Innovations derived from technological advances and the associated potential competitive advantages are keenly sought within elite sport. However, successfully gaining a competitive advantage relies heavily on the coaches and sport scientists responsible for utilising and implementing any new technology. Establishing the accuracy of new technology or metrics, efficiently integrating new technology or innovative methods into existing practice, and ensuring that any new innovation is adding value to the service being provided without causing a distraction are all areas where the individual sport scientist or coach must lead the technological innovation rather than allowing the technology to lead them.

Elite

10.7790/sa.v12i2.438

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Citations (7)

Reliability and Validity of the Polhemus Liberty System for Upper Body Segment and Joint Angular Kinematics of Elite Golfers

Sensors (2021)

Matilda Jane Wheare M. J. Nelson Ryan Lumsden Alec Buttfield Robert G. Crowther

Golf swing analysis is common in both recreational and professional levels where players are searching for improvements in shot accuracy and distance. The use of motion analysis systems such as the portable Polhemus Liberty system is gaining interest by coaches and players; however, to date, no research has examined the usefulness of the Polhemus Liberty system for golf swing analysis. Therefore, the purpose of this study was to determine the reliability of the Polhemus Liberty system and validity compared to the VICON Nexus motion analysis system when assessing segment (pelvis and thorax) and joint (shoulder, elbow and wrist) angular kinematics during a golf swing at key events (address, top of backswing and impact). Fifteen elite amateur/professional golfers performed ten golf swing trials within specified bounds using their 5-iron club. Reliability was assessed using interclass coefficient, effect size and t-test statistics by all participants completing two separate testing sessions on separate days following the same experimental protocol. Validity was assessed using effect size, Pearson correlation and t-test statistics by comparing swings captured using both Polhemus Liberty and VICON Nexus concurrently. Results demonstrated no difference in ball outcome results using the Trackman launch monitor (P > 0.05) and that the Polhemus Liberty system was reliable across the two sessions for all segment (pelvis and thorax) and joint (lead shoulder (gleno-humeral joint), elbow and wrist) angular kinematics (P > 0.05). Validity analysis showed that the Polhemus Liberty system for the segments (pelvis and thorax) and joints (lead shoulder and wrist) were different compared to the VICON Nexus data at key events during the golf swing. Although validity could not be confirmed against VICON Nexus modeling, the Polhemus Liberty system may still be useful for golf swing analysis across training sessions. However, caution should be applied when comparing data from the system to published research data using different motion analysis methods.

Motion analysis

10.3390/s21134330

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The practical application of a method of analysing the variability of within-step accelerations collected via athlete tracking devices

Journal of Sports Sciences (2019)

Alec Buttfield Kevin Ball

Resolving intra-stride accelerations from training and game data routinely collected by athlete tracking devices is rarely attempted, even though these data can provide important insights into the physical condition of athletes. This study describes in detail a novel analysis tool which uses accelerometer-based measures of step variability to assess longitudinal consistency of stride technique. The performance of the analysis tool was examined by combining results from the analysis of data collected over the course of an Australian Football League season with instances of missed or modified training. Results demonstrated increased gait-related trunk acceleration variability when training was modified due to load or accumulated game and training activity (p = 0.02) and reduced trunk acceleration variability in the week following a training modification due to any injury described as "ankle", "heel", or any other description that would loosely refer to a joint or bone in the leg (p = 0.01). These results support the findings of recent research which used a slightly modified version of the same analysis tool to demonstrate an increase in gait-related trunk acceleration variability with the increased acute physical load.

STRIDE

Tracking (education)

10.1080/02640414.2019.1699987

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The Development and Application of a Novel Method of Analysing Within-step Accelerations Collected During Australian Rules Football Games

Alec Buttfield

Resolving intra-stride accelerations from training and game data routinely collected by athlete tracking devices is rarely attempted, even though these data can provide important insights into the physical condition of athletes. This thesis proposes a new method of extracting stride accelerations from athlete tracking data via a novel analysis tool, describes methods of analysing the results generated by the analysis tool and reports and the influence of instances of missed or modified training and game activity on those results. Accelerometer and GPS Data from twenty-two professional Australian Rules Footballers were examined from competitive games during an Australian Football League season. These data were processed with a novel analysis tool developed specifically for the purpose of identifying instances of high speed running in a straight line during games, extracting step waveforms in three axes from those sections and determining the variability of those waveforms via a within-section and between-section co-efficient of multiple determination (CMD) over the course of the game. The steps taken in the development of the analysis tool are described in the thesis. Numerous approaches to identifying matched sections of high speed running in a straight line were investigated, with the method resulting in the highest number of waveforms while still being mindful of theoretical considerations adopted. Similarly, numerous statistical approaches to identifying step waveform variability were investigated and the methods demonstrating the highest repeatability within the context of the number of waveforms available for analysis were adopted, and methods with a high possibility of providing limited value in an applied setting eliminated. Results exported from the analysis tool were analysed in a number of contexts. Season averages from raw CMD scores were calculated on steps taken on the left and right foot, and the magnitude of the difference between those scores within each subject was estimated through determining the 99% confidence interval for the mean raw CMD on each side and identifying where those confidence intervals for the left and right foot did not overlap. There was one subject whose 99% confidence intervals did not overlap in any analysis condition (within-section and between-section CMD across x, y and z axes), one subject where the 99% confidence intervals did not overlap in four of the six analysis conditions, ten subjects where there was an overlap in between one and three of the analysis conditions, and ten subjects where there were no analysis conditions in which there was an overlap. Raw co-efficient of multiple correlation scores were converted to z-scores within side and axis for each subject, and confidence intervals for z-scores collated by axis (combining steps from all subjects on right and left side) were determined via an empirical bootstrapping procedure. When combined with data on ii instances of missed or modified training in the week preceding or following a game, some significant results were identified. Instances of missed or modified training were divided into five categories; “load”, “groin”, “leg soft tissue”, “leg structural” and “other”. A lower within-section z-score (indicating more step waveform variability) was found when a training was modified due to “load” (p=0.02) and higher between-section z-scores (which indicates less step waveform variability) were found in the week preceding a training modification due to “leg structural” injuries encompassing injuries to a leg not encompassed by soft tissue injuries, such as an ankle ligament sprain (p=0.02). Subjects with no difference between sides in average within-section z-axis raw CMD scores or average between-section x-axis raw CMD scores were unlikely to require training modifications due to “load” (correctly predicted in 82% of cases) and “groin” (correctly predicted in 92% of cases) respectively. These procedures and results can immediately be integrated into athlete monitoring systems, though investigations into combining these procedures with more established parameters may enhance their ability to predict adverse events. In addition, results supported previous research into the association between movement variability and pathology, and further research into the mechanism behind the changes in step waveform variability utilising the procedures outlined in this study will aid in the development and testing of our theoretical hypothesis.

