Using Barbell Acceleration to Determine the 1 Repetition Maximum of the Jump Shrug.

Techmanski, Baylee S; Kissick, Cameron R; Loturco, Irineu; Suchomel, Timothy J

Abstract

The purpose of this study was to determine the 1 repetition maximum (1RM) of the jump shrug (JS) using the barbell acceleration characteristics of repetitions performed with relative percentages of the hang power clean (HPC). Fifteen resistance-trained men (age = 25.5 ± 4.5 years, body mass = 88.5 ± 15.7 kg, height = 176.1 ± 8.5 cm, relative 1RM HPC = 1.3 ± 0.2 kg·kg−1) completed 2 testing sessions that included performing a 1RM HPC and JS repetitions with 20, 40, 60, 80, and 100% of their 1RM HPC. A linear position transducer was used to determine concentric duration and the percentage of the propulsive phase (P%) where barbell acceleration was greater than gravitational acceleration (i.e., a>−9.81 m·s−2). Two 1 way repeated measures ANOVA were used to compare each variable across loads, whereas Hedge's g effect sizes were used to examine the magnitude of the differences. Concentric duration ranged from 449.7 to 469.8 milliseconds and did not vary significantly between loads (p = 0.253; g = 0.20–0.39). The P% was 57.4 ± 7.2%, 64.8 ± 5.9%, 73.2 ± 4.3%, 78.7 ± 4.0%, and 80.3 ± 3.5% when using 20, 40, 60, 80, and 100% 1RM HPC, respectively. P% produced during the 80 and 100% 1RM loads were significantly greater than those at 20, 40, and 60% 1RM (p < 0.01, g = 1.30–3.90). In addition, P% was significantly greater during 60% 1RM compared with both 20 and 40% 1RM (p < 0.01, g = 1.58–2.58) and 40% was greater than 20% 1RM (p = 0.003, g = 1.09). A braking phase was present during each load and, thus, a 1RM JS load was not established. Heavier loads may be needed to achieve a 100% propulsive phase when using this method.

Citation

Techmanski, B. S., Kissick, C. R., Loturco, I., & Suchomel, T. J. (2024). Using Barbell Acceleration to Determine the 1 Repetition Maximum of the Jump Shrug. Journal of Strength and Conditioning Research, 38(8), 1486-1493. https://doi.org/10.1519/JSC.0000000000004872

• Journal Article Type: Article
• Publication Date: Aug 1, 2024
• Deposit Date: Dec 16, 2024
• Journal: Journal of strength and conditioning research
• Print ISSN: 1064-8011
• Publisher: Lippincott, Williams & Wilkins
• Peer Reviewed: Peer Reviewed
• Volume: 38
• Issue: 8
• Pages: 1486-1493
• DOI: https://doi.org/10.1519/JSC.0000000000004872
• Keywords: Male, Young Adult, Resistance Training - methods, Acceleration, Muscle, Skeletal - physiology, Humans, Muscle Strength - physiology, Adult