scholarly journals Normalization of Early Isometric Force Production as a Percentage of Peak Force During Multijoint Isometric Assessment

2020 ◽  
Vol 15 (4) ◽  
pp. 478-482
Author(s):  
Paul Comfort ◽  
Thomas Dos’Santos ◽  
Paul A. Jones ◽  
John J. McMahon ◽  
Timothy J. Suchomel ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Intraclass Correlation ◽  
Force Production ◽  
Correlation Coefficients ◽  
Collegiate Athletes ◽  
Peak Force ◽  
Specific Force ◽  
Intraclass Correlation Coefficients ◽  
Time Specific ◽  
Very High

Purpose: To determine the reliability of early force production (50, 100, 150, 200, and 250 ms) relative to peak force (PF) during an isometric mid-thigh pull and to assess the relationships between these variables. Methods: Male collegiate athletes (N = 29; age 21.1 [2.9] y, height 1.71 [0.07] m, body mass 71.3 [13.6] kg) performed isometric mid-thigh pulls during 2 separate testing sessions. Net PF and net force produced at each epoch were calculated. Within- and between-session reliabilities were determined using intraclass correlation coefficients and coefficient of variation percentages. In addition, Pearson correlation coefficients and coefficient of determination were calculated to examine the relationships between PF and time-specific force production. Results: Net PF and time-specific force demonstrated very high to almost perfect reliability both within and between sessions (intraclass correlation coefficients .82–.97; coefficient of variation percentages 0.35%–1.23%). Similarly, time-specific force expressed as a percentage of PF demonstrated very high to almost perfect reliability both within and between sessions (intraclass correlation coefficients .76–.86; coefficient of variation percentages 0.32%–2.51%). Strong to nearly perfect relationships (r = .615–.881) exist between net PF and time-specific net force, with relationships improving over longer epochs. Conclusion: Based on the smallest detectable difference, a change in force at 50 milliseconds expressed relative to PF > 10% and early force production (100, 150, 200, and 250 ms) expressed relative to PF of >2% should be considered meaningful. Expressing early force production as a percentage of PF is reliable and may provide greater insight into the adaptations to the previous training phase than PF alone.

scholarly journals The Test–Retest Reliability of Bilateral and Unilateral Force Plate–Derived Parameters of the Countermovement Push-Up in Elite Boxers

2020 ◽  
pp. 1-5
Author(s):  
Gemma N. Parry ◽  
Lee C. Herrington ◽  
Ian G. Horsley ◽  
Ian Gatt
Keyword(s):  
Upper Limb ◽  
Coefficient Of Variation ◽  
Athletic Performance ◽  
Intraclass Correlation ◽  
Force Plate ◽  
Correlation Coefficients ◽  
Vertical Stiffness ◽  
Intraclass Correlation Coefficients ◽  
Test Retest Reliability ◽  
Push Up

Context: Maximal power describes the ability to immediately produce power with the maximal velocity at the point of release, impact, and/or take off—the greater an athlete’s ability to produce maximal power, the greater the improvement of athletic performance. In reference to boxing performance, regular consistent production of high muscular power during punching is considered an essential prerequisite. Despite the importance of upper limb power to athletic performance, presently, there is no gold standard test for upper limb force development performance. Objective: To investigate the test–retest reliability of the force plate–derived measures of countermovement push-up in elite boxers. Design: Test–retest design. Setting: High Performance Olympic Training Center. Participants: Eighteen elite Olympic boxers (age = 23 [3] y; height = 1.68 [0.39] m; body mass = 70.0 [17] kg). Intervention: Participants performed 5 repetitions of countermovement push-up trials on FD4000 Forcedeck dual force platforms on 2 separate test occasions 7 days apart. Main Outcome Measures: Peak force, mean force, flight time, rate of force development, impulse, and vertical stiffness of the bilateral and unilateral limbs from the force–time curve. Results: No significant differences between the 2 trial occasions for any of the derived bilateral or unilateral performance measures. Intraclass correlation coefficients indicated moderate to high reliability for performance parameters (intraclass correlation coefficients = .68–.98) and low coefficient of variation (3%–10%) apart from vertical stiffness (coefficient of variation = 16.5%–25%). Mean force demonstrated the greatest reliability (coefficient of variation = 3%). In contrast, no significant differences (P < .001) were noted between left and right limbs (P = .005–.791), or between orthodox or southpaw boxing styles (P = .19–.95). Conclusion: Force platform–derived kinetic bilateral and unilateral parameters of countermovement push-up are reliable measures of upper limb power performance in elite-level boxers; results suggest unilateral differences within the bilateral condition are not the norm for an elite boxing cohort.

