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.

scholarly journals Reliability and Validity of the Polar V800 Sports Watch for Estimating Vertical Jump Height

2021 ◽  
pp. 149-157
Author(s):  
Manuel V. Garnacho-Castaño ◽  
Marcos Faundez-Zanuy ◽  
Noemí Serra-Payá ◽  
José L. Maté-Muñoz ◽  
Josep López-Xarbau ◽  
...  
Keyword(s):  
High Speed ◽  
Vertical Jump ◽  
Reliability And Validity ◽  
Force Platform ◽  
Systematic Bias ◽  
High Speed Camera ◽  
Jump Height ◽  
Random Errors ◽  
Physically Active ◽  
Vertical Jump Height

This study aimed to assess the reliability and validity of the Polar V800 to measure vertical jump height. Twenty-two physically active healthy men (age: 22.89 ± 4.23 years; body mass: 70.74 ± 8.04 kg; height: 1.74 ± 0.76 m) were recruited for the study. The reliability was evaluated by comparing measurements acquired by the Polar V800 in two identical testing sessions one week apart. Validity was assessed by comparing measurements simultaneously obtained using a force platform (gold standard), high-speed camera and the Polar V800 during squat jump (SJ) and countermovement jump (CMJ) tests. In the test-retest reliability, high intraclass correlation coefficients (ICCs) were observed (mean: 0.90, SJ and CMJ) in the Polar V800. There was no significant systematic bias ± random errors (p > 0.05) between test-retest. Low coefficients of variation (<5%) were detected in both jumps in the Polar V800. In the validity assessment, similar jump height was detected among devices (p > 0.05). There was almost perfect agreement between the Polar V800 compared to a force platform for the SJ and CMJ tests (Mean ICCs = 0.95; no systematic bias ± random errors in SJ mean: -0.38 ± 2.10 cm, p > 0.05). Mean ICC between the Polar V800 versus high-speed camera was 0.91 for the SJ and CMJ tests, however, a significant systematic bias ± random error (0.97 ± 2.60 cm; p = 0.01) was detected in CMJ test. The Polar V800 offers valid, compared to force platform, and reliable information about vertical jump height performance in physically active healthy young men.

scholarly journals The Reliability and Validity of Current Technologies for Measuring Barbell Velocity in the Free-Weight Back Squat and Power Clean

Sports ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 94
Author(s):  
Steve W. Thompson ◽  
David Rogerson ◽  
Harry F. Dorrell ◽  
Alan Ruddock ◽  
Andrew Barnes
Keyword(s):  
Peak Velocity ◽  
Reliability And Validity ◽  
Systematic Bias ◽  
Mean Velocity ◽  
Validity Data ◽  
Back Squat ◽  
Free Weight ◽  
Device Reliability ◽  
Measurement Units ◽  
Power Clean

This study investigated the inter-day and intra-device reliability, and criterion validity of six devices for measuring barbell velocity in the free-weight back squat and power clean. In total, 10 competitive weightlifters completed an initial one repetition maximum (1RM) assessment followed by three load-velocity profiles (40–100% 1RM) in both exercises on four separate occasions. Mean and peak velocity was measured simultaneously on each device and compared to 3D motion capture for all repetitions. Reliability was assessed via coefficient of variation (CV) and typical error (TE). Least products regression (LPR) (R2) and limits of agreement (LOA) assessed the validity of the devices. The Gymaware was the most reliable for both exercises (CV < 10%; TE < 0.11 m·s−1, except 100% 1RM (mean velocity) and 90‒100% 1RM (peak velocity)), with MyLift and PUSH following a similar trend. Poorer reliability was observed for Beast Sensor and Bar Sensei (CV = 5.1–119.9%; TE = 0.08–0.48 m·s−1). The Gymaware was the most valid device, with small systematic bias and no proportional or fixed bias evident across both exercises (R2 > 0.42–0.99 LOA = −0.03–0.03 m·s−1). Comparable validity data was observed for MyLift in the back squat. Both PUSH devices produced some fixed and proportional bias, with Beast Sensor and Bar Sensei being the least valid devices across both exercises (R2 > 0.00–0.96, LOA = −0.36–0.46 m·s−1). Linear position transducers and smartphone applications could be used to obtain velocity-based data, with inertial measurement units demonstrating poorer reliability and validity.

