scholarly journals Wheelchair Mobility Performance Enhancement by Changing Wheelchair Properties: What Is the Effect of Grip, Seat Height, and Mass?

2018 ◽  
Vol 13 (8) ◽  
pp. 1050-1058 ◽  
Author(s):  
Rienk M.A. van der Slikke ◽  
Annemarie M.H. de Witte ◽  
Monique A.M. Berger ◽  
Daan J.J. Bregman ◽  
Dirk Jan H.E.J. Veeger
Keyword(s):  
Performance Enhancement ◽  
Inertial Sensor ◽  
Wheelchair Basketball ◽  
Additional Mass ◽  
Seat Height ◽  
Performance Effect ◽  
Mobility Performance ◽  
Sport Practice ◽  
Performance Effects ◽  
Low Mass

Purpose: To provide insight on the effect of wheelchair settings on wheelchair mobility performance (WMP). Methods: Twenty elite wheelchair basketball athletes of low (n = 10) and high classification (n = 10) were tested in a wheelchair-basketball-directed field test. Athletes performed the test in their own wheelchairs, which were modified for 5 additional conditions regarding seat height (high–low), mass (central–distributed), and grip. The previously developed inertial-sensor-based WMP monitor was used to extract wheelchair kinematics in all conditions. Results: Adding mass showed most effect on WMP, with a reduced average acceleration across all activities. Once distributed, additional mass also reduced maximal rotational speed and rotational acceleration. Elevating seat height had an effect on several performance aspects in sprinting and turning, whereas lowering seat height influenced performance minimally. Increased rim grip did not alter performance. No differences in response were evident between low- and high-classified athletes. Conclusions: The WMP monitor showed sensitivity to detect performance differences due to the small changes in wheelchair configuration. Distributed additional mass had the most effect on WMP, whereas additional grip had the least effect of conditions tested. Performance effects appear similar for both low- and high-classified athletes. Athletes, coaches, and wheelchair experts are provided with insight into the performance effect of key wheelchair settings, and they are offered a proven sensitive method to apply in sport practice, in their search for the best wheelchair–athlete combination.

The Performance Effect of Centralizing a Nation’s Elite Swim Program

2015 ◽  
Vol 10 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Sian V. Allen ◽  
Tom J. Vandenbogaerde ◽  
Will G. Hopkins
Keyword(s):  
New Zealand ◽  
Mixed Model ◽  
Performance Enhancement ◽  
Mixed Linear Model ◽  
Confidence Limits ◽  
Performance Effect ◽  
Important Improvement ◽  
Performance Trends ◽  
Performance Effects ◽  
Long Course

Many national sporting organizations recruit talented athletes to well-resourced centralized training squads to improve their performance.Purpose: To develop a method to monitor performance progression of swimming squads and to use this method to assess the progression of New Zealand’s centralized elite swimming squad.Methods: Best annual long-course competition times of all New Zealand swimmers with at least 3 y of performances in an event between 2002 and 2013 were downloaded from takeyourmarks.com (~281,000 times from ~8500 swimmers). A mixed linear model accounting for event, age, club, year, and elite-squad membership produced estimates of mean annual performance for 175 swim clubs and mean estimates of the deviation of swimmers’ performances from their individual quadratic trajectories after they joined the elite squad. Effects were evaluated using magnitude-based inferences, with a smallest important improvement in swim time of –0.24%.Results: Before 2009, effects of elite-squad membership were mostly unclear and trivial to small in magnitude. Thereafter, both sexes showed clear additional performance enhancements, increasing from large in 2009 (males –1.4% ± 0.8%, females –1.5% ± 0.8%; mean ± 90% confidence limits) to extremely large in 2013 (males –6.8% ± 1.7%, females –9.8% ± 2.9%). Some clubs also showed clear performance trends during the 11-y period.Conclusions: Our method of quantifying deviations from individual trends in competition performance with a mixed model showed that Swimming New Zealand’s centralization strategy took several years to produce substantial performance effects. The method may also be useful for evaluating performance-enhancement strategies introduced at national or club level in other sports.

scholarly journals Effects of seat height, wheelchair mass and additional grip on a field-based wheelchair basketball mobility performance test

2020 ◽  
Vol 32 (2) ◽  
pp. 93-102 ◽  
Author(s):  
A.M.H. de Witte ◽  
R.M.A. van der Slikke ◽  
M.A.M. Berger ◽  
M.J.M. Hoozemans ◽  
H.E.J. Veeger ◽  
...  
Keyword(s):  
Performance Test ◽  
Wheelchair Basketball ◽  
Seat Height ◽  
Mobility Performance

scholarly journals Spinoffs’ alliance network growth beyond parental ties: performance diminishing, then performance enhancing

