Previous experiences can influence individual cricket spin bowlers' perceptions of affordances in the performance landscape.

The ecological dynamics framework emphasises that movement solutions are guided by the relationship that exists between the performer and their environment, scaled to an individual's own action capabilities. This suggests that representative practice tasks should be used in high performance settings to encourage individually optimised movement solutions for both team and individual sports. This study specifically focuses on individual cricket spin bowlers and aims to understand the influence of their prior learning experiences on their perceptual attunement strategies when tasked with performing on a familiar Australian cricket pitch and a less familiar bespoke international (Indian) pitch. Two right hand leg spin bowlers that were part of a group of eight emerging expert spin bowlers were chosen for individual analysis. Bowler A reported 80 prior experiences of bowling on subcontinental (i.e., India, Pakistan, or Bangladesh) pitches whereas Bowler B had only 20 prior experiences. Overall, both bowlers' outcome performances either met or exceeded their expectations. Bowler A chose to calibrate his bowling style on the less familiar pitch to improve the fit between his delivery characteristics and the environmental pitch conditions, whereas Bowler B maintained his bowling style, even though he recognised a difference in the pitch conditions. Therefore, Bowler A maintained stable performance outcomes by implementing flexible movement solutions. In contrast, while Bowler B achieved his expected performance outcomes, his lack of diverse learning experiences may limit his action capabilities, although more performance trials are needed to confirm this conclusion. Regardless, this study demonstrates that there is valuable information in knowing how a player achieves a successful result, which should be coupled with performance outcomes to help create individualised development strategies.

Patients' and parents' expectations of orthodontic treatment in university settings.

INTRODUCTION: The primary aim was to compare patients' and parents' orthodontic treatment expectations at the Eastman Institute for Oral Health, University of Rochester, Rochester, NY (UR) in the United States. Secondary aims were to assess the association between sociodemographic factors and UR participants' expectations; and compare participants' expectations between UR, Academic Centre for Dentistry Amsterdam (ACTA) and King's College Dental Hospital, London, United Kingdom (KC) (previously published data). METHODS: One hundred and forty participants [70 patients and one of their parents (n = 70)] completed a validated questionnaire (10 questions) to measure orthodontic treatment expectations before screening at the Orthodontic Department at UR. Various sociodemographic factors were assessed. The paired t test (for continuous responses) and the Fisher exact test (for categorical responses) were used to compare UR patients' and parents' responses. Two-sample t test and the Fisher exact test were used to compare participants' responses among sociodemographic groups. One-way analysis of variance followed by the Tukey test, and the Fisher exact test were used to compare participants' responses between UR, and ACTA and KC (data collected from previous publications). A multiplicity correction was performed to control the false discovery rate. RESULTS: Patients at UR expected less check-up and diagnosis, and less discussion about treatment at the initial visit, more dietary restrictions, and less improvement in smile esthetics and social confidence with orthodontic treatment than parents. Participants' responses differed by sociodemographic factors at UR and between UR, ACTA, and KC. CONCLUSIONS: Expectations of orthodontic treatment differ between patients and their parents, are associated with sociodemographic factors, and vary among United States and European University centers.

Psychometric validation of a pre-existing questionnaire used to measure patient satisfaction following orthodontic treatment in a UK population.

