The Intraday Reliability of the Reactive Strength Index Calculated From a Drop Jump in Professional Men’s Basketball

2015 ◽  
Vol 10 (4) ◽  
pp. 482-488 ◽  
Author(s):  
William J. Markwick ◽  
Stephen P. Bird ◽  
James J. Tufano ◽  
Laurent B. Seitz ◽  
G. Gregory Haff

Purpose:To evaluate the reliability of the Reactive Strength Index (RSI) and jump-height (JH) performance from multiple drop heights in an elite population.Methods:Thirteen professional basketball players (mean ±SD age 25.8 ± 3.5 y, height 1.96 ± 0.07 m, mass 94.8 ± 8.2 kg) completed 3 maximal drop-jump attempts onto a jump mat at 4 randomly assigned box heights and 3 countermovement-jump trials.Results:No statistical difference was observed between 3 trials for both the RSI and JH variable at all the tested drop heights. The RSI for drop-jump heights from 20 cm resulted in a coefficient of variation (CV) = 3.1% and an intraclass correlation (ICC α) = .96, 40 cm resulted in a CV = 3.0% and an ICC α = .95, and 50 cm resulted in a CV = 2.1% and an ICC α = .99. The JH variable at the 40-cm drop-jump height resulted in the highest reliability CV = 2.8% and an ICC α = .98.Conclusion:When assessing the RSI the 20-, 40-, and 50-cm drop heights are recommended with this population. When assessing large groups it appears that only 1 trial is required when assessing the RSI variable from the 20, 40-, and 50-cm drop heights.

2016 ◽  
Vol 52 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Artur Struzik ◽  
Grzegorz Juras ◽  
Bogdan Pietraszewski ◽  
Andrzej Rokita

AbstractThe basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05) between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05) than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05) than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players.


Sports ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 166
Author(s):  
Lorcan S. Daly ◽  
Ciarán Ó Catháin ◽  
David T. Kelly

This study investigated acute changes in markers of fatigue and performance attenuation during and following a competitive senior club-level Gaelic football match. Forty-one players were tested immediately pre-match, at half-time, full-time, 24 h post-match and 48 h post-match. Creatine kinase, drop jump height and contact-time, reactive strength index, countermovement jump height and perceptual responses were assessed at the aforementioned time-points. 18 Hz global positioning system devices were used to record players in-game workload measures. Compared to pre-match, perceptual responses (−27.6%) and countermovement jump height (−3.9%) were significantly reduced at full-time (p < 0.05). Drop jump height (−8.8%), perceptual responses (−27.6%), reactive strength index (−15.6%) and countermovement jump height (−8.6%) were significantly lower 24 h post-match (p < 0.05). Pre-match creatine kinase was significantly increased (+16.2% to +159.9%) when compared to all other time-points (p < 0.05). Total distance, total accelerations, total sprints, sprint distance and average heart rate were all correlated to changes in perceptual responses (r = 0.34 to 0.56, p < 0.05). Additionally, maximum speed achieved (r = 0.34) and sprint distance (r = 0.31) were significantly related to countermovement jump changes (p < 0.05), while impacts (r = 0.36) were correlated to creatine kinase increases (p < 0.05). These results demonstrate that Gaelic football match-play elicits substantial neuromuscular, biochemical and perceptual disturbances.


Sports ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 37 ◽  
Author(s):  
Aaron Heishman ◽  
Brady Brown ◽  
Bryce Daub ◽  
Ryan Miller ◽  
Eduardo Freitas ◽  
...  

The purpose of the present investigation was to evaluate differences in Reactive Strength Index Modified (RSIMod) and Flight Time to Contraction Time Ratio (FT:CT) during the countermovement jump (CMJ) performed without the arm swing (CMJNAS) compared to the CMJ with the arm swing (CMJAS), while exploring the relationship within each variable between jump protocols. A secondary purpose sought to explore the relationship between RSIMod and FT:CT during both jump protocols. Twenty-two collegiate basketball players performed both three CMJNAS and three CMJAS on a force plate, during two separate testing sessions. RSIMod was calculated by the flight-time (RSIModFT) and impulse-momentum methods (RSIModIMP). CMJ variables were significantly greater during the CMJAS compared to CMJNAS (p < 0.001). There were large to very large correlations within each variable between the CMJAS and CMJNAS. There were significant positive correlations among RSIModFT, RSIModIMP, and FT:CT during both the CMJAS (r ≥ 0.864, p < 0.001) and CMJNAS (r ≥ 0.960, p < 0.001). These findings identify an increase in RSIMod or FT:CT during the CMJAS, that may provide independent information from the CMJNAS. In addition, either RSIMod or FT:CT may be utilized to monitor changes in performance, but simultaneous inclusion may be unnecessary.