2022 ◽  
Author(s):  
Forough Zarea Fazlelahi ◽  
J. Henri Burgers ◽  
Martin Obschonka ◽  
Per Davidsson
Keyword(s):  
Strategic Alliances ◽  
Mining Industry ◽  
Adjustment Costs ◽  
Theory And Practice ◽  
Time Lags ◽  
Network Growth ◽  
Performance Effect ◽  
Alliance Networks ◽  
Alliance Network ◽  
Performance Effects

Abstract Spinoff firms are a common phenomenon in entrepreneurship where employees leave incumbent parent firms to found their own. Like other types of new firms, such new spinoffs face liabilities of newness and smallness. Previous research has emphasised the role of the initial endowments from their parent firm to overcome such liabilities. In this study, we argue and are the first to show, that, in addition to such endowments, growing an alliance network with firms other than their parents’ is also critical for spinoff performance. Specifically, we investigate the performance effect of alliance network growth in newly founded spinoffs using a longitudinal sample of 248 spinoffs and 3370 strategic alliances in the mining industry. Drawing on theory based on the resource adjustment costs of forming alliances, we posit and find a U-shaped relationship between the alliance network growth and spinoff performance, above and beyond the parent firm’s influence. We further hypothesise and find that performance effects become stronger with increased time lags between alliance network growth and spinoff performance, and when spinoffs delay growing their alliance networks. Implications for theory and practice are discussed.

scholarly journals The Performance Effects of Squeeze Film Stiffness on Non-Resonate Interferometric Inertial Sensors

2007 ◽  
Author(s):  
Maximillian A. Perez ◽  
Andrei M. Shkel
Keyword(s):  
Inertial Sensors ◽  
Inertial Sensor ◽  
Film Theory ◽  
Nonlinear Effects ◽  
Squeeze Film ◽  
Nonlinear Frequency ◽  
Reduced Pressure ◽  
Performance Effects ◽  
Film Stiffness ◽  
Kinetic Gas Theory

This paper studies the nonlinear effects of squeeze film stiffening on the performance of a high resolution MEMS nonresonant inertial sensor. It is shown that these effects introduce a surprising dynamic response that extends the operational frequency range of the devices by retarding the resonate response. In addition, this performance advantage will occur without the traditional gain trade-off associated with linear systems of this type. A method is introduced to experimentally characterize the squeeze film stiffness of a passive inertial sensor through the resonant characterization of a Fabry-Pe´rot interferometric accelerometer under reduced pressure. Such passive devices are uniquely suited for the study of squeeze films and, due to the dependence of both the sensitivity and bandwidth on the device structural stiffness, variation of the stiffness with frequency must be considered to accurately predict sensor performance. The characterization confirms established analytical squeeze film stiffness theory in the continuous gas regime for conditions of Knudsen numbers less then one. As the Knudsen number equal to one is approached, it is shown that ideal kinetic gas theory and continuous squeeze film theory converge yielding a simplified stiffness estimate under the resonant response under reduced pressure. These analytical results are used to predict the performance gains due to the nonlinear, frequency dependent total stiffness of the sensor during non-resonant operation.

Multinationality and performance effects: an integrated theory of new patterns of multinationality and home political influence

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
I-Fan Yen ◽  
Hsin-Mei Lin
Keyword(s):  
Multinational Enterprises ◽  
Positive Relationship ◽  
Political Influence ◽  
Superior Performance ◽  
Foreign Investments ◽  
Content Type ◽  
Performance Effect ◽  
Performance Effects ◽  
And Performance ◽  
The Relationship

Purpose This paper aims to develop an integrated perspective on the relationship between multinationality and performance in the outward foreign direct investment (OFDI) of Chinese firms. The study not only represents contrasting OFDI patterns – namely, born global-natured multiple synchronous foreign investments versus conventional internationalization process (IP)-natured steady increasing foreign investments – but also contributes to understanding the extent to which explanations of home political influence need to be rooted within the general theory of multinationality. Design/methodology/approach By testing a comprehensive panel observation of 8,635 OFDI projects from 1991-2016 in China, this study found that multinationality with the new pattern of multiple synchronous OFDIs has a superior performance effect compared with the conventional pattern of steady increasing OFDIs. Findings This study also finds a positive relationship between multinationality (international diversification and home political influence) and the performance effect with the new pattern of multiple synchronous OFDIs, as well as a partial positive relationship between multinationality and the performance effect with the conventional pattern of steady increasing OFDIs. Research limitations/implications The study extends the understanding of the performance effects of Chinese multinational enterprises, which may benefit more from the new pattern of multiple synchronous OFDIs than from the conventional pattern of steady increasing OFDIs when the home-country institution is strongly positioned. Originality/value This paper concludes that multinationality needs an integrated framework that accounts for the new pattern of OFDI and the influence of diversification and home politics, particularly for the emerging country, China.