STRIDE

Source

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The effect of technique on loading at the knee during common sporting manoeuvres

Jodie Cochrane David G. Lloyd Thor F. Besier Tim Ackland Alec Buttfield

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Citations (0)

Audio interview with Mark Williams

Sensoria A Journal of Mind Brain and Culture (2016)

Alec Buttfield

Williams Syndrome

10.7790/sa.v12i2.444

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Using the interaction of speed and acceleration to detect repeated-sprint activity in team sports

Journal of Sports Sciences (2020)

Ted Polglaze Brian Dawson Alec Buttfield Peter Peeling

To compare the occurrence and characteristics of repeated-sprint (RS) activity in elite team sport competition when classified according to speed and/or acceleration, and their interaction via metabolic power (Pmet). Methods: Elite male hockey players (N = 16) wore player-tracking devices in six international matches. Sprint efforts were defined using four separate classifications: speed >5.5 m∙s-1, acceleration >1.5 m∙s-2, speed-or-acceleration, and Pmet >25.5 W∙kg-1. RS bouts were defined as ≥3 efforts with mean recovery ≤21 s. For Pmet, RS bouts were also classified using a maximal recovery period ≤21 s. The number of sprint efforts and RS bouts, and the number of efforts, effort durations and recovery periods within RS bouts, were compared across each classification method, and between mean and maximal recovery criteria. Results: More RS bouts were identified via Pmet (8.5 ± 2.8) than either speed and/or acceleration, and comprised more efforts (4.0 ± 0.4) with shorter recovery periods (11.5 ± 1.8 s). Fewer RS bouts (7.3 ± 2.8 vs. 8.5 ± 2.8) were identified with a maximum rather than mean recovery criterion. Conclusions: Definitions of sprint efforts and recovery periods which reflect ATP depletion and replenishment via Pmet suggest that RS activity occurs frequently in team sport competition, and is more demanding than when speed and/or acceleration are used to define RS activity in variable-speed locomotion.

Sprint

Team sport

Match play

10.1080/02640414.2020.1776464

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Citations (7)

Physical Demands of Elite Women's Ultimate Frisbee Between Halves and Across Matches in an International Tournament

The Journal of Strength and Conditioning Research (2020)

Jodie A. Palmer Grant Landers Alec Buttfield Ted Polglaze

Palmer, JA, Landers, G, Buttfield, A, and Polglaze, T. Physical demands of elite women's Ultimate Frisbee between halves and across matches in an international tournament. J Strength Cond Res 36(3): 838-844, 2022-To quantify the physical match demands of elite women's Ultimate Frisbee across a tournament, elite female Ultimate players (N = 9) from the Australian Under 24 Women's team wore global positioning system units in all 12 matches of the 2018 Under 24 World Championship competition. Temporal, displacement, and energetic parameters were obtained. Distribution of activity above and below a generic speed threshold (12.42 km·h-1) and its equivalent metabolic power value (16.02 W·kg-1) were determined. Players spent 12:44 ± 6:41 min:s on the field, covered 1,559 ± 741 m and expended 8.95 ± 4.21 kJ·kg-1 during a match. The mean stint duration was 2:00 ± 0:48 min:s, mean bench duration was 13:25 ± 7:05 min:s, and work-to-recovery ratio was 0.22 ± 0.11. Players performed 57 ± 27 high-speed runs per match and 45 ± 20 high-accelerations. Mean match speed was 127 ± 18 m·min-1, mean metabolic power was 12.2 ± 1.7 W·kg-1, and mean intermittency index was 1.24 ± 0.04. No differences were found between halves for any parameters. Compared with the first 4 matches, the last 4 matches were shorter and more intense (p < 0.05). At the international level, Ultimate is an intense and highly intermittent sport, characterized by brief playing stints interspersed with long periods of recovery, which allow playing intensity to be maintained throughout a match and elevated in the latter stages of a tournament. The information gained from this research can be used to guide the creation of Ultimate-specific conditioning programs for elite female players.

Tournament

Sprint

Elite

10.1519/jsc.0000000000003527

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Citations (5)

Muscle pre-activation strategies play a role in modulating Kvert for change of direction manoeuvres: An observational study

Journal of Electromyography and Kinesiology (2014)

Benjamin G. Serpell Nick Ball Jennie M. Scarvell Alec Buttfield Paul N. Smith

Vastus medialis

Motor Unit Recruitment

10.1016/j.jelekin.2014.06.008

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Citations (11)