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 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.

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.

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.

scholarly journals Acute Effects of a Percussive Massage Treatment on Movement Velocity during Resistance Training

2021 ◽  
Vol 18 (15) ◽  
pp. 7726
Author(s):  
Manuel García-Sillero ◽  
Jose Manuel Jurado-Castro ◽  
Javier Benítez-Porres ◽  
Salvador Vargas-Molina
Keyword(s):  
Resistance Training ◽  
Bench Press ◽  
Therapy Group ◽  
Control Group ◽  
Acute Effects ◽  
Movement Velocity ◽  
Repetition Maximum ◽  
Rest Periods ◽  
Massage Treatment ◽  
Male University Students

The aim of this research was to verify whether the application of percussion therapy during inter-set rest periods increases the number of repetitions performed before reaching a 30% velocity loss threshold during a bench press exercise. Methods: Twenty-four male university students participated in this study (24.3 ± 1.3 years; 77.5 ± 8.3 kg; 177.0 ± 5.6 cm; 24.7 ± 2.6 kg∙m−2). Participants were randomized into two groups: a percussion therapy group (PTG) and a control group (CG). They performed 4 sets at 70% of a one-repetition maximum before reaching a 30% velocity loss threshold with an inter-set recovery of 3 min. Results: The PTG performed a greater total number of repetitions compared to the CG (44.6 ± 4.8 vs. 39.5 ± 6.8; p = 0.047; ES = 0.867). No differences were observed for the different movement velocity variables and fatigue control (p > 0.05). Conclusions: Percussion therapy is an effective method to delay the loss of movement velocity in the bench press exercise.

scholarly journals Design and psychometric evaluation of epilepsy-related apathy scale (E-RAS) in adults with epilepsy: a sequential exploratory mixed methods design

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Abbas Shamsalinia ◽  
Mozhgan Moradi ◽  
Reza Ebrahimi Rad ◽  
Reza Ghadimi ◽  
Mansoureh Ashghali Farahani ◽  
...  
Keyword(s):  
Factor Analysis ◽  
Mixed Methods ◽  
Care Providers ◽  
Divergent Validity ◽  
Validity And Reliability ◽  
Mixed Methods Design ◽  
Scale Evaluation ◽  
Wide Range ◽  
Epileptic Patients ◽  
Convergent And Divergent Validity

Abstract Background Apathy in patients with epilepsy is associated with a wide range of consequences that reduce the patient’s ability to perform social functions and participate in self-care and rehabilitation programs. Therefore, apathy is one of the important diagnoses of the healthcare team in the process of caring for epileptic patients and its dimensions need to be examined and recognized. Therefore, appropriate instruments with the sociocultural milieu of each community should be provided to health care providers. The aim of the present study was to design and measure epilepsy–related apathy scale (E-RAS) in adults with epilepsy. Methods This study of sequential exploratory mixed methods design was conducted in Iran from April 2019 to December 2019. In the Item generation stage, two inductive (face-to-face and semi-structured interviews with 17 adult epileptic patients) and deductive (literature review) were used. In item reduction, integration of qualitative and literature reviews and scale evaluation were accomplished. For Scale Evaluation, face, content, construct [exploratory factor analysis (EFA) (n = 360) and confirmatory factor analysis (CFA) (n = 200)], convergent and divergent Validity and reliability (internal consistency and stability) were investigated. Results The results of EFA showed that E-RAS has four factors, namely, motivation; self-regulatory; cognition and emotional-effective. These four latent factors accounted for a total of 48.351% of the total variance in the E-RAS construct. The results of CFA showed that the 4-factor model of E-RAS has the highest fit with the data. The results of convergent and divergent validity showed that the values of composite reliability (CR) and average variance extracted (AVE) for the four factors were greater than 0.7 and 0.5, respectively, and the value of AVE for each factor was greater than CR. The Cronbach’s alpha coefficient for the whole scale was obtained 0.815. The results of the test-retest showed that there was a significant agreement between the test and retest scores (P < 0.001). Conclusion E-RAS is a multidimensional construct consisting of 24 items, and has acceptable validity and reliability for the study of epilepsy-related apathy in adult epileptic patients.

