scholarly journals Variability in Baseball Throwing Metrics During a Structured Long-Toss Program: Does One Size Fit All or Should Programs Be Individualized?

2019 ◽  
Vol 11 (6) ◽  
pp. 535-542 ◽  
Author(s):  
Nels D. Leafblad ◽  
Dirk R. Larson ◽  
Glenn S. Fleisig ◽  
Stan Conte ◽  
Stephen A. Fealy ◽  
...  
Keyword(s):  
High School ◽  
Coefficient Of Variation ◽  
Inertial Measurement Unit ◽  
Intraclass Correlation ◽  
Measurement Unit ◽  
Level Of Evidence ◽  
Inertial Measurement ◽  
Ball Velocity ◽  
Maximum Effort ◽  
Level 3

Background: The variability of throwing metrics, particularly elbow torque and ball velocity, during structured long-toss programs is unknown. Hypotheses: (1) Elbow torque and ball velocity would increase as throwers progressed through a structured long-toss program and (2) intrathrower reliability would be high while interthrower reliability would be variable. Study Design: Descriptive laboratory study. Level of Evidence: Level 3. Methods: Sixty healthy high school and collegiate pitchers participated in a structured long-toss program while wearing a validated inertial measurement unit, which measured arm slot, arm velocity, shoulder rotation, and elbow varus torque. Ball velocity was assessed by radar gun. These metrics were compared within and between all pitchers at 90, 120, 150, and 180 ft and maximum effort mound pitching. Intra- and interthrower reliabilities were calculated for each metric at every stage of the program. Results: Ball velocity significantly changed at each progressive throwing distance, but elbow torque did not. Pitching from the mound did not place more torque on the elbow than long-toss throwing from 120 ft and beyond. Intrathrower reliability was excellent (intraclass correlation coefficient >0.75) throughout the progressive long-toss program, especially on the mound. Ninety-one percent of throwers had acceptable interthrower reliability (coefficient of variation <5%) for ball velocity, whereas only 79% of throwers had acceptable interthrower reliability for elbow torque. Conclusion: Based on trends in elbow torque, it may be practical to incorporate pitching from the mound earlier in the program (once a player is comfortable throwing from 120 ft). Ball velocity and elbow torque do not necessarily correlate with one another, so a degree of caution should be exercised when using radar guns to estimate elbow torque. Given the variability in elbow torque between throwers, some athletes would likely benefit from an individualized throwing program. Clinical Relevance: Increased ball velocity does not necessarily equate to increased elbow torque in long-toss. Some individuals would likely benefit from individualized long-toss programs for rehabilitation.

Validity and Reliability of a New Device to Measure Type of Actions in Indoor Sports

2020 ◽  
Author(s):  
Carlos Lago-Fuentes ◽  
Paolo Aiello ◽  
Mauro Testa ◽  
Iker Muñoz ◽  
Marcos Mecías Calvo
Keyword(s):  
Coefficient Of Variation ◽  
Inertial Measurement Unit ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Measurement Unit ◽  
Validity And Reliability ◽  
Inertial Measurement ◽  
New Device ◽  
Standing Up ◽  
Indoor Sports

AbstractThe purpose of this study was to analyze the validity and the reliability of the intensity ranges, number of actions and changes of direction measured by a commercial inertial measurement unit. Eleven elite youth futsal players performed a circuit with different type of displacements as sprinting, running at low-medium intensity, standing up and changes of direction. Data recorded by the Overtraq system were compared with video-analyzer during the six trials of each player. Standard error mean, Intraclass Correlation Coeficient and Coefficient of variation, were calculated to analyze the reliability of the device, as well as the Root Mean Square Error and Confidence Interval with correlation of Pearson for its validity. The results reported good validity for three intensity ranges (R2>0.7) with high reliability (Intraclass Correlation Coeficient: 0.8–0.9), especially for high intensity actions (Intraclass Correlation Coeficient: 0.95, Coefficient of Variation: 3.06%). Furthermore, the validity for the number of different actions was almost perfect (96.3–100%), with only small differences regarding changes of activity (mean error: 2.0%). The Overtraq system can be considered as a valid and reliable technology for measuring and monitoring actions at different intensities and changes of direction in futsal, likewise common actions for other indoor sports.

