Should We Base Training Prescription on the Force–Velocity Profile? Exploratory Study of Its Between-Day Reliability and Differences Between Methods

Author(s):  
Pedro L. Valenzuela ◽  
Guillermo Sánchez-Martínez ◽  
Elaia Torrontegi ◽  
Javier Vázquez-Carrión ◽  
Zigor Montalvo ◽  
...  

Purpose: To analyze the differences in the force–velocity (F–v) profile assessed under unconstrained (ie, using free weights) and constrained (ie, on a Smith machine) vertical jumps, as well as to determine the between-day reliability. Methods: A total of 23 trained participants (18 [1] y) performed an incremental load squat jump test (with ∼35%, 45%, 60%, and 70% of the subjects’ body mass) on 2 different days using free weights and a Smith machine. Nine of these participants repeated the tests on 2 other days for an exploratory analysis of between-day reliability. F–v variables (ie, maximum theoretical force [F0], velocity [v0], and power, and the imbalance between the actual and the theoretically optimal F–v profile) were computed from jump height. Results: A poor agreement was observed between the F–v variables assessed under constrained and unconstrained conditions (intraclass correlation coefficient [ICC] < .50 for all). The height attained during each single jump performed under both constrained and unconstrained conditions showed an acceptable reliability (coefficient of variation < 10%, ICC > .70). The F–v variables computed under constrained conditions showed an overall good agreement (ICC = .75–.95 for all variables) and no significant differences between days (P > .05), but a high variability for v0, the imbalance between the actual and the theoretically optimal F–v profile, and maximal theoretical power (coefficient of variation = 17.0%–27.4%). No between-day differences were observed for any F–v variable assessed under unconstrained conditions (P > .05), but all of the variables presented a low between-day reliability (coefficient of variation > 10% and ICC < .70 for all). Conclusions: F–v variables differed meaningfully when obtained from constrained and unconstrained loaded jumps, and most importantly seemed to present a low between-day reliability.

2020 ◽  
Vol 15 (7) ◽  
pp. 1012-1018
Author(s):  
Guillaume Levernier ◽  
Pierre Samozino ◽  
Guillaume Laffaye

Purpose: To compare the force-production capacities among boulderers, lead climbers, and speed climbers during a pull-up test using a force–velocity–power profile. Methods: In total, 24 high-elite climbers (11 boulderers, 8 lead climbers, and 5 speed climbers) did 2 pull-ups at different percentages of their body mass (0%, 30%, 45%, 60%, and 70%). Force–velocity–power profile analyses were performed with the use of an accelerometer for each load. The intraclass correlation and coefficients of variation were calculated. A 1-way analysis of variance was performed with a Tukey post hoc test to assess the difference between the groups. Results: Regarding force, the coefficient of variation ranged from 1.00% to 6.18% and the intraclass correlation ranged from .98 to .99. For velocity, the coefficient of variation ranged from 2.75% to 6.62% and the intraclass correlation ranged from .84 to .95. The linear regression slope showed R2 to be between .93 and .99, confirming the high quality of the linear relationship between velocity and the external force produced during a pull-up. Boulderers presented significantly higher (P < .05) maximal power (+22.30% and +26.29%), mean power for the pull-up at body weight (+23.49% and +25.35%), and theoretical maximal velocity at zero force (+23.92% and +21.53%) than lead and speed climbers and a more significant curve increase (+35.21% compared with lead climbers). Conclusions: The reliability of the method was shown to be high. Moreover, boulderers were able to develop an important external force and had the capacity to maintain high speed when force production increased.


Author(s):  
Hichem Chtara ◽  
Yassine Negra ◽  
Helmi Chaabene ◽  
Moktar Chtara ◽  
John Cronin ◽  
...  