scholarly journals Prediction of One Repetition Maximum Using Reference Minimum Velocity Threshold Values in Young and Middle-Aged Resistance-Trained Males

2021 ◽  
Vol 11 (5) ◽  
pp. 71
Author(s):  
John F. T. Fernandes ◽  
Amelia F. Dingley ◽  
Amador Garcia-Ramos ◽  
Alejandro Perez-Castilla ◽  
James J. Tufano ◽  
...  
Keyword(s):  
Bench Press ◽  
Absolute Error ◽  
Young Group ◽  
Middle Aged ◽  
Repetition Maximum ◽  
Back Squat ◽  
Velocity Threshold ◽  
Low Load ◽  
The Absolute ◽  
Minimum Velocity

Background: This study determined the accuracy of different velocity-based methods when predicting one-repetition maximum (1RM) in young and middle-aged resistance-trained males. Methods: Two days after maximal strength testing, 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males completed three repetitions of bench press, back squat, and bent-over-row at loads corresponding to 20–80% 1RM. Using reference minimum velocity threshold (MVT) values, the 1RM was estimated from the load-velocity relationships through multiple (20, 30, 40, 50, 60, 70, and 80% 1RM), two-point (20 and 80% 1RM), high-load (60 and 80% 1RM) and low-load (20 and 40% 1RM) methods for each group. Results: Despite most prediction methods demonstrating acceptable correlations (r = 0.55 to 0.96), the absolute errors for young and middle-aged groups were generally moderate to high for bench press (absolute errors = 8.2 to 14.2% and 8.6 to 20.4%, respectively) and bent-over-row (absolute error = 14.9 to 19.9% and 8.6 to 18.2%, respectively). For squats, the absolute errors were lower in the young group (5.7 to 13.4%) than the middle-aged group (13.2 to 17.0%) but still unacceptable. Conclusion: These findings suggest that reference MVTs cannot accurately predict the 1RM in these populations. Therefore, practitioners need to directly assess 1RM.

scholarly journals Asbestos Detection with Fluorescence Microscopy Images and Deep Learning

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4582
Author(s):  
Changjie Cai ◽  
Tomoki Nishimura ◽  
Jooyeon Hwang ◽  
Xiao-Ming Hu ◽  
Akio Kuroda
Keyword(s):  
Deep Learning ◽  
Fluorescence Microscopy ◽  
Occupational Safety ◽  
Graphics Processing Unit ◽  
Reference Method ◽  
Processing Unit ◽  
Fiber Concentration ◽  
Art Object ◽  
Wide Range ◽  
Microscopy Images

Fluorescent probes can be used to detect various types of asbestos (serpentine and amphibole groups); however, the fiber counting using our previously developed software was not accurate for samples with low fiber concentration. Machine learning-based techniques (e.g., deep learning) for image analysis, particularly Convolutional Neural Networks (CNN), have been widely applied to many areas. The objectives of this study were to (1) create a database of a wide-range asbestos concentration (0–50 fibers/liter) fluorescence microscopy (FM) images in the laboratory; and (2) determine the applicability of the state-of-the-art object detection CNN model, YOLOv4, to accurately detect asbestos. We captured the fluorescence microscopy images containing asbestos and labeled the individual asbestos in the images. We trained the YOLOv4 model with the labeled images using one GTX 1660 Ti Graphics Processing Unit (GPU). Our results demonstrated the exceptional capacity of the YOLOv4 model to learn the fluorescent asbestos morphologies. The mean average precision at a threshold of 0.5 ([email protected]) was 96.1% ± 0.4%, using the National Institute for Occupational Safety and Health (NIOSH) fiber counting Method 7400 as a reference method. Compared to our previous counting software (Intec/HU), the YOLOv4 achieved higher accuracy (0.997 vs. 0.979), particularly much higher precision (0.898 vs. 0.418), recall (0.898 vs. 0.780) and F-1 score (0.898 vs. 0.544). In addition, the YOLOv4 performed much better for low fiber concentration samples (<15 fibers/liter) compared to Intec/HU. Therefore, the FM method coupled with YOLOv4 is remarkable in detecting asbestos fibers and differentiating them from other non-asbestos particles.