scholarly journals Effect of Sampling Frequency on Isometric Midthigh-Pull Kinetics

2019 ◽  
Vol 14 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Thomas Dos’Santos ◽  
Paul A. Jones ◽  
Jonathan Kelly ◽  
John J. McMahon ◽  
Paul Comfort ◽  
...  
Keyword(s):  
Repeated Measures ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Rugby League ◽  
Sampling Frequency ◽  
Peak Force ◽  
Specific Force ◽  
Skeletal Muscle Function ◽  
Force Time ◽  
Time Specific

Purpose: Skeletal-muscle function can be evaluated using force-times curves generated via the isometric midthigh pull (IMTP). Various sampling frequencies (500–1000 Hz) have been used for IMTP assessments; however, no research has investigated the influence of sampling frequency on IMTP kinetics. Therefore, the purpose of this study was to investigate the influence of sampling frequency on kinetic variables during the IMTP, including peak force, time-specific force values (100, 150, and 200 ms), and rate of force development (RFD) at 3 time bands (0–100, 0–150, 0–200 ms). Methods: Academy rugby league players (n = 30, age 17.5 ± 1.1 y, height 1.80 ± 0.06 m, mass 85.4 ± 10.3 kg) performed 3 IMTP trials on a force platform sampling at 2000 Hz, which was subsequently down-sampled to 1500, 1000, and 500 Hz for analysis. Results: Intraclass correlation coefficients (ICC) and coefficients of variation (CV) demonstrated high within-session reliability for all force and RFD variables across all sampling frequencies (ICC ≥ .80, CV ≤ 14.4%) except RFD 0–100 and 0–150, which demonstrated slightly greater levels of variance (CV = 18.0–24.1%). Repeated-measures analysis of variance revealed no significant differences (P > .05, Cohen d ≤ 0.0171) in kinetic variables between sampling frequencies. Overall, high reliability was observed across all sampling frequencies for peak force, time-specific force, and RFD 0- to 200-ms variables, with no significant differences (P > .05) for each kinetic variable across sampling frequencies. Conclusions: Practitioners and scientists may consider sampling as low as 500 Hz when measuring peak force, time-specific force values, and RFD at predetermined time bands during the IMTP for accurate and reliable data.

scholarly journals Validity of an Inexpensive Hanging Scale During Isometric Shoulder Movements

2020 ◽  
Vol 29 (8) ◽  
pp. 1218-1221
Author(s):  
Matheus Lima Oliveira ◽  
Isabela Christina Ferreira ◽  
Kariny Realino Ferreira ◽  
Gabriela Silveira-Nunes ◽  
Michelle Almeida Barbosa ◽  
...  
Keyword(s):  
Low Cost ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Load Cell ◽  
Peak Force ◽  
Shoulder Abduction ◽  
Strength Assessment ◽  
Intraclass Correlation Coefficients ◽  
Flexion Extension ◽  
Maximal Peak

Context: Strength assessment is essential to prescribe exercise in sports and rehabilitation. Low-cost valid equipment may allow continuous monitoring of training. Objective: To examine the validity of a very low-cost hanging scale by comparing differences in the measures of peak force to a laboratory grade load cell during shoulder abduction, flexion, extension, and internal and external rotations. Design: Analytical study. Participants: Thirty-two healthy subjects (18 women, age 26 [10] y, height 172 [8] cm, mass 69 [13] kg, body mass index 23 [4] kg/m2). Main Outcome Measures: The dependent variable was the maximal peak force (in kilogram-force). The independent variable was the instrument (laboratory grade load cell and hanging scale). Results: No differences were observed while comparing the results. The intraclass correlation coefficients1,1 ranged from .96 to .99, showing excellent results. The Cronbach alpha test also returned >.99 for all comparisons. The SEM ranged from 0.02 to 0.04 kgf, with an averaged SD from 0.24 to 0.38 kgf. The correlation was classified as high for all tested movements (r > .99; P < .001), with excellent adjusted coefficients of determination (.96 < r2 < .99). Bland–Altman results showed high levels of agreement with bias ranging from 0.27 to 0.48. Conclusions: Hanging scale provides valid measures of isometric strength with similar output measures as laboratory grade load cell.