OBJECTIVE: To determine the psychometric properties of a pre-existing orthodontic satisfaction questionnaire and to assess patient satisfaction of their orthodontic treatment. DESIGN: Psychometric assessment of a pre-existing orthodontic satisfaction questionnaire. SETTING: Two sites at King's College Hospital NHS Foundation Trust. PARTICIPANTS: Individuals aged 12-15 years who had completed fixed orthodontic treatment. METHODS: An expert panel assessed a pre-existing orthodontic treatment satisfaction questionnaire for validity and readability. As a result, revisions were made to the questionnaire and it was distributed to 103 participants aged 12-15 years, on completion of their fixed orthodontic treatment (T1). Test-retest reliability of the questionnaire was assessed through completion of a second questionnaire by 17 participants, at a two-week interval (T2). The questionnaire was assessed for reliability using item-total correlations (I-TC) and Cronbach's alpha. Factor analysis allowed exploration of the underlying factor structure of the questionnaire. Test-retest reliability was assessed using Cohen's kappa coefficient. Multiple regression analysis was used to find out the significant demographic variables that predicts the satisfaction level of treatment. RESULTS: Following validity and readability assessment by the expert panel, the questionnaire was revised. Eleven items were removed following item analysis (with I-TC ⩽ 0.3). Factor analysis was deemed uninterpretable. The overall scale demonstrated greater reliability than the underlying sub-scales. Therefore, the sub-scales were removed, resulting in one scale which assessed overall orthodontic satisfaction, comprising 37 items, with a Cronbach alpha of 0.92. The test-retest reliability of the revised 37-item scale was deemed to be poor (kappa coefficient = 0.39). Multiple regression analysis identified ethnicity as a significant predictor of orthodontic treatment satisfaction (P = 0.01). CONCLUSION: This study provides a valid measure to assess orthodontic treatment satisfaction for use in a UK population aged 12-15 years on completion of fixed orthodontic treatment.

Influence of technique on upper body force and power production during medicine ball throws.

This project examined the interrelationships between power production and upper body kinematics during a series of medicine ball push-press (MBP-P) throws. Twenty-five regular weight trainers (body mass = 86 ± 10 kg) performed a series of ballistic vertical MBP-P throws at loads representing 5% and 10% of their assessed 5RM bench press. Throws were performed lying supine on a force platform (1 kHz) with upper body kinematics assessed using standard infra-red motion capture techniques (0.5 kHz). Gross measures of performance and power production such as peak vertical ball velocity (Velpeak), peak force (Fpeak) and power (Ppeak) were recorded during the propulsive phase of the movement. Comparative analyses indicated that despite significant reductions in Velpeak from the 5% to 10% loads (P < 0.001), Fpeak remained largely unchanged (P = 0.167). Analysis of inter-trial variability showed that the gross measures of performance and power were relatively stable (Coefficient of Variation [CV%] <13%), while most upper limb segmental kinematics varied considerably between trials (CV% up to 70%). This project highlights the complexity of the relationships between power production and upper body kinematics during light load ballistic MBP-P throwing. Additionally, it shows how trained athletes can achieve similar outcomes during ballistic movements using a variety of movement strategies.

The effect of elevating the heels on spinal kinematics and kinetics during the back squat in trained and novice weight trainers.

This research assessed the influence of various heel elevation conditions on spinal kinematic and kinetic data during loaded (25% and 50% of body weight) high-bar back squats. Ten novice (mass 67.6 ± 12.4 kg, height 1.73 ± 0.10 m) and ten regular weight trainers (mass 66.0 ± 10.7 kg, height 1.71 ± 0.09 m) completed eight repetitions at each load wearing conventional training shoes standing on the flat level floor (LF) and on an inclined board (EH). The regular weight training group performed an additional eight repetitions wearing weightlifting shoes (WS). Statistical parametric mapping (SPM1D) and repeated measures analysis of variance were used to assess differences in spinal curvature and kinetics across the shoe/floor conditions and loads. SPM1D analyses indicated that during the LF condition the novice weight trainers had greater moments around L4/L5 than the regular weight trainers during the last 20% of the lift (P < 0.05), with this difference becoming non-significant during the EH condition. This study indicates that from a perspective of spinal safety, it appears advantageous for novice weight trainers to perform back squats with their heels slightly elevated, while regular weight trainers appear to realize only limited benefits performing back squats with either EH or WS.

Wrist pain in gymnasts: Efficacy of a wrist brace to decrease wrist pain while performing gymnastics.