Author(s):  
Xiang Yao ◽  
Christopher Curtis ◽  
Anthony Turner ◽  
Chris Bishop ◽  
Alex Austerberry ◽  
...  

Rugby union (RU) is a field-based team sport with a large number of high-intensity actions such as sprinting, change of direction, tackling, scrummaging, rucking, and mauling. Competitive success in female RU has previously been related to anthropometric and physical characteristics, and with the recent introduction of professionalism in female rugby, characterizing such physical attributes may provide insight into selection and training processes. Purpose: To identify anthropometric and physical characteristics of competitive female RU players and differences between playing positions. Methods: Twenty-two players were recruited from the top tier of female RU in the United Kingdom during the 2018–2019 Premiership season. Players were split into forwards and backs and underwent body composition testing via dual-X-ray absorptiometry and physical characteristic tests (10- and 20-m speed, 1-repetition-maximum bench press and squat, countermovement jump, drop jump, isometric midthigh pull, and 1200-m shuttle). Results: Moderate to large significant differences between playing positions in both anthropometric and physical characteristics were found (P < .01). Forwards displayed greater body mass (P = .03), fat mass (P = .01), and absolute upper-body strength (P = .03), whereas backs demonstrated superior countermovement jump height (P = .01), drop jump height (P = .01), greater reactive strength (P = .03), and speed (P = .03). Conclusion: These findings provide practitioners with a greater understanding of anthropometric and physical characteristics of professional female RU players.


2018 ◽  
Vol 7 (4) ◽  
pp. 1-12
Author(s):  
Paul J Byrne ◽  
Jeremy Moody ◽  
Stephen-Mark Cooper ◽  
Sharon Kinsella

The purposes of this study were to a) compare a 4-min to an 8-min rest interval between composite training (jump-sprint combination) repetitions in a single session to allow for the recovery of neuromuscular and bounce drop-jump (BDJ) performance and b) investigate if super compensation would occur after 168hrs of rest. Twelve players were randomly assigned to either a 4-min or an 8-min rest interval group. Participants first completed a BDJ test to identify individual BDJ drop heights followed by a 20m sprint test. Seventy-two hours later, a composite training session of two repetitions (three BDJs followed by a 20m sprint after a 15s rest) with either a 4-min or an 8-min rest interval was performed. A three repetition maximum (3RM) back squat strength test, a BDJ, countermovement jump (CMJ) and a sprint performance test were completed 10-mins pre- and immediately post-session, and 168 hrs post-session. CMJ force (8-min group) and BDJ (height and reactive strength index (RSI)) measures decreased significantly post-session (4-min and 8-min groups; P ≤ 0.05). Pre-session to 168 hrs post-session, relative 3RM back squat strength and 20m sprint performance increased significantly for the 4-min group only (P ≤ 0.05). In conclusion, a 4-min composite training inter-repetition rest interval leads to a significant decline in BDJ measures (RSI and jump height) which may act as fatigue markers for monitoring. However, 4-mins provides sufficient recovery during the session which, in conjunction with 168 hrs of recovery, causes super compensation in neuromuscular performance in hurling players.


2015 ◽  
Vol 10 (2) ◽  
pp. 160-165 ◽  
Author(s):  
Anne Delextrat ◽  
Bernard Grosgeorge ◽  
Francois Bieuzen

Purpose:To investigate the reliability and determinants of performance in a new test of planned agility in elite junior basketball players.Methods:Seventeen female (15.1 ± 0.4 y, 176.9 ± 11.2 cm, 65.7 ± 10.9 kg) and 42 male (14.9 ± 0.4 y, 193.7 ± 8.1 cm, 79.0 ± 12.0 kg) elite junior basketball players performed 5 fitness tests presented in a random order, including a 20-m sprint, a planned-agility test, a triple bilateral horizontal countermovement jump, and 2 triple unilateral horizontal countermovement jumps (with each leg separately). The novelty of the planned-agility test is that it included both offensive and defensive movements. The determinants of planned agility were assessed by a stepwise-regression analysis, and the reliability of the new test was evaluated by the intraclass correlation coefficient and the typical error of measurement.Results:The main results show good reliability of the new test of planned agility. In addition, the determinants of planned-agility performance were different between genders, with sprint performance explaining 74.8% of the variance for girls, while unilateral jump performance and body mass were the most important for boys, accounting for 24.0% and 8.9% of the variance, respectively, in planned agility.Conclusions:These results highlight a gender effect on the determinants of planned-agility performance in young elite basketball players and suggest that straight-line sprint and unilateral horizontal tests must be implemented to test elite junior players.