scholarly journals Tibial Accelerations During the Single-Leg Hop Test: Influence of Fixation

2020 ◽  
pp. 1-4
Author(s):  
Hannah W. Tucker ◽  
Emily R. Tobin ◽  
Matthew F. Moran
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Repeated Measures ◽  
Inertial Measurement Unit ◽  
Intraclass Correlation ◽  
Return To Sport ◽  
Fixation Method ◽  
Measurement Unit ◽  
Inertial Measurement ◽  
Hop Test

Context: Performance on single-leg hopping (SLH) assessments is commonly included within return-to-sport criteria for rehabilitating athletes. Triaxial accelerometers have been used to quantify impact loading in a variety of movements, including hopping; however, they have never been attached to the tibia during SLH, and their method of fixation has not been investigated. Objective: The purpose of this study was to quantify triaxial accelerations and evaluate the influence of the fixation method of a lightweight inertial measurement unit (Blue Trident) mounted to the tibia during SLH performance. Design: Single cohort, repeated-measures experimental design. Participants: Sixteen healthy participants (10 females and 6 males; 20 [0.9] y; 1.67 [0.08] m; 66.0 [8.5] kg) met the inclusion criteria, volunteered, and completed this study. Interventions: Participants performed 2 sets of 3 SLH trials with an inertial measurement unit (1500 Hz) fixated to the tibia, each set with 1 of 2 attachment methods (double-sided tape [DST] with athletic tape and silicon strap [SS] with Velcro adhesion). Main Outcome Measures: Hop distance, peak tibial acceleration (PTA), time to PTA, and the acceleration slope were assessed during each hop landing. Results: Repeated-measures analysis of variance determined no significant effect of the attachment method on hop metrics (P = .252). Across 3 trials, both fixation methods (DST and SS) had excellent reliability values (intraclass correlation coefficient: .868–.941) for PTA and acceleration slope but not for time to PTA (intraclass correlation coefficient: .397–.768). The PTA for DST (27.22 [7.94] g) and SS (26.21 [10.48] g) was comparable and had a moderate, positive relationship (DST: r = .72, P < .01; SS: r = .77, P < .01) to SLH distance. Conclusions: Tibial inertial measurement units with triaxial accelerometers can reliably assess PTA during performance of the SLH, and SS is a viable alternative tibial attachment to DST.

scholarly journals Valid and Reliable Barbell Velocity Estimation Using an Inertial Measurement Unit

2021 ◽  
Vol 18 (17) ◽  
pp. 9170
Author(s):  
Steffen Held ◽  
Ludwig Rappelt ◽  
Jan-Philip Deutsch ◽  
Lars Donath
Keyword(s):  
Inertial Measurement Unit ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Velocity Estimation ◽  
Measurement Unit ◽  
Systematic Bias ◽  
Validity And Reliability ◽  
Inertial Measurement ◽  
Intraclass Correlation Coefficients ◽  
Reliability Indicators

The accurate assessment of the mean concentric barbell velocity (MCV) and its displacement are crucial aspects of resistance training. Therefore, the validity and reliability indicators of an easy-to-use inertial measurement unit (VmaxPro®) were examined. Nineteen trained males (23.1 ± 3.2 years, 1.78 ± 0.08 m, 75.8 ± 9.8 kg; Squat 1-Repetition maximum (1RM): 114.8 ± 24.5 kg) performed squats and hip thrusts (3–5 sets, 30 repetitions total, 75% 1RM) on two separate days. The MCV and displacement were simultaneously measured using VmaxPro® and a linear position transducer (Speed4Lift®). Good to excellent intraclass correlation coefficients (0.91 < ICC < 0.96) with a small systematic bias (p < 0.001; ηp2 < 0.50) for squats (0.01 ± 0.04 m·s−1) and hip thrusts (0.01 ± 0.05 m·s−1) and a low limit of agreement (LoA < 0.12 m·s−1) indicated an acceptable validity. The within- and between-day reliability of the MCV revealed good ICCs (0.55 < ICC < 0.91) and a low LoA (<0.16 m·s−1). Although the displacement revealed a systematic bias during squats (p < 0.001; ηp2 < 0.10; 3.4 ± 3.4 cm), no bias was detectable during hip thrusts (p = 0.784; ηp2 < 0.001; 0.3 ± 3.3 cm). The displacement showed moderate to good ICCs (0.43 to 0.95) but a high LoA (7.8 to 10.7 cm) for the validity and (within- and between-day) reliability of squats and hip thrusts. The VmaxPro® is considered to be a valid and reliable tool for the MCV assessment.