The aim of this study was to validate a new test of change of direction (COD) for fencer athletes and to establish its relationship with selected measures of physical fitness. Thirty-nine fencer athletes participated to this study (age: 20.8 ± 3.0 years). They performed the new specific fencing COD test (SFCODT) on two separate occasions to establish its reliability. In addition, assessment of COD, jumping ability (i.e., squat jump, countermovement jump, five jump test), sprint time (e.g., 5-m, 10-m and 20-m), isokinetic concentric and eccentric quadriceps, and hamstring force tests were assessed. To establish SFCODT’s construct validity, two subgroups were identified based on their international and national fencing results: High- vs. low-ranked fencer athletes. Reliability, validity, and sensitivity of the SFCODT were established from the intraclass correlation coefficient (ICC), typical error of measurement (TEM), smallest worthwhile change (SWC), and receiving operator characteristic (ROC) analysis. The ICC of SFCODT was excellent at >0.95, and the TEM was < 5%. Based on the usefulness analysis, the ability to detect small performance changes can be rated as “good” in fencer athletes (SWC > TEM). SFCODT was very largely associated with the COD test and moderate to very large associated with jumping ability, sprint time, and isokinetic strength. High-ranked fencer athletes were better than low-ranked fencer athletes on SFCODT (p < 0.01). The area under the ROC curve was 0.76. In conclusion, the SFCODT is a highly reliable, valid, and sensitive test. Therefore, the SFCODT could be used by practitioners to evaluate specific CODS performance in fencer athletes.


2018 ◽  
Vol 40 (1) ◽  
pp. 33655
Author(s):  
Igor Martins Barbosa ◽  
Hyago Bernardes da Rosa ◽  
Lucas Souza Santos ◽  
Samuel Klippel Prusch ◽  
Vinicius Da Silva Lessa de Oliveira ◽  
...  

The present study has the objective to correlate the variables of flexibility and muscle power present in the vertical jumps, through tests done with female individuals, performing analyzes about two groups: Handball players (HG); weight lifters (WL). Initially, the protocol consisted on the performing of the flexibility test at Wells Bank. Subsequently, the jump test was performed, using the Counter movement jump (CMJ) and Squat jump (SJ). About the study groups, it can be observed that they have similar physical characteristics, but practice times (HG = 9.25 ± 3.28  versus WL = 1.85 ± 1.47 years) and weekly hours of activities (HG = 3.33 ± 1.23 versus WL = 5.29 ± 1.81 hours) were distinct. In the execution of SJ for HG, a high correlation was presented for all variables (Height 0.615; Power 0.718; Standard power 0.618). It also presented a high correlation in the non-normalized power (0.688) in CMJ. WL did not present a significant correlation for any of the variables. Based on the findings of the present study, jump test results have correlation with variables of flexibility, muscle power and handball players. However, there is no correlation for any variable for weight lifters. 


Author(s):  
Paul T Donahue ◽  
Christopher M Hill ◽  
Samuel J Wilson ◽  
Charles C Williams ◽  
John C Garner

Background of Study: Differing movement onset thresholds have been used when analyzing the squat jump movement from force-time data obtained from a force platform. This makes comparisons difficult between investigations as this will impact the amount of the force-time curve that is analyzed. Objective: Thus, study examined the effect onset threshold had on kinetic and kinematic variables used in the assessment of the squat jump. Methods: Using a within-subject study design, fifteen recreational trained males performed three trials of squat jumps on a force platform. Each trial was analyzed using one of five different onset thresholds (2.5% SW, 5% SW, 10% SW, 20N, 5SD). Force, velocity, and power, as well as time to peak force, velocity, power and jump height were calculated using the vertical force data obtain from the force plate. Reliability was assessed using intraclass correlation coefficients and coefficients of variation. A one-way ANOVA was used to examine the impact of onset thresholds on all variables of interest. Results: The use of 10% SW and 5SD met minimum reliability criteria for all variables. Temporal related variables were impact to the greatest extent by differing thresholds with large (d > 1.20) significant differences. 10% SW showed the highest mean values of force, velocity, and power. Conclusions: The use of 5SD of the weighting phase is recommended as this showed high level of both absolute and relative reliability in addition to preserving a large portion of the force – time curve to be used in the analysis.


2017 ◽  
Vol 33 (5) ◽  
pp. 388-392 ◽  
Author(s):  
Alejandro Pérez-Castilla ◽  
Belén Feriche ◽  
Slobodan Jaric ◽  
Paulino Padial ◽  
Amador García-Ramos