2020 ◽  
Vol 8 (9) ◽  
pp. 232596712095003
Author(s):  
David Carolan ◽  
Enda King ◽  
Chris Richter ◽  
Andy Franklyn-Miller ◽  
Ray Moran ◽  
...  

Background: Patient-reported outcomes and return-to-play (RTP) rates are inferior after revision anterior cruciate ligament reconstruction (ACLR) compared with primary ACLR. Physical properties such as maximal, explosive, and reactive strength influence reinjury and RTP rates after ACLR. No study has compared these outcomes between revision and primary ACLR. Purpose: To compare maximal, explosive, and reactive strength of the ACLR limb, as well as patient-reported outcomes and RTP rates between primary and revision ACLR at 9 months after surgery. Study Design: Cohort study; Level of evidence, 2. Methods: A comparative study was performed at 9 months after surgery for 344 male athletes who had undergone ACLR (298 primary, 46 revision). Maximal strength of the ACLR limb was measured by means of isokinetic dynamometry. Explosive strength was measured by use of single-leg countermovement jump height, and reactive strength was measured by single-leg drop jump. Patient-reported outcomes and responses to RTP questionnaires were recorded for both groups. Results: The primary ACLR group had higher scores than the revision ACLR group for single-leg countermovement jump height ( P = .02) and single-leg drop jump reactive strength index ( P = .01) on the ACLR limb. No significant difference was observed between groups on maximal strength of the quadriceps or hamstring, and no significant difference in limb symmetry index was observed between groups on any strength or jump test. The primary ACLR group demonstrated higher scores on the Marx Activity Rating Scale ( P = .03) and the Anterior Cruciate Ligament–Return to Sport after Injury scale ( P < .001). Athletes in the primary ACLR group were more likely to have returned to sport ( P < .001). Conclusion: At 9 months after surgery, athletes who had undergone revision ACLR achieved maximal strength similar to that of athletes who had undergone primary ACLR. However, athletes who had revision ACLR demonstrated lower scores on explosive and reactive strength tests. Athletes who underwent revision ACLR had lower RTP rates at 9 months after surgery, potentially due to explosive and reactive strength deficits and lower perceived readiness for RTP.


2019 ◽  
Vol 0 (Avance Online) ◽  
Author(s):  
Antenor Calandrini Azevedo ◽  
Deivison Soares Meninea ◽  
Arthur Pinto Magno ◽  
Thyago Martins Silva ◽  
Romulo Oliveira Sousa ◽  
...  

