Thigh positioned wearable resistance affects step frequency not step length during 50 m sprint-running. Issue 4 (20th April 2020)

• Record Type: Journal Article
• Authors: Macadam, Paul; Nuell, Sergi; Cronin, John B.; Uthoff, Aaron M.; Nagahara, Ryu; Neville, Jono; Graham, Scott P.; Tinwala, Farhan
• Is Part Of: European journal of sport science. Volume 20:Issue 4(2020)
• Page Start: 444
• Page End: 451
• Publication Date: 2020-04-20
• Subjects: Specificity -- acceleration -- maximum velocity -- kinematics; Sports sciences -- Periodicals; Sports Medicine -- Periodicals; Exercise -- Periodicals; Sports -- Periodicals; 612
• DOI: 10.1080/17461391.2019.1641557
• Languages: English
• ISSNs: 1746-1391

Abstract

Abstract: This study determined the acute changes in spatio-temporal and impulse variables when wearable resistance (WR) of 2% body mass was attached distally to the thighs during 50 m maximal sprint-running. Fifteen sub-elite male sprinters performed sprints with and without WR over 50 m of in-ground force platforms in a randomised order. A paired t-test was used to determine statistical differences ( p < .05), with effect sizes (ES) calculated between conditions over steps: 1–4, 5–14, and 15–23. WR resulted in small increased 10 and 50 m sprint times (1.0%, ES = 0.31, 0.9%, ES = 0.44, respectively, p > .05) compared to the unloaded sprint condition. For spatio-temporal variables, the WR condition resulted in moderate ES changes in step frequency (−2.8%, ES = −0.53, steps 5–14, p > .05), and contact time (2.5%, ES = 0.57, steps 5–14, and 3.2%, ES = 0.51, average of 23 steps, p > .05), while step length was unaffected during all step phases of the sprint (ES = 0.02–0.07, p > .05). Regarding kinetics, during steps 5–14, WR resulted in a moderate decrease (−4.8%, ES = −0.73, p < .05) in net anterior-posterior impulses and a moderate decrease in vertical stiffness (−5.7%, ES = −0.57, p > .05). For athletes seeking to overload step frequency and develop anterior-posterior impulse during mid to late accelerated sprinting, WR enables the application of a sprint-specific form of resistance training to be completed without decreasing step length.