scholarly journals Study the Effect of Culture on Customer Loyalty on the Target Markets for Successful Export

2017 ◽  
Vol 9 (2) ◽  
pp. 148 ◽  
Author(s):  
Farzad Tarhani ◽  
Solmaz Janfadaei
Keyword(s):  
Cultural Values ◽  
Customer Loyalty ◽  
Cultural Beliefs ◽  
Foreign Market ◽  
Structural Equations ◽  
Cultural Dimension ◽  
Target Market ◽  
Validity And Reliability ◽  
Wide Range ◽  
Target Markets

Export deals with a wide range of environmental factors, customers and competitors that are different with the domestic market. That’s why market research and export promotion require management plans and appropriate procedures to their target markets and audiences. Exporter before entering a foreign market requires that by doing the necessary research on the marketrealizethe type of information required and how to collect it from a country other than their country and study about the cultural dimensions.In fact, differences in the environment, cultural, legal, political, economic, financial, geographic, multinational markets, free trade zones and economic agreements include the level of economic development and the risks and major exporter that they should do an investigation to consider the conditions of satisfaction and thus increase customer loyalty.This applied research was done aims to determine the effect of culture on customer loyalty at target markets for successful export using a descriptive method by a questionnaire that its validity and reliability was calculated. To analyze the issue of structural equations and correlation test was used. Based on the results, this study found a relationship between the cultural dimension, cultural beliefs and cultural values and traditions with customer loyalty at target market.

scholarly journals Concurrent Validity and Reliability of the Load-Velocity Relationship to Predict the One-Repetition Maximum during Three Weightlifting Derivatives

Kinesiology ◽  
2021 ◽  
Vol 53 (2) ◽  
pp. 215-225
Author(s):  
Ricardo Berton ◽  
Marcos Soriano ◽  
Demostenys David da Silva ◽  
Marcel Lopes dos Santos ◽  
Gustavo Teixeira ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Concurrent Validity ◽  
Direct Test ◽  
Validity And Reliability ◽  
Repetition Maximum ◽  
Typical Error ◽  
Velocity Relationship ◽  
The One ◽  
Power Clean ◽  
Adequate Reliability

The study investigated the concurrent validity and reliability of the load-velocity relationship to predict the one-repetition maximum (1RM) of the power clean from the knee (PCK), high pull from the knee (HPK), and mid-thigh clean pull (MTCP). For each exercise, 12 participants performed two 1RM sessions tests and two sessions to measure the barbell’s load-velocity relationship at 30, 45, 60, 75, and 90% of 1RM. The velocity recorded at each load was used to establish the linear regression equation and, consequently, to predict 1RM value. A low validity between the 1RM direct test and predicted 1RM was observed for PCK (typical error [TE]=3.96 to 4.50 kg, coefficient of variation [CV]=4.68 to 5.27%, effect size [ES]=-0.76 to -0.58, Bland-Altman bias [BAB]=9.83 to 11.19 kg), HPK (TE=4.58 to 5.82 kg, CV=6.44 to 8.14%, ES=-0.40 to -0.39, BAB=3.52 to 4.17 kg), and MTCP (TE=6.33 to 8.08 kg, CV=4.78 to 6.16%, ES=-0.29 to -0.19, BAB=3.98 to 6.17 kg). Adequate reliability was observed for the 1RM direct test and for the predicted 1RM. However, based on Bland-Altman limits of agreement, lower measurement errors were obtained for the 1RM direct test in comparison to the predicted 1RM for all the exercises. In conclusion, the load-velocity relationship was not able to predict 1RM values with high accuracy in the PCK, HPK, and MTCP. Moreover, the 1RM direct test was the most reliable for PCK, HPK and MTCP.

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