Changes in bar-path kinematics and kinetics after power-clean training.

The purpose of this study was to investigate the direction and magnitude of kinematic changes in bar path and kinetic variable changes in the power clean (PC) after 4 weeks of PC training. Eighteen healthy adult men who had a minimum of 1 year of previous experience in the PC participated as subjects in this study. The subjects were pretested for their 1 repetition maximum (1RM) and provided with visual and verbal cues during PC training sessions, which took place 3 times per week for 4 weeks. Variables measured during data collection include pre- and post-peak force, peak power, and several bar-path kinematic variables through videography at 50, 70, and 90% of the subjects' pre-1RM. Peak force was improved at 50% of 1RM from 936 +/- 338 N to 1,299 +/- 384 N, at 70% from 1,216 +/- 315 N to 1,395 +/- 331 N, and at 90% from 1,255 +/- 329 N to 1,426 +/- 321 N. Peak power was increased at 50% of 1RM from 3,430 +/- 1,280 W to 4,230 +/- 1,326 W. All variables with respect to bar-path kinematics were improved significantly. These results indicate that both kinematic and kinetic variables improve through training and feedback. It is possible that persons beginning the PC exercise or coaches who provide instruction on the PC to beginning lifters should focus on proper bar path during the movement. This may result in force and power output to develop as technique improves. However, further investigation is required to establish the link between bar-path changes and kinetic variable performance improvements.

Effect of resistance exercise volume and complexity on EMG, strength, and regional body composition.

This study was designed to examine the effects of a 12-week resistance training program using single versus multiple sets of a complex versus simple exercise on EMG, strength and regional body composition. Twenty-eight untrained men ( n=15) and women ( n=13) performed resistance training twice per week. Group 1 (S-1, n=9) performed one set of a leg press (LP) and bicep curl (BC) exercise, group 2 (M-6, n=9) performed six sets of a LP and BC exercise, and group 3 (C, n=10) was the control group. One-repetition maximums (1RMs) and EMG were measured in the LP and BC during pre-, mid-, and post-training. Lean body mass of the legs and arms were measured pre- and post-training by dual energy X-ray absorptiometry. Results of the study indicated that both S-1 and M-6 groups significantly increased percentage strength pre- to post-training in both the LP and BC [S-1 pre-/post-LP=41.2 (23.7)%, BC=8.5 (6.71)%; M-6 pre-/post-LP=52.6 (12.6)%, BC=22.8 (15.6)%; mean (SD)]. However, compared to S-1, M-6 showed a significantly greater increase in percentage strength in the BC ( P