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Brendan Burkett, Rebecca Mellifont and Bruce Mason

This study compared the components of the 15-m swimming start for 20 international male Olympic and Paralympic swimmers. The time, distance, and velocity components for freestyle swimming were measured. There were significantly (p < .05) different absolute and relative swim start measures among the swimming groups. Using stepwise regression three variables significantly influenced the start to 15-m time: (i) underwater velocity, (ii) free swim velocity, and (iii) whether the swimmer had cerebral palsy. This new knowledge provides useful information for swimmers and coaches on which components to prioritize, along with the practical applications of improving the streamline position to increase underwater velocity and to ensure that the transition from underwater to surface breakout occurs at the optimal time for maximum free swim velocity.

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Mark R. McKean and Brendan J. Burkett

Dry-land strength training is a fundamental component for elite kayak performance. The aims of this research were 3-fold: 1st, to determine the relationship between performance time and strength scores for elite kayakers; 2nd, to identify how strength changes (gains or losses) over 3 training y relate with changes in performance time for elite kayakers; and 3rd, to compare the progression in performance times for elite athletes with the top 3 performers from the national championships. The performance data for 15 elite male and 10 elite female kayakers were collected over 2 y. This group was reduced to 9 men and 8 women in the 3rd and final year. There were direct and significant correlations between strength scores and performance times across the 3 y. Bench-press 1RM increased by 34.8% for men and 42.3% for women. Over the 3 seasons, mean 1000-m time decreased by approximately 4.8%, 500-m times decreased by 7.3% (women), and 200-m times decreased by 9.1%. The women’s 500-m changed from 11.9% difference from medalists to within 1.1% during the 3 y. During the 3 y of this study a change in 1-repetitionmaximum (1RM) bench press of 13% for men and 6.5% in women coincided with a change in performance times of 1%. For 1RM pull-up a change of 10% in men and 2.3% in women coincided with a change in performance times of 1%.

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Andrew A. Dingley, David B. Pyne and Brendan Burkett

Purpose:

To characterize relationships between propulsion, anthropometry, and performance in Paralympic swimming.

Methods:

A cross-sectional study of swimmers (13 male, 15 female) age 20.5 ± 4.4 y was conducted. Subject locomotor categorizations were no physical disability (n = 8, classes S13–S14) and low-severity (n = 11, classes S9–S10) or midseverity disability (n = 9, classes S6–S8). Full anthropometric profiles estimated muscle mass and body fat, a bilateral swim-bench ergometer quantified upper-body power production, and 100-m time trials quantified swimming performance.

Results:

Correlations between ergometer mean power and swimming performance increased with degree of physical disability (low-severity male r = .65, ±0.56, and female r = .68, ±0.64; midseverity, r = .87, ±0.41, and r = .79, ±0.75). The female midseverity group showed nearperfect (positive) relationships for taller swimmers’ (with a greater muscle mass and longer arm span) swimming faster, while for female no- and low-severity-disability groups, greater muscle mass was associated with slower velocity (r = .78, ±0.43, and r = .65, ±0.66). This was supported with lighter females (with less frontal surface area) in the low-severity group being faster (r = .94, ±0.24). In a gender contrast, low-severity males with less muscle mass (r = -.64, ±0.56), high skinfolds (r = .78, ±0.43), a longer arm span (r = .58, ±0.60) or smaller frontal surface area (r = -.93, ±0.19) were detrimental to swimming-velocity production.

Conclusion:

Low-severity male and midseverity female Paralympic swimmers should be encouraged to develop muscle mass and upper-body power to enhance swimming performance. The generalized anthropometric measures appear to be a secondary consideration for coaches.

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Luke W. Hogarth, Brendan J. Burkett and Mark R. McKean

Purpose:

To examine the neuromuscular and perceptual fatigue responses to consecutive tag football matches played on the same day and determine the relationship between fatigue and match running performance.

