Authors’ Reply to McMahon et al. Comment on: “Anthropometric and Physical Qualities of Elite Male Youth Rugby League Players”

Journal of Applied Biomechanics

Lake

Ripley

et al. 2020

The purpose of this study was to determine the usefulness of calculating jump take-off momentum in rugby league (RL) by exploring its relationship with sprint momentum, due to the latter being an important attribute of this sport. Twenty-five male RL players performed 3 maximal-effort countermovement jumps on a force platform and 3 maximal effort 20-m sprints (with split times recorded). Jump take-off momentum and sprint momentum (between 0 and 5, 5 and 10, and 10 and 20 m) were calculated (mass multiplied by velocity) and their relationship determined. There was a very large positive relationship between both jump take-off and 0- to 5-m sprint momentum (r = .781, P < .001) and jump take-off and 5- to 10-m sprint momentum (r = .878, P < .001). There was a nearly perfect positive relationship between jump take-off and 10- to 20-m sprint momentum (r = .920, P < .001). Jump take-off and sprint momentum demonstrated good–excellent reliability and very large–nearly perfect associations (61%–85% common variance) in an RL cohort, enabling prediction equations to be created. Thus, it may be practically useful to calculate jump take-off momentum as part of routine countermovement jump testing of RL players and other collision-sport athletes to enable the indirect monitoring of sprint momentum.

Section: Introductionmentioning

confidence: 99%

Vertical Jump Testing in Rugby League: A Rationale for Calculating Take-Off Momentum

Journal of Applied Biomechanics

Lake

Ripley

et al. 2020

“…The countermovement jump (CMJ) has been suggested to be an important test in rugby league given that the CMJ height distinguishes between age groups (25) and shares positive associations with faster 5, 10, and 30 m sprint performances ( r = 0.56–0.62, p < 0.05) (3) and better tackling ability ( r = 0.38, p < 0.05) (6) in this sport. It has been recommended that CMJ testing in rugby league should ideally be performed using a force platform (13,26). This recommendation has since been supported by recent empirical studies that have revealed specific CMJ force-time variables that, alongside jump height (JH), distinguish between levels of play in rugby league.…”

Section: Introductionmentioning

confidence: 99%

Countermovement Jump Standards in Rugby League: What is a “Good” Performance?

Journal of Strength and Conditioning Research

Lake

Dos’Santos

et al. 2020

The countermovement jump (CMJ) is considered an important test in rugby league and the force platform is the recommended tool for assessing CMJ performance in this cohort. Due to inconsistent methods applied across previous studies, there is currently a lack of understanding of what constitutes a 'good' CMJ performance, with respect to the typical CMJ metrics that are reported for rugby league players. The purpose of this study was, therefore, to produce a scale of reference values for the jump height (JH), reactive strength index modified (RSImod) and mean (PPmean) and peak (PPpeak) propulsion power (relative to body mass) for top-level senior rugby league players competing in the global 'forward' and 'back' positional groups. One hundred and four players (55 forwards and 49 backs) from the top two tiers of English rugby league performed three CMJs on a force platform at the beginning of pre-season training. The JH, RSImod, PPmean and PPpeak were calculated using criterion methods and a scale of norm-referenced values (percentiles) was produced for each positional group.The backs outperformed the forwards for each CMJ metric reported, thus supporting the production of position-specific norm-referenced values. When each positional group was separated into quartile subgroups, the respective JH, RSImod, PPmean and PPpeak values were mostly largely and significantly different both within and between positions. The presented scale of reference values can, therefore, be used to determine the performance standards of rugby league forwards and backs with respect to the most commonly reported CMJ-derived variables for this cohort.

“…The importance of assessing countermovement jump (CMJ) performance as part of talent identification testing batteries within rugby league (RL) was recently highlighted (29), with the utilization of valid/accurate methods of doing so, such as force platform analysis, subsequently emphasized (18,30). The rationale for including CMJ performance testing within RL physical testing batteries is in-part based on previous research that has shown it to be correlated to faster 5-, 10- and 30-m sprint performances ( r = 0.56–0.62, p < 0.05) (2) and better tackling ability ( r = 0.38, p < 0.05) (4) in high-level RL players.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Countermovement Jump–Derived Reactive Strength Index Modified and Underpinning Force-Time Variables Between Super League and Championship Rugby League Players

Journal of Strength and Conditioning Research

Jones

Comfort

2019