Reliability and validity of a new accelerometer (Wimu®) system for measuring velocity during resistance exercises

2017 ◽  
Vol 232 (3) ◽  
pp. 218-224 ◽  
Author(s):  
José M Muyor ◽  
Paulino Granero-Gil ◽  
José Pino-Ortega
Keyword(s):  
Standard Error ◽  
Intraclass Correlation ◽  
Maximum Velocity ◽  
Velocity Measurements ◽  
Mean Velocity ◽  
Back Squat ◽  
Intraclass Correlations ◽  
Resistance Exercises ◽  
Linear Encoder ◽  
Systematic Biases

This study had two main goals. The first was to determine the reliability of the Wimu® system (accelerometer) for mean velocity measurements during resistance exercises at 40% and 80% 1 repetition maximum (1RM). The second was to compare the results for the Wimu system to a linear encoder (gold standard) for mean velocity measurements when clipped to the bar during back squat exercises using the Smith machine. In all, 23 trained men (aged 22.3 ± 3.2 years) participated in this study. At maximum velocity in the concentric phase, they performed 10 repetitions with 40% 1RM and eight repetitions with 80% 1RM while using the Wimu system and T-Force linear encoder simultaneously to record data. Reliability was analysed using intraclass correlation, standard error of measurement and coefficient of variation. The validity was assessed using R2, intraclass correlation and Bland-Altman plots. The differences in test–retest reliability of both systems and systematic biases were non-significant ( p = 0.08–0.85) and very close to 0. The random errors averaged ±0.010 m/s. All the calculated coefficient of variations were less than 5% and all measurements had high intraclass correlations (mean: 0.936). Least-square linear regression and intraclass correlations for validity were very close to 1. Significant systematic biases were observed between the linear encoder and the Wimu system ( p < 0.001), although the effect sizes were small (0.21–0.44) and standard error of the estimate in concentric and eccentric phases at both intensities was less than 0.030. In conclusion, the findings of this study suggest that the Wimu system is a reliable and valid tool for the assessment of mean velocity during the back squat exercise using the Smith machine. These findings could help coaches and sport researchers evaluate athletes performing resistance exercises similar to squats with a reliable, valid and portable tool.

scholarly journals Eccentric Force-Velocity Characteristics during a Novel Squat Protocol in Trained Rugby Union Athletes—Pilot Study

2021 ◽  
Vol 6 (2) ◽  
pp. 32
Author(s):  
Conor McNeill ◽  
C. Martyn Beaven ◽  
Daniel T. McMaster ◽  
Nicholas Gill
Keyword(s):  
Pilot Study ◽  
Dynamic Performance ◽  
Intraclass Correlation ◽  
Rugby Union ◽  
Mean Velocity ◽  
Force Development ◽  
Back Squat ◽  
Force Velocity ◽  
Force Time ◽  
Change In Mean

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.

The Reliability of Individualized Load–Velocity Profiles

2018 ◽  
Vol 13 (6) ◽  
pp. 763-769 ◽  
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.

Velocity measurements in a ceramic candle filter element undergoing pulse cleaning

1997 ◽  
Vol 211 (1) ◽  
pp. 11-16 ◽  
Author(s):  
M Biffin ◽  
P Panagiotidis ◽  
C Pitsillides
Keyword(s):  
Pulse Length ◽  
Maximum Velocity ◽  
Operating Conditions ◽  
Velocity Measurements ◽  
Mean Velocity ◽  
Gas Streams ◽  
Wire Probe ◽  
Ceramic Candle Filter ◽  
Reverse Pulse ◽  
Stress Models

Ceramic candle filters have been developed for cleaning high-temperature gas streams. They have demonstrated high collection efficiencies under normal operating conditions, but the brittle materials can fail suddenly with disastrous consequences. Reverse pulse cleaning has been shown to introduce severe thermal stressing of the material. Modelling of the flows to estimate the life of the element is difficult due to non-uniformities in the material. It is important to obtain experimental measurements of flows in the candle to provide input to stress models. In addition it is essential to ensure uniform cleaning of the filter and knowledge of the pulse cleaning flow processes are also important for this. This paper reports velocity measurements obtained using a hot-wire probe located at different positions along the length of a ceramic candle filter. The data have been analysed to estimate the outflow along the length of the candle filter to investigate the cleaning potential of different configurations and operating parameters. The effect of pulse length on cleaning performance was investigated for cases with and without a venturi educer. It was found that the maximum peak mean velocity was produced at a pulse duration of 0.2 s. Longer duration pulses did not have a significant influence on the maximum velocity levels inside the filter.

