Variability of PlayerLoad, Bowling Velocity, and Performance Execution in Fast Bowlers Across Repeated Bowling Spells

2015 ◽  
Vol 10 (8) ◽  
pp. 1009-1014 ◽  
Author(s):  
Dean J. McNamara ◽  
Tim J. Gabbett ◽  
Paul Chapman ◽  
Geraldine Naughton ◽  
Patrick Farhart

Purpose:The use of wearable microtechnology to monitor the external load of fast bowling is challenged by the inherent variability of bowling techniques between bowlers. This study assessed the between-bowlers variability in PlayerLoad, bowling velocity, and performance execution across repeated bowling spells.Methods:Seven national-level fast bowlers completed two 6-over bowling spells at a batter during a competitive training session. Key dependent variables were PlayerLoad calculated with a MinimaxX microtechnology unit, ball velocity, and bowling execution based on a predetermined bowling strategy for each ball bowled. The between-bowlers coefficient of variation (CV), repeated-measures ANOVA, and smallest worthwhile change were calculated over the 2 repeated 6-over bowling spells and explored across 12-over, 6-over, and 3-over bowling segments.Results:From the sum of 6 consecutive balls, the between-bowlers CV for relative peak PlayerLoad was 1.2% over the 12-over bowling spell (P = .15). During this 12-over period, bowling-execution (P = .43) scores and ball-velocity (P = .31) CVs were calculated as 46.0% and 0.4%, respectively.Conclusions:PlayerLoad was found to be stable across the repeated bowling spells in the fast-bowling cohort. Measures of variability and change across the repeated bowling spells were consistent with the performance measure of ball velocity. The stability of PlayerLoad improved when assessed relative to the individual’s peak PlayerLoad. Only bowling-execution measures were found to have high variability across the repeated bowling spells. PlayerLoad provides a stable measure of external workload between fast bowlers.

2002 ◽  
Vol 10 (4) ◽  
pp. 489-503 ◽  
Author(s):  
George J. Salem ◽  
Man-Ying Wang ◽  
Susan Sigward

In order to obtain joint-specific baseline strength characteristics in older adults, clinicians and researchers must have knowledge regarding the relative stability of the various strength tests (the strength difference between repeated measures) and the number of prebaseline practice sessions required to obtain consistent data. To address these needs, the relative multiple-test stability and reliability associated with lower extremity isokinetic and 1-repetition-maximum (1RM) strength measures were assessed in a sample of older adults (N= 30, 65.2 ± 6.3 years), over 4 weeks (T1-T4). Isokinetic ankle plantar-flexion (30°/s) strength and 1RM ankle plantar-flexion, leg-press, and knee-flexion strength exhibited poor stability between Weeks T1 and T2 but stabilized between Weeks T2 and T3 and Weeks T3 and T4. The measures exhibited low incidence of injury and induced low levels of residual muscle soreness. Findings suggest that the 1RM measures require at least 1 prebaseline training session in order to establish consistent baseline performance and are more reliable than isokinetic ankle plantar-flexion tests.


2020 ◽  
Vol 29 (4) ◽  
pp. 483-487
Author(s):  
Matt Greig ◽  
Benjamin Child

Context: Cricket fast bowlers are particularly susceptible to lumbar spine loading and injury. Quantitative analysis of technique typically involves laboratory-based biomechanical systems with limited ecological validity, whereas contemporary developments in global positioning satellite microtechnologies facilitate an on-field evaluation of loading. Objective: To quantify the influence of submaximal bowling from reduced approach lengths on performance and loading. Design: Repeated-measures, field-based design. Setting: Regulation cricket pitch. Participants: A total of 12 male cricket academy fast bowlers (18.7 [0.7] y), injury free with ≥3 years of competitive experience. Interventions: Each bowler wore 2 global positioning satellite units placed at C7 and L4 to measure triaxial acceleration (100 Hz). Bowlers completed an over (6 deliveries) from a randomized 3-, 6-, 9-, and 12-stride approach. Main Outcome Measures: Ball speed was recorded as the performance measure, with PlayerLoad in the anteroposterior, mediolateral, and vertical planes also calculated for each delivery length. Results: In ball speed, there was a significant main effect for delivery length (P = .02), with a 3-stride approach eliciting significantly less ball speed than a 9-stride (P = .03) or 12-stride (P = .002) approach. In loading, there was a significant main effect for delivery length (P < .001) in the anteroposterior, mediolateral, and vertical planes, with loading increasing linearly as a function of delivery strides. The 6-stride approach elicited a 44% reduction in loading, with a disproportionately small 3.5% decrease in performance. There was a significant main effect for global positioning satellite location (P ≤ .023) in all planes, with L4 eliciting greater loading than C7. Conclusions: A submaximal 6-stride approach yielded the optimum balance between reduced loading and performance inhibition. Reduced delivery length, therefore, offers an alternative to reduced overs in reducing loading in young bowlers and might also have practicable value in the rehabilitation of bowlers postinjury.


