Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Spectral and Spatial Analysis of Plantar Force Distributions Across Foot-Strike Patterns During Treadmill Running(MDPI (Basel, Switzerland), 2025-08-06) Macdermid PW; Walker SJ; King MTreadmill running gait differs to overland running and is commonly used to evaluate interventions. One challenge is accurately defining strike pattern and related impact kinetics. This study aimed to characterise foot-strike patterns during treadmill running using the spatial distribution of in-shoe plantar forces and to identify differences in impact kinetics through spectral analysis. Low- and high-frequency power components were analysed in heel, midfoot and forefoot strike patterns. No distinct impact peaks were identified in the force traces; however, significant spatial differences were found. Forefoot strikes exhibited lower peak impact force, average loading rate, and high-frequency power spectral density (PSD) components compared to heel and midfoot strikes, with heel also lower than midfoot. Strike pattern classification was derived from spatial force distribution, where >70% posterior and >50% anterior denote heel and forefoot strikes, while midfoot strikes demonstrate a more balanced distribution with >25% in the central zone. These findings support the integration of spatial, force-based classification with frequency-domain analysis to enhance the evaluation of impact attenuation in treadmill-based running interventions.Item VLamax Correlates Strongly With Glycolytic Performance(Taylor and Francis Group on behalf of SHAPE America, 2025-04-18) Clark B; Macdermid PWVLamax estimates an athlete’s maximal-glycolytic rate. This study aimed to determine the relationships between the VLamax and cycle ergometry efforts with a high-glycolytic energy contribution and the influence of VLamax and VO2max on respiratory compensation point. Eleven national-international endurance cyclists (VO2max = 70.7 ± 5.9 ml·kg−1·min−1) completed a 15-s isokinetic-test with pre- and postlactate measurements to determine VLamax, a 1-min maximal effort, and a ramp test to exhaustion in a single test session. The main findings showed strong relationships between VLamax and the mean absolute (r = 0.83, p =.002) and relative (r = 0.88, p =.0004) power during the lactic interval of the 15-s isokinetic-test. This relationship weakened when comparing VLamax with mean absolute (r = 0.52, p =.098) and relative (r = 0.29, p =.393) power during a 1-min maximal effort. Combining the VLamax and VO2max data through multiple regression resulted in a positive effect on the estimation of respiratory compensation point. It was concluded that the VLamax is a relevant indicator of maximal glycolytic rate. However, this metric currently lacks scientific validation as an accurate estimate of glycolytic rate and provides minimal extra information over using the power output from the isokinetic test alone. Practitioners may simply measure power over glycolytically demanding efforts to understand the maximal glycolytic rate of their athletes.Item Editorial: Advancements in cycling performance enhancement strategies for cyclists: from amateurs to elite(Frontiers Media S A, 2025-03-10) Polanco A; Macdermid PW; Berisha M; Girard OItem The Effects of Cushioning Properties on Parameters of Gait in Habituated Females While Walking and Running(MDPI (Basel, Switzerland), 2025-01-23) Macdermid PW; Walker SJ; Cochrane D; Voloshin AFeatured Application: Understanding the interaction between running shoe properties and parameters of gait are somewhat scarce, particularly in female runners. This study demonstrates that contrasting energy absorption properties reduce kinetic variables associated with injuries in females while running, but not walking. The purpose of this study was to compare the mechanical properties of a non-cushioned minimalistic shoe and cushioned shoe during walking at 6 and running at 10 and 14 km∙h−1 in habituated female runners. Twelve habituated female runners completed two trials (cushioned shoe vs. minimalist shoe) with three within-trial speeds (6, 10, and 14 km∙h−1) in a counter-balanced design. Flexible pressure insole sensors were used to determine kinetic variables (peak vertical impact force, average loading rate, active vertical peak force, time to active peak vertical force, and impulse) and spatiotemporal variables (stride duration, cadence, ground contact time, swing time, and time to midstance). Cushioned running shoes exhibited greater energy absorption (690%), recovered energy (920%), and heat dissipation (350%). The cushioned shoes significantly reduced peak vertical impact (~12%) and average loading rate (~11%) at running speeds 10–14 km∙h−1. However, these effects were not observed during walking, nor did the cushioned shoes influence peak active force, impulse, stride duration, ground contact or swing time. Cushioned running shoes provide significant benefits in energy absorption, energy recovery, and