scholarly journals Validity and sensitivity of an inertial measurement unit-driven biomechanical model of motor variability for gait

2021 ◽  
Author(s):  
Christopher Bailey ◽  
Thomas Uchida ◽  
Julie Nantel ◽  
Ryan Graham
Keyword(s):  
Inertial Measurement Unit ◽  
Intraclass Correlation ◽  
Biomechanical Model ◽  
Measurement Unit ◽  
Local Dynamic ◽  
Joint Angles ◽  
Motor Variability ◽  
Arm Swing ◽  
Inertial Measurement ◽  
Local Dynamic Stability

Motor variability in gait is frequently linked to fall risk, yet field-based biomechanical joint evaluations are scarce. We evaluated the validity and sensitivity of an inertial measurement unit (IMU)-driven biomechanical model of joint angle variability for gait. Fourteen healthy young adults completed seven-minute trials of treadmill gait at several speeds and arm swing amplitudes. Joint kinematics were estimated by IMU- and optoelectronic-based models using OpenSim. We calculated range of motion (ROM), magnitude of variability (meanSD), local dynamic stability (λmax), persistence of ROM fluctuations (DFAα), and regularity (SaEn) of each angle over 200 continuous strides, and evaluated model accuracy (e.g., RMSD: root mean square difference), consistency (ICC2,1: intraclass correlation), biases, limits of agreement, and sensitivity to within-participant gait responses (effects of Speed and Swing). RMSDs of joint angles were 1.7–7.5° (pooled mean of 4.8°), excluding ankle inversion. ICCs were mostly good–excellent in the primary plane of motion for ROM and in all planes for meanSD and λmax, but were poor–moderate for DFAα and SaEn. Modeled Speed and Swing responses for ROM, meanSD, and λmax were similar. Results suggest that the IMU-driven model is valid and sensitive for field-based assessments of joint angles and several motor variability features.

scholarly journals Variability in Baseball Throwing Metrics During A Structured Long-toss Program: Does One Size Fit All?

2019 ◽  
Vol 7 (7_suppl5) ◽  
pp. 2325967119S0039
Author(s):  
Nels Leafblad ◽  
Dirk Larson ◽  
Glenn S. Fleisig ◽  
Stan Conte ◽  
Stephen Fealy ◽  
...  
Keyword(s):  
High School ◽  
Laboratory Study ◽  
Coefficient Of Variation ◽  
Wearable Technology ◽  
Ball Velocity ◽  
Maximum Effort

