Friday, November 11, 2011

"Depth Jumps"

The BLUF:  Before you do heavy back squats, do some depth jumps (in this case, 2-6 from 33cm/1 foot), wait four minutes, and your 1RM is likely to be higher than if you tried it without doing the depth jumps.
Research has demonstrated that high-load low-velocity (HLLV) exercises (≥85% 1 repetition maximum [1RM]) increase performance in subsequent low-load high-velocity (LLHV) exercises, when separated by a rest period ≥4 minutes. To date, few studies have investigated LLHV exercises on subsequent HLLV exercises. The purpose of this study was to compare the effects of 2, 4, or 6 depth jumps (DJs) on subsequent 1RM back squat performance. Fourteen subjects (age 22 ± 4 years, height 177 ± 10 cm, body mass 80.3 ± 14.4 kg) completed five 1RM back squat testing sessions, either control, retest, or 1 of 3 interventions (2, 4, or 6 DJs from a height of 33 cm, 4 minutes before the first 1RM attempt), in a counterbalanced order. Intraclass correlation coefficients demonstrated a high test-retest reliability for the 1RMs (r = 0.989, p < 0.001). Repeated-measures analysis of variance with Bonferroni post hoc analysis revealed significantly greater 1RM performance (140.71 ± 35.68 kg: p = 0.004, 140.50 ± 33.77 kg: p < 0.001, 141.43 ± 34.39 kg: p = 0.002, respectively) for each intervention (2, 4, or 6 repetitions, respectively) compared to the control condition (132.43 ± 34.56 kg). No significant differences were found between interventions (p > 0.05). The findings of this investigation demonstrate that the inclusion of 2, 4, or 6 DJs, 4 minutes before a maximal squat, enhances subsequent strength performance.
http://www.ncbi.nlm.nih.gov/pubmed/21993028
HT:  Martin Berkhan

What's a depth jump? 
http://www.ehow.com/how_4510248_do-depth-jumps.html

http://www.youtube.com/watch?v=teyc5pxc_FQ

http://www.youtube.com/watch?v=AKtSJc39QNc


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