Resistance training at fast velocities is suggested to be more effective for improving muscular strength and movement speed compared to slow, heavy training. This study aimed to examine the effects of a fast-velocity (FVRT) compared to a slow-velocity (SVRT) resistance training program on maximal strength, maximal movement speed, and load-velocity characteristics in older adults. Nineteen community-dwelling older adults were randomly assigned to either the FVRT or SVRT group and completed a twice weekly, progressive resistance training protocol for 8-weeks.
View Article and Find Full Text PDFJ Strength Cond Res
September 2022
Harry, JR, Krzyszkowski, J, Harris, K, Chowning, L, Mackey, E, Bishop, C, and Barker, LA. Momentum-based load prescriptions: Applications to jump squat training. J Strength Cond Res 36(9): 2657-2662, 2022-Velocity-based training is often applied to ballistic exercises, like the barbell jump squat, to improve vertical jump performance.
View Article and Find Full Text PDFBarker, L, Siedlik, J, Magrini, M, Uesato, S, Wang, H, Sjovold, A, Ewing, G, and Harry, JR. . Eccentric force velocity profiling: motor control strategy considerations and relationships to strength and jump performance.
View Article and Find Full Text PDFDependent variables commonly studied during countermovement vertical jump (CMVJ) tests largely stem from male-only studies despite females'distinct energy storage and reutilisation strategies. This could limit progress among females seeking increased CMVJ performance through targeted changes in certain variables. We explored relationships between CMVJ performance metrics (jump height, modified reactive strength index, jump power, and takeoff momentum) and (a) temporal and force application variables and (b) inter-limb force and yank (i.
View Article and Find Full Text PDFJ Strength Cond Res
February 2021
Barker, L, Siedlik, J, and Mercer, J. The influence of countermovement strategy and external load on amortization forces during jump squats. J Strength Cond Res 35(2): 332-339, 2021-The purpose of this study was to investigate the influence of countermovement strategy on amortization forces when performing jump squats.
View Article and Find Full Text PDFHarry, JR, Blinch, J, Barker, LA, Krzyszkowski, J, and Chowning, L. Low-pass filter effects on metrics of countermovement vertical jump performance. J Strength Cond Res 36(5): 1459-1467, 2022-Countermovement vertical jump (CMVJ) studies using ground reaction force (GRF) data analyze either unfiltered (i.
View Article and Find Full Text PDFMed Sci Sports Exerc
April 2020
Unlabelled: Conflicting methodologies are used to define certain countermovement vertical jump (CMVJ) phases, which limits the identification of performance-enhancing factors (e.g., rate of force development).
View Article and Find Full Text PDFIt is unclear whether weighted vest (WV) use improves countermovement vertical jump (CMVJ) performance by enhancing stretch-shortening cycle (SSC) function via increased storage and utilisation of elastic strain energy. In is also unknown whether WV use stimulates different responses in men and women. WV effects on energy storage and utilisation during CMVJ were examined in men and women.
View Article and Find Full Text PDFThe ability to rapidly complete a jump landing has received little attention in the literature despite the need for rapid performance in a number of sports. As such, our purpose was to investigate differences between groups of individuals who land quickly (FAST) and slowly (SLOW) relative to peak vertical ground reaction forces (vGRFs), loading rates, rates of vGRF attenuation, contributions to lower extremity mechanical energy absorption at the involved joints, and the onsets of preparatory joint flexion/dorsiflexion. Twenty-four healthy adults (26.
View Article and Find Full Text PDFThe purpose of this study was to describe the mechanical characteristics of a trampoline circus act and its individual tracks performed in training and shows using a tri-axial accelerometer. A track is an artist's specific role within a choreographed act. Seven male acrobats performed their trampoline act during training and shows while wearing a triaxial accelerometer and reported ratings of perceived exertion (RPE) after each trial.
View Article and Find Full Text PDFThis study sought to identify kinetic and electromyographic subphase characteristics distinguishing good from poor jumpers during countermovement vertical jumps (CMVJs), as defined by the reactive strength index (RSI, CMVJ displacement divided by jump time; cutoff = 0.46 m·s). A total of 15 men (1.
View Article and Find Full Text PDFHarry, JR, Barker, LA, James, CR, and Dufek, JS. Performance differences among skilled soccer players of different playing positions during vertical jumping and landing. J Strength Cond Res 32(2): 304-312, 2018-Both jumping and landing performance of skilled soccer players is diminished when task demands are increased.
View Article and Find Full Text PDFBarker, LA, Harry, JR, and Mercer, JA. Relationships between countermovement jump ground reaction forces and jump height, reactive strength index, and jump time. J Strength Cond Res 32(1): 248-254, 2018-The purpose of this study was to determine the relationship between ground reaction force (GRF) variables to jump height, jump time, and the reactive strength index (RSI).
View Article and Find Full Text PDFHarry, JR, Barker, LA, Mercer, JA, and Dufek, JS. Vertical and horizontal impact force comparison during jump landings with and without rotation in NCAA Division I male soccer players. J Strength Cond Res 31(7): 1780-1786, 2017-There is a wealth of research on impact force characteristics when landing from a jump.
View Article and Find Full Text PDFBarker, LA, Harry, JR, Dufek, JS, and Mercer, JA. Aerial rotation effects on vertical jump performance among highly skilled collegiate soccer players. J Strength Cond Res 31(4): 932-938, 2017-In soccer matches, jumps involving rotations occur when attempting to head the ball for a shot or pass from set pieces, such as corner kicks, goal kicks, and lob passes.
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