scholarly journals Validity and Reliability of Isometric-Bench for Knee Isometric Assessment

2020 ◽  
Vol 17 (12) ◽  
pp. 4326
Author(s):  
Johnny Padulo ◽  
Nebojša Trajković ◽  
Drazen Cular ◽  
Zoran Grgantov ◽  
Dejan M. Madić ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Concurrent Validity ◽  
High Reliability ◽  
Low Cost ◽  
Isometric Strength ◽  
Systematic Bias ◽  
Validity And Reliability ◽  
Isokinetic Dynamometer ◽  
Isometric Forces ◽  
Flexion And Extension

There is a strong need for a new, probably cheaper, smaller, and more portable isometric dynamometer. With this aim, we investigated the concurrent validity and reliability of a low-cost portable dynamometer to measure the isometric strength of the lower limb. Seventeen young participants (age 16.47 ± 0.51 years) were randomly assessed on three different days for knee flexion and extension isometric forces with two different devices: a commonly used isokinetic dynamometer (ISOC) and a portable isometric dynamometer prototype (ISOM). No significant differences were observed between the ISOC and the ISOM (all comparisons p > 0.05). Test–retest comparison showed the ISOM to have high reliability (ICC 0.879–0.990). This study showed that measurements with the ISOM could be performed without systematic bias and with high reliability. The ISOM is a device that is able to assess knee isometric strength with excellent concurrent validity and reliability.

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.

A Low-Cost and High-Reliability Communication Protocol for Remote Monitoring Devices

2004 ◽  
Vol 53 (2) ◽  
pp. 612-618
Author(s):  
M.A. Garcia ◽  
R.S.G. Villar ◽  
A.L.R. Cardoso ◽  
J.C.T.B. Moraes
Keyword(s):  
Remote Monitoring ◽  
Communication Protocol ◽  
High Reliability ◽  
Low Cost ◽  
Monitoring Devices

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.

scholarly journals Video-Based System for Automatic Measurement of Barbell Velocity in Back Squat

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 925
Author(s):  
Basilio Pueo ◽  
Jose J. Lopez ◽  
Jose M. Mossi ◽  
Adrian Colomer ◽  
Jose M. Jimenez-Olmedo
Keyword(s):  
Real Time ◽  
High Speed ◽  
Human Error ◽  
Reference Points ◽  
Systematic Bias ◽  
Random Errors ◽  
Validity And Reliability ◽  
Mean Velocity ◽  
Video System ◽  
Back Squat

Velocity-based training is a contemporary method used by sports coaches to prescribe the optimal loading based on the velocity of movement of a load lifted. The most employed and accurate instruments to monitor velocity are linear position transducers. Alternatively, smartphone apps compute mean velocity after each execution by manual on-screen digitizing, introducing human error. In this paper, a video-based instrument delivering unattended, real-time measures of barbell velocity with a smartphone high-speed camera has been developed. A custom image-processing algorithm allows for the detection of reference points of a multipower machine to autocalibrate and automatically track barbell markers to give real-time kinematic-derived parameters. Validity and reliability were studied by comparing the simultaneous measurement of 160 repetitions of back squat lifts executed by 20 athletes with the proposed instrument and a validated linear position transducer, used as a criterion. The video system produced practically identical range, velocity, force, and power outcomes to the criterion with low and proportional systematic bias and random errors. Our results suggest that the developed video system is a valid, reliable, and trustworthy instrument for measuring velocity and derived variables accurately with practical implications for use by coaches and practitioners.

scholarly journals Sequential Testing in Reliability and Validity Studies With Repeated Measurements per Subject

2018 ◽  
Vol 8 (1) ◽  
pp. 120
Author(s):  
Steven B. Kim ◽  
Jeffrey O. Wand
Keyword(s):  
Sample Size ◽  
High Reliability ◽  
Reliability And Validity ◽  
Repeated Measurements ◽  
Sequential Test ◽  
Ratio Test ◽  
Systematic Bias ◽  
Average Sample Size ◽  
Validity Studies ◽  
Average Sample