1997 ◽  
Vol 11 (3) ◽  
pp. 294-304 ◽  
Author(s):  
Iris Orbach ◽  
Robert N. Singer ◽  
Milledge Murphey

There is a shortage of research in which the effect of attribution training interventions on sport performance has been investigated. Therefore, the primary goal of this study was to determine the influence of an attribution training program on individuals who attribute their sport performance to dysfunctional attributions. Sixty college recreational basketball players were oriented to perceive their performance in a basketball skill task as due to (a) controllable, unstable factors, (b) uncontrollable, stable factors, or (c) no specific factors. Dependent variables included attributions and performance time. Using MANOVA and repeated measures factorial ANOVAs, results revealed that it is possible to modify attributions and performance in regard to a basketball performance task. The data are supportive of the potential influence of attribution training in a sport setting and the use of a controllable, unstable dimensional orientation as a means to improve performance.


2019 ◽  
Vol 67 (1) ◽  
pp. 175-184
Author(s):  
Petros G. Botonis ◽  
Argyris G. Toubekis ◽  
Gerasimos D. Terzis ◽  
Nickos D. Geladas ◽  
Theodoros I. Platanou

AbstractThe purpose of the study was to examine changes in performance and match-induced fatigue over a 27-week training period. Eight national-level water-polo players performed a 5 x 200 m swimming test to calculate velocities corresponding to blood lactate concentration of 4.0, 5.0 and 10.0 mmol.l-1 at three testing periods: i) baseline, ii) end of the pre-season (8 weeks of 4 x 4 min swimming bouts), iii) end of the in-season (8 weeks of 8 x 20 m swimming sprints). During each testing period, four competitive matches were played and repeated sprints (8 x 20 m), 400 m swimming, and shooting accuracy were evaluated at the pre- and post-match. Repeated sprint tests were also conducted at mid-game. Analysis of variance for repeated measures was used to detect changes among training periods and within games. Swimming velocities corresponding to 4.0, 5.0 and 10.0 mmol.l-1 were increased after the pre-season by 9%, 7.7%, and 6.7% (p < 0.01) and decreased following the in-season compared to the pre-season by 8.9%, 7.0% and 3.3% (p < 0.01), respectively. Pre-match repeated sprints and 400 m performance were improved after the pre-season by 4.3% and 3.8% (p < 0.01) and decreased by ~3% after the in-season compared to the pre-season (p < 0.01). Mid- and post-match repeated sprint performance was improved after the pre-season by 4.8 ± 1.4% and 4.4 ± 1.1% and remained unchanged after the in-season compared to the pre-season. Post-match 400 m speed was improved by 3.2% after the pre-season (p < 0.01) and decreased by 2.8% after the in-season (p = 0.04).Pre-season training improved players’ aerobic endurance and performance. Intensified in-season training decreased aerobic power, endurance, and pre-match performance while maintaining match repeated sprint performance.


2020 ◽  
Vol 36 (1) ◽  
pp. 196-206 ◽  
Author(s):  
Almut Rudolph ◽  
Michela Schröder-Abé ◽  
Astrid Schütz

Abstract. In five studies, we evaluated the psychometric properties of a revised German version of the State Self-Esteem Scale (SSES; Heatherton & Polivy, 1991 ). In Study 1, the results of a confirmatory factor analysis on the original scale revealed poor model fit and poor construct validity in a student sample that resembled those in the literature; thus, a revised 15-item version was developed (i.e., the SSES-R) and thoroughly validated. Study 2 showed a valid three-factor structure (Performance, Social, and Appearance) and good internal consistency of the SSES-R. Correlations between subscales of trait and state SE empirically supported the scale’s construct validity. Temporal stability and intrapersonal sensitivity of the scale to naturally occurring events were investigated in Study 3. Intrapersonal sensitivity of the scale to experimentally induced changes in state SE was uncovered in Study 4 via social feedback (acceptance vs. rejection) and performance feedback (positive vs. negative). In Study 5, the scale’s interpersonal sensitivity was confirmed by comparing depressed and healthy individuals. Finally, the usefulness of the SSES-R was demonstrated by assessing SE instability as calculated from repeated measures of state SE.


Methodology ◽  
2011 ◽  
Vol 7 (4) ◽  
pp. 157-164
Author(s):  
Karl Schweizer

Probability-based and measurement-related hypotheses for confirmatory factor analysis of repeated-measures data are investigated. Such hypotheses comprise precise assumptions concerning the relationships among the true components associated with the levels of the design or the items of the measure. Measurement-related hypotheses concentrate on the assumed processes, as, for example, transformation and memory processes, and represent treatment-dependent differences in processing. In contrast, probability-based hypotheses provide the opportunity to consider probabilities as outcome predictions that summarize the effects of various influences. The prediction of performance guided by inexact cues serves as an example. In the empirical part of this paper probability-based and measurement-related hypotheses are applied to working-memory data. Latent variables according to both hypotheses contribute to a good model fit. The best model fit is achieved for the model including latent variables that represented serial cognitive processing and performance according to inexact cues in combination with a latent variable for subsidiary processes.


