scholarly journals Feasibility of the two-point method to determine the load−velocity relationship variables during the countermovement jump exercise

2021 ◽  
Author(s):  
Alejandro Pérez-Castilla ◽  
Rodrigo Ramirez-Campillo ◽  
John F.T. Fernandes ◽  
Amador García-Ramos
Keyword(s):  
Point Method ◽  
Countermovement Jump ◽  
Jump Exercise ◽  
Velocity Relationship

scholarly journals Force-Velocity Relationship in the Countermovement Jump Exercise Assessed by Different Measurement Methods

2019 ◽  
Vol 67 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Amador García-Ramos ◽  
Alejandro Pérez-Castilla ◽  
Antonio J. Morales-Artacho ◽  
Filipa Almeida ◽  
Paulino Padial ◽  
...  
Keyword(s):  
Maximum Velocity ◽  
Measurement Methods ◽  
Loading Conditions ◽  
Countermovement Jump ◽  
Mean Values ◽  
Velocity Transducer ◽  
Jump Exercise ◽  
Velocity Relationship ◽  
Force Velocity ◽  
The Mean

AbstractThis study aimed to compare force, velocity, and power output collected under different loads, as well as the force-velocity (F-V) relationship between three measurement methods. Thirteen male judokas were tested under four loading conditions (20, 40, 60, and 80 kg) in the countermovement jump (CMJ) exercise, while mechanical output data were collected by three measurement methods: the Samozino's method (SAM), a force platform (FP), and a linear velocity transducer (LVT). The variables of the linear F-V relationship (maximum force [F0], maximum velocity [V0], F-V slope, and maximum power [P0]) were determined. The results revealed that (1) the LVT overestimated the mechanical output as compared to the SAM and FP methods, especially under light loading conditions, (2) the SAM provided the lowest magnitude for all mechanical output, (3) the F-V relationships were highly linear either for the SAM (r = 0.99), FP (r = 0.97), and LVT (r = 0.96) methods, (4) the F-V slope obtained by the LVT differed with respect to the other methods due to a larger V0 (5.28 ± 1.48 m·s-1) compared to the SAM (2.98 ± 0.64 m·s-1) and FP (3.06 ± 0.42 m·s-1), and (5) the methods were significantly correlated for F0 and P0, but not for V0 or F-V slope. These results only support the accuracy of the SAM and FP to determine the F-V relationship during the CMJ exercise. The very large correlations of the SAM and LVT methods with respect to the FP (presumed gold-standard) for the mean values of force, velocity and power support their concurrent validity for the assessment of mechanical output under individual loads.

Effects of jump training on jumping performance of handball players: A systematic review with meta-analysis of randomised controlled trials

2020 ◽  
Vol 15 (4) ◽  
pp. 584-594 ◽  
Author(s):  
Rodrigo Ramirez-Campillo ◽  
Cristian Alvarez ◽  
Antonio Garcia-Hermoso ◽  
Justin WL Keogh ◽  
Felipe García-Pinillos ◽  
...  
Keyword(s):  
Methodological Quality ◽  
Randomised Controlled Trials ◽  
Meta Analysis ◽  
Control Group ◽  
Controlled Trials ◽  
Countermovement Jump ◽  
Jumping Performance ◽  
Jump Training ◽  
Jump Exercise ◽  
Randomised Controlled

This study aimed to assess the effects of jump training on the jumping performance of handball players compared with a control condition. The data sources utilised were PubMed, MEDLINE, Web of Science Core Collection and SCOPUS. Only peer-review randomised controlled trials were included. The inclusion criteria comprised: a jump training programme of at least 2 weeks; a control group; the assessment of the countermovement jump. The Physiotherapy Evidence Database scale was used to assess the risk of bias and methodological quality of eligible studies included in the meta-analysis. Risk of publication bias across studies was assessed using the extended Egger’s test. Cohen’s d effect sizes (ESs) were calculated from the countermovement jump and presented together with 95% confidence intervals (CIs). From 6108 records initially identified through database searching, 5 were eligible for meta-analysis. A significant improvement in countermovement jump height was observed, corresponding to 6.4 cm (95% CI = 4.9–7.9; Z = 8.4, p < 0.001), showing moderate heterogeneity ( I2 = 51.4%). The magnitude of the main effect was very large (ES = 2.2 (95% CI = 0.95–3.4), Z = 3.5, p < 0.001). Jump training is effective in increasing vertical jump performance in handball players. However, the insufficient number of studies conducted precluded analyses of moderator variables. In future, researchers are advised to conduct jump training studies of high methodological quality (e.g. randomised controlled trials) and assess different jump exercise prescriptions across handball players of different sexes, ages and competitive levels to analyse if exercise prescription and player characteristics may influence training responses.

scholarly journals Group versus Individualised Minimum Velocity Thresholds in the Prediction of Maximal Strength in Trained Female Athletes

2020 ◽  
Vol 17 (21) ◽  
pp. 7811
Author(s):  
Elias J. G. Caven ◽  
Tom J. E. Bryan ◽  
Amelia F. Dingley ◽  
Benjamin Drury ◽  
Amador Garcia-Ramos ◽  
...  
Keyword(s):  
Bench Press ◽  
Female Athletes ◽  
Group Versus ◽  
Absolute Error ◽  
Point Method ◽  
Multiple Point ◽  
Loading Test ◽  
Mean Velocity ◽  
Velocity Relationship ◽  
Minimum Velocity