STUDY DESIGN: This was a clinical trial of prospective cohort. INTRODUCTION: Wrist pain in gymnasts is a global phenomenon. Compression forces acting on wrists while performing gymnastics is a predisposing factor in the development of wrist pain and consequential injury of the distal radial physis in skeletally immature gymnasts. One approach to mitigate these forces is wrist bracing; however, studies on the efficacy of wrist braces to reduce wrist pain experienced by gymnasts are limited. PURPOSE OF THE STUDY: The purpose of this study was to investigate the efficacy of an innovative design of a wrist brace to decrease gymnasts' wrist pain while performing gymnastics. METHODS: A wrist brace was designed and trialled over 3 weeks by 48 male gymnasts (aged 8-22 years, levels 4-7) with wrist pain. Wrist pain was recorded on a visual analog scale of 1 to 10 before and after trial. Data analysis was performed using SPSS-22 (IBM Inc). Paired t-tests were performed to compare variables before and after trial, with effect size analyses used to quantify the relative magnitude of any differences. RESULTS: Paired t-tests indicated the gymnasts reported significantly reduced pain (P = .002; 53.5%) while wearing the braces for training on the pommel, floor, and parallel bars. The overall large effect size value was practically significant (d = 0.902). DISCUSSION: For any wrist brace to be effective, it needs to be implemented when the gymnast experiences wrist pain before an injury occurs. This would minimize the development of pain-provoked adaptive movement patterns that perpetuate dysfunction. CONCLUSIONS: The brace with the volar gel pad is recommended to be worn as an adjunct to current strategies in management of gymnasts' wrist pain or as an injury prevention device in skeletally immature gymnasts.

How do you identify the patient with 'high expectations' of orthodontic treatment: An empirical approach.

OBJECTIVES: To identify an empirical method for identifying patients with 'high expectations' of orthodontic treatment with fixed appliances using a questionnaire-based approach. DESIGN: Secondary analysis of data from four studies which collected data on patients' expectations of orthodontic treatment using the same questionnaire. SETTING: Secondary care orthodontic services. PARTICIPANTS: All four datasets comprised new patients aged 12-15 years, with no history of orthodontic treatment, who fulfilled the criteria for NHS treatment using the Index of Orthodontic Treatment Need (IOTN). Unpublished dataset 1 comprised 100 participants, while dataset 2 had 70 participants, dataset 3 had 67 participants and dataset 4 comprised 40 participants. METHODS: The questionnaire utilised in all studies had a question which asked respondents to rate seven different expectations of outcome relating to straight teeth, better smile, ease of eating, speaking, cleaning teeth, improved career prospects and social confidence. Dataset 1 was analysed to determine the proportion of patients who had rated all seven outcome expectation items at a maximum score. Similar analyses were performed for the other three datasets to explore the trend in the proportion of patients with high expectations over time. RESULTS: For dataset 1, 2.0% of participants had high expectations, as defined by their scores on the questionnaire. The proportions for the datasets 2, 3 and 4 were 4.0%, 4.5% and 2.5%, respectively. CONCLUSION: The method outlined provides an empirical basis for identifying patients with statistically infrequent high expectations. This can potentially help clinicians in the management of such patients.

Patients' expectations: is there a typical patient?

OBJECTIVES: To qualitatively explore, and analyse, patients' expectations before the start of fixed appliance orthodontic treatment and determine whether typologies exist. DESIGN: A prospective cross-sectional qualitative study, which involved 13 patients (aged 12-15 years). SETTING: NHS Hospital Orthodontic Department (UK). MATERIALS AND METHODS: In-depth interviews were conducted with patients who consented to participate before the start of fixed appliance orthodontic treatment. The in-depth interview data were transcribed and then managed using a framework approach, followed by associative analysis. RESULTS: The in-depth interviews revealed two major themes and associated subthemes which were: first, patients' expectations about the treatment process and outcome; and second, patients' expectations of themselves during and after treatment. Three typologies related to patients' expectations of the orthodontic treatment process were also identified. The first group of participants had minimal expectations of the treatment process, did not anticipate discomfort or pain and did not anticipate that treatment would cause disruption to their daily life. The second group of participants had expectations that treatment would involve arch wire changes, dental extractions and result in some discomfort/pain, which would cause some limited disruption to their daily life (moderate expectations). The third type of participant had expectations of the treatment process involving arch wire changes and dental extractions, and anticipated that the discomfort and pain experienced would significantly affect their daily life (marked expectations). CONCLUSIONS: These results provide the clinician with information about patient typologies and provide the clinician with some direction when communicating with their patients and managing their expectations before the start of treatment.