scholarly journals Sensitivity to change of the field-based Wheelchair Mobility Performance Test in wheelchair basketball

2018 ◽  
Vol 50 (6) ◽  
pp. 556-562 ◽  
Author(s):  
A Witte ◽  
F Sjaarda ◽  
J Helleman ◽  
M Berger ◽  
L Woude ◽  
...  
Keyword(s):  
Performance Test ◽  
Sensitivity To Change ◽  
Wheelchair Basketball ◽  
Mobility Performance

When Children’s Perceived and Actual Motor Competence Mismatch: Sport Participation and Gender Differences

2018 ◽  
Vol 6 (s2) ◽  
pp. S440-S460 ◽  
Author(s):  
Caterina Pesce ◽  
Ilaria Masci ◽  
Rosalba Marchetti ◽  
Giuseppe Vannozzi ◽  
Mirko Schmidt
Keyword(s):  
Motor Development ◽  
Sport Participation ◽  
Inertial Sensor ◽  
Perceived Competence ◽  
Added Value ◽  
Motor Competence ◽  
Object Control ◽  
Sport Practice ◽  
And Gender ◽  
Motor Skill Competence

This study examined the (mis)match between children’s perceived and actual motor skill competence, the role played by sport practice and gender when children under- or overestimate their motor competence, and the biomechanical correlates of perceived competence and perceived–actual competence (mis)match. Ninety children aged 7.5±1.2 years performed the Tests of Gross Motor Development-2 (TGMD-2), with a subsample of 44 children wearing inertial sensor devices for objective measurement of running and throwing, and completed the Pictorial Scale of Perceived Movement Skill Competence. Scores of perceived locomotor and object control competence were regressed on TGMD data. Underestimators (UE), realists (R), and overestimators (OE) were identified and it was assessed whether they differed in gender, amount of sport practice, and selected biomechanical parameters. Differences emerged with respect to gender, with most girls underestimating and most boys overestimating their object control competence, and with respect to sport participation, with OE of locomotor competence practicing a larger amount of sport than UE. Some kinematic parameters were associated with perceived competence without differences between UE, R, and OE. Results suggest: (a) the need for specific motivation strategies to ensure a skill-appropriate enhancement of perceived competence in girls; (b) the relevance of feeling skilled for sport practice; (c) the added value of biomechanical assessment to further our understanding of perceived motor competence.

scholarly journals Correlations Between Medicine Ball Throw With Wheelchair Mobility and Isokinetic Tests in Basketball Para-Athletes

2021 ◽  
pp. 1-5
Author(s):  
Frederico Ribeiro Neto ◽  
Irineu Loturco ◽  
Guilherme Henrique Lopes ◽  
Jefferson Rodrigues Dorneles ◽  
José Irineu Gorla ◽  
...  
Keyword(s):  
Female Athletes ◽  
Field Tests ◽  
Peak Torque ◽  
Cross Sectional Study ◽  
Wheelchair Basketball ◽  
Basketball Players ◽  
Cross Sectional ◽  
Male And Female ◽  
Mobility Performance ◽  
Medicine Ball

Context: A detailed analysis of wheelchair basketball skills in beginner wheelchair basketball players (WBP) can provide practitioners with important indications regarding the selection and prospective development of potential sports talents. A comprehensive WBP evaluation can be very time consuming, mainly during the initial phases of the training processes, which could be a barrier in clinical and practical settings. Moreover, the large number and the turnover of beginner WBP attending rehabilitation centers make the applicability of field and strength tests unfeasible. Objective: To verify the relationships between the medicine ball throw (MBT) and wheelchair basketball mobility performance field tests and the shoulder and trunk peak torque in male and female beginner WBP. Design: Cross-sectional study. Setting: Rehabilitation Hospital Network, Paralympic Program. Participants: Thirty-seven female and male beginner WBP. Main Outcomes Measures: Participants performed wheelchair basketball field tests (speed, agility, strength, and power tests) and the maximum strength test in the isokinetic dynamometer. The outcomes were correlated with the MBT results. Results: The MBT presented significantly very high and perfect correlations with all wheelchair basketball field tests assessed (5-m sprint, 20-m sprint, and zig-zag agility test with and without a ball), and peak torque (R2 ranging from .810 to .995; P ≤ .05) for male and female athletes. Conclusions: The MBT, a simple and feasible test, can be used for estimating and determining the wheelchair mobility performance of female and male beginner WBP. It is suggested to measure the distance of a 5-kg medicine ball thrown by athletes during training and testing routines to follow the players’ progression.

