Unsuccessful vs. successful performance in snatch lifts: a kinematic approach.

The purpose of the present study was to determine the kinematic characteristics of snatch movements that result in an unsuccessful performance, involving the barbell's drop in front of the weightlifter. The sample comprised 7 high-level men weightlifters competing at the international level. Their successful and unsuccessful snatch lifts with the same load were recorded with 2 S-VHS camcorders (60 Hz), and selected points onto the body and the barbell were digitized manually using the Ariel Performance Analysis System. The statistical treatment of the data showed no significant differences (p > 0.05) between successful and unsuccessful lifts in the angular displacement and velocity data of the lower-limb joints, the trajectory and vertical linear velocity of the barbell, or the generated work and power output during the first and second pulls of the lift. Consequently, the general movement pattern of the limbs and the barbell was not modified in unsuccessful lifts in relation to the successful ones. However, significant differences (p < 0.05) were found in the direction of the barbell's resultant acceleration vector, suggesting that proper direction of force application onto the barbell is crucial for a successful performance in snatch lifts. Thus, coaches should pay particular attention to the applied force onto the barbell from the first pull.

Effect of a submaximal half-squats warm-up program on vertical jumping ability.

The purpose of the current research was to study the effect of a warm-up program including submaximal half-squats on vertical jumping ability. Twenty physically active men participated in the study. Each subject performed 5 sets of half-squats with 2 repetitions at each of the following intensities: 20, 40, 60, 80, and 90% of the 1 repetition maximum (1RM) load. Prior to the first set and immediately after the end of the last set, the subjects performed 2 countermovement jumps on a Kistler force platform; the primary goal was to jump as high as possible. The results showed that mean vertical jumping ability improved by 2.39% after the warm-up period. Subjects were then divided into 2 groups according to their 1RM values for the half-squat. Subjects with greater maximal strength ability improved their vertical jumping ability (4.01%) more than did subjects with lower maximal strength (0.42%). A warm-up protocol including half-squats with submaximal loads and explosive execution can be used for short-term improvements of vertical jumping performance, and this effect is greater in athletes with a relatively high strength ability.

Comparative 3-dimensional kinematic analysis of the snatch technique in elite male and female greek weightlifters.

The purpose of the current research was the comparison of the snatch technique between elite male and female weightlifters. Two S-VHS cameras operating at 60 fields per second were used to record the snatch lifts of 6 male and 6 female Greek weightlifters under competitive conditions. The spatial coordinates of selected points on the body and the barbell were calculated using the direct linear transformation procedure, and the raw data were digitally filtered with a cutoff frequency of 4 Hz. Analyses of variance for dependent and independent samples were used to compare the selected variables in men with the corresponding variables in women. The results revealed that women flexed their knees significantly less and slower than men did during the transition phase (p < 0.05). Women also dropped under the barbell during the turnover and catch phases significantly less and slower than men did (p < 0.05). Moreover, the external mechanical work for the vertical displacement of the barbell in men was significantly greater in the first pull than in the second pull (p < 0.05). In contrast, women showed similar work outputs in the 2 phases. These differences between the 2 sexes might be because of the lower skill level of women in comparison with men, which is partly because of the recent participation of women in weightlifting.