An effective, low-cost method to improve the movement velocity measurement of a smartphone app during the bench press exercise

2021 ◽  
pp. 175433712110580
Author(s):  
Wladymir Külkamp ◽  
Jairo L Rosa-Junior ◽  
Jonathan Ache-Dias ◽  
Lorival J Carminatti
Keyword(s):  
Older Adults ◽  
Velocity Measurement ◽  
Bench Press ◽  
Low Cost ◽  
Reference Method ◽  
Velocity Measurements ◽  
Range Of Movement ◽  
Mean Velocity ◽  
Movement Velocity ◽  
The Mean

Some studies have reported considerable errors in the movement velocity measurement when using the My Lift app. This study aimed to investigate whether these errors may be related to the use of a range of movement (ROM) statically measured prior to the movement (ROMMYLIFT) instead of ROM dynamically monitored. Ten young adults performed two repetitions of the bench press exercise on a Smith machine with loads that allowed two velocity conditions (above and below 0.6 m s−1). The exercises were monitored by the My Lift app, a magnet and a rotary encoder. After, 15 older adults performed the same exercise at different percentages of 1RM, monitored by the My Lift app and a magnet. The results revealed that ROM dynamically obtained by encoder (reference method) with the mean velocity above (0.497 ± 0.069 m) and below (0.450 ± 0.056 m) 0.6 m s−1 were quite different ( p < 0.05; large effect) from the ROMMYLIFT (0.385 ± 0.040 m). These errors provided highly biased and heteroscedastic mean velocity measurements (mean errors approximately 22%). The errors observed in adults were also observed in the older participants, except for loads equal to 85% of 1RM. The magnet method proved to be valid, presenting measurements very close to the encoder (mean errors approximately 1.7%; r > 0.99). In conclusion, the use of ROMMYLIFT is inadequate, as the higher the movement velocity, the higher the errors, both for young and older adults. Thus, to improve the measurement of the My Lift app, it is recommended that the magnet method be used in conjunction with the app to more accurately determine the ROM.

Influence of Grip Width and Anthropometric Characteristics on the Bench-Press Load–Velocity Relationship

2020 ◽  
Vol 15 (7) ◽  
pp. 949-957
Author(s):  
Alejandro Pérez-Castilla ◽  
Daniel Jerez-Mayorga ◽  
Dario Martínez-García ◽  
Ángela Rodríguez-Perea ◽  
Luis J. Chirosa-Ríos ◽  
...  
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Regression Models ◽  
Bench Press ◽  
Linear Regression Models ◽  
Mean Velocity ◽  
Movement Velocity ◽  
Anthropometric Characteristics ◽  
The Mean ◽  
The Individual

Purpose: To compare the load–velocity (L-V) relationship between bench-press exercises performed using 4 different grip widths, to determine the association between the anthropometric characteristics and L-V profile, and to explore whether a multiple linear-regression model with movement velocity and subjects’ anthropometric characteristics as predictor variables could increase the goodness of fit of the individualized L-V relationship. Methods: The individual L-V relationship of 20 men was evaluated by means of an incremental loading test during the bench-press exercise performed on a Smith machine using narrow, medium, wide, and self-selected grip widths. Simple and multiple linear-regression models were performed. Results: The mean velocity associated with each relative load did not differ among the 4 grip widths (P ≥ .130). Only body height and total arm length were correlated with the mean velocity associated with light and medium loads (r ≥ .464). A slightly higher variance of the velocity attained at each relative load was explained when some anthropometric characteristics were used as predictor variables along with the movement velocity (r2 = .969 [.965–.973]) in comparison with the movement velocity alone (r2 = .966 [.955–.968]). However, the amount of variance explained by the individual L-V relationships was always higher than with the multiple linear-regression models (r2 = .995 [.985–1.000]). Conclusions: These results indicate that the individual determination of the L-V relationship using a self-selected grip width could be recommended to monitor relative loads in the Smith machine bench-press exercise.

scholarly journals Validity and Reliability of Kinematics Measured with PUSH Band vs. Linear Encoder in Bench Press and Push-Ups