Resumo Objetivo: Investigar a confiabilidade e reprodutibilidade do aplicativo Jumpo® para medida de saltos verticais de lutadores. Método: Participaram 16 atletas de ambos os sexos com idade média de 19 ± 5 anos, estatura de 1.7 ± 0.1 m, massa corporal de 65 ± 15 kg. A presente investigação contabilizou dois encontros, nos quais foram realizados teste-reteste de ambos os instrumentos de avaliações para os seguintes saltos verticais: Countermovement Jump, Squat Jump e Drop Jump, medidos simultaneamente com o Tapete de Contato e o Jumpo®. Foram analisados o tempo de contato com o solo e a altura máxima de salto. Para análise estatística foi aplicado coeficiente de correlação intraclasse destinado às avaliações intra e inter-avaliadores. Já os comparativos entre Jumpo® e tapete de contato foram utilizados novamente o coeficiente de correlação intraclasse e a análise gráfica de Bland-Altman. Resultados: Concordâncias “quase perfeitas” para altura máxima em todos os saltos, tanto intra-avaliadores (CCI= 0.911-0.959), como inter-avaliadores (CCI= 0.939-0.951) e inter-instrumentos (CCI= 0.939-0.972) foram encontradas. Porém, o tempo de solo não apresentou concordância significante inter-instrumentos (p<0.360). Entretanto, foram encontrados valores inter-avaliadores estatisticamente significativos (p<0.001). Conclusão: O Jumpo® parece ser uma ferramenta válida e reprodutível para medida de altura máxima de saltos verticais, mas não para o tempo de contato com o solo. Sugere-se, portanto, que treinadores e técnicos podem ser encorajados a utilizar esta ferramenta para avaliação e monitoramento do desempenho de saltos em lutadores. Resumen Objetivo: Investigar la confiabilidad y reproducibilidad de la aplicación Jumpo® para la medida de saltos verticales en luchadores. Método: Participaron 16 atletas de ambos os sexos con edad media de 19 ± 5 años, estatura de 1.7 ± 0.1 m, masa corporal de 65 ± 15 kg. La presente investigación contabilizó dos encuentros en los que se realizaron pruebas y re-test de ambos instrumentos de evaluación para los siguientes saltos verticales: Countermovement Jump, Squat Jump y Drop Jump, medidos simultáneamente con la Superfície de Contacto y el Jumpo®. Se analizaron el tiempo de contacto con el suelo y la altura máxima de salto. Para el análisis estadístico se aplicó coeficiente de correlación intraclase destinado a las evaluaciones intra e inter-evaluadores. Los comparativos entre Jumpo® y la superfície de contacto se utilizaron nuevamente el coeficiente de correlación intraclase y el análisis gráfico de Bland-Altman. Resultados: Concordancias "casi perfectas" para altura máxima en todos los saltos, tanto intra-evaluadores (CCI = 0.911-0.959), como inter-evaluadores (CCI = 0.939-0.951) e inter-instrumentos (CCI = 0.939-0.972) encontrado. Sin embargo, el tiempo de contacto con el suelo no presentó concordancia significante inter-instrumentos (p <0.360). Sin embargo, se encontraron valores inter-evaluadores estadísticamente significativos (p <0.001). Conclusión: El Jumpo® parece ser una herramienta válida y reproducible para medida de altura máxima de saltos verticales, pero no para el tiempo de contacto. Se sugiere, por lo tanto, que entrenadores y técnicos puedan ser alentados a utilizar esta herramienta para evaluación y monitoreo del desempeño de saltos en luchadores. Abstract Objective: To investigate the reliability and reproducibility of the Jumpo® application for vertical jumping measurement. Method: 16 athletes of both sexes with a mean age of 19 ± 5 years, height of 1.7 ± 0.1 m, body mass of 65 ± 15 kg were included. The present investigation counted two meetings, in which test-retest of both assessment instruments for the following vertical jumps: Countermovement Jump, Squat Jump and Drop Jump, measured simultaneously with the Contact Mat and Jumpo®. Contact time with soil the ground and maximum jump height were analyzed. For statistical analysis, intraclass correlation coefficient was applied for intra- and inter-rater assessments. The comparisons between Jumpo® and contact mat performed by intraclass correlation coefficient and the Bland-Altman graphic analysis. Results: Almost perfect agreement for maximum height in all jumps, both intra-rater (ICC = 0.911-0.959), and inter-rater (ICC = 0.939-0.951) and inter-instrument (ICC = 0.939-0.972) were found. However, the contact time presented no significance (p <0.360) in relation to inter-instrument measurements. However, statistically significant inter-rater values ​​were found (p <0.001). Conclusion: Jumpo® seems to be a valid and reproducible tool for measuring maximum vertical jumps height, but not for contact time. It is suggested, therefore, that coaches and trainers can be encouraged to use this tool for evaluation and monitoring of jumping performance in fighters.


Author(s):  
Shane M. Heffernan ◽  
Ross Neville ◽  
Mark Waldron ◽  
Ryan Stewart ◽  
Liam P. Kilduff ◽  
...  

Rugby union (RU) is an intermittent team sport, with diverse playing positions, played internationally by both men and women. Considerable scientific attention has been devoted to men’s RU, however despite the growth in the women’s professional game, there is a significant lack of available physiological and normative data. The purpose of the present study was to investigate positional variation in countermovement jump characteristics from elite women’s RU players. Qualitative data were collected from women’s Rugby World Cup (2017) competitors (n = 86; age: 27 ± 5 years; body mass: 77.8 ± 10.6 kg; height: 1.69 ± 0.07 cm) and jump data (countermovement jumps) were collected using a 1200 Hz force platform (n = 63). Athletes were divided into positional unit (backs: n = 39 and forwards: n = 47) and by positional subgroups. Backs had greater jump height (ES = 0.72, 95%CL ± 0.50), relative power output (ES = 0.84, 95%CL ± 0.50), relative force production (ES = 0.62, 95%CL ± 0.51) and reactive strength index (RSI; ES = 0.62, 95%CL ± 0.50), compared to forwards (for all, P < 0.02). Backrows, halves and back-three players had greater relative force, relative power and jump height, compared to the front and second rows (P < 0.03; ES > 0.70). These data could aid in programming for long-term player development in women’s RU and could have implications for “readiness” to compete at international level.


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