Objectives: The variability of throwing metrics, particularly elbow torque and ball velocity, during structured long-toss programs is yet to be fully elucidated. The primary aims of this study were to assess various throwing metrics through a structured long-toss program using wearable technology and to quantify the intra and inter thrower variability of these metrics at each stage of throwing. Methods: This was a descriptive laboratory study in which 60 high school and collegiate pitchers participated in a predetermined, structured, progressive long-toss program. All players wore a motusBASEBALL sleeve (Motus Global, Inc.; Rockville Centre, NY), which measured arm slot, arm velocity, shoulder rotation, and elbow varus torque. Radar guns were used to measure ball velocity. These metrics were compared within and between all pitchers at each of the following throwing distances: 90 ft, 120 ft, 150 ft, 180 ft, and maximum effort mound pitching. Intra- and inter- thrower reliabilities were calculated for each throwing metric at every stage of the program. Excellent intra-thrower reliability was defined by an Intra-class coefficient (ICC) >0.750. Acceptable inter-thrower reliability was defined by a Coefficient of Variation (CV) <5%. Results: Ball velocity significantly changed at each progressive throwing distance, but this did not consistently correlate with an increase in elbow torque. Pitching from the mound did not place more torque on the elbow than throwing from 120 ft and beyond. Intra-thrower reliability was excellent throughout the progressive long-toss program for each throwing metric. Ninety-one percent of throwers had acceptable inter-thrower reliability for ball velocity, whereas only 79% of throwers had acceptable inter-thrower reliability for elbow torque. Conclusion: Based on trends in elbow torque, it may be practical to incorporate pitching from the mound earlier in the program (once a player is comfortable throwing from 120 ft). Ball velocity and elbow torque do not necessarily correlate with one another, so a degree of caution should be exercised when using radar guns to estimate elbow torque. Given the variability in elbow torque between throwers, some athletes would likely benefit from an individualized throwing program.

Relationships between ball speed and arm speed during the volleyball serve in youth elite male players, and why statistical significance might be misleading

2020 ◽  
pp. 175433712097144
Author(s):  
Ricardo Lima ◽  
José Afonso ◽  
Ana Filipa Silva ◽  
Rui Silva ◽  
Filipe Manuel Clemente
Keyword(s):  
Coefficient Of Variation ◽  
Inertial Measurement Unit ◽  
Statistical Significance ◽  
Cross Sectional Study ◽  
Measurement Unit ◽  
Cross Sectional ◽  
Ball Speed ◽  
National Team ◽  
Ball Velocity ◽  
One Way Anova

The purpose of the study was three-fold: (i) to describe ball speed and arm speed during power jump serve in volleyball; (ii) compare the outcomes among playing positions, and (iii) analyze the relationships among outcomes. One middle blocker (MI), three opposites (OP), three setters (S), and six outside hitters or receiver-attackers (RA) youth elite volleyball players from the French national team participated in this study. This cross-sectional study analyzed the ball and arm speeds while serving over two consecutive weeks. A total of 150 valid power speed serves (ball speed = 103.0 ± 7.0 km h−1; arm speed = 40.0 ± 4.2 km h−1) were recorded during the six training sessions using a radar-gun and an inertial measurement unit. Ball speed varied from 90 to 110 km h−1, while the coefficient of variation ranged from 1.5% to 7.5%. Arm speed varied between 35 and 45 km h−1, while the coefficient of variation ranged between 2 and 14%. One-way ANOVA revealed significant differences among playing positions for the variables of ball speed ( p = 0.018), arm speed ( p = 0.019) and ratio of ball to arm speed ( p = 0.002). Very large correlations between arm speed and the ratio of ball speed to arm speed were found ( r = −0.77 [−0.83; −0.69]; p ≤ 0.001). The results suggest that players reduce their variability regarding the outcome. Finally, despite being related, the velocity of the arm and ball were not perfectly correlated. Thus, measuring both the arm and ball velocity may be necessary.

scholarly journals Validity and Sensitivity of an Inertial Measurement Unit-Driven Biomechanical Model of Motor Variability for Gait

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7690
Author(s):  
Christopher A. Bailey ◽  
Thomas K. Uchida ◽  
Julie Nantel ◽  
Ryan B. Graham
Keyword(s):  
Dynamic Stability ◽  
Inertial Measurement Unit ◽  
Joint Angle ◽  
Intraclass Correlation ◽  
Biomechanical Model ◽  
Measurement Unit ◽  
Local Dynamic ◽  
Motor Variability ◽  
Inertial Measurement ◽  
Local Dynamic Stability