Sports ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 207 ◽  
Author(s):  
Roland van den Tillaar ◽  
Nick Ball
Keyword(s):  
Bench Press ◽  
Peak Velocity ◽  
Validity And Reliability ◽  
Mean Velocity ◽  
Movement Velocity ◽  
Lower Velocity ◽  
Linear Encoder ◽  
Measurement Devices ◽  
Level Of Agreement ◽  
Push Up

Background: The aim of this study was to compare the validity and reliability of a PUSH band device with a linear encoder to measure movement velocity with different loads during the push-up and bench press exercises. Methods: Twenty resistance-trained athletes performed push-up and bench press exercises with four different loads: without weight vest, 10-20-30 kg weight vest, bench press: 50–82% of their assumed 1 repetition maximum (1 RM) in steps of 10 kg. A linear encoder (Musclelab) and the PUSH band measured mean and peak velocity during both exercises. Several statistical analyses were used to investigate the validity and reliability of the PUSH band with the linear encoder. Results: The main findings of this study demonstrated only moderate associations between the PUSH band and linear encoder for mean velocity (r = 0.62, 0.70) and peak velocity (r = 0.46, 0.49) for both exercises. Furthermore, a good level of agreement (peak velocity: ICC = 0.60, 0.64; mean velocity: ICC = 0.77, 0.78) was observed between the two measurement devices. However, a significant bias was found with lower velocity values measured with the PUSH band in both exercises. In the push-up, both the linear encoder and PUSH band were deemed very reliable (ICC > 0.98; the coefficient of variation (CV): 5.9–7.3%). Bench press reliability decreased for the PUSH band (ICC < 0.95), and the coefficient of variance increased to (12.8–13.3%) for the velocity measures. Calculated 1 RM with the two devices was the same for the push-up, while in bench press the PUSH band under-estimated the 1 RM by 14 kg compared to the linear encoder. Conclusions: It was concluded that the PUSH band will show decreased reliability from velocity measures in a bench press exercise and underestimate load-velocity based 1 RM predictions. For training, the PUSH band can be used during push-ups, however caution is suggested when using the device for the purposes of feedback in bench press at increasing loads.

Prediction of the Maximum Number of Repetitions and Repetitions in Reserve From Barbell Velocity

2018 ◽  
Vol 13 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Amador García-Ramos ◽  
Alejandro Torrejón ◽  
Belén Feriche ◽  
Antonio J. Morales-Artacho ◽  
Alejandro Pérez-Castilla ◽  
...  
Keyword(s):  
Body Mass ◽  
General Equation ◽  
Bench Press ◽  
Body Height ◽  
Strong Relationship ◽  
Training Set ◽  
Mean Velocity ◽  
The Mean ◽  
Acceptable Reliability

Purpose: To provide 2 general equations to estimate the maximum possible number of repetitions (XRM) from the mean velocity (MV) of the barbell and the MV associated with a given number of repetitions in reserve, as well as to determine the between-sessions reliability of the MV associated with each XRM. Methods: After determination of the bench-press 1-repetition maximum (1RM; 1.15 ± 0.21 kg/kg body mass), 21 men (age 23.0 ± 2.7 y, body mass 72.7 ± 8.3 kg, body height 1.77 ± 0.07 m) completed 4 sets of as many repetitions as possible against relative loads of 60%1RM, 70%1RM, 80%1RM, and 90%1RM over 2 separate sessions. The different loads were tested in a randomized order with 10 min of rest between them. All repetitions were performed at the maximum intended velocity. Results: Both the general equation to predict the XRM from the fastest MV of the set (CV = 15.8–18.5%) and the general equation to predict MV associated with a given number of repetitions in reserve (CV = 14.6–28.8%) failed to provide data with acceptable between-subjects variability. However, a strong relationship (median r2 = .984) and acceptable reliability (CV < 10% and ICC > .85) were observed between the fastest MV of the set and the XRM when considering individual data. Conclusions: These results indicate that generalized group equations are not acceptable methods for estimating the XRM–MV relationship or the number of repetitions in reserve. When attempting to estimate the XRM–MV relationship, one must use individualized relationships to objectively estimate the exact number of repetitions that can be performed in a training set.

