Changes in Power Output following 6 weeks of Jump Shrug Training with a Hexagonal Barbell or an Olympic Barbell in Adolescent American Football Players
Authors
Strøm, Jacob Buhl ; Sørensen, Dennis Nygaard ; Rysgaard, Jukka Kleinnibbelink
Term
4. semester
Education
Publication year
2018
Submitted on
2018-06-07
Abstract
Dette studie undersøgte, om seks ugers jump shrug-træning med enten en hexagonal vægtstang (Hbar) eller en olympisk vægtstang (Obar) kan øge eksplosiv kraftudvikling og sprintpræstation hos unge amerikansk fodboldspillere. I et præ–post design trænede to grupper to gange ugentligt med progressive belastninger på 15, 30 og 45% af kropsvægten, mens en lille kontrolgruppe ikke udførte jump shrugs. I alt indgik Hbar-gruppen (n = 14) og Obar-gruppen (n = 11); kontrolgruppen bestod af basketballspillere (n = 5). Testene omfattede countermovement-jumps, jump shrugs ved 15, 30 og 45% samt 10- og 20-m spurter. Effekt per kg (middel og peak) blev målt med en lineær positionssensor (GymAware), og sprinttider blev registreret med fotoceller. Resultaterne viste signifikante forbedringer i Obar-gruppen: middel effekt per kg steg med 14,38% ved 15% og 16,19% ved 30% belastning, og peak effekt per kg steg med 15,91% ved 30%. Hbar-gruppen viste et fald på 6,34% i middel effekt per kg ved 45%. Ingen grupper forbedrede 10- eller 20-m sprinttiderne. Samlet peger fundene på, at seks ugers jump shrug-træning med olympisk vægtstang kan øge underkrops effekt, men at denne forbedring ikke overføres til korte sprint, og at den hexagonale stang ikke gav en fordel i denne sammenhæng.
This study examined whether six weeks of jump shrug training using either a hexagonal barbell (Hbar) or an Olympic barbell (Obar) can increase explosive power and sprint performance in adolescent American football players. In a pre–post design, two groups trained twice weekly with progressive loads of 15, 30, and 45% of body weight, while a small control group did not perform jump shrugs. The Hbar group (n = 14) and the Obar group (n = 11) were tested alongside a control group of basketball players (n = 5). Assessments included countermovement jumps, jump shrugs at 15, 30, and 45% loads, and 10- and 20-m sprints. Mean and peak power per kilogram were recorded with a linear position transducer (GymAware), and sprint times were captured with photocells. Results showed significant improvements in the Obar group: mean W/kg increased by 14.38% at 15% and 16.19% at 30% body weight, and peak W/kg increased by 15.91% at 30%. The Hbar group exhibited a 6.34% decrease in mean W/kg at 45%. No changes were found in 10- or 20-m sprint performance. Overall, six weeks of Olympic-bar jump shrug training enhanced lower-limb power but did not translate to short sprint improvements, and the hex bar conferred no advantage in this setting.
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