heat dissipation, which decrease impact-related forces and loading rates in female runners without changing the spatiotemporal variables of gait.Item Evaluating the Usefulness of a PNT Solution Using DGNSS-SBAS for Canoe Slalom: Simulated and Real-World Analysis(MDPI (Basel, Switzerland), 2024-11-18) Macdermid PW; Irwin ME; Cochrane D; Daniel M-LFeatured Application: dGNSS-SBAS combined with geographical mapping software and georeferenced drone imagery is a cutting-edge approach to geographically track activities pertaining to canoe slalom. The PNT solution provided <0.3 m accuracy and provided a reliable means of tracking athletes’ trajectory, which could be used to monitor or develop best practice in athlete trajectories. This study investigated the accuracy and precision of a commercially available PNT solution that uses DGNSS-SBAS technology. Time and position data were sampled at a frequency of 20Hz during both a short and long trajectory of a simulated controlled dry-land slalom, as well as during a real-world on-water slalom exercise. The primary objective was to assess the positional accuracy, availability, integrity, and service continuity of the PNT solution while evaluating its ability to differentiate between trajectories. Additionally, the simulated results were compared with an on-water real-world slalom test to validate the findings. The results of the controlled dry-land slalom test indicate that the PNT solution provided accurate measurements with an overall mean ± SD Hrms of 0.20 ± 0.02 m. The integrity measures, HDOD and PDOP, were found to be ideal to excellent, with values of 0.68 ± 0.03 and 1.36 ± 0.07, respectively. The PNT solution utilised an average of 20 ± 1 satellites from the constellation, resulting in an accuracy of <1.5% when measuring the known trajectory of 50 simulated slalom runs. The data from the real-world on-water slalom test supported these findings, providing similar or improved results. Based on these findings, a PNT solution using DGNSS-SBAS can be considered an effective means of tracking athlete trajectory in the sport of canoe slalom. Future research should be conducted to quantify its efficacy more precisely.Item The Relationship between Stroke Metrics, Work Rate and Performance in Slalom Kayakers(MDPI (Basel, Switzerland), 2022-01-28) Macdermid PW; Olazabal T; Keogh J; Hortobagyi TThe purpose of this study was to assess the relationship between work rate, stroke metrics, and performance in whitewater slalom. Twelve Spanish, nationally competitive whitewater slalom kayakers took part in a simulated competition while using an instrumented kayak paddle to record stroke metrics over a simulated race, total duration and sectional splits. Performance time was highly correlated to overall power output (r2 = 0.511, p < 0.001), where kayakers demonstrated a positive pacing strategy with power output significantly decreasing over successive sectional splits (158 ± 40, 112 ± 32 and 65 ± 33 W, p < 0.001). This resulted in an increased stroke duration (p < 0.001), time to peak force (p < 0.001), a decrease in stroke peak force (p < 0.001), and rate of peak force development (p < 0.001) over elapsed time. As such, work rate is deemed an objective metric to monitor performance, prescribe training, and ascertain optimal pacing strategies in canoe slalom.Item The Validity and Reliability of a Global Navigation Satellite System in Canoe Slalom(MDPI (Basel, Switzerland), 2022-01-21) Macdermid PW; Coppelmans A; Cochrane D; Keogh JThis study investigates the usefulness of a 10 Hz GPS device for tracking scalar performance in canoe slalom through assessing the validity of automated-informed-aerial video tracking (30 fps and 10 fps) and GPS capability in relation to a known track. Additionally, a real-world (canoe-slalom). A comparison between manual-aerial video tracking (10 fps) and the 10 Hz GPS was performed. All three methods of tracking used during the dry-land test (30 fps or 10 fps video and GPS) reported significantly lower distances (−3.2, −5.1 and −8.5%, p < 0.0001) but were deemed useful based on sample rate and body positioning difference. Intra-method reliability was good (CV = 2.5−2.6%) but requires visual inspection for dataset errors. Informed-colour filtered automated tracking on-water was not possible, but manual tracking provided fewer dataset errors than dry-land automated tracking. GPS significantly (p < 0.0001) under reports distance travelled at key moments during real-world slalom with a bias ± SD of 2.26 ± 2.07 m compared to 10 fps manual-aerial video tracking. The aerial video combined with manual tracking proved most suitable for tracking canoe slalom athlete trajectory in a real-world setting but needs to be automated into an application-based package to make it useable for coaches. GPS, as presented, provides insight but does not accurately quantify movements critical in determining the performance of canoe slalom.Item A comparative analysis of critical power models in elite road cyclists(Elsevier B.V, 2021) Clark B; Macdermid PWThe aims of this study were to compare four different critical power model's ability to ascertain critical power and W' in elite road cyclists, while making comparison to power output at respiratory compensation point, work rate (J·sec-1) at Wmax, and the work done above critical power during the Wmax test in relation to the W'. Ten male, elite endurance cyclists (V̇O2max = 71.9 ± 5.9 ml kg-1·min-1) all familiar with critical power testing, participated in 3 testing sessions comprising 1. 