scholarly journals Validity and reliability of an optoelectronic system to measure movement velocity during bench press and half squat in a Smith machine

2019 ◽  
Vol 234 (1) ◽  
pp. 88-97
Author(s):  
Borja Muniz-Pardos ◽  
Gabriel Lozano-Berges ◽  
Jorge Marin-Puyalto ◽  
Alex Gonzalez-Agüero ◽  
German Vicente-Rodriguez ◽  
...  
Keyword(s):  
Bench Press ◽  
Reference Method ◽  
Testing Session ◽  
Validity And Reliability ◽  
Optoelectronic System ◽  
Movement Velocity ◽  
Force System ◽  
Repetition Maximum ◽  
Strength Exercises ◽  
Wide Range

The purpose of this study was to determine the validity and reliability of a camera-based optoelectronic system to measure movement velocity during bench press and half squat at different load intensities. A total of 22 active males (age: 28.2 ± 3.9 years; one-repetition maximum bench press: 77.9 ± 19.0 kg; one-repetition maximum half squat: 116.6 ± 22.5 kg) participated in this study. After an initial one-repetition maximum testing session, participants performed five repetitions for each load (40%, 60% and 80% one-repetition maximum) and exercise (bench press and half squat) on a Smith machine in the second testing session. A third testing session was used for the test–retest reliability study. Time, displacement and mean propulsive velocity were simultaneously determined by the reference method (T-Force system) and the Velowin system. In bench press, ordinary least products regression analysis revealed low fixed biases for mean propulsive velocity at 40%, time at 60% and displacement at 80% one-repetition maximum (intercept = 0.065 m s−1, −28.02 ms and 0.87 cm, respectively). In half squat, low fixed biases were also detected for mean propulsive velocity at 40% and 80% one-repetition maximum (intercept = −0.040 and 0.023 m s−1, respectively), time at 40% and 60% one-repetition maximum (intercept = −53.05 and −101.85 ms, respectively) and displacement at 60% one-repetition maximum (intercept = −1.95 cm). Proportional bias was only observed for mean propulsive velocity at 80% bench press. In half squat, there was proportional bias for time and mean propulsive velocity at 40% one-repetition maximum, and also for time at 60% one-repetition maximum. The reliability test showed low and comparable fixed and proportional biases between systems across exercises and intensities. Velowin confirmed to be a valid and reliable system to measure movement velocity across a wide range of intensities (40%–80% one-repetition maximum) for two basic strength exercises through a robust statistical approach. Velowin would provide coaches and trainers with a suitable, affordable and easy-to-use equipment capable of measuring movement velocity in various exercises at different load intensities.

scholarly journals A novel model to quantify balance alterations in older adults based on the center of pressure (CoP) measurements with a cross-sectional study

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256129
Author(s):  
Ángel Gabriel Estévez-Pedraza ◽  
Lorena Parra-Rodríguez ◽  
Rigoberto Martínez-Méndez ◽  
Otniel Portillo-Rodríguez ◽  
Zoraida Ronzón-Hernández
Keyword(s):  
Older Adults ◽  
Fall Risk ◽  
Center Of Pressure ◽  
Low Cost ◽  
Area Under The Curve ◽  
Public Health Problem ◽  
Cross Sectional Study ◽  
Community Dwelling ◽  
Mean Velocity ◽  
Cross Sectional