2020 ◽  
Vol 16 (2) ◽  
pp. 152-159
Author(s):  
Arezoo Shayan ◽  
Mansoureh Refaei ◽  
Farkhondeh Jamshidi

Background: Treatment of breast cancer can be accompanied by long-term consequences affecting women’s participation in many tasks. Objective: This study aimed to assess the effect of cognitive behavioral stress management (CBSM) program on occupational performance of women with breast cancer. Methods: In this randomized clinical trial, conducted between Feb 3 and Oct 26, 2016, 104 women with breast cancer who had referred to Imam Khomeini clinic in Hamadan, and who fulfilled the inclusion criteria (20-60 years old, married, suffering from grade 1-3 breast cancer with a history of recent surgery) were enrolled. They were randomly divided into two groups of 52 using a permuted block size of four. The intervention group took part in four 60-minute sessions of CBSM over four weeks. The study data were collected using a demographic information form and the Canadian Occupational Performance Measure. The statistical analyst was masked to intervention allocation. The data were analyzed using descriptive statistics, paired t-test, and repeated measures ANOVA. Results: A significant difference was observed between the two groups regarding the mean scores of occupational performance (p=0.02) and satisfaction (p=0.005) after the intervention. Each variable was measured at three time points (before the intervention, immediately and 2 weeks after intervention). A significant difference was observed in the two groups’ mean scores of performance (p=0.026) and satisfaction (p=0.01), irrespective of the time of assessment. Conclusion: The CBSM program promoted the occupational performance immediately and two weeks after the intervention in women with breast cancer. This technique can be used as a complementary method alongside medical therapies in oncology centers.


Author(s):  
Nuno Batalha ◽  
Jose A. Parraca ◽  
Daniel A. Marinho ◽  
Ana Conceição ◽  
Hugo Louro ◽  
...  

The purpose of this study was to analyze the acute effects of a standardized water training session on the shoulder rotators strength and balance in age group swimmers, in order to understand whether a muscle-strengthening workout immediately after the water training is appropriate. A repeated measures design was implemented with two measurements performed before and after a standardized swim session. 127 participants were assembled in male (n = 72; age: 16.28 ± 1.55 years, height: 174.15 ± 7.89 cm, weight: 63.97 ± 6.51 kg) and female (n = 55; age: 15.29 ± 1.28 years, height: 163.03 ± 7.19 cm, weight: 52.72 ± 5.48 kg) cohorts. The isometric torque of the shoulder internal (IR) and external (ER) rotators, as well as the ER/IR ratios, were assessed using a hand-held dynamometer. Paired sample t-tests and effect sizes (Cohen’s d) were used (p ≤ 0.05). No significant differences were found on the shoulder rotators strength or balance in males after training. Females exhibited unchanged strength values after practice, but there was a considerable decrease in the shoulder rotators balance of the non-dominant limb (p < 0.01 d = 0.366). This indicates that a single practice seems not to affect the shoulders strength and balance of adolescent swimmers, but this can be a gender specific phenomenon. While muscle-strengthening workout after the water session may be appropriate for males, it can be questionable regarding females. Swimming coaches should regularly assess shoulder strength levels in order to individually identify swimmers who may or may not be able to practice muscle strengthening after the water training.


2021 ◽  
Vol 9 (3) ◽  
pp. 290
Author(s):  
Yukai Li ◽  
Yuli Hu ◽  
Youguang Guo ◽  
Baowei Song ◽  
Zhaoyong Mao

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.


Author(s):  
Xiao Qiu ◽  
Blanca De la Fuente ◽  
Alberto Lorenzo ◽  
Santiago Veiga

The present study investigated swimmers’ performances on the starting and turning segments between individual and relay races. A total number of 72 race performances of the same swimmers in both relay 4 × 100 m finals (freestyle, medley, and mixed freestyle) and individual 100 m finals or semi-finals (butterfly, breaststroke, and freestyle) from the LEN European Swimming Championships were compared with repeated measures MANOVA. Swimmers performed 5–7% faster starts in the relay than in the corresponding individual events, despite no differences in the flight phase and a lower performance (shorter distances and slower velocities) on the underwater start section. The 15 m turn times were slower in the butterfly relay races although no specific differences in the underwater parameters were observed. These results suggest that specific training of the starting and turning segments should be performed under relay conditions to optimise pacing and performance in the underwater sections.


Sign in / Sign up

Export Citation Format

Share Document