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The primary purpose of this study was to assess the sensitivity of cell-free DNA (cf-DNA) to different resistance training volume loads. The secondary purpose was to examine the relationship between change in cf-DNA and relative strength. Researchers hypothesized that (a) cf-DNA concentrations would increase with increasing volume load and (b) increases in relative strength would result in predicted decreases to %Δ of cf-DNA. Thirty subjects were recruited for this study, 15 men and 15 women. Blood was collected through venous draws into 4-ml vacutainers at 3 time points: immediately before (T1), after 3 sets (T2), and after 6 sets (T3) of the back squat exercise. A critical alpha of 0.05 was set for inferential statistics. A repeated-measures ANOVA showed that cf-DNA increased significantly from T1 (407.72 ± 320.83) to T2 (1,244.6 ± 875.83) (p < 0.01) and T1 (407.72 ± 320.83) to T3 (1,331.15 ± 1,141.66) (p < 0.01), whereas no difference was found from T2 to T3 (p = 1.00). The linear regression model used to examine the predictive capabilities relative strength had on cf-DNA %Δ from T1 to T3 was found to be significant (p = 0.04; R² = 0.15). The results of this study demonstrate the short response of cf-DNA in relation to variations in resistance training volume load. Results also demonstrated the positive relationship between relative strength and cf-DNA %Δ. The current study builds on the body of research that cf-DNA provides insight regarding the level of immune response after exercise training. [ABSTRACT FROM AUTHOR]

Travis, SK, Pritchard, HJ, Mujika, I, Gentles, JA, Stone, MH, and Bazyler, CD. Characterizing the tapering practices of United States and Canadian raw powerlifters. J Strength Cond Res 35(12S): S26–S35, 2021—The purpose of this study was to characterize the tapering practices used by North American powerlifters. A total of 364 powerlifters completed a 41-item survey encompassing demographics, general training, general tapering, and specific tapering practices. Nonparametric statistics were used to assess sex (male and female), competition level (regional/provincial, national, and international), and competition lift (squat, bench press, and deadlift). The highest training volume most frequently took place 5–8 weeks before competition, whereas the highest training intensity was completed 2 weeks before competition. A step taper was primarily used over 7–10 days while decreasing the training volume by 41–50% with varied intensity. The final heavy (>85% 1 repetition maximum [1RM]) back squat and deadlift sessions were completed 7–10 days before competition, whereas the final heavy bench press session was completed <7 days before competition. Final heavy lifts were completed at 90.0–92.5% 1RM but reduced to 75–80% 1RM for back squat and bench press and 70–75% for deadlift during the final training session of each lift. Set and repetition schemes during the taper varied between lifts with most frequent reports of 3 × 2, 3 × 3, and 3 × 1 for back squat, bench press, and deadlift, respectively. Training cessation durations before competition varied between deadlift (5.8 ± 2.5 days), back squat (4.1 ± 1.9 days), and bench press (3.9 ± 1.8 days). Complete training cessation was implemented 2.8 ± 1.1 days before competition and varied between sex and competition level. These findings provide novel insights into the tapering practices of North American powerlifters and can be used to inform powerlifting coaches and athlete's tapering decisions. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine if successive heavy sets of back squats can augment the concentric velocity of a lighter down set performed by strength-trained men. Twelve trained men with experience in the back squat volunteered to perform a 5 repetition maximum (5RM) along with 2 separate squat sessions consisting of 3 sets of 5 repetitions with 85% of their 5RM. One condition involved performing a "down set" (DS) after the 3 working sets at 85% of 5RM equivalent to 60% of the working-set load that was also performed during the warm-up. A "No down set" condition involved performing an additional warm-up set before the working sets with 60% of the working-set load instead of the down set to determine if velocity was augmented because of postactivation potentiation in the DS condition. In both conditions, 3 minutes of rest was applied between all sets. A paired sample t-test was used to compare the mean concentric velocities (MCVs) of the working sets of both conditions, and a repeated measures analysis of variance was used to assess differences in MCVs between sets performed at 60% of the working-set load. Cohen's d effect sizes were reported for all comparisons, and the critical alpha was set at p # 0.05. No significant differences were observed in the working-set MCVs in both conditions (p 5 0.412, d 5 0.246) or between MCVs in the down set and equivalent warm-up set load in the DS condition (p50.270, d50.002). Although performing a down set may still be efficacious for developing power across a broad spectrum of loads, the results of this study suggest successive heavy sets of back squats do not acutely augment down set concentric velocity in strength-trained men. [ABSTRACT FROM AUTHOR]