Background The timely detection of fall risk or balance impairment in older adults is transcendental because, based on a reliable diagnosis, clinical actions can be taken to prevent accidents. This study presents a statistical model to estimate the fall risk from the center of pressure (CoP) data. Methods This study is a cross-sectional analysis from a cohort of community-dwelling older adults aged 60 and over living in Mexico City. CoP balance assessments were conducted in 414 older adults (72.2% females) with a mean age of 70.23 ± 6.68, using a modified and previously validated Wii Balance Board (MWBB) platform. From this information, 78 CoP indexes were calculated and analyzed. Multiple logistic regression models were fitted in order to estimate the relationship between balance alteration and the CoP indexes and other covariables. Results The CoP velocity index in the Antero-Posterior direction with open eyes (MVELAPOE) had the best value of area under the curve (AUC) to identify a balance alteration (0.714), and in the adjusted model, AUC was increased to 0.827. Older adults with their mean velocity higher than 14.24 mm/s had more risk of presenting a balance alteration than those below this value (OR (Odd Ratio) = 2.94, p<0.001, 95% C.I.(Confidence Interval) 1.68–5.15). Individuals with increased age and BMI were more likely to present a balance alteration (OR 1.17, p<0.001, 95% C.I. 1.12–1.23; OR 1.17, p<0.001, 95% C.I. 1.10–1.25). Contrary to what is reported in the literature, sex was not associated with presenting a balance alteration (p = 0.441, 95% C.I. 0.70–2.27). Significance The proposed model had a discriminatory capacity higher than those estimated by similar means and resources to this research and was implemented in an embedded standalone system which is low-cost, portable, and easy-to-use, ideal for non-laboratory environments. The authors recommend using this technology to support and complement the clinical tools to attend to the serious public health problem represented by falls in older adults.

scholarly journals Relación entre la potencia y velocidad en press de banca y la velocidad de lanzamiento de balón en jugadores profesionales de balonmano (Relationship between barbell power and velocity in bench press exercise and ball throwing velocity in professional ha

Retos ◽  
2020 ◽  
pp. 53-59
Author(s):  
Iker Javier Bautista ◽  
Juan Vicente-Mampel ◽  
Luis Baraja-Vegas ◽  
Isidoro Martínez
Keyword(s):  
Bench Press ◽  
Average Power ◽  
Mean Velocity ◽  
Specific Performance ◽  
Relevant Variables ◽  
The Mean ◽  
Incremental Protocol ◽  
The One ◽  
The Relationship ◽  
Correlation Range

 Los objetivos de este estudio fueron (a) analizar la relación existente entre la una repetición máxima (1-RM) en press de banca y la velocidad de lanzamiento en jugadores de balonmano U18 de nivel internacional y, (b) analizar qué variables del ejercicio del press de banca son más relevantes en el rendimiento específico (velocidad de lanzamiento del balón) durante el test de velocidad de lanzamiento (T3-Step). Dieciséis jugadores de la Selección Española de Balonmano Juvenil participaron en la presente investigación. Todos los sujetos realizaron un protocolo incremental en el ejercicio del press de banca, además del T3-Step de velocidad de lanzamiento del balón. Por un lado, se analizó la relación existente entre la velocidad media (Velmedia), velocidad media de la fase propulsiva (VelMFP), velocidad pico (Velpico), potencia media (Potmedia), potencia media de la fase propulsiva (PotMFP), y potencia pico (Potpico) en todo el espectro de cargas en relación con la velocidad de lanzamiento. También se realizaron los mismos análisis con la carga en donde se obtuvo la máxima potencia media (CargaMP). Los resultados mostraron, por un lado que el rango de correlación de la CargaMP, PotmediaMP, PotMFPMP y PotpicoMP y la velocidad de lanzamiento fueron de .61 (p= .012), .702 (p< .01), .734 (p< .01) y .63 (p< .01), respectivamente. El coeficiente de correlación de Pearson entre la 1-RM y la velocidad de lanzamiento fue de r = .61 (p < .01). En conclusión, las variables relevantes a nivel de rendimiento específico con la velocidad de lanzamiento fueron la 1RM, la CargaMP, la PotMFPMP y la VelMFPMP. Todas estas analizadas en función del 60% de la 1-RM.  Abstract. The objectives of this study were (a) to analyze the relationship between one repetition maximum (1-RM) in free bench press exercise and ball throwing velocity in handball players U18 of international level and, (b) to analyze which variables of bench press exercise are more relevant in the specific performance during the ball throwing velocity test (T3-Step). Sixteen (n = 16) players of the Spanish Youth Handball Team participated in the present investigation. All subjects included performed an incremental protocol bench press exercise, in addition to the T3-Step. On the one hand, it analyzed the relationship between the mean velocity (Velmean), the mean velocity of propulsive phase (VelmeanPP), peak velocity (Velpeak), the average power (Powermean), the average power of the propulsive phase (PowermeanPP), and peak power (Powerpeak) over the entire spectrum of charges in relation to the launch speed. The same analyzes were also obtained with the load where the maximum average power (LoadMP). The results obtained, on the one hand that the correlation range of the LoadMP, PowermeanPP, PowerMPPMP and PowerpeakPP and ball throwing velocity were .61 (p = .012), .70 (p < .01), .73 (p < .01) and 0.63 (p < .01), respectively. The correlation coefficient between the 1-RM and ball throwing velocity was r = 0.61 (p< .01). In conclusion, the relevant variables at the specific performance level with the ball throwing velocity were 1-RM, LoadMP, PowerMFPMP and VelMFPMP. All these analyzed according to 60% of the 1-RM.

