Is there a biomechanically efficient vertical ground reaction force profile for countermovement jumps?

McHugh, Malachy P.; Hickok, Marc; Cohen, Josef A.; Virgile, Adam; Connolly, Daniel J.

doi:10.1002/tsm2.200

Cited by 17 publications

(50 citation statements)

References 25 publications

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“…In these types of analyses, the low position of the center of mass (bottom of the countermovement) represents the end of the braking phase and start of the propulsive phase. However, McHugh et al 4 recently suggested this may not accurately reflect the GRFs obtained during the different phases of the CMJ. It is possible that the peak GRF may occur at the low position of the countermovement, suggesting that peak braking and propulsive phase forces occur at the same point.…”

Section: Introductionmentioning

confidence: 99%

“…Arguably, the most popular vertical jump test is the countermovement jump (CMJ), which involves a downward countermovement followed by a maximal vertical jump. Recently, it has become more common to assess vertical ground reaction forces (GRFs) during CMJs, typically performed with the hands on the hips, to observe acute changes or differences in vertical jump performance in adults and youth 1‐4 . Previous studies utilizing this technique often report peak braking (eccentric) and peak propulsive (concentric) force, among several other metrics across the phases of the CMJ 5‐9 .…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, when peak force occurred at the low position, the authors reported more efficient CMJ metrics during the unweighting and braking phases, as well as superior performance (jump height and reactive strength index (RSI)) compared to athletes in which peak force did not occur at the low position. McHugh et al 4 concluded that examining peak force relative to the low position of the countermovement may provide unique insights for practitioners who train athletes to improve biomechanical efficiency during jumping tasks. Similarly, in pre‐pubertal female children, Floría et al 15 reported that the high‐performing jumpers exhibited force profiles in which peak force tended to coincide with the low position of the countermovement, though this study did not specifically examine CMJ metrics during the unweighting, braking, and propulsive phases.…”

Section: Introductionmentioning

confidence: 99%

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Comparisons of countermovement jump force profiles in youth athletes

et al. 2021

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The purposes of this study were to determine whether countermovement jump (CMJ) force profiles differ for jumps in which peak force occurred at the low position of the countermovement (LP) compared to jumps in which peak force did not occur at the low position of the countermovement (NLP), and compare relationships among CMJ and isokinetic metrics between groups. Thirty‐nine male and female youth athletes between 9‐ and 17‐year‐old participated. Participants completed CMJs and isokinetic knee extensions from 60 to 300°·s−1. Ground reaction forces were collected during CMJs to quantify unweighting, braking, propulsive, and performance metrics. Torque and power were quantified during all isokinetic knee extensions. Forty‐one percent of participants had LP force profiles, while 59% of participants had NLP force profiles. The LP group had more efficient unweighting and braking phase metrics than the NLP group, while the NLP group had greater isokinetic torque and power, and greater relationships between CMJ and isokinetic metrics, than the LP group. CMJs from the LP group represent more biomechanically efficient jumps than CMJs from the NLP group. Additionally, the NLP group may be more reliant on concentric force production during the CMJ, while the LP group may have more efficient storage and utilization of elastic energy.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparisons of countermovement jump force profiles in youth athletes

et al. 2021

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“…Two distinct force-time waveform shapes, consisting of either one peak (unimodal) or two peaks (bimodal), have been observed during the CMJ [24][25][26]. In their analysis of force-time waveforms for 33 athletes, Kennedy and Drake [26] concluded that a bimodal force-time curve was not an optimal shape for jump performance.…”

Section: Discussionmentioning

confidence: 99%

“…In their analysis of force-time waveforms for 33 athletes, Kennedy and Drake [26] concluded that a bimodal force-time curve was not an optimal shape for jump performance. In a similar study on 100 athletes, McHugh et al [25] determined that a peak force occurring at the low position of the COM (amortization phase) was a better indicator of jump performance, as determined by jump height and reactive strength index, than whether the waveform shape was unimodal or bimodal. The findings of the current study are generally in agreement with the conclusions of both Kennedy and Drake and McHugh et al, but may offer more insight into the relationship between waveform shape and jump performance.…”

