scholarly journals Measurement of Flight Dynamics of a Frisbee Using a Triaxial MEMS Gyroscope

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 66
Author(s):  
Yehuda Weizman ◽  
Adin Ming Tan ◽  
Franz Konstantin Fuss
Keyword(s):  
Drag Force ◽  
Angular Acceleration ◽  
Flight Dynamics ◽  
Peak Torque ◽  
Power Input ◽  
Mems Gyroscope ◽  
Damping Effect ◽  
Measurement Limit ◽  
Before And After ◽  
Angular Velocities

A Frisbee with a mass of 0.21 kg, diameter of 0.27 m and moment of inertia (MOI) of 0.002 kg·m2 was instrumented with a triaxial gyroscope. The Frisbee was thrown at low angular velocities as the measurement limit of a single gyroscope was at 6.065 rps. The angular velocities of the triaxial gyroscope were analysed to study the attitude of a Frisbee before and after release. The angular velocities measured were post-processed and the following data were obtained: spin rate at release—3.9–6.14 rps; user-induced peak torque—0.483–0.9 Nm, and peak angular acceleration—204–358 rad/s2; and power input 7.53–19.56 W. The Frisbee wobbled at release which decreased during the flight due to a damping effect. This affected the spin decay, the reduction of wobble lead to a reduced drag force and thus to a smaller spin decay, which was initially 1.12–0.31 rev/s2 and then asymptoted to 0.11–0.01 rev/s2.

scholarly journals Acute Effects of Proprioceptive Neuromuscular Facilitation on Peak Torque and Muscle Imbalance

2018 ◽  
Vol 3 (4) ◽  
pp. 63 ◽  
Author(s):  
Cassio Ruas ◽  
Ryan McManus ◽  
Claudio Bentes ◽  
Pablo Costa
Keyword(s):  
Body Mass ◽  
Injury Risk ◽  
Peak Torque ◽  
Knee Extension ◽  
Acute Effects ◽  
Muscle Imbalance ◽  
Proprioceptive Neuromuscular Facilitation ◽  
Before And After ◽  
Angular Velocities ◽  
Muscle Actions

Background: The effects of proprioceptive neuromuscular facilitation (PNF) stretching on muscle imbalance are not fully understood. The aim of this study was to examine the acute effects of PNF stretching on knee extension and flexion peak torque (PT), as well as the conventional and functional hamstrings to quadriceps (H:Q) ratios. Methods: Fifteen men (age = 22 ± 1 years; body mass = 76 ± 12 kg; height = 176 ± 7 cm) and fifteen women (age = 22 ± 2 years; body mass = 63 ± 8 kg; height = 161 ± 5 cm) performed concentric quadriceps and hamstrings, and eccentric hamstrings muscle actions at different angular velocities (60, 180, and 300°·s−1 concentric; 60 and 180°·s−1 eccentric) before and after a bout of PNF stretching, and a control condition. Results: Neither PNF or control conditions affected concentric PT or H:Q ratios (p > 0.05), apart from knee extension at 60°·s−1 in men (p = 0.001). However, there was a reduction in hamstrings eccentric PT in both control and PNF conditions for men and women (p = 0.003). Conclusions: PNF stretching of the hamstrings may not adversely affect the H:Q ratios, and consequently not negatively affect injury risk associated with muscular strength imbalances.

scholarly journals Comparison of upper body strength gains between men and women after 10 weeks of resistance training

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1627 ◽  
Author(s):  
Paulo Gentil ◽  
James Steele ◽  
Maria C. Pereira ◽  
Rafael P.M. Castanheira ◽  
Antonio Paoli ◽  
...  
Keyword(s):  
Resistance Training ◽  
Peak Torque ◽  
Elbow Flexor ◽  
Upper Body ◽  
Men And Women ◽  
Body Strength ◽  
Before And After ◽  
Upper Body Strength ◽  
Few Data ◽  
Flexor Strength

Resistance training (RT) offers benefits to both men and women. However, the studies about the differences between men and women in response to an RT program are not conclusive and few data are available about upper body strength response. The aim of this study was to compare elbow flexor strength gains in men and women after 10 weeks of RT. Forty-four college-aged men (22.63 ± 2.34 years) and forty-seven college-aged women (21.62 ± 2.96 years) participated in the study. The RT program was performed two days a week for 10 weeks. Before and after the training period, peak torque (PT) of the elbow flexors was measured with an isokinetic dynamometer. PT values were higher in men in comparison to women in pre- and post-tests (p< 0.01). Both males and females significantly increased elbow flexor strength (p< 0.05); however, strength changes did not differ between genders after 10 weeks of RT program (11.61 and 11.76% for men and women, respectively;p> 0.05). Effect sizes were 0.57 and 0.56 for men and women, respectively. In conclusion, the present study suggests that men and women have a similar upper body strength response to RT.

