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

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.

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

Sports ◽

10.3390/sports8070094 ◽

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.

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Reliability and concurrent validity of the Velowin optoelectronic system to measure movement velocity during the free-weight back squat

International Journal of Sports Science & Coaching ◽

10.1177/1747954118791525 ◽

2018 ◽

Vol 13 (5) ◽

pp. 737-742 ◽

Cited By ~ 15

Author(s):

Amador García-Ramos ◽

Alejandro Pérez-Castilla ◽

Fernando Martín

Keyword(s):

Concurrent Validity ◽

Body Height ◽

Maximum Velocity ◽

Single Session ◽

Optoelectronic System ◽

Mean Velocity ◽

Movement Velocity ◽

Back Squat ◽

Free Weight ◽

Squat Exercise

The objective of this study was to explore the reliability and concurrent validity of the Velowin optoelectronic system to measure movement velocity during the free-weight back squat exercise. Thirty-one men (age = 27.5 ± 3.2 years; body height = 1.76 ± 0.15 m; body mass: 78.3 ± 7.6 kg) were evaluated in a single session against five different loads (20, 40, 50, 60 and 70 kg) and three velocity variables (mean velocity, mean propulsive velocity and maximum velocity) were recorded simultaneously by a linear velocity transducer (T-Force; gold-standard) and a camera-based optoelectronic system (Velowin). The main findings revealed that (1) the three velocity variables were determined with a high and comparable reliability by both the T-Force and Velowin systems (median coefficient of variation of the five loads: T-Force: mean velocity = 4.25%, mean propulsive velocity = 4.49% and maximum velocity = 3.45%; Velowin: mean velocity = 4.29%, mean propulsive velocity = 4.60% and maximum velocity = 4.44%), (2) the maximum velocity was the most reliable variable when obtained by the T-force ( p < 0.05), but no significant differences in the reliability of the variables were observed for the Velowin ( p > 0.05) and (3) high correlations were observed for the values of mean velocity ( r = 0.976), mean propulsive velocity ( r = 0.965) and maximum velocity ( r = 0.977) between the T-Force and Velowin systems. Collectively, these results support the Velowin as a reliable and valid system for the measurement of movement velocity during the free-weight back squat exercise.

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Estimation of Relative Load From Bar Velocity in the Full Back Squat Exercise

Sports Medicine International Open ◽

10.1055/s-0043-102933 ◽

2017 ◽

Vol 01 (02) ◽

pp. E80-E88 ◽

Cited By ~ 49

Author(s):

Luis Sánchez-Medina ◽

Jesús Pallarés ◽

Carlos Pérez ◽

Ricardo Morán-Navarro ◽

Juan González-Badillo

Keyword(s):

Relative Strength ◽

Loading Test ◽

Mean Velocity ◽

Relative Load ◽

Back Squat ◽

Training Approach ◽

Velocity Relationship ◽

Squat Exercise ◽

Close Relationship ◽

Bar Velocity

AbstractThe use of bar velocity to estimate relative load in the back squat exercise was examined. 80 strength-trained men performed a progressive loading test to determine their one-repetition maximum (1RM) and load-velocity relationship. Mean (MV), mean propulsive (MPV) and peak (PV) velocity measures of the concentric phase were analyzed. Both MV and MPV showed a very close relationship to %1RM (R2=0.96), whereas a weaker association (R2=0.79) and larger SEE (0.14 vs. 0.06 m·s−1) were found for PV. Prediction equations to estimate load from velocity were obtained. When dividing the sample into 3 groups of different relative strength (1RM/body mass), no differences were found between groups for the MPV attained against each %1RM. MV attained with the 1RM was 0.32±0.03 m·s−1. The propulsive phase accounted for ~82% of concentric duration at 40% 1RM, and progressively increased until reaching 100% at 1RM. Provided that repetitions are performed at maximal intended velocity, a good estimation of load (%1RM) can be obtained from mean velocity as soon as the first repetition is completed. This finding provides an alternative to the often demanding, time-consuming and interfering 1RM or nRM tests and allows implementing a velocity-based resistance training approach.

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The effects of a high-intensity free-weight back-squat exercise protocol on postural stability in resistance-trained males

Journal of Sports Sciences ◽

10.1080/02640414.2014.934709 ◽

2014 ◽

Vol 33 (2) ◽

pp. 211-218 ◽

Cited By ~ 3

Author(s):

R.M. Thiele ◽

E.C. Conchola ◽

T.B. Palmer ◽

J.M. DeFreitas ◽

B.J. Thompson

Keyword(s):

High Intensity ◽

Postural Stability ◽

Exercise Protocol ◽

Back Squat ◽

Free Weight ◽

Squat Exercise

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The Reliability of Individualized Load–Velocity Profiles

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2017-0610 ◽

2018 ◽

Vol 13 (6) ◽

pp. 763-769 ◽

Cited By ~ 24

Author(s):