15-s isokinetic (130 rpm) sprint, 1-min time trial, a ramp test to exhaustion, 2-3. a 4-min and/or 10-min self-paced maximal time trial separated by at least 24-h but limited to a 3-week period. The main findings show that all critical power models provided different W' (F(1.061,8.486) = 39.07, p = 0.0002) and critical powers (F(1.022,8.179) = 32.31, p = 0.0004), while there was no difference between each model's critical power and power output at respiratory compensation point (F(1.155, 9.243) = 2.72, p = 0.131). Differences between models or comparisons with respiratory compensation point were deemed not clinically useful in the provision of training prescription or performance monitoring if the aim is to equal work rate at compensation point. There was also no post-hoc difference between work completed at Wmax (kJ) (p = 0.890) and W' using the nonlinear-3 model. Further research is required to investigate the physiological markers of intensity associated with respiratory compensation point and critical power work rate and the bioenergetic contribution to W'.Item Using a kayak paddle power-meter in the sport of whitewater slalom(Research Group on Physical Activity and Sports Sciences (GICAFD). Department of Didactic General and Specific Training, University of Alicante, 1/03/2020) Macdermid PW; Gilbert C; Jayes JThe purpose of this paper was to demonstrate the use of a kayak-paddle power-meter to enhance scientific understanding, quantification of athlete assessment and training prescription in slalom kayaking. Data was collected from a continental-championship race, in addition to the author’s work, which included testing and prescribing training for elite athletes preparing for national and international competition. Results indicate that work rate varies considerably over a competition run (CV=74.4-80.5 %). Intra-athlete performance between two competition runs of one of the leading competitors differed by 1.1% or 0.94 s, while power output decreased by 9.0 % for the fastest run due to an increase in number of steering strokes (11 vs 3). Turning strokes had greater impulse (208 vs 94 N∙s), peak force (362 vs 321 N), and a lower rate of peak force development (810 vs 1925 N∙s-1). Methods to identify biomechanical/technical issues via analysis of force profiles per stroke exhibit bilateral comparisons of strength, while quantification of physical and physiological capability is determined through power output. Training zones are categorised into seven zones (Easy, Threshold, Critical Power, Speed Endurance, Speed and Strength) enabling coaches and athletes to implement specific training programmes targeting key facets of performance. The importance of testing venue is established where river technicality grade (I, II and IV) showed power output at the onset of blood lactate to be 120, 90, and 84 W, respectively. This paper thus supports the efficacy of using a paddle power-meter to enhance scientific understanding of slalom kayak racing through real-world competition analysis capability along with enabling the quantification of training prescription and monitoring based around work rate capability during sport specific testing, in conjunction with technical, physical and physiological qualities.Item The validation of a paddle power meter for slalom kayaking(Georg Thierne Verlag KG Stuttgart, 15/03/2017) Macdermid PW; FinkThe ability to quantify power within the sport of slalom kayaking would provide coaches and athletes objective data to monitor performance. This study determined the validity of a kayak paddle power meter and subsequent relationship between work rate and stroke kinetics. One participant completed multiple trials of a flat-water, straight-line sprint and a sequence of slalom gates at numerous intensities to attain the velocity:power relationship. Laboratory results identified the kayak paddles' strain gauges were valid and reliable, and field tests presented a cubic relationship for power as a function of velocity in the straight-line sprint (R 2 =0.982) and the slalom-specific test (R 2 =0.993). Further analysis of stroke kinetics identified velocity of hand movement at individual peak force capability to be critical in the highest work rates achieved for both slalom and flat-water sprinting. It was concluded that the kayak paddle power meter tested is a valid means of recording work rate and stroke kinetics during kayaking in the field.