scholarly journals Wearable Wheelchair Mobility Performance Measurement in Basketball, Rugby, and Tennis: Lessons for Classification and Training

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3518 ◽  
Author(s):  
Rienk M. A. van der Slikke ◽  
Monique A. M. Berger ◽  
Daan J. J. Bregman ◽  
Dirkjan H. E. J. Veeger
Keyword(s):  
Technology Use ◽  
National Level ◽  
Classification Systems ◽  
Wheelchair Basketball ◽  
Individual Level ◽  
Wheelchair Rugby ◽  
Mobility Performance ◽  
Wheelchair Sports ◽  
Further Development ◽  
And Training

Athlete impairment level is an important factor in wheelchair mobility performance (WMP) in sports. Classification systems, aimed to compensate impairment level effects on performance, vary between sports. Improved understanding of resemblances and differences in WMP between sports could aid in optimizing the classification methodology. Furthermore, increased performance insight could be applied in training and wheelchair optimization. The wearable sensor-based wheelchair mobility performance monitor (WMPM) was used to measure WMP of wheelchair basketball, rugby and tennis athletes of (inter-)national level during match-play. As hypothesized, wheelchair basketball athletes show the highest average WMP levels and wheelchair rugby the lowest, whereas wheelchair tennis athletes range in between for most outcomes. Based on WMP profiles, wheelchair basketball requires the highest performance intensity, whereas in wheelchair tennis, maneuverability is the key performance factor. In wheelchair rugby, WMP levels show the highest variation comparable to the high variation in athletes’ impairment levels. These insights could be used to direct classification and training guidelines, with more emphasis on intensity for wheelchair basketball, focus on maneuverability for wheelchair tennis and impairment-level based training programs for wheelchair rugby. Wearable technology use seems a prerequisite for further development of wheelchair sports, on the sports level (classification) and on individual level (training and wheelchair configuration).

scholarly journals Performance effects of periodized carbohydrate restriction in endurance trained athletes – a systematic review and meta-analysis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Kasper Degn Gejl ◽  
Lars Nybo
Keyword(s):  
Acute Exercise ◽  
Meta Analysis ◽  
Endurance Performance ◽  
Endurance Athletes ◽  
Carbohydrate Restriction ◽  
Dietary Interventions ◽  
Major Drawback ◽  
Performance Effect ◽  
Performance Effects ◽  
Physiological Benefits

AbstractEndurance athletes typically consume carbohydrate-rich diets to allow for optimal performance during competitions and intense training. However, acute exercise studies have revealed that training or recovery with low muscle glycogen stimulates factors of importance for mitochondrial biogenesis in addition to favourable metabolic adaptations in trained athletes. Compromised training quality and particularly lower intensities in peak intervals seem to be a major drawback from dietary interventions with chronic carbohydrate (CHO) restriction. Therefore, the concept of undertaking only selected training sessions with restricted CHO availability (periodized CHO restriction) has been proposed for endurance athletes. However, the overall performance effect of this concept has not been systematically reviewed in highly adapted endurance-trained athletes. We therefore conducted a meta-analysis of training studies that fulfilled the following criteria: a) inclusion of females and males demonstrating a VO2max ≥ 55 and 60 ml · kg− 1 · min− 1, respectively; b) total intervention and training periods ≥ 1 week, c) use of interventions including training and/or recovery with periodized carbohydrate restriction at least three times per week, and d) measurements of endurance performance before and after the training period. The literature search resulted in 407 papers of which nine studies fulfilled the inclusion criteria. The subsequent meta-analysis demonstrated no overall effect of CHO periodization on endurance performance compared to control endurance training with normal (high) CHO availability (standardized mean difference = 0.17 [− 0.15, 0.49]; P = 0.29). Based on the available literature, we therefore conclude that periodized CHO restriction does not per se enhance performance in endurance-trained athletes. The review discusses different approaches to CHO periodization across studies with a focus on identifying potential physiological benefits.

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