Section: Discussionmentioning

confidence: 99%

Force-Time Waveform Shape Reveals Countermovement Jump Strategies of Collegiate Athletes

Guess

Gray

Willis

et al. 2020

Sports

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The purpose of this study was to relate the shape of countermovement jump (CMJ) vertical ground reaction force waveforms to discrete parameters and determine if waveform shape could enhance CMJ analysis. Vertical ground reaction forces during CMJs were collected for 394 male and female collegiate athletes competing at the National Collegiate Athletic Association (NCAA) Division 1 and National Association of Intercollegiate Athletics (NAIA) levels. Jump parameters were calculated for each athlete and principal component analysis (PCA) was performed on normalized force-time waveforms consisting of the eccentric braking and concentric phases. A K-means clustering of PCA scores placed athletes into three groups based on their waveform shape. The overall average waveforms of all athletes in each cluster produced three distinct vertical ground reaction force waveform patterns. There were significant differences across clusters for all calculated jump parameters. Athletes with a rounded single hump shape jumped highest and quickest. Athletes with a plateau at the transition between the eccentric braking and concentric phase (amortization) followed by a peak in force near the end of the concentric phase had the lowest jump height and slowest jump time. Analysis of force-time waveform shape can identify differences in CMJ strategies in collegiate athletes.

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Building for the Future: A Systematic Review of the Effects of Eccentric Resistance Training on Measures of Physical Performance in Youth Athletes

Bright

Handford

Mundy³

et al. 2023

Sports Med

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Background Eccentric resistance training is recognised as an effective stimulus for enhancing measures of muscular strength and power in adult populations; however, its value in youth athletes is currently not well understood. Objective The aim of this systematic review was to critically appraise the effects of eccentric resistance training on measures of physical performance (i.e. muscular strength, jump, sprint and change of direction) in youth athletes 18 years of age and under. Methods Original journal articles published between 1950 and June 2022 were retrieved from electronic search engines of PubMed, SPORTDiscus and Google Scholar’s advanced search option. Full journal articles investigating the acute and chronic effects of eccentric resistance training on measures of physical performance in youth athletes (i.e. a person 18 years of age or under who competes in sport) were included. The methodological quality and bias of each study were assessed prior to data extraction using a modified Downs and Black checklist. Results The search yielded 749 studies, of which 436 were duplicates. Three-hundred studies were excluded based upon title and abstract review and a further 5 studies were removed following the modified Downs and Black checklist. An additional 14 studies were identified during backward screening. Accordingly, 22 studies were included in our systematic review. The Nordic hamstring exercise and flywheel inertial training were the most frequently used eccentric resistance training methods in youth athletes. Improvements in physical performance following the Nordic hamstring exercise are dependent upon an increase in the breakpoint angle, rather than training volume (sets and repetitions), and are further elevated with the addition of hip extension exercises or high-speed running. A minimum of 3 familiarisation trials is necessary to elicit meaningful adaptations following flywheel inertial training. Furthermore, an emphasis should be placed upon decelerating the rotating flywheel during the final one to two thirds of the eccentric phase, rather than gradually throughout the entire eccentric phase. Conclusions The findings of this systematic review support the inclusion of eccentric resistance training in youth athletes to improve measures of muscular strength, jump, sprint and change of direction performance. The current eccentric resistance training methods are predominantly limited to the Nordic hamstring exercise and flywheel inertial training; however, the efficacy of accentuated eccentric loading to improve jump performance warrants attention in future investigations.

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Is there a biomechanically efficient vertical ground reaction force profile for countermovement jumps?

Cited by 17 publications

References 25 publications

Comparisons of countermovement jump force profiles in youth athletes

Comparisons of countermovement jump force profiles in youth athletes

Force-Time Waveform Shape Reveals Countermovement Jump Strategies of Collegiate Athletes

Building for the Future: A Systematic Review of the Effects of Eccentric Resistance Training on Measures of Physical Performance in Youth Athletes

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