Effects of Water Immersion on Squat and Split Squat Kinematics in Older Adults.

This study examined the effect of water immersion on trunk and lower limb kinematics during squat exercises in older participants. A total of 24 active older adults (71.4 ± 5.4 years) performed squats and split squats on land and while partially submerged in water. Inertial sensors (100 Hz) were used to record trunk and lower body kinematics. Water immersion increased the squat depth (squat: p = .028, d = 0.63 and split squat: p = .005, d = 0.83) and reduced the trunk flexion range (squat: p = .006, d = 0.76 and split squat: p < .001, d = 1.35) during both exercises. In addition, water immersion increased the hip range of motion during the split squat (p = .002, d = 0.94). Waveform analyses also indicated differences in the timing of the movements. These results showed that water-based exercise generates a different exercise outcome and appears to provide an alternative option for older adults, enabling exercisers to perform these tasks in a manner not possible on land.

Influence of football size on kicking performance in youth Australian rules footballers.

In Australian rules football structured increases in ball size during development end with the transition to the Size 5 (adult) ball at the Under-15 age group. This study assessed changes in kick technique and performance in experienced junior performers when using Size 4 and 5 Australian rules footballs. Participants (n = 22, 13.77 ± 0.61 years) performed drop punt kicks in 2 representative tasks; a Decision-Making Test (DMT) (n = 14) and Set-Shot Test (SST) (n = 14 + 8). Results indicate participants sustained their level of kick performance (accuracy and quality of ball spin) in both tests when using a Size 5 football. Sustained kick performance in the DMT primarily resulted from adaptations to time-point technical measures at ball release. No significant differences were detected for technical measures between ball sizes in the SST. A dynamic kicking task (DMT) in combination with ball size manipulation may have placed greater demand on skill execution in comparison to a self-paced kicking task (SST). Results provide initial support for the utility of challenging representative dynamic and self-paced tasks, such as the DMT and SST used here for Australian football, for skill testing and practice in sport.

Reliability of a New Medicine Ball Throw Power Test.

The purpose of this study was to examine the reliability of a new upper body medicine ball push-press (MBP-P) test. Twenty-three strength trained volunteers performed a series of supine MBP-P throws using loads representing 5% and10% of their 5RM bench press (5 repetitions at each load). Throws were performed on a force platform (2000 Hz), with medicine ball kinematic data collected using a high-speed motion capture (500 Hz). Testing was repeated after 7-10 days to quantify intertest reliability. Maximal force (Fmax), impulse at Fmax, time to Fmax, and maximum rate of force development (RFDmax) were all calculated from the force platform outputs, with maximum ball velocity (Velmax) and maximum ball acceleration (Accelmax) developed from the kinematic data. Reliability was assessed using intraclass correlation (ICC), coefficient of variation (%CV), and typical error. Medicine ball kinematic variables were more reliable (CV% = 2.6-5.3, ICC = 0.87-0.95) than the various force platform derived power variables (CV% = 7.9-26.7, ICC = 0.51-0.90). The MBP-P test produces reliable data and can be used to quantify many standard power based measures, with the key findings have implications for athletic populations requiring high velocity, light load upper body pushing power.

Patient's expectations of lingual orthodontic treatment: a qualitative study.

