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

McMahon, John J.; Jones, Paul A.; Comfort, Paul

doi:10.1519/jsc.0000000000003380

Cited by 20 publications

(41 citation statements)

References 29 publications

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“…This outcome is most probably due to the small non-significant decline in CT observed. Regarding PF, this variable is another valuable force platform outcome for coaches (Gerodimos et al, 2008 ; Bishop et al, 2018 ; McMahon et al, 2018 ) since it has been recently recommended to be used in conjunction with JH to assess subtle differences in vertical jump performance (McMahon et al, 2019 ; Souza et al, 2020 ). In fact, both peak and time course force plate variables have been used to assess neuromuscular fatigue in athletes (Cormack et al, 2008 , 2013 ; Gonzalez et al, 2013 ; Gathercole et al, 2015 ; Suchomel et al, 2016 ; Edwards et al, 2018a ; McMahon et al, 2018 , 2019 ; Neal et al, 2018 ; Heishman et al, 2020 ).…”

Section: Discussionmentioning

confidence: 99%

“…Regarding PF, this variable is another valuable force platform outcome for coaches (Gerodimos et al, 2008 ; Bishop et al, 2018 ; McMahon et al, 2018 ) since it has been recently recommended to be used in conjunction with JH to assess subtle differences in vertical jump performance (McMahon et al, 2019 ; Souza et al, 2020 ). In fact, both peak and time course force plate variables have been used to assess neuromuscular fatigue in athletes (Cormack et al, 2008 , 2013 ; Gonzalez et al, 2013 ; Gathercole et al, 2015 ; Suchomel et al, 2016 ; Edwards et al, 2018a ; McMahon et al, 2018 , 2019 ; Neal et al, 2018 ; Heishman et al, 2020 ). Interestingly, a trend toward a small decline was found in PF when comparing CONF to NON-CONF ( Figure 1B ), hence supporting the notion that fatigue (or insufficient recovery) was present and vertical jump ability was affected during the more congested phase of the season.…”

Section: Discussionmentioning

confidence: 99%

“…There are typically 3 phases to the season: (i) the Non-Conference (NON-CONF) season, which lasts from November until December and has an inconsistent schedule and variability in competition density patterns; (ii) the Conference (CONF) schedule, held from January until early March, which is consistent in nature and has at least two competitions every calendar week; (iii) the NCAA Tournament which is played in March for teams that qualify. Despite the abundance of literature describing the demands of basketball in different levels of competition (Caterisano et al, 1997 ; Abdelkrim et al, 2010a ; Aoki et al, 2017 ; McMahon et al, 2019 ; Souza et al, 2020 ), no study has focused on analyzing changes in game demands throughout the NCAA college season and the implications this could have on neuromuscular outputs.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal Variations in Game Activity Profiles and Players' Neuromuscular Performance in Collegiate Division I Basketball: Non-conference vs. Conference Tournament

Petway

Freitas

Calleja-González

et al. 2020

Front. Sports Act. Living

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Basketball has a high demand on a player's neuromuscular system due to a high volume of explosive high-intensity actions. This study aimed to examine the seasonal variations on game demands and players' neuromuscular performance during the Non-Conference (NON-CONF) and Conference (CONF) seasons in NCAA Division I Men's Basketball. Seven NCAA Division I Basketball players' (20 ± 1.2 years, 1.95 ± 0.1 m, and 94 ± 15 kg) match activity profiles were tracked in 17 home games (7 NON-CONF; 10 CONF); furthermore, players performed a repeat hop test on a force platform the day before competition to assess neuromuscular performance. A t-test for paired samples was used to analyze the differences between NON-CONF and CONF. Results indicated no significant differences in Total Distance, Peak Speed, Acceleration, and Deceleration loads when comparing NON-CONF and CONF match-play. Regarding neuromuscular performance, Jump Height (p = 0.03; ES = 0.43) was negatively affected during CONF. Moreover, a trend toward a decline in Peak Force (p = 0.06; ES = 0.38) was found in CONF. Conversely, no differences were obtained regarding Reactive Strength Index and Contact Time. In conclusion, match-play demands remained constant across the season whilst neuromuscular outputs were inhibited during the CONF season.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seasonal Variations in Game Activity Profiles and Players' Neuromuscular Performance in Collegiate Division I Basketball: Non-conference vs. Conference Tournament