Test–Retest Reliability of Soccer Dribbling Tests in Children

2021 ◽  
pp. 1-7
Author(s):  
Michael J. Duncan ◽  
Darren Richardson ◽  
Rhys Morris ◽  
Emma Eyre ◽  
Neil D. Clarke
Keyword(s):  
Coefficient Of Variation ◽  
Pediatric Population ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Systematic Bias ◽  
Limits Of Agreement ◽  
Good Reliability ◽  
Retest Reliability ◽  
Intraclass Correlation Coefficients ◽  
Test Retest Reliability

The present study examined the test–retest reliability of the Ghent University dribbling test and short dribble test in a pediatric population. Fifty-four boys aged 9–14 years (mean ± SD = 11 ± 2 years) undertook the Ghent University and dribbling tests on two occasions separated by 2 weeks. Intraclass correlation coefficients, coefficient of variation, and 95% limits of agreement were conducted for each test. Intraclass correlation coefficients and coefficient of variation indicated good to excellent reliability, and relatively small variability for both dribbling tests. The 95% limits of agreement indicated relatively little bias Ghent University dribbling test for both running alone and running with the ball components, and the Bangsbo and Mohr short dribble test. The results of the present study suggest both dribbling tests examined in the present study demonstrate good reliability and low levels of systematic bias.

The reliability of a linear position transducer and commercially available accelerometer to measure punching velocity in junior boxing athletes

2020 ◽  
pp. 174795412095257
Author(s):  
Dale M Harris ◽  
Kevin Caillaud ◽  
Saumya Khullar ◽  
G Gregory Haff ◽  
Christopher Latella
Keyword(s):  
Peak Velocity ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Dominant Hand ◽  
Maximum Peak ◽  
Intraclass Correlation Coefficients ◽  
Direct Measures ◽  
Fixed Bias ◽  
Maximal Effort ◽  
Very High

Limited evidence exists demonstrating reliability of using direct measures to quantify punching velocity. The aim of this study was to establish the intra- and inter-day reliability of a linear positional transducer (GymAware) and accelerometer (PUSH Band 2.0) for the quantification of peak punching velocity in trained junior boxing athletes. Eighteen males aged 16.7 years (±1.2) with at least two years of boxing experience participated in the study. On two separate days, participants performed five dominant-hand crosses with maximal effort. Ordinary least-products regression analysis was used to compare mean and maximum peak velocity scores between devices within each day of testing. Two-way mixed intraclass correlation coefficients (ICC3,1) and Pearson’s r with 95% confidence intervals (95%CI) were also used to compare mean and maximum peak velocity within devices across days. Maximum peak (∼7.5 ms vs. ∼6.2 ms) and mean peak (∼7.0 ms vs. 5.4 ms) velocity was higher when measured via GymAware compared to PUSH Band 2.0 on both days (all P ≤ 0.012). The within-device mean (ICC3,1 = 0.871, 95%CI  =  0.689, 0.950) and maximum (ICC3,1 =  0.853 95%CI  =  0.650, 0.942) peak velocity scores for the GymAware across Days 1 and 2 demonstrated very high reliabilities. Mean (ICC3,1 = 0.309, 95%CI = –0.170, 0.670) and maximum (ICC3,1 = 0.227, 95%CI = –0.173, 0.637) peak velocity for PUSH Band 2.0 demonstrated weak reliabilities. Proportional bias was found for Day 2 mean and maximum peak velocity and when both days were pooled. Fixed bias was observed for mean (Day 1) and maximum peak velocity when both days were pooled. These results may provide useful information for professionals working with boxing or combat-sport athletes.