OBJECTIVE: To investigate patients' expectations of lingual orthodontic treatment. DESIGN: In-depth interviews were conducted. A framework analysis was carried out to identify themes, concepts and a typology. SETTING: Two secondary care hospital departments and four primary care orthodontic practices, UK. MATERIALS AND METHODS: Fifteen new orthodontic patients aged 16-60 years participated in the interviews. All interviews were transcribed verbatim and analysed using framework analysis, including identification of themes within the responses, and typologies of respondents. RESULTS: Patients seeking lingual orthodontics reported expectations that were similar in quality but different in extent to those seeking labial orthodontics. These patients were well informed about lingual orthodontic treatment before they decide to start treatment. Two typologies were identified. Firstly, males less than 30 years of age, undergoing changes in their lives, who were confident that they wanted a hidden brace, but were not entirely sure of the specifics of the system. Secondly, females aged 30-45, who request a hidden brace and had actively researched what particular systems were available. CONCLUSIONS: This study shows that patients requesting lingual orthodontics have expectations that are similar in quality but greater in extent when compared to those seeking labial orthodontics.

A morphological adaptation? The prevalence of enlarged external occipital protuberance in young adults.

Enthesophytes are bony projections that arise from the sites of ligament, tendon or joint capsule attachment to a bone. They are seen rarely in radiographic findings in young adults, as these bony adaptations are assumed to develop slowly over time. However, in recent years, the presence of an enlarged external occipital protuberance (EEOP) has been observed frequently in radiographs of relatively young patients at the clinic of the lead author. Accordingly, the aim of this project was to assess the prevalence of an EEOP in a young adult population. Analysis involved a retrospective analysis of 218 lateral cervical radiographic studies of 18-30-year-old participants. Group A (n = 108; males = 45, females = 63) consisted of asymptomatic university students, while Group B (n = 110; males = 50, females = 60) were an age-matched mildly symptomatic, non-student population. The external occipital protuberance (EOP) size was defined as the distance from the most superior point of the EOP (origin) to a point on the EOP that is most distal from the skull. To avoid ambiguity, the threshold for recording the size of an EOP was set at 5 mm, and an EOP was classified as enlarged if it exceeded 10 mm. Reliability testing was also undertaken. Results indicated that an EEOP was present in 41% of the total population, with 10% of all participants presenting with an EOP ≥ 20 mm. An EEOP was significantly more common in males (67.4%) than in females (20.3%), with the mean EEOP size for the combined male population (15 ± 7 mm) being significantly larger (P < 0.001) than for females (10 ± 4 mm). The longest EEOP in the male population was 35.7 mm, while in the female population it was 25.5 mm. Additionally, the mean EEOP size for Group A (14 ± 7 mm) was also significantly greater (P = 0.006) than that recorded for Group B (12 ± 6 mm). This study identified that an EEOP is a condition that is prevalent in the populations tested. The age of the populations, and the prevalence of EEOP, suggest that biomechanical drivers for this phenomenon may be the main reason for this condition in these populations.

Mechanisms of anterior cruciate ligament injuries in elite women's netball: a systematic video analysis.

This study involved a systematic video analysis of 16 anterior cruciate ligament (ACL) injuries sustained by elite-level netball players during televised games in order to describe the game situation, the movement patterns involved, the player's behaviour, and a potential injury mechanism. Eight of the ACL injuries were classified as "indirect contact" and eight as "non-contact". Two common scenarios were identified. In Scenario A the player was jumping to receive or intercept a pass and whilst competing for the ball experienced a perturbation in the air. As a result the player's landing was unbalanced with loading occurring predominantly on the knee of the injured side. In Scenario B the player was generally in a good position at ground contact, but then noticeably altered the alignment of the trunk before the landing was completed. This involved rotating and laterally flexing the trunk without altering the alignment of the feet. Apparent knee valgus collapse on the knee of the injured side was observed in 3/6 Scenario A cases and 5/6 Scenario B cases. Players may benefit from landing training programmes that incorporate tasks that use a ball and include decision-making components or require players to learn to cope with being unbalanced.

Balance control during the delivery stride in competitive older age lawn bowlers.