The ADR Encoder is a reliable and valid device to measure barbell mean velocity during the Smith machine bench press exercise

2021 ◽  
pp. 175433712110628
Author(s):  
Alejandro Pérez-Castilla ◽  
Sergio Miras-Moreno ◽  
Agustín J García-Vega ◽  
Amador García-Ramos
Keyword(s):  
Bench Press ◽  
High Reliability ◽  
Low Cost ◽  
Reliability And Validity ◽  
Systematic Bias ◽  
Random Errors ◽  
Strength And Conditioning ◽  
Mean Velocity ◽  
Standard Linear ◽  
Monitoring Devices

Velocity-based training is a contemporary resistance training method, which uses lifting velocity to prescribe and assess the effects of training. However, the high cost of velocity monitoring devices can limit their use among strength and conditioning professionals. Therefore, this study aimed to examine the reliability and concurrent validity of an affordable linear position transducer (ADR Encoder) for measuring barbell velocity during the Smith machine bench press exercise. Twenty-eight resistance-trained males performed two blocks of six repetitions in a single session. Each block consisted of two repetitions at 40%, 60%, and 80% of their estimated one-repetition maximum. The mean velocity of the lifting phase was simultaneously recorded with the ADR Encoder and a gold-standard linear velocity transducer (T-Force® System). Both devices demonstrated high reliability for measuring mean velocity (ADR Encoder: CVrange = 2.80%–6.40% and ICCrange = 0.78–0.82; T-Force® System: CVrange = 3.27%–6.62% and ICCrange = 0.77–0.81). The ADR Encoder provided mean velocity at 40%1RM with a higher reliability than the T-Force® System (CVratio = 1.17), but the reliability did not differ between devices at higher loads (60%1RM–80%1RM) (CVratio ≤ 1.08). No fixed or proportional bias was observed for the different loads using least-products regression analysis, while the Bland–Altman plots revealed low systematic bias (0.01 m·s−1) and random errors (0.03 m·s−1). However, heteroscedasticity of the errors was observed between both devices ( R2 = 0.103). The high reliability and validity place the ADR Encoder as a low-cost device for accurately measuring mean velocity during the Smith machine bench press exercise.

Reliability and concurrent validity of a functional electromechanical dynamometer device for the assessment of movement velocity

2021 ◽  
pp. 175433712098488
Author(s):  
Ángela Rodriguez-Perea ◽  
Daniel Jerez-Mayorga ◽  
Amador García-Ramos ◽  
Dario Martínez-García ◽  
Luis J Chirosa Ríos
Keyword(s):  
Concurrent Validity ◽  
Reliability And Validity ◽  
Random Errors ◽  
Range Of Movement ◽  
Mean Velocity ◽  
Movement Velocity ◽  
Paired Samples ◽  
Linear Movement ◽  
Standard Error Of Measurement ◽  
Acceptable Reliability