scholarly journals The effects of phosphocreatine disodium salts plus blueberry extract supplementation on muscular strength, power, and endurance

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
John Paul V. Anders ◽  
Tyler J. Neltner ◽  
Robert W. Smith ◽  
Joshua L. Keller ◽  
Terry J. Housh ◽  
...  
Keyword(s):  
Placebo Group ◽  
Exercise Performance ◽  
Muscular Strength ◽  
Minimal Important Difference ◽  
Average Power ◽  
Creatine Supplementation ◽  
Peak Torque ◽  
Before And After ◽  
Group A ◽  
Percent Decline

Abstract Background Numerous studies have demonstrated the efficacy of creatine supplementation for improvements in exercise performance. Few studies, however, have examined the effects of phosphocreatine supplementation on exercise performance. Furthermore, while polyphenols have antioxidant and anti-inflammatory properties, little is known regarding the influence of polyphenol supplementation on muscular strength, power, and endurance. Thus, the purpose of the present study was to compare the effects of 28 days of supplementation with phosphocreatine disodium salts plus blueberry extract (PCDSB), creatine monohydrate (CM), and placebo on measures of muscular strength, power, and endurance. Methods Thirty-three men were randomly assigned to consume either PCDSB, CM, or placebo for 28 days. Peak torque (PT), average power (AP), and percent decline for peak torque (PT%) and average power (AP%) were assessed from a fatigue test consisting of 50 maximal, unilateral, isokinetic leg extensions at 180°·s− 1 before and after the 28 days of supplementation. Individual responses were assessed to examine the proportion of subjects that exceeded a minimal important difference (MID). Results The results demonstrated significant (p < 0.05) improvements in PT for the PCDSB and CM groups from pre- (99.90 ± 22.47 N·m and 99.95 ± 22.50 N·m, respectively) to post-supplementation (119.22 ± 29.87 N·m and 111.97 ± 24.50 N·m, respectively), but no significant (p = 0.112) change for the placebo group. The PCDSB and CM groups also exhibited significant improvements in AP from pre- (140.18 ± 32.08 W and 143.42 ± 33.84 W, respectively) to post-supplementation (170.12 ± 42.68 W and 159.78 ± 31.20 W, respectively), but no significant (p = 0.279) change for the placebo group. A significantly (p < 0.05) greater proportion of subjects in the PCDSB group exceeded the MID for PT compared to the placebo group, but there were no significant (p > 0.05) differences in the proportion of subjects exceeding the MID between the CM and placebo groups or between the CM and PCDSB groups. Conclusions These findings indicated that for the group mean responses, 28 days of supplementation with both PCDSB and CM resulted in increases in PT and AP. The PCDSB, however, may have an advantage over CM when compared to the placebo group for the proportion of individuals that respond favorably to supplementation with meaningful increases in muscular strength.

Two Stretching Treatments for the Hamstrings: Proprioceptive Neuromuscular Facilitation Versus Kinesio Taping

2013 ◽  
Vol 22 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Che-Hsiu Chen ◽  
Tsun-Shun Huang ◽  
Huei-Ming Chai ◽  
Mei-Hwa Jan ◽  
Jiu-Jenq Lin
Keyword(s):  
Outcome Measures ◽  
Peak Torque ◽  
Muscle Stiffness ◽  
Muscle Performance ◽  
Static Stretch ◽  
Kinesio Taping ◽  
Negative Results ◽  
Significant Difference ◽  
Proprioceptive Neuromuscular Facilitation ◽  
Before And After

Context:Recent studies have shown that the static stretch (SS) may adversely affect leg-muscle performance.Objectives:The authors examined the short-term effects of 2 stretching exercises on hamstrings muscle before and after exercise.Design:Crossover.Setting:Laboratory.Participants:9 healthy, physically active men.Interventions:There were 3 protocols in a randomized order with a 7-d interval: nonstretching (CON protocol), hamstrings static stretching (SS) with proprioceptive neuromuscular facilitation (PNF), and SS with kinesio-taping application on the hamstrings.Main Outcome Measures:Outcome measures included first-felt and maximum tolerant-felt range of motion (FROM and TROM), maximal knee-flexion peak torque (PT) at 180°/s, and hamstrings muscle stiffness.Results:Groups were not different at prestretching in terms of hamstrings flexibility, PT, and muscle stiffness. At poststretching, both stretching protocols showed significant increases in FROM and TROM (P < .05). Stiffer hamstrings muscle and decreased PT were found in both SS+PNF and CON protocols (P < .05). However, there was no significant difference in the SS+Taping protocol (P > .05).Conclusion:The stretching protocols improve hamstrings flexibility immediately, but after exercise hamstrings peak torque is diminished in the SS+PNF but not in the SS+Taping group. This means that SS+Taping can prevent negative results from exercise, which may prevent muscle injury.