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

2018 ◽  
Vol 13 (5) ◽  
pp. 737-742 ◽  
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.

scholarly journals The validity and reliability of a novel mobile app to measure agility performance in the physically active youth population

2020 ◽  
Vol 45 ◽  
pp. 85-92
Author(s):  
Juan A. Escobar-Alvarez ◽  
Rocio Carrasco ◽  
Pedro R. Olivares ◽  
Sebastián Feu ◽  
Robinson Ramírez-Velez ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Confidence Interval ◽  
Standard Error ◽  
Low Cost ◽  
Intraclass Correlation ◽  
Mobile App ◽  
Validity And Reliability ◽  
Physically Active ◽  
Youth Population ◽  
Acceptable Reliability

Agility is a key component of physical fitness in adolescents. However, the measurement of this variable is usually complex, requiring high cost instruments and complex software. To test the validity and reliability of a novel iPhone app (Lap Tracker Auto-timer) to measure agility performance among adolescents. Twenty-four physically active adolescents (15.7 ± 2.3 years old) participated in two testing sessions (separated by 7 days). They performed three 4 x 10 m agility test trials measured by Photocell or the iPhone app. The correlation analysis revealed high validity (r = .92; 95% confidence interval [CI] = .88 – .95), with a standard error of the estimate of 0.56 s (p < 0.001). The coefficient of variation (CV; 0.09) and intraclass correlation coefficient (ICC; .93; 95% CI = .85 – .97) showed an acceptable reliability. This study demonstrated that the iPhone App Lap Tracker Auto-timer could be a valid, reliable and low-cost tool to evaluate agility performance in adolescents. However, more studies are required to guarantee the utility of this app.

Assessment of Knee Laxity Following Anterior Cruciate Ligament Reconstruction

1993 ◽  
Vol 2 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Kelly R. Holcomb ◽  
Cheryl A. Skaggs ◽  
Teddy W. Worrell ◽  
Mark DeCarlo ◽  
K. Donald Shelbourne
Keyword(s):  
Anterior Cruciate Ligament ◽  
Standard Error ◽  
Cruciate Ligament ◽  
Intraclass Correlation ◽  
Knee Laxity ◽  
Testing Procedures ◽  
Kt 1000 ◽  
Anterior Cruciate ◽  
Standard Error Of Measurement ◽  
Error Of Measurement

A paucity of information exists concerning reliability of the KT-1000 knee arthrometer (MEDmetric Corp., San Diego, CA) when used by different clinicians to assess the same anterior cruciate ligament-deficient patient. The purpose of this study was to determine the reliability and standard error of measurement of four clinicians who routinely report KT-1000 arthrometer values to referring orthopedic surgeons. Two physical therapists and two athletic trainers performed anterior laxity tests using the KT-1000 on 19 subjects. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to determine reliability. Intratester ICC ranged from .98 to 1.0 and intratesterSEMranged from 0.0 to .28 mm. Intertester ICC andSEMfor all four testers were .53 and 1.2 mm, respectively. A 95% confidence interval (M ± 1.96 ×SEM) of the intertester variability ranged from −0.18 to 4.52 mm. Therefore, large intertester variation existed in KT-1000 values. Each facility should standardize testing procedures and establish intratester and intertester reliability for all clinicians reporting KT-1000 values.