This project assessed dynamic balance and stability in aged lawn bowlers during the delivery stride. Participants were divided into two groups: aged 65 years or less (n = 14) and aged over 65 years (n = 16). Standard balance-based center of pressure (CoP) and ground reaction force variables were recorded and a Dynamic Postural Stability Index (DPSI) was used for calculating during ten deliveries. None of the balance variables correlated significantly with age although years of bowling experience correlated with DPSI scores (r = -.42, P = .019). The over 65 group had significantly greater variance in the mediolateral CoP movements, with no other significant differences in balance or postural stability variables between groups. Analysis of covariance indicated that the DPSI data were influenced significantly by bowling experience regardless of age group. It was concluded that in older aged lawn bowlers, playing experience rather than age is a key determinant of balance control during the lawn bowls delivery action.

Influence of Test Distance on Change of Direction Speed Test Results.

This study assessed the relationships between linear running velocity and change of direction (CoD) ability and how assessing CoD ability over distances ≤5 m influences test reliability. Participants (n = 15) from amateur rugby league teams performed 3 trials of a 20-m sprint test (light gates at 5, 10, and 20 m) and 6 trials of the 5-0-5 agility test. Twelve participants repeated the 5-0-5 test several weeks later. A three-dimensional motion capture system (250 Hz) was used to track the center of mass at 0.3, 0.5, and 1.0 m either side of the turn and identify specific CoD phase times. Pearson's correlations showed strong significant relationships between the 5-0-5 time and 5-m (r = 0.89, p < 0.001), 10-m (r = 0.91, p < 0.001), and 20-m sprint times (r = 0.93, p < 0.001). However, the strength of these relationships decreased (r < 0.65, p > 0.05) when CoD ability was measured over distances less than 0.5 m. Analysis of coefficient of variation (CV%) data indicated that the 5-0-5 test had high intratest (CV% = 2.8) and intertest reliability (CV% = 1.3), with these data decreasing for distances less than 1 m (CV% = 3.5-6.9). Specific movement phase times were the least reliable measures of CoD ability (CV% = 4.7-53.6). Results suggest a bias between high-speed linear running ability and 5-0-5 time. However, an effective compromise can be found between test reliability and the external validity by assessing CoD ability over 1 m. Findings indicate that the current practice of assessing CoD ability over large distances in questionable.

How patient and carer expectations of orthodontic treatment vary with ethnicity.

OBJECTIVE: To investigate if the orthodontic treatment expectations of Black British children and their primary carers vary compared with White British children and their primary carers. SETTING: A hospital orthodontic department (Queen Mary's Hospital, Sidcup, London, UK). PARTICIPANTS: Patients and their accompanying primary carers who had not received fixed orthodontic appliance treatment and were aged between 12 and 14 years old. METHOD: Informed consent was obtained from 100 patients and their primary carers, who completed a psychometrically validated questionnaire, to measure their expectations before a new patient orthodontic consultation. This cohort consisted of 50 Black British patients and their primary carers and 50 White British patients and their primary carers. RESULTS: Mean responses from patients and their primary carers for each ethnic group were compared using the independent groups t-test. Significant statistical differences were found between the two ethnic groups. The greatest statistical differences occurred between Black British patients and their primary carer and Black British primary carers and White British primary carers. Patients tended to have similar orthodontic expectations. There were no statistical significant differences in expectations between White British children and their primary carers. CONCLUSION: Differences in expectations of orthodontic treatment were more common between Black British and White British primary carers, than their children. White British primary carers had higher expectations at their child's initial appointment and expected dental extractions to be part of the orthodontic treatment plan. These differences have some implications for the provision of orthodontic care. A clinicians understanding of patients and their primary carer's expectations at the start of treatment can help in the quality and delivery of orthodontic care provided.

Unfit for duty? Evaluation of 4 years of paramedic preemployment fitness screening test results.