Gyroscope-Free Link Parameter Measurement Using Accelerometers and Magnetometer

2014 ◽  
Author(s):  
Vishesh Vikas ◽  
Carl D. Crane
Keyword(s):  
Angular Velocity ◽  
Joint Angle ◽  
Inertial Sensors ◽  
Angular Acceleration ◽  
Parameter Measurement ◽  
Joint Angles ◽  
Symmetry Constraint ◽  
Estimation Techniques ◽  
Angular Velocities ◽  
Joint Parameters

Knowledge of joint angles, angular velocities is essential for control of link mechanisms and robots. The estimation of joint angles and angular velocity is performed using combination of inertial sensors (accelerometers and gyroscopes) which are contactless and flexible at point of application. Different estimation techniques are used to fuse data from different inertial sensors. Bio-inspired sensors using symmetrically placed multiple inertial sensors are capable of instantaneously measuring joint parameters (joint angle, angular velocities and angular acceleration) without use of any estimation techniques. Calibration of inertial sensors is easier and more reliable for accelerometers as compared to gyroscopes. The research presents gyroscope-less, multiple accelerometer and magnetometer based sensors capable of measuring (not estimating) joint parameters. The contribution of the improved sensor are four-fold. Firstly, the inertial sensors are devoid of symmetry constraint unlike the previously researched bio-inspired sensors. However, the accelerometer are non-coplanarly placed. Secondly, the accelerometer-magnetometer combination sensor allows for calculation of a unique rotation matrix between two link joined by any kind of joint. Thirdly, the sensors are easier to calibrate as they consist only of accelerometers. Finally, the sensors allow for calculation of angular velocity and angular acceleration without use of gyroscopes.

Isokinetic Strength Profiles of Thigh Muscles of Modern Dancers in Relation to Their Experience Level

2013 ◽  
Vol 28 (3) ◽  
pp. 137-144
Author(s):  
Ani Agopyan ◽  
Demet Tekin ◽  
Mehmet Unal ◽  
Hizir Kurtel ◽  
Gullu Turan ◽  
...  
Keyword(s):  
Body Weight ◽  
Peak Torque ◽  
Thigh Muscle ◽  
Isokinetic Strength ◽  
Total Work ◽  
Isokinetic Dynamometer ◽  
Experience Level ◽  
Strength Tests ◽  
Angular Velocities ◽  
Modern Dancers

The aim of this study was to determine maximal voluntary peak torque (PT), PT% body weight (PT%BW), total work (TW), and hamstring/quadriceps ratio (HQR) for bilateral and unilateral thigh muscle strength during isokinetic muscle contractions in modern dancers in relation to their experience level. METHODS: Twenty-two female dancers were divided into two groups: intermediate dancers (ID, n=11) and advanced dancers (AD, n=11). Strength tests were performed using the Biodex System-III Pro Multijoint System isokinetic dynamometer to determine three joint angular velocities (60, 180, 300°/s). RESULTS: During extension, ADs exhibited higher ratios in the HQR (p=0.016) on right leg at 300°/s, IDs generated greater TW (p=0.042), and within groups, there was a significant left-to-right difference in the HQR at 300°/s for ADs (p=0.042). During flexion, within groups, the ADs exhibited significant differences between legs for both PT (p=0.026) and PT%BW (p=0.022) at 300°/s. CONCLUSION: For both groups, the average HQR in all angular velocities was not within the recommended range, which is required to prevent injuries; at the same time, unilateral muscular imbalances existed. Lower extremities of ADs exhibited asymmetric strength patterns at a certain level. Further research should be done to confirm the findings of this pilot study.

Can Hip Joint Position affect Quadriceps Muscle Responses during Knee Extension Exercise?

2020 ◽  
Vol 41 (13) ◽  
pp. 929-935
Author(s):  
Denis César Leite Vieira ◽  
Marco Aurélio Araujo Dourado ◽  
Lucas Ugliara ◽  
Joao Luiz Quagliotti Durigan ◽  
Brad J. Schoenfeld ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Knee Extensors ◽  
Work Output ◽  
Before And After ◽  
Knee Extension Exercise

