participated in the first Japan International Friendship Tournament in 1993. Trajectories of the barbell during snatch lifts in the competition were video-taped. Three vertical acceleration peaks of the barbell during the pull movement were observed and corresponded to the first pull transition, and second pull phases. The angle of the resultant acceleration (ARA) of the barbell averaged 85° in the first pull and transition pull phases. In the second pull phase, the ARA was almost 140°, indicating that the barbell was accelerated anteriorly, away from the lifter. The results of this study suggest that during the first pull and transition pull phases, elite lifters pulled the barbell toward themselves to produce the needed vertical acceleration and that the resulting posterior movement of the barbell was controlled by the forward acceleration produced in the second pull phase.

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Wolfgang Baumann, Volker Gross, Karl Quade, Peter Galbierz, and Ansgar Schwirtz

The purpose of this study was (a) to describe the snatch technique in terms of kinematic and external and internal kinetic parameters, and (b) to compare the results for athletes of different groups and weight categories. By means of three-dimensional film analysis and measurements of ground reaction forces during the 1985 World Championships in Sweden, it was possible to analyze the spatial movements and to calculate joint moments of force in each leg. Concerning the kinematics, a snatch technique starting with a strong pull toward the lifter could be established. The most interesting kinetic results are that the knee joint moments are relatively small (one third of the hip joint moments of force) and do not correlate very well with the total load. The best lifters seem able to limit the knee joint moment by precise control of the knee position with respect to the ground reaction force. Altogether, the results concerning the internal kinetic parameters question the logic of the classical division of the lifting technique into phases according to external kinetic parameters.

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Christian Collet, Aymeric Guillot, Olivier Bolliet, and André Dittmar

Purpose:

To examine the preparation phase for the snatch lift in Olympic weight lifting. Two behavioral periods were studied, each corresponding to specific mental processes: a stance in front of the bar and placement of hands on the bar. Each period was hypothesized to elicit different responses of autonomic-nervous-system activity.

Methods:

Twelve elite male subjects completed 12 lifts at 90% to 95% of their best grade after warm-up (80% of their best grade). Because peripheral autonomic-nervous-system activity is related to arousal and activation variation, 6 variables were continuously recorded: electrodermal (skin resistance and potential), thermovascular (skin temperature and skin blood flow), and cardiorespiratory (heart rate and respiratory frequency).

Results:

Responses (ie, phasic activities) were evident during the fi rst behavioral period. Decrease in heart rate (mean = 19 beats/min) or in respiratory frequency (mean = 8.6 beats/min) was related to attention processes. These responses were weaker (−0.16°C vs −0.25°C in skin temperature) and shorter (2.7 seconds vs 4.3 seconds in skin resistance) than those recorded during execution. The second phase showed variations in basal levels (mean increase in heart rate of 25%), related to increase in activation, thus attesting the muscle system’s process of preparation for effort.

Conclusion:

Weight lifters separated the preparation phase into 2 stages that were closely matched by different physiological activities. Weight lifting requires participants to share their mental resources among the 2 demanding concentration phases by first focusing their attention on the execution and then mobilizing energizing resources.

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Gerasimos Terzis, Thomas Kyriazis, Giorgos Karampatsos, and Giorgos Georgiadis

Purpose:

Although muscle mass and strength are thought to be closely related to throwing performance, there are few scientific data about these parameters in elite shot-putters. The purpose of this case report was to present longitudinal data for muscle strength and body composition in relation to performance of an elite male shot-putter.

Methods:

A male national champion with the best rotational shot-put performance of 20.36 m (in 2010) was followed from 2003 to 2011 (current age: 29 y). Data regarding body composition (dual X-ray absorptiometry), as well as 1-repetition-maximum muscle strength (bench press, squat, snatch) and rotational shot-put performance, were collected every February for the last 9 y, 4 wk before the national indoor championship event.

Results:

The athlete’s personal-best performances in squat, bench press, and snatch were 175 kg, 210 kg, and 112.5 kg, respectively. His peak total lean body mass was 92.4 kg, bone mineral density 1.55 g/cm2, and lowest body fat 12.9%. His shot-put performance over these 9 years was significantly correlated with 1-repetition-maximum squat strength (r = .93, P < .01), bench press (r = .87, P < .01), and snatch (r = .92, P < .01). In contrast, shot-put performance was not significantly correlated with any of the body-composition parameters.

Conclusions:

The results of this case study suggest that elite rotational shot-put performance may not be directly correlated with lean body mass. Instead, it seems that it is closely related with measures of muscle strength.

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John Garhammer

The heaviest successful snatch and clean and jerk for five Gold medalists in weight-lifting at the 1984 Olympic Games were analyzed from 16mm film. Bar trajectories all showed that as the barbell was lifted from the platform it moved toward the athlete during the first pull, then away from the athlete and finally toward him again as it began to descend during the catch phase. Bar velocity profiles showed that most lifters decelerated the barbell at the end of the first pull while reorienting their body position for the second pull. Calculated power outputs were large in magnitude and showed considerable similarities for selected phases of the lifts of a given athlete. Power output values for complete snatch and clean pulls typically ranged between 28 and 35 W/Kg of body mass. Higher values were found for subphases of the pulls and for the jerk thrusts. Previously published data on one of the Gold medalists permitted longitudinal comparisons of his lifting technique. High power output capacity was the most distinguishing characteristic of the athletes studied and is likely necessary for successful participation in weightlifting at the elite level.

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John Garhammer

Films taken at the first Women’s World Weightlifting Championship were analyzed to determine the average power output during the total pulling phase, and the second pull phase, for the heaviest successful snatch and clean lift of gold medalists in each of nine body-weight divisions. Comparisons were made with previously published data on power output by male lifters in World and Olympic competition. Average relative power output values were one and a half to two times greater for both men and women when only the second pull phase of each lift was analyzed. Results show that women can generate higher short-term power outputs than previously documented, but lower than for men in absolute values and relative to body mass. Male/female comparisons in other high power sport events and basic strength measures are discussed. The high power outputs suggest the value of including the types of lifts analyzed in training programs to improve short-term power output.