Methods:

Neuromuscular and perceptual fatigue responses of 15 national tag football players were assessed before and during the 2014 State of Origin tournament. Global positioning systems (GPS) provided data on players’ match running performance, and a vertical-jump test and subjective questionnaire were used to assess players’ neuromuscular and perceptual fatigue, respectively.

Results:

There were small to moderate reductions in the majority of match-running-performance variables over consecutive matches, including distance (ES = −0.81), high-speed-running (HSR) distance (ES = −0.51), HSR efforts (ES = −0.64), and maximal accelerations (ES = −0.76). Prematch vertical jump was initially below baseline values before the first match (ES = 0.68−0.88). There were no substantial reductions in vertical-jump performance from baseline values over consecutive matches, although there was a small decline from after match 2 to after match 3 (3.3%; ES = −0.45 ± 0.62). There were progressive reductions in perceived well-being scores after matches 1 (ES = −0.38), 2 (ES = −0.70), and 3 (ES = −1.14). There were small to moderate associations between changes in fatigue measures and match running performance.

Conclusions:

Perceptual fatigue accumulates over consecutive tag football matches, although there were only marginal increases in neuromuscular fatigue. However, both neuromuscular and perceptual fatigue measures were found to contribute to reduced match running performance in the final match.

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Mark R. McKean, Gary Slater, Florin Oprescu and Brendan J. Burkett

Australia has approximately 26,000 registered exercise professionals (REP), in comparison with 3,379 accredited practicing dietitians (APD). The REP workforce has the potential to reach more than 10% of the Australian population but there is limited data on their educational background and professional behaviors with regards to nutritional counseling of clients. The purpose of this research was to determine if REPs are working within their scope of practice and if their qualifications align with their practice, specifically as it relates to nutrition advice. Using a cross sectional descriptive study design, a self-administered online survey of REPs was conducted over 5 months. REPs were recruited through electronic and social media using a snowballing technique. The study focused on education, nutrition advice, and sources of information. A total of 286 respondents completed the survey, including 13 with tertiary dietetic qualifications i.e., APDs. The nationally recognized industry Certificate III/IV in Fitness was the most common qualification. The majority of REPs responding (88%) were working outside of their professional scope of practice, offering individual nutrition advice to clients across fitness and medical issues. This was despite 40% of REPs undertaking no further training in nutrition since graduating, and primarily basing advice on use of readily accessible sources of nutrition information. It is recommended the nutrition advice provided to REPs during training be limited to general nonmedical nutrition information in accordance with nationally endorsed evidence based guidelines and that issues pertaining to scope of practice be addressed with onward referral to other health professionals be advocated.

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Danielle P. Formosa, Mark Gregory Leigh Sayers and Brendan Burkett

This study explored and quantified gender differences in passive drag and instantaneous net drag force profile for elite backstroke swimmers (FINA points 938 ± 71). Nine female and ten male backstroke swimmers completed eight maximum speed trials. During the passive drag condition participants were towed at the speed achieved within the maximum effort backstroke swimming trials, while holding a supine stationary streamline position. The remaining trials, swimmers performed their natural swimming stroke, while attached to an assisted towing device. Male participant’s passive (P < .001) and mean net drag force (P < .001) were significantly higher compared with female participants. In addition, there were no significant differences by gender between either the minimum or maximum net drag forces produced during the left and right arm strokes. Instantaneous net drag force profiles demonstrated differences within and between individuals and genders. The swimmers who recorded the fastest speed also recorded the smallest difference in net drag force fluctuations. The instantaneous net drag force profile within elite backstroke swimming provides further insight into stroke technique of this sport.