AbstractThis study investigated the acute effects of seated and supine knee extension exercise on muscle swelling, torque, and work output. Twelve resistance-trained men performed two isokinetic concentric-only knee-extension training protocols at different hip positions in a counter-balanced order. They completed the knee extension exercise in the seated (hip angle at 85°) and supine (hip angle at 180°) positions. The torque and work output were assessed during each set. Moreover, muscle thickness of the middle and proximal vastus lateralis and rectus femoris were evaluated before and after each protocol and used as an indicator of muscle swelling. Middle rectus femoris and proximal vastus lateralis thickness increased significantly (p=0.01) with no difference between exercise variations. However, the middle vastus lateralis thickness increased (p=0.01) only after the seated knee extension exercise (~7%). Knee extensors’ peak torque and work output were approximately 8% higher (p=0.04) in the seated when compared to the supine hip position. There was a similar decrease in torque and work output throughout both protocols (p=0.98). In conclusion, seated knee extension exercises produced greater torque, work output, and muscle swelling in the vastus lateralis when compared to the supine knee extension exercise.

scholarly journals Isokinetic Strength Profile of Elite Female Handball Players

2015 ◽  
Vol 49 (1) ◽  
pp. 257-266 ◽  
Author(s):  
Zuzana Xaverova ◽  
Johannes Dirnberger ◽  
Michal Lehnert ◽  
Jan Belka ◽  
Herbert Wagner ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Peak Torque ◽  
Systematic Assessment ◽  
Risk Of Injury ◽  
Training Cycle ◽  
Isokinetic Muscle Strength ◽  
Angular Velocities ◽  
Individual Evaluation ◽  
Knee Flexors ◽  
Flexion And Extension

Abstract Systematic assessment of muscle strength of the lower extremities throughout the annual training cycle in athletes is crucial from a performance perspective for the optimization of the training process, as well as a health perspective with regard to injury prevention. The main aim of the present study was to determine isokinetic muscle strength of the knee flexors and extensors in female handball players at the beginning of a preparatory period and to assess whether there were any differences between players of different performance levels. The performance level was expressed by means of membership of the Women’s Junior National Handball Team (JNT, n=8) or the Women’s National Handball Team (NT, n=9). The isokinetic peak torque during concentric and eccentric single-joint knee flexion and extension was measured at angular velocities of 60, 180, 240°/s (concentric) and 60°/s (eccentric). The Mann- Whitney test showed no significant differences in the peak torques or ipsilateral ratios between the two groups. The bilateral force deficit (BFD) for concentric extension at 240°/s was significantly higher in the JNT compared with the NT (p=0.04; d=1.02). However, the results of individual evaluation show that the BFD was more frequent in the NT in most measurements. A high BFD was evident in the eccentric mode in both groups highlighting a need for particular strengthening. With regard to low strength ratios a prevention programme should be suggested for both observed groups of professional female handball players to reduce the risk of injury.

scholarly journals Pelvic floor muscle training decreases hip adductors isometric peak torque in incontinent women: an exploratory study

2013 ◽  
Vol 26 (1) ◽  
pp. 183-190 ◽  
Author(s):  
Grasiéla Nascimento Correia ◽  
Cristine Homsi Jorge Ferreira ◽  
Mariana Chaves Aveiro ◽  
Vanessa Santos Pereira ◽  
Patricia Driusso
Keyword(s):  
Urinary Incontinence ◽  
Pelvic Floor ◽  
Exploratory Study ◽  
Pelvic Floor Muscle ◽  
Peak Torque ◽  
Physically Active ◽  
Pad Test ◽  
Digital Evaluation ◽  
Before And After ◽  
Dominant Side

INTRODUCTION: The pelvic floor muscle (PFM) training is the most common treatment for urinary incontinence (UI), however many women performed the contraction of PFM with associated contraction of abdominal, gluteus and hip adductors muscles. OBJECTIVE: To assess the effects of pelvic floor muscle (PFM) training on isometric and isokinetic hip adductors peak torque (PT) among women suffering from urinary incontinence (UI). MATERIALS AND METHODS: It is a longitudinal and prospective exploratory study. This study included 15 physically active women aged 45 years old and over, who presented complaints of UI. The PFM function (digital evaluation and perineometry), isometric and isokinetic hip adductors PT and one hour pad test were performed before and after treatment. The PFM training was performed in group, one hour once a week for 12 sessions. RESULTS: Significant improvement of PFM function and pressure level (p = 0.003), and significant decrease of hip adductors isometric PT and one-hour pad test, were found post-treatment. Moderate negative correlations between PFM contraction pressure and hip adductors isokinetic PT for dominant side (DS) (r = -0.62; p = 0.03) and non-dominant side (NDS) (r = -0.64; p = 0.02); and between PFM fast fibers contraction and hip adductors isometric PT for DS (r = -0.60; p = 0.03) and NDS (r = -0.59; p = 0.04) were also found. CONCLUSIONS: The PFM training decreased hip adductors PT and improved PFM functions and UI.

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