BACKGROUND: Preemployment testing is utilized by many ambulance services. Surprisingly, there is limited published research on the efficacy of this testing in determining an employee's ability to complete the requirements of this physically demanding occupation. OBJECTIVES: The purpose of this study was to analyze the preemployment fitness test results from a 4-year cohort of paramedic students from an Australian university. To date, no published studies have reported on the fitness test scores for paramedic students or on whether overall test score is biased toward any particular test components. Similarly, no data have been presented on whether there are gender differences in scores for individual test components or overall test score. METHODS: Retrospective cohort study of de-identified data from 4 years of data from Paramedic Science students (n = 251) (mean age = 24.9 years). Data were recorded from the Queensland Ambulance Service (QAS) Health Related Fitness Test (HRFT), a preemployment fitness test used by an Australian state ambulance service. HRFT score is calculated out of a possible 100 points and is based on performance scores in nine component fitness tests. Raw test scores for each of these component tests are ranked on a 0-4 scale prior to these data being scaled and summed to generate the overall HRFT score. An overall score >24.99 is awarded a "Pass." Results. Five individuals failed to "Pass" the HRFT. Overall HRFT scores were influenced significantly by performance in the strength tests, with males also recording significantly (p < 0.005) higher scores in all of the strength tests than females. Similarly, approximately 40% of the female participants, compared to 6% of males, achieved an overall test "Pass" and yet gained a ranked score of 0 in at least three of the component tests. CONCLUSIONS: It was concluded that the scoring system did not exclude participants with poor fitness levels, as many participants recorded low scores in several test components yet still passed the test. We recommend that before redesigning the HRFT, studies should be first conducted on the occupational demands and physical standards required for this important profession.

Stroke-coordination and symmetry of elite backstroke swimmers using a comparison between net drag force and timing protocols.

Stroke-coordination and symmetry influence the force fluctuations within any net drag force profile. The aim of this study was to analyse elite (FINA points 938) backstroke swimmers stroke-coordination using an instantaneous net drag force and timing protocols using a symmetry index tool. Ten male and nine female elite backstroke swimmers completed three maximum speed trials and five maximum speed net drag force swimming trials. Net drag force was measured using an assisted motorised dynamometer device. Each trial was filmed using three genlocked 50 Hz cameras, synchronised to the net drag force output from the force-platform. This methodology enabled the comparison of stroke-coordination timing symmetry index to net drag force symmetry index. The timing symmetry index and net drag force symmetry index yielded different results, the timing reflects the stroke-coordination, whilst the force index identified the effectiveness of the stroke. The only variable that was significantly different when comparing left and right stroke patterns was the location of minimum net drag forces. Conversely, gender influenced the location of maximum net drag force. Relationship analysis identified that location of maximum net drag force production was the only variable to correlate with speed within this cohort. Backstroke arm coordination was minimally influenced by gender.

Quantifying stroke coordination during the breathing action in front-crawl swimming using an instantaneous net drag force profile.

This study used both an instantaneous net drag force profile and a symmetry timing to evaluate the effect of the breathing action on stroke coordination. Twenty elite swimmers completed a total of six randomised front-crawl towing trials: (i) three breathing trials and (ii) three non-breathing trials. The net drag force was measured using an assisted towing device mounted upon a Kistler force platform, and this equipment towed the swimmer at a constant speed. The net drag force profile was used to create a stroke symmetry index for each swimming trial. Analysis using the symmetry indices identified that the majority of participants demonstrated an asymmetrical instantaneous net drag force stroke profile in both the breathing and non-breathing conditions, despite no significant differences in the time from finger-tip entry to finger-tip exit. Within the breathing condition, the faster swimmers compared to the slower swimmers demonstrated a lesser percentage of overlap between stroke phases on their breathing stroke side. During the non-breathing condition, the faster participants compared to the slower swimmers recorded a reduction in the percentage of overlap between stroke phases and less duration in the underwater stroke on their breathing stroke side. This study identified that the majority of participants demonstrated an asymmetrical net drag force profile within both conditions; however, asymmetry was less prevalent when examining with only the timing symmetry index.