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Andrew A. Dingley, David B. Pyne and Brendan Burkett

Disabilities in Paralympic swimming could impact a swimmer’s ability to execute an effective swim-start. We examined how swim-start performance differed between severity and type of physical disability. Swim-starts were measured in 55 elite Paralympic swimmers from eight different Paralympic classes; S14, S13, S10-S6, S3 grouped as no- (classes S13 & S14), low- (S9 & S10), mid- (S7 & S8) or high- (≤ S6) severity of physical disability and also by type of physical disability (upper, lower, and palsy) to provide meaningful comparisons. The swimmer’s competitive level was determined by the international point score (IPS). Swimmers with no physical disability were significantly faster in most swim-start phases compared with those with physical disabilities, as were swimmers with low-severity disabilities compared with the mid- and high-severity groups. Block velocity was highly negatively correlated (r = –0.57 to –0.86) with 15-m swimming time for all groups except high-severity disabilities. Free-swim velocity is a priority area for improving swim-starts for swimmers regardless of disability, given large correlations between this measure and IPS. Swimmers with lower body or high-severity disabilities spent a smaller percentage of time overall in the underwater phase. Assessment of four specific phases of the swim-start highlight distinctive priorities for coaches working with Paralympic swimmers in an applied biomechanical manner.

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Alysha Hyde, Luke Hogarth, Mark Sayers, Emma Beckman, Mark J. Connick, Sean Tweedy and Brendan Burkett

Purpose:

To quantify the influence of the assistive pole, seat configuration, and upper-body and trunk strength on seated-throwing performance in athletes with a spinal-cord injury (SCI).

Methods:

Ten Paralympic athletes competing in wheelchair rugby, basketball, or athletics (seated throws) participated in 2 randomized sessions: seated throwing and strength tests. Participants threw a club from a custom-built throwing chair, with and without a pole. 3D kinematic data were collected (150 Hz) for both conditions using standardized and self-selected seat configurations. Dominant and nondominant grip strength were measured using a dynamometer, and upper-body and trunk strength were measured using isometric contractions against a load cell.

Results:

Seated throwing with an assistive pole resulted in significantly higher hand speed at release than throwing without a pole (pole = 6.0 ± 1.5 m/s, no pole = 5.3 ± 1.5 m/s; P = .02). There was no significant difference in hand speed at release between standardized and self-selected seating configurations during seated throwing with or without an assistive pole. Grip strength (r = .59–.77), push/pull synergy (r = .81–.84), and trunk-flexion (r = .50–.58) strength measures showed large and significant correlations with hand speed at release during seated throwing with and without an assistive pole.

Conclusions:

This study has demonstrated the importance of the pole for SCI athletes in seated throwing and defined the relationship between strength and seated-throwing performance, allowing us to better understand the activity of seated throws and provide measures for assessing strength that may be valid for evidence-based classification.

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Anna C. Severin, Brendan J. Burkett, Mark R. McKean, Aaron N. Wiegand and Mark G.L. Sayers

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.

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Brendan Burkett, James Smeathers and Timothy M. Barker

For amputees to perform an everyday task, or to participate in physical exercise, it is crucial that they have an appropriately designed and functional prosthesis. Past studies of transfemoral amputee gait have identified several limitations in the performance of amputees and in their prosthesis when compared with able-bodied walking, such as asymmetrical gait, slower walking speed, and higher energy demands. In particular the different inertial characteristics of the prosthesis relative to the sound limb results in a longer swing time for the prosthesis. The aim of this study was to determine whether this longer swing time could be addressed by modifying the alignment of the prosthesis. The following hypothesis was tested: Can the inertial characteristics of the prosthesis be improved by lowering the prosthetic knee joint, thereby producing a faster swing time? To test this hypothesis, a simple 2-D mathematical model was developed to simulate the swing-phase motion of the prosthetic leg. The model applies forward dynamics to the measured hip moment of the amputee in conjunction with the inertial characteristics of prosthetic components to predict the swing-phase motion. To evaluate the model and measure any change in prosthetic function, we conducted a kinematic analysis on four Paralympic runners as they ran. When evaluated, there was no significant difference (p > 0.05) between predicted and measured swing time. Of particular interest was how swing time was affected by changes in the position of the prosthetic knee axis. The model suggested that lowering the axis of the prosthetic knee could reduce the longer swing time. This hypothesis was confirmed when tested on the amputee runners.