Effects of Load on Jerk Technical Efficiency in Masters Olympic Weightlifters
Abstract or Description
Presentation given at the National Strength and Conditioning Association Annual Meeting, Washington, D.C.
The ability to jerk the barbell overhead is often the limiting factor in an athlete’s maximal clean and jerk (C&J). Studying the effect of increasing load on jerk performance might identify common underlying technical inefficiencies and limiting factors, with the effects being greater for less successful weightlifters. PURPOSE: To determine the effects of increasing load on jerk technical efficiency, and to determine differences between sexes and championship meet success groups. METHODS: 31 National Masters Olympic Weightlifting Championship competitors (19 women, 12 men, 35-65yrs) completed two C&J lifts using 65, 75, and 85% of their self-reported maximum two to three days before the Championship meet. A 12-camera high-speed kinematic system captured three-dimensional barbell kinematics. From the barbell kinematics, three jerk characteristics that have been suggested to relate to jerk technical proficiency were computed: peak vertical barbell velocity (PVBV) and vertical (VBTR) and horizontal (HBTR) barbell travel range. PVBV was computed during the drive phase. HBTR was defined as the peak posterior to anterior barbell displacement during the dip and drive phases. VBTR was defined as the difference between peak vertical displacement and minimum vertical displacement during the unsupported catch and supported catch phases, respectively. Both HBTR and VBTR were normalized to body height. Within each sex, participants were split into two groups based on the median meet C&J maximum performance relative to body mass. Each characteristic was entered into a sex by load by meet success analysis of variance with statistical significance considered at α=.05. RESULTS: Post-hoc linear trend analysis of a significant group x sex x load interaction (P=.016, η2p=.141) for PVBV revealed below median men to be most affected by load (P< .020, d=.44-.71) compared to the other sub-groups. Increasing load had similar effects on the PVBV between the above median men and women groups (P=.077, d=.34). Load had a significant effect on VBTR, with post-hoc testing revealing significantly less travel for the 85% load compared to the 75% (P=.015, d=.48) and 65% (P=.001, d=.81) loads. Only a significant sex main effect was revealed for HBTR (P=.022, d=.42), with the women demonstrating 61% greater HBTR. CONCLUSION: Increasing loads influences VBTR and PVBV. Interestingly, in the sample studied, the below median men demonstrated the greatest PVBV response to increasing load. Additionally, the above median men and women demonstrated similar PVBR responses suggesting equal proficiency. Increasing load had no effect on HBTR. PRACTICAL APPLICATION: The results of this study show that PVBV and VBTR are influenced by increasing the load. Both parameters were measured during the drive, unsupported, and supported phase. A strength and conditioning coach that coaches Masters Olympic Weightlifters should focus on decreasing horizontal displacement in women, and increasing peak velocity at heavier loads in men with less jerk aptness.
National Strength and Conditioning Association Annual Meeting
Carreker, Jadeon D., Jeremy Ford, Ammar Achraf, Robert LeFavi, Bryan L. Riemann.
"Effects of Load on Jerk Technical Efficiency in Masters Olympic Weightlifters."
Department of Health Sciences and Kinesiology Faculty Presentations.