This study aimed to examine the validity of mechanical variables obtained by a linear velocity transducer from the unconstrained and constrained squat jump (SJ). Twenty-three men were tested on the unconstrained SJ and the SJ constrained by a Smith machine. Maximum values of force, velocity, and power were simultaneously recorded both by a linear velocity transducer attached to a bar of mass of 17, 30, 45, 60, and 75 kg and by a force plate. Linear velocity transducer generally overestimated the outcomes measured as compared to the force plate, particularly in unconstrained SJ. Bland-Altman plots revealed that heteroscedasticity of errors was mainly observed for velocity variables (r 2 = .26–.58) where the differences were negatively associated with the load magnitude. However, exceptionally high correlations were observed between the same outcomes recorded with the 2 methods in both unconstrained (median r = .89 [.71–.95]) and constrained SJ (r = .90 [.65–.95]). Although the systematic and proportional bias needs to be acknowledged, the high correlations between the variables obtained by 2 methods suggest that the linear velocity transducer could provide valid values of the force, velocity, and power outputs from both unconstrained and constrained SJ.


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.


2011 ◽  
Vol 23 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Rafael Martín Acero ◽  
Miguel Fernández-del Olmo ◽  
José Andrés Sánchez ◽  
Xosé Luis Otero ◽  
Xavier Aguado ◽  
...  

The aim of this study was to determine the reliability of the squat jump test (SJ) and countermovement jump test (CMJ), in fifty-six children (30 girls and 26 boys) with ages ranging from 6 to 8 years. Each subject performed two evaluation sessions (T1, T2) with seven days between tests. The results show that the CMJ test has a high intratrial reproducibility in T1 and T2 measured through intraclass correlation coefficient (ICC ≥ 0.95). The ICC for the SJ test had a high value (0.99) only in T1. The variability for both tests among children under 9 years of age is higher than those reported for adult subjects in other studies. The intersession reliability was questionable with a high methodical error (ME= 9.86–15.1%, for the SJ and CMJ, respectively) and a significant worsening of the results of CMJ in T2 (p < .05).


2019 ◽  
Vol 22 (sup1) ◽  
pp. S350-S351
Author(s):  
C. Giroux ◽  
R. Hager ◽  
J. Feugray ◽  
G. Lauby ◽  
S. Dorel ◽  
...  

2021 ◽  
Vol 6 (2) ◽  
pp. 32
Author(s):  
Conor McNeill ◽  
C. Martyn Beaven ◽  
Daniel T. McMaster ◽  
Nicholas Gill

Eccentric strength characteristics have been shown to be important factors in physical performance. Many eccentric tests have been performed in isolation or with supramaximal loading. The purpose of this study was to investigate within- and between- session reliability of an incremental eccentric back squat protocol. Force plates and a linear position transducer captured force-time-displacement data across six loading conditions, separated by at least seven days. The reliability of eccentric specific measurements was assessed using coefficient of variation (CV), change in mean, and intraclass correlation coefficient (ICC). Eccentric peak force demonstrated good ICC (≥0.82) and TE (≤7.3%) for each load. Variables based on mean data were generally less reliable (e.g., mean rate of force development, mean force, mean velocity). This novel protocol meets acceptable levels of reliability for different eccentric-specific measurements although the extent to which these variables affect dynamic performance requires further research.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Domenico Schiano-Lomoriello ◽  
Kenneth J. Hoffer ◽  
Irene Abicca ◽  
Giacomo Savini

AbstractWe assess repeatability of automatic measurements of a new anterior segment optical coherence tomographer and biometer (ANTERION) and their agreement with those provided by an anterior segment-optical coherence tomography device combined with Placido-disk corneal topography (MS-39) and a validated optical biometer (IOLMaster 500). A consecutive series of patients underwent three measurements with ANTERION and one with MS-39. A subgroup of patients underwent biometry also with IOLMaster 500. Repeatability was assessed by means of within-subject standard deviation, coefficient of variation (COV), and intraclass correlation coefficient (ICC). Agreement was investigated with the 95% limits of agreement. Paired t-test and Wilcoxon matched-pairs test were performed to compare the measurements of the different devices. Repeatability of ANTERION measurements was high, with ICC > 0.98 for all parameters except astigmatism (0.963); all parameters apart from those related to astigmatism revealed a COV < 1%. Repeatability of astigmatism improved when only eyes whose keratometric astigmatism was higher than 1.0 D were investigated. Most measurements by ANTERION and MS-39 showed good agreement. No significant differences were found between measurements by ANTERION and IOLMaster, but for corneal diameter. ANTERION revealed high repeatability of automatic measurements and good agreement with both MS-39 and IOLMaster for most parameters.


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