This study examined the accuracy of different velocity-based methods in the prediction of bench press and squat one-repetition maximum (1RM) in female athletes. Seventeen trained females (age 17.8 ± 1.3 years) performed an incremental loading test to 1RM on bench press and squat with the mean velocity being recorded. The 1RM was estimated from the load–velocity relationship using the multiple- (8 loads) and two-point (2 loads) methods and group and individual minimum velocity thresholds (MVT). No significant effect of method, MVT or interaction was observed for the two exercises (p > 0.05). For bench press and squat, all prediction methods demonstrated very large to nearly perfect correlations with respect to the actual 1RM (r range = 0.76 to 0.97). The absolute error (range = 2.1 to 3.8 kg) for bench press demonstrated low errors that were independent of the method and MVT used. For squat, the favorable group MVT errors for the multiple- and two-point methods (absolute error = 7.8 and 9.7 kg, respectively) were greater than the individual MVT errors (absolute error = 4.9 and 6.3 kg, respectively). The 1RM can be accurately predicted from the load–velocity relationship in trained females, with the two-point method offering a quick and less fatiguing alternative to the multiple-point method.

Feasibility of the two-point method for assessing the force-velocity relationship during lower-body and upper-body isokinetic tests

2019 ◽  
Vol 37 (20) ◽  
pp. 2396-2402 ◽  
Author(s):  
Danica Janicijevic ◽  
Amador García-Ramos ◽  
Olivera M. Knezevic ◽  
Dragan M. Mirkov
Keyword(s):  
Point Method ◽  
Upper Body ◽  
Lower Body ◽  
Velocity Relationship ◽  
Force Velocity

Optimal Resistive Forces for Maximizing the Reliability of Leg Muscles’ Capacities Tested on a Cycle Ergometer

2018 ◽  
Vol 34 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Amador García-Ramos ◽  
Alejandro Torrejón ◽  
Antonio J. Morales-Artacho ◽  
Alejandro Pérez-Castilla ◽  
Slobodan Jaric
Keyword(s):  
Cycle Ergometer ◽  
Standard Test ◽  
Point Method ◽  
Power Capacity ◽  
Leg Muscles ◽  
Cycle Ergometer Test ◽  
Velocity Relationship ◽  
Force Velocity ◽  
Resistive Forces ◽  
Ergometer Test

This study determined the optimal resistive forces for testing muscle capacities through the standard cycle ergometer test (1 resistive force applied) and a recently developed 2-point method (2 resistive forces used for force-velocity modelling). Twenty-six men were tested twice on maximal sprints performed on a leg cycle ergometer against 5 flywheel resistive forces (R1–R5). The reliability of the cadence and maximum power measured against the 5 individual resistive forces, as well as the reliability of the force-velocity relationship parameters obtained from the selected 2-point methods (R1–R2, R1–R3, R1–R4, and R1–R5), were compared. The reliability of outcomes obtained from individual resistive forces was high except for R5. As a consequence, the combination of R1 (≈175 rpm) and R4 (≈110 rpm) provided the most reliable 2-point method (CV: 1.46%–4.04%; ICC: 0.89–0.96). Although the reliability of power capacity was similar for the R1–R4 2-point method (CV: 3.18%; ICC: 0.96) and the standard test (CV: 3.31%; ICC: 0.95), the 2-point method should be recommended because it also reveals maximum force and velocity capacities. Finally, we conclude that the 2-point method in cycling should be based on 2 distant resistive forces, but avoiding cadences below 110 rpm.

The force–velocity relationship obtained during the squat jump exercise is meaningfully influenced by the initial knee angle

2020 ◽  
pp. 1-10 ◽  
Author(s):  
Danica Janicijevic ◽  
Olivera M. Knezevic ◽  
Dragan M. Mirkov ◽  
Alejandro Pérez-Castilla ◽  
Milos Petrovic ◽  
...  
Keyword(s):  
Knee Angle ◽  
Squat Jump ◽  
Jump Exercise ◽  
Velocity Relationship ◽  
Force Velocity

Scanning Electron Microscopy of Dried and Acid Treated Shells of Difflugia

1973 ◽  
Vol 31 ◽  
pp. 448-449
Author(s):  
Barry S. Eckert ◽  
S. M. McGee-Russell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Point Method ◽  
External Structure ◽  
Cell Locomotion ◽  
Single Opening ◽  
Scanning Electron

Difflugia lobostoma is a shelled amoeba. The shell is an external structure of considerable mass which presents the animal with special restrictions in cell locomotion which are met by the development of active pseudopodial lobopodia containing, apparently, an organized system of thick and thin microfilaments (Eckert and McGee-Russell, 1972). The shell is constructed of sand grains picked up from the environment, and cemented into place with a secretion. There is a single opening through which lobopods extend. The organization of the shell was studied by scanning electron microscopy (SEM).Intact shells or animals with shells were dried by the critical point method of Anderson (1966) or air dried, after primary fixation in glutaraldehyde.

Dermoscopy Analysis Easy by Three-Point Method

2007 ◽  
Vol 38 (3) ◽  
pp. 62
Author(s):  
SHERRY BOSCHERT
Keyword(s):  
Point Method
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