scholarly journals Effect of Sampling Frequency on Isometric Midthigh-Pull Kinetics

2016 ◽  
Vol 11 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Thomas Dos’Santos ◽  
Paul A. Jones ◽  
Jonathan Kelly ◽  
John J. McMahon ◽  
Paul Comfort ◽  
...  
Keyword(s):  
Repeated Measures ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Rugby League ◽  
Sampling Frequency ◽  
Peak Force ◽  
Specific Force ◽  
Skeletal Muscle Function ◽  
Force Time ◽  
Time Specific

Purpose:Skeletal-muscle function can be evaluated using force–times curves generated via the isometric midthigh pull (IMTP). Various sampling frequencies (500–1000 Hz) have been used for IMTP assessments; however, no research has investigated the influence of sampling frequency on IMTP kinetics. Therefore, the purpose of this study was to investigate the influence of sampling frequency on kinetic variables during the IMTP, including peak force, time-specific force values (100, 150, and 200 ms), and rate of force development (RFD) at 3 time bands (0–100, 0–150, 0–200 ms).Methods:Academy rugby league players (n = 30, age 17.5 ± 1.1 y, height 1.80 ± 0.06 m, mass 85.4 ± 10.3 kg) performed 3 IMTP trials on a force platform sampling at 2000 Hz, which was subsequently down-sampled to 1500, 1000, and 500 Hz for analysis.Results:Intraclass correlation coefficients (ICC) and coefficients of variation (CV) demonstrated high within-session reliability for all force and RFD variables across all sampling frequencies (ICC ≥ .80, CV ≤ 10.1%). Repeated-measures analysis of variance revealed no significant differences (P > .05, Cohen d ≤ 0.009) in kinetic variables between sampling frequencies. Overall, high reliability was observed across all sampling frequencies for all kinetic variables, with no significant differences (P > .05) for each kinetic variable across sampling frequencies.Conclusions:Practitioners and scientists may consider sampling as low as 500 Hz when measuring peak force, time-specific force values, and RFD at predetermined time bands during the IMTP for accurate and reliable data.

Concurrent validity and reliability of a functional electromechanical dynamometer to assess isometric mid-thigh pull performance

2021 ◽  
pp. 175433712110301
Author(s):  
Andrés Baena-Raya ◽  
David M. Díez-Fernández ◽  
Amador García-Ramos ◽  
Alberto Soriano-Maldonado ◽  
Manuel A. Rodríguez-Pérez
Keyword(s):  
Concurrent Validity ◽  
Force Production ◽  
Collegiate Athletes ◽  
Specific Force ◽  
Validity And Reliability ◽  
Force Development ◽  
Acceptable Alternative ◽  
Time Specific ◽  
Initial Force ◽  
Acceptable Reliability

The aim of this study was to examine the concurrent validity and reliability of a functional electromechanical dynamometer (FEMD) to assess the isometric mid-thigh pull (IMTP) kinetic variables: peak force (PF), rate of force development (RFD), and time-specific force values (50-, 100-, 150-, and 200-ms). Twenty-seven male collegiate athletes (age: 22.9 ± 1.9 years; stature: 184.8 ± 10.4 cm; body mass: 84.2 ± 11.8 kg) performed four IMTP trials simultaneously on a force platform and the FEMD. The PF variables calculated from performance of the IMTP on both devices were reliable (CV < 3%; ICC > 0.90) and valid (bias < 13.9 N; random error < 52.1 N; r = 1.00), but they showed heteroscedasticity of the errors ( R2 > 0.23). The RFD (CV > 10.88%; ICC < 0.76) and initial force (CV > 8.81%; ICC < 0.76) variables did not reach an acceptable reliability for any device, but they showed strong associations between them ( r range = 0.53–0.69). These results indicate that the FEMD is an acceptable alternative to assess athlete’s maximal force production (i.e. PF), but the data collected with FEMD and force plates should not be used interchangeably.