In medical, health, and sports sciences, researchers desire a device with high reliability and validity. This article focuses on reliability and validity studies with n subjects and m &ge;2 repeated measurements per subject. High statistical power can be achieved by increasing n or m, and increasing m is often easier than increasing n in practice unless m is too high to result in systematic bias. The sequential probability ratio test (SPRT) is a useful statistical method which can conclude a null hypothesis H0 or an alternative hypothesis H1 with 50% of the required sample size of a non-sequential test on average. The traditional SPRT requires the likelihood function for each observed random variable, and it can be a practical burden for evaluating the likelihood ratio after each observation of a subject. Instead, m observed random variables per subject can be transformed into a test statistic which has a known sampling distribution under H0 and under H1. This allows us to formulate a SPRT based on a sequence of test statistics. In this article, three types of study are considered: reliabilityof a device, reliability of a device relative to a criterion device, and validity of a device relative to a&nbsp; criterion device. Using SPRT for testing the reliability of a device, for small m, results in an average sample size of about 50% of the fixed sample size for a non-sequential test. For comparing a device to criterion, the average sample size approaches to 60% approximately as m increases. The SPRT tolerates violation of normality assumption for validity study, but it does not for reliability study.

Comparison of the two most commonly used gold-standard velocity monitoring devices (GymAware and T-Force) to assess lifting velocity during the free-weight barbell back squat exercise

2021 ◽  
pp. 175433712110296
Author(s):  
Danica Janicijevic ◽  
Amador García-Ramos ◽  
Juan Luis Lamas-Cepero ◽  
Felipe García-Pinillos ◽  
Aitor Marcos-Blanco ◽  
...  
Keyword(s):  
Systematic Bias ◽  
Maximal Velocity ◽  
Force Coefficient ◽  
Mean Velocity ◽  
Back Squat ◽  
Free Weight ◽  
Squat Exercise ◽  
The Right ◽  
Monitoring Devices ◽  
Overall Reliability

This study aimed to compare the reliability and agreement of mean velocity (MV) and maximal velocity (Vmax) between the two velocity monitoring devices (GymAware vs T-Force) most commonly used in the scientific literature. Twenty resistance-trained males completed two testing sessions. The free-weight barbell back squat one-repetition maximum (1RM) was determined in the first session (125.0 ± 24.2 kg; mean ± standard deviation). The second session consisted of two blocks of 16 repetitions (six repetitions at 45% 1RM and 65% 1RM, and four repetitions at 85% 1RM). Half of the repetitions were performed with the GymAware on the left side of the barbell and the other half of the repetitions were performed on the right side of the barbell (opposite placement for the T-Force). MV and Vmax were recorded simultaneously with the GymAware and T-Force. The overall reliability, which was calculated pooling together the data of three loads, did not differ between the T-Force (coefficient of variation (CV) = 5.28 ± 1.79%) and GymAware (CV = 5.79 ± 2.26%) (CVratio = 1.10), but the reliability was higher for Vmax (CV = 5.08 ± 1.79%) compared to MV (CV = 5.98 ± 2.73%) (CVratio = 1.18). MV was significantly higher for the T-Force ( p < 0.001, Δ = 4.42%), but no significant differences were detected between the devices for Vmax ( p = 0.455, Δ = 0.22%). These results support the use of both the GymAware and T-Force as gold-standards in studies designed to validate other velocity monitoring devices. However, systematic bias, albeit rather constant, exists for the magnitude of MV between the two devices.

MEMS Gyroscope Random Error Modeling and Filtering

2010 ◽  
Vol 29-32 ◽  
pp. 829-834 ◽  
Author(s):  
Bo Ren ◽  
De Ming Zhang ◽  
Huan Li
Keyword(s):  
Real Time ◽  
Random Error ◽  
High Reliability ◽  
Low Cost ◽  
Random Sequence ◽  
Engineering Application ◽  
Error Modeling ◽  
Ar Model ◽  
Random Errors ◽  
Mems Gyroscope

MEMS gyroscope is a new type of inertial device with small size, low cost, light weight, high reliability, but less precise and random error is relatively large. In this paper, from a practical engineering application point of view, first, the MEMS gyroscope random errors is real-time average filtered. Then, based on the basic principle of time series analysis of random sequence , the first-order AR model of MEMS gyroscope random errors is established. Finally, based on Markov characteristic of kalman filtering algorithm, each output of the MEMS gyroscope is multiple real-time filtered. Through the specific data processing, MEMS gyroscope random errors reduced to about two per cent of the original.

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