Harry G. Banyard ◽

Kazunori Nosaka ◽

Alex D. Vernon ◽

G. Gregory Haff

Keyword(s):

Linear Regression ◽

Peak Velocity ◽

Intraclass Correlation ◽

Velocity Profiles ◽

Mean Velocity ◽

Movement Velocity ◽

Repetition Maximum ◽

Back Squat ◽

Free Weight ◽

Order Polynomial

Purpose: To examine the reliability of peak velocity (PV), mean propulsive velocity (MPV), and mean velocity (MV) in the development of load–velocity profiles (LVP) in the full-depth free-weight back squat performed with maximal concentric effort. Methods: Eighteen resistance-trained men performed a baseline 1-repetition maximum (1-RM) back-squat trial and 3 subsequent 1-RM trials used for reliability analyses, with 48-h intervals between trials. 1-RM trials comprised lifts from 6 relative loads including 20%, 40%, 60%, 80%, 90%, and 100% 1-RM. Individualized LVPs for PV, MPV, or MV were derived from loads that were highly reliable based on the following criteria: intraclass correlation coefficient (ICC) >.70, coefficient of variation (CV) ≤10%, and Cohen d effect size (ES) <0.60. Results: PV was highly reliable at all 6 loads. MPV and MV were highly reliable at 20%, 40%, 60%, 80%, and 90% but not 100% 1-RM (MPV: ICC = .66, CV = 18.0%, ES = 0.10, SEM = 0.04 m·s−1; MV: ICC = .55, CV = 19.4%, ES = 0.08, SEM = 0.04 m·s−1). When considering the reliable ranges, almost perfect correlations were observed for LVPs derived from PV20–100% (r = .91–.93), MPV20–90% (r = .92–.94), and MV20–90% (r = .94–.95). Furthermore, the LVPs were not significantly different (P > .05) between trials or movement velocities or between linear regression versus 2nd-order polynomial fits. Conclusions: PV20–100%, MPV20–90%, and MV20–90% are reliable and can be utilized to develop LVPs using linear regression. Conceptually, LVPs can be used to monitor changes in movement velocity and employed as a method for adjusting sessional training loads according to daily readiness.

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

Proceedings of the Institution of Mechanical Engineers Part P Journal of Sports Engineering and Technology ◽

10.1177/17543371211062811 ◽

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.

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Validity and reliability of the WIMU® system to measure barbell velocity during the half-squat exercise

Proceedings of the Institution of Mechanical Engineers Part P Journal of Sports Engineering and Technology ◽

10.1177/1754337119831890 ◽

2019 ◽

Vol 233 (3) ◽

pp. 408-415 ◽

Cited By ~ 1

Author(s):

Felipe García-Pinillos ◽

Pedro A Latorre-Román ◽

Fernando Valdivieso-Ruano ◽

Carlos Balsalobre-Fernández ◽

Juan A Párraga-Montilla

Keyword(s):

Gold Standard ◽

Concurrent Validity ◽

Pearson Correlation ◽

Maximum Velocity ◽

Systematic Bias ◽

Loading Test ◽

Mean Velocity ◽

Velocity Relationship ◽

Squat Exercise ◽

The Mean

This study aimed at determining the reliability and concurrent validity of the WIMU® system when measuring barbell velocity during the half-squat exercise by comparing data with the gold standard. A total of 19 male competitive powerlifters performed an incremental loading test using the half-squat exercise. The mean velocity, mean propulsive velocity and maximum velocity of all repetitions were recorded through both WIMU and T-Force systems. As a measure of reliability, coefficient of variations ranged from 6%–17% and standard error of means ranged from 0.02–0.11 m/s, showing very close reliability of data from both devices. Validity, in terms of coefficient of correlations and pairwise comparisons, was also tested. Except for some relative loads, the Pearson correlation analysis revealed significant correlations between both devices for mean velocity, mean propulsive velocity and maximum velocity (r > 0.6, p < 0.05). The mean velocity, mean propulsive velocity and maximum velocity were underestimated for the WIMU system compared to T-Force data at some points of the load–velocity relationship. The linear regression models performed revealed a strong load–velocity relationship in the half-squat exercise for each individual using mean velocity, mean propulsive velocity and maximum velocity, regardless of the instrument used (R2 > 0.77 in all cases). Bland–Altman plots revealed low systematic bias (≤0.06 m s−1) and random error (≤0.07 m s−1) for the mean velocity and mean propulsive velocity obtained from the WIMU system as compared to the T-Force, while the maximum velocity resulted in an underestimation by the WIMU system (–0.16 m s−1) as compared to the linear position transducer system. The results indicate that the WIMU system is a reliable tool for tracking barbell velocity in the half squat, but these data also reveal some limitations regarding its concurrent validity as compared to the gold standard, with velocity measures slightly underestimated in the tested conditions.

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

Sensors ◽

10.3390/s21030925 ◽

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.

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