Motor variability in gait is frequently linked to fall risk, yet field-based biomechanical joint evaluations are scarce. We evaluated the validity and sensitivity of an inertial measurement unit (IMU)-driven biomechanical model of joint angle variability for gait. Fourteen healthy young adults completed seven-minute trials of treadmill gait at several speeds and arm swing amplitudes. Trunk, pelvis, and lower-limb joint kinematics were estimated by IMU- and optoelectronic-based models using OpenSim. We calculated range of motion (ROM), magnitude of variability (meanSD), local dynamic stability (λmax), persistence of ROM fluctuations (DFAα), and regularity (SaEn) of each angle over 200 continuous strides, and evaluated model accuracy (RMSD: root mean square difference), consistency (ICC2,1: intraclass correlation), biases, limits of agreement, and sensitivity to within-participant gait responses (effects of speed and swing). RMSDs of joint angles were 1.7–7.5° (pooled mean of 4.8°), excluding ankle inversion. ICCs were mostly good to excellent in the primary plane of motion for ROM and in all planes for meanSD and λmax, but were poor to moderate for DFAα and SaEn. Modelled speed and swing responses for ROM, meanSD, and λmax were similar. Results suggest that the IMU-driven model is valid and sensitive for field-based assessments of joint angle time series, ROM in the primary plane of motion, magnitude of variability, and local dynamic stability.

scholarly journals Can Machine Learning with IMUs Be Used to Detect Different Throws and Estimate Ball Velocity in Team Handball?

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2288
Author(s):  
Roland van den Tillaar ◽  
Shruti Bhandurge ◽  
Tom Stewart
Keyword(s):  
Machine Learning ◽  
Injury Prevention ◽  
Inertial Measurement Unit ◽  
Measurement Unit ◽  
Prevention Strategies ◽  
Inertial Measurement ◽  
Automated Method ◽  
Team Handball ◽  
Different Types ◽  
Ball Velocity

Injuries in handball are common due to the repetitive demands of overhead throws at high velocities. Monitoring workload is crucial for understanding these demands and improving injury-prevention strategies. However, in handball, it is challenging to monitor throwing workload due to the difficulty of counting the number, intensity, and type of throws during training and competition. The aim of this study was to investigate if an inertial measurement unit (IMU) and machine learning (ML) techniques could be used to detect different types of team handball throws and predict ball velocity. Seventeen players performed several throws with different wind-up (circular and whip-like) and approach types (standing, running, and jumping) while wearing an IMU on their wrist. Ball velocity was measured using a radar gun. ML models predicted peak ball velocity with an error of 1.10 m/s and classified approach type and throw type with 80–87% accuracy. Using IMUs and ML models may offer a practical and automated method for quantifying throw counts and classifying the throw and approach types adopted by handball players.

scholarly journals Evaluation of head posture using an inertial measurement unit

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mustafa Al-Yassary ◽  
Kelly Billiaert ◽  
Gregory S. Antonarakis ◽  
Stavros Kiliaridis
Keyword(s):  
Inertial Measurement Unit ◽  
Electronic Device ◽  
Intraclass Correlation ◽  
Measurement Unit ◽  
Index Test ◽  
In Vitro Test ◽  
Inertial Measurement ◽  
Head Posture

AbstractAn inertial measurement unit (IMU) is an electronic device that measures and track the orientation of a body. We conducted this study in accordance with the STARD guidelines to evaluate the accuracy of IMU (index test) for measuring head posture compared to the current gold standard using a cervical range of motion (CROM) device. The reproducibility of the hunter and mirror-guided head posture was also evaluated. In vitro and in vivo tests were carried out to assess the validity of the IMU. To assess reproducibility, thirty healthy young adults were asked to look at four different locations in two different sessions while the head posture was recorded. Excellent correlation (r = 0.99; p < 0.001) was found between the IMU and CROM device with an absolute mean difference of 0.45° ± 0.58° (p = 0.85) for the in vitro test and 0.88° ± 1.20° (p = 0.99) for the in vivo test. For the reproducibility test, moderate to good correlation coefficients were found (r = 0.55 to 0.89; all p < 0.05) between the two sessions. The intraclass correlation coefficient ranged from moderate to excellent reliability (ICC from 0.74 to 0.96). These results suggest that the IMU sensors, when calibrated correctly, can be adequate to analyze head posture.

Sign in / Sign up

Export Citation Format

Share Document