Intratester Reliability for Determining an 8-Repetition Maximum for 3 Shoulder Exercises Using Elastic Bands

2005 ◽  
Vol 14 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Craig J. Newsam ◽  
Cindy Leese ◽  
Jennifer Fernandez-Silva
Keyword(s):  
Outcome Measures ◽  
External Rotation ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Training Load ◽  
Elastic Band ◽  
Repetition Maximum ◽  
Intraclass Correlation Coefficients ◽  
Elastic Bands ◽  
Very High

Context:Standardization of training load using the 1-repetition maximum (1RM) test cannot be directly applied when using elastic bands as resistance.Objective:To determine the intratester reliability for establishing an 8-repetition maximum (8RM) using elastic bands.Design:Test–retest.Participants:5 men, 10 women, 23–29 years.Intervention:An 8RM test was established for 3 shoulder exercises using the Dura-Band® exercise system.Main Outcome Measures:The length of the elastic band was recorded. An analysis of variance was performed, and intraclass correlation coefficients (ICC) were calculated for each exercise.Results:Intratester reliability for determining the elastic-band length required to establish an 8RM was very high for internal rotation (ICC = .91) and high for external rotation (ICC = .77). The diagonal pull-down 8RM test had moderate reliability (ICC = .65).Conclusion:Training load can be reliably standardized in healthy young adults using moderate-to high-resistance elastic bands with a goal-based multiple-RM test.

Consistency of Peak and Mean Concentric and Eccentric Force Using a Novel Squat Testing Device

2014 ◽  
Vol 30 (2) ◽  
pp. 322-325 ◽  
Author(s):  
Matt S. Stock ◽  
Micheal J. Luera
Keyword(s):  
High Reliability ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Peak Force ◽  
Isokinetic Dynamometry ◽  
Intraclass Correlation Coefficients ◽  
Force Curves ◽  
Mean Differences ◽  
Test Retest Reliability ◽  
Muscle Actions

The ability to examine force curves from multiple-joint assessments combines many of the benefits of dynamic constant external resistance exercise and isokinetic dynamometry. The purpose of this investigation was to examine test-retest reliability statistics for peak and mean force using the Exerbotics eSQ during maximal concentric and eccentric squats. Seventeen resistance-trained men (mean ± SD age = 21 ± 2 years) visited the laboratory on two occasions. For each trial, the subjects performed two maximal concentric and eccentric squats, and the muscle actions with the highest force values were analyzed. There were no mean differences between the trials (P> .05), and the effect sizes were < 0.12. When the entire force curve was examined, the intraclass correlation coefficients (model 2,1) and standard errors of measurement, respectively, were concentric peak force = 0.743 (8.8%); concentric mean force = 0.804 (6.0%); eccentric peak force = 0.696 (10.6%); eccentric mean force = 0.736 (9.6%). These findings indicated moderate-to-high reliability for the peak and mean force values obtained from the Exerbotics eSQ during maximal squat testing. The analysis of force curves from multiple-joint testing provides researchers and practitioners with a reliable means of assessing performance, especially during concentric muscle actions.

Interobserver Reliability Using the Phonetic Level Evaluation With Severely and Profoundly Hearing-Impaired Children

1991 ◽  
Vol 34 (5) ◽  
pp. 989-999 ◽  
Author(s):  
Stephanie Shaw ◽  
Truman E. Coggins
Keyword(s):  
Interrater Reliability ◽  
Interobserver Reliability ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Hearing Impaired ◽  
Intraclass Correlation Coefficients ◽  
Assessment Measure ◽  
Impaired Children ◽  
Speech Assessment ◽  
Hearing Impaired Children

This study examines whether observers reliably categorize selected speech production behaviors in hearing-impaired children. A group of experienced speech-language pathologists was trained to score the elicited imitations of 5 profoundly and 5 severely hearing-impaired subjects using the Phonetic Level Evaluation (Ling, 1976). Interrater reliability was calculated using intraclass correlation coefficients. Overall, the magnitude of the coefficients was found to be considerably below what would be accepted in published behavioral research. Failure to obtain acceptably high levels of reliability suggests that the Phonetic Level Evaluation may not yet be an accurate and objective speech assessment measure for hearing-impaired children.

Sign in / Sign up

Export Citation Format

Share Document