The aims of the study were (i) to determine the reliability and concurrent validity of a functional electromechanical dynamometer (FEMD) to measure different isokinetic velocities, and (ii) to identify the real range of isokinetic velocity reached by FEMD for different prescribed velocities. Mean velocities were collected simultaneously with FEMD and a linear velocity transducer (LVT) in two sessions that were identical, consisting of 15 trials at five isokinetic velocities (0.40, 0.60, 0.80, 1.00, and 1.20 m·s−1) over a range of movement of 40 cm. The results obtained using each method were compared using Paired samples t-tests, Bland-Altman plots and the Pearson’s product–moment correlation coefficient, while the reliability was determined using the standard error of measurement and coefficient of variation (CV). The results indicate that the mean velocity values collected with FEMD and LVT were practically perfect correlations ( r > 0.99) with low random errors (<0.06 m·s−1), while mean velocity values were systematically higher for FEMD ( p < 0.05). FEMD provided a high or acceptable reliability for mean velocity (CV ≤ 0.24%), time to reach the isokinetic velocity (CV range = 1.68%–9.70%) and time spent at the isokinetic velocity (CV range = 0.53%–8.94%). These results suggest that FEMD offers valid and reliable measurements of mean velocity during a fixed linear movement, as well as a consistent duration of the isokinetic phase. FEMD could be an appropriate device to evaluate movement velocity during linear movements. More studies are needed to confirm the reliability and validity of FEMD to measure different velocity metrics during more complex functional exercises.

Turbulent flow over large-amplitude wavy surfaces

1984 ◽  
Vol 140 ◽  
pp. 27-44 ◽  
Author(s):  
Jeffrey Buckles ◽  
Thomas J. Hanratty ◽  
Ronald J. Adrian
Keyword(s):  
Boundary Layer ◽  
Turbulent Flow ◽  
Velocity Fields ◽  
Laser Doppler Velocimeter ◽  
Free Shear Layer ◽  
Wave Surface ◽  
Velocity Measurements ◽  
Mean Velocity ◽  
Wavy Surfaces ◽  
The Mean

The laser-Doppler velocimeter is used to measure the mean and the fluctuating velocity for turbulent flow over a solid sinusoidal wave surface having a wavelength λ of 50.8 mm and a wave amplitude of 5.08 mm. For this flow, a large separated region exists, extending from x/λ = 0.14 to 0.69. From the mean velocity measurements, the time-averaged streamlines and therefore the extent of the separated region are calculated. Three flow elements are identified: the separated region, an attached boundary layer, and a free shear layer formed by the detachment of the boundary layer from the wave surface. The characteristics of these flow elements are discussed in terms of the properties of the mean and fluctuating velocity fields.

scholarly journals Validity and Reliability of a Smartphone Accelerometer for Measuring Lift Velocity in Bench-Press Exercises

2020 ◽  
Vol 12 (6) ◽  
pp. 2312
Author(s):  
Javier Peláez Barrajón ◽  
Alejandro F. San Juan
Keyword(s):  
Bench Press ◽  
Basic Program ◽  
Validity And Reliability ◽  
Training Experience ◽  
Mean Velocity ◽  
Repetition Maximum ◽  
Linear Transducer ◽  
The Mean ◽  
One Year ◽  
The One

The aim of this study was to determine the validity and reliability that a smartphone accelerometer (ACC) used by a mobile basic program (MBP) can provide to measure the mean velocity of a bench-press (BP) lift. Ten volunteers participated in the study (age 23.1 ± 2.5 years; mean ± SD). They had more than one year of resistance training experience in BP exercise. All performed three attempts with different loads: 70%, 90%, and 100% of the estimated value of the one-repetition maximum (1RM). In each repetition, the mean velocity was measured by a validated linear transducer and the ACC. The smartphone accelerometer used by the mobile basic program showed no significant differences between the mean velocities at 70% 1RM lifts (ACC = 0.52 ± 0.11 m/s; transducer = 0.54 ± 0.09 m/s, p > 0.05). However, significant differences were found in the mean velocities for 90% 1RM (ACC = 0.46 ± 0.09 m/s; transducer = 0.31 ± 0.03 m/s, p < 0.001), and 100% 1RM (ACC = 0.33 ± 0.21 m/s; transducer = 0.16 ± 0.04 m/s, p < 0.05). The accelerometer is sensitive enough to measure different lift velocities, but the algorithm must be correctly calibrated.

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