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.

scholarly journals Validation of Inertial Sensor to Measure Barbell Kinematics across a Spectrum of Loading Conditions

Sports ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 93
Author(s):  
John C. Abbott ◽  
John P. Wagle ◽  
Kimitake Sato ◽  
Keith Painter ◽  
Thaddeus J. Light ◽  
...  
Keyword(s):  
Effect Size ◽  
Peak Velocity ◽  
Inertial Sensor ◽  
Measurement Unit ◽  
Mean Velocity ◽  
Back Squat ◽  
Pearson Correlations ◽  
Internal Error ◽  
3D Motion Capture ◽  
Level Of Agreement

The aim of this study was to evaluate the level of agreement in measuring back squat kinematics between an inertial measurement unit (IMU) and a 3D motion capture system (3DMOCAP). Kinematic variables included concentric peak velocity (CPV), concentric mean velocity (CMV), eccentric peak velocity (EPV), eccentric mean velocity (EMV), mean propulsive velocity (MPV), and POP-100: a proprietary variable. Sixteen resistance-trained males performed an incrementally loaded one repetition maximum (1RM) squat protocol. A series of Pearson correlations, 2 × 4 RM ANOVA, Cohen’s d effect size differences, coefficient of variation (CV), and standard error of the estimate (SEE) were calculated. A large relationship existed for all variables between devices (r = 0.78–0.95). Between-device agreement for CPV worsened beyond 60% 1RM. The remaining variables were in agreement between devices with trivial effect size differences and similar CV magnitudes. These results support the use of the IMU, regardless of relative intensity, when measuring EMV, EPV, MPV, and POP-100. However, practitioners should carefully select kinematic variables of interest when using the present IMU device for velocity-based training (VBT), as certain measurements (e.g., CMV, CPV) do not possess practically acceptable reliability or accuracy. Finally, the IMU device exhibited considerable practical data collection concerns, as one participant was completely excluded and 13% of the remaining attempts displayed obvious internal error.

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 Applicability of Dmax Method on Heart Rate Variability to Estimate the Lactate Thresholds in Male Runners

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Eduardo Marcel Fernandes Nascimento ◽  
Diego Antunes ◽  
Paulo Cesar do Nascimento Salvador ◽  
Fernando Klitzke Borszcz ◽  
Ricardo Dantas de Lucas
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Blood Lactate ◽  
Standard Error ◽  
Intraclass Correlation ◽  
Effect Sizes ◽  
Initial Speed ◽  
Limits Of Agreement ◽  
Aerobic Threshold ◽  
Post Hoc

Introduction. The purpose of this study was to evaluate the application of the Dmax method on heart rate variability (HRV) to estimate the lactate thresholds (LT), during a maximal incremental running test (MIRT). Methods. Nineteen male runners performed two MIRTs, with the initial speed at 8 km·h−1 and increments of 1 km·h−1 every 3 minutes, until exhaustion. Measures of HRV and blood lactate concentrations were obtained, and lactate (LT1 and LT2) and HRV (HRVTDMAX1 and HRVTDMAX2) thresholds were identified. ANOVA with Scheffe’s post hoc test, effect sizes (d), the bias ± 95% limits of agreement (LoA), standard error of the estimate (SEE), Pearson’s (r), and intraclass correlation coefficient (ICC) were calculated to assess validity. Results. No significant differences were observed between HRVTDMAX1 and LT1 when expressed for speed (12.1 ± 1.4 km·h−1 and 11.2 ± 2.1 km·h−1; p=0.55; d = 0.45; r = 0.46; bias ± LoA = 0.8 ± 3.7 km·h−1; SEE = 1.2 km·h−1 (95% CI, 0.9–1.9)). Significant differences were observed between HRVTDMAX2 and LT2 when expressed for speed (12.0 ± 1.2 km·h−1 and 14.1 ± 2.5 km·h−1; p=0.00; d = 1.21; r = 0.48; bias ± LoA = −1.0 ± 1.8 km·h−1; SEE = 1.1 km·h−1 (95% CI, 0.8–1.6)), respectively. Reproducibility values were found for the LT1 (ICC = 0.90; bias ± LoA = −0.7 ± 2.0 km·h−1), LT2 (ICC = 0.97; bias ± LoA = −0.1 ± 1.1 km·h−1), HRVTDMAX1 (ICC = 0.48; bias ± LoA = −0.2 ± 3.4 km·h−1), and HRVTDMAX2 (ICC = 0.30; bias ± LoA = 0.3 ± 3.5 km·h−1). Conclusions. The Dmax method applied over a HRV dataset allowed the identification of LT1 that is close to aerobic threshold, during a MIRT.

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