Petway

Freitas

Calleja-González

et al. 2020

Front. Sports Act. Living

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“…3,5,17 Subjects initiated the sprint from a stationary two point, split start 3 was considered to represent good and excellent reliability, respectively. 16 All momentum calculations met parametric assumptions, therefore, relationships between sprint momentum (at all distances) and jump take-off momentum were explored using the Pearson correlation coefficient and CI95 via SPSS software (version 25; SPSS Inc., Chicago, IL, USA) with the alpha level set at p ≤ .05. Correlation coefficients were interpreted as very large (0.7-0.9) and nearly perfect (0.9-1.0).…”

Section: Twentymentioning

confidence: 99%

“…15,22 A shift towards testing rugby league player CMJ performance on force platforms has been noted in more recently published studies, although the reported metrics have still been biased towards lighter athletes/tasks that require acceleration of the athlete's body mass alone. 16,18 Because force platform assessment of CMJs is being more routinely conducted in rugby league, propulsion net impulse (and, therefore, take-off momentum) can be readily calculated. The CMJ propulsion net impulse attained by rugby league players has, indeed, been reported by McMahon et al 18 and was shown to be much larger for senior players (d = 1.56) than for academy players owing to the heavier body mass of the former.…”

Section: Introductionmentioning

confidence: 99%

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

McMahon

Lake

Ripley

et al. 2020

Journal of Applied Biomechanics

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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.

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Reactive Strength Index and its Associations with Measures of Physical and Sports Performance: A Systematic Review with Meta-Analysis

et al. 2021

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Background Reactive strength index (RSI) is used frequently in the testing and monitoring of athletes. Associations with sports performance measures may vary dependent on the task but a literature synthesis has not been performed. Objectives The aim of this meta-analysis was to examine associations between RSI measured during rebound jumping tasks and measures of strength, linear and change of direction speed, and endurance performance. Methods A systematic literature search with meta-analysis was conducted using databases PubMed, SPORTDiscus, Web of Science, and Ovid. Inclusion criteria required studies to (1) examine the relationship between RSI and an independent measure of physical or sporting performance for at least one variable; and (2) provide rebound test instructions to minimise ground contact time and maximise displacement of the jump. Methodological quality was assessed using a modified version of the Downs and Black Quality Index tool. Heterogeneity was examined via the Q statistic and I2. Pooled effect sizes were calculated using a random-effects model, with Egger's regression test used to assess small study bias (inclusive of publication bias). Results Of the 1320 citations reviewed, a total of 32 studies were included in this meta-analysis. RSI was significantly and moderately associated with strength (isometric: r = 0.356 [95% CI 0.209-0.504]; isotonic: r = 0.365 [0.075-0.654]; pooled strength measures: r = 0.339 [0.209-0.469]) and endurance performance (r = 0.401 [0.173-0.629]). Significant moderate and negative associations were indicated for acceleration (r = − 0.426 [− 0.562 to − 0.290]), top speed (r = − 0.326 [− 0.502 to − 0.151]), and significant large negative associations were noted for change of direction speed (r = − 0.565 [− 0.726 to − 0.404]). Heterogeneity was trivial to moderate across all measures (I2 = 0-66%), and significant for isotonic strength and change of direction speed (p < 0.1). Evidence of small study bias was apparent for both acceleration and change of direction speed (p < 0.05). Conclusions We identified primarily moderate associations between RSI and independent measures of physical and sporting performance, and the strength of these relationships varied based on the task and physical quality assessed. The findings from this meta-analysis can help practitioners to develop more targeted testing and monitoring processes. Future research may wish to examine if associations are stronger in tasks that display greater specificity. Key points Key Points• Measures of physical and sporting performance are moderately (strength, speed, endurance performance) and largely (change of direction speed) associated with reactive strength index (RSI). • Large discrepancies exist concerning testing strategies for RSI, with variations reported for jump type, box drop height, equation used to calculate RSI, and units of measurement, indicating a need for consistency in approach to measuring RSI. • At present, no valid and reliable measure of RSI acquired horizontally exists, which may pr...

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

Cited by 20 publications

References 29 publications

Seasonal Variations in Game Activity Profiles and Players' Neuromuscular Performance in Collegiate Division I Basketball: Non-conference vs. Conference Tournament

Seasonal Variations in Game Activity Profiles and Players' Neuromuscular Performance in Collegiate Division I Basketball: Non-conference vs. Conference Tournament

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

Reactive Strength Index and its Associations with Measures of Physical and Sports Performance: A Systematic Review with Meta-Analysis

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