Minh Huynh’s research while affiliated with La Trobe University and other places

This study investigated the inter-rater reliability and validity of the Fulltrack AI application, to measure ball speed under a range of cricket training conditions in comparison to a radar gun. Ball speed (km/hr) of 1081 deliveries (pace = 783; spin = 298) from a range of training sessions and conditions were recorded simultaneously using a radar gun (Stalker Pro IIs) and iOS device running Fulltrack AI (v1.13.1). Statistical analyses were conducted in R Statistical Software. Reliability was assessed with standard error of measurement (SEM), coefficient of variation (CV) and intraclass correlation coefficient (ICC). Agreement was assessed using Bland Altman's 95% limits of agreement (LOA). Validity was assessed using generalised additive models (GAMs). Pace deliveries were associated with good agreement (ICC: 0.87–0.90, CV: 2.56–3.13%), whilst spin deliveries demonstrated lower agreement (ICC: 0.72–0.76, CV: 3.08–4.33%). LOA established poor to fair levels of agreement, exceeding maximal allowable differences (>3%). GAMs identified Fulltrack AI overestimated ball speed (pace: estimate 0.72–0.77 m/s, SE = 0.34–0.34; spin: estimate 1.09–1.18 m/s, SE = 0.23–0.25) when compared to the radar gun. Fulltrack AI is an ecologically valid and reliable field-based method for measuring ball speed. However, caution is warranted given the significant overestimation of ball speed in contrast with a radar gun, even after controlling for different training conditions, suggesting software could benefit from refinement.

Purpose: This investigation sought to determine industry perceptions of postgraduate strength and conditioning (S&C) degrees to understand whether graduates are equipped for the demands of sport performance service roles. Methods: Survey data were collected from 111 participants employed as performance staff or in a role that recruits and supervises performance staff. The survey consisted of 3 main sections: (1) perceptions of career-development opportunities in S&C, (2) perception of S&C postgraduate programs, and (3) perceptions of employability in S&C. Exploratory factor analysis was conducted to identify the key factors considered to be of greatest relevance to career progression in S&C. Results: A 2-factor solution was achieved for each of the 3 sections, resulting in 6 total factors. These factors are Academic and Professional Development, Mentorship and Sport Diversity, Student Preparation, Require Greater Emphasis, Testing and Training, and Personal and Professional Growth. Conclusions: Postgraduate S&C programs require a broad range of placement/internship opportunities to (1) provide diverse experiences, (2) allow students to build contacts and develop professional networks, (3) gain exposure to working in high-performance environments and multidisciplinary teams, and (4) access high-quality mentors. Alongside the ability to deliver training and testing, graduates should be equipped with strong organizational and relationship-building skills. Improved graduate capabilities can raise the standards of the profession and result in enhanced service provision to athletes.

Pairwise comparison of heavy dynamic strength and fast dynamic strength interventions on sprint performance: a systematic review and meta-analysis. J Strength Cond Res 38(8): 1509–1520, 2024—Previous studies have shown that both heavy dynamic strength (HDS) and fast dynamic strength (FDS) training can be used to improve sprint performance; however, a review and meta-analysis investigating pairwise studies that compare these two training interventions have not been performed. The aims of the study were to systematically review and analyze HDS and FDS training methodologies and evaluate their effect size difference, in pairwise comparison studies to determine and compare their effects on sprint performance. Databases were systematically searched using Boolean phrasing to identify eligible articles, and meta-analyses were performed on the extracted data. Seven studies met the inclusion criteria, which resulted in data from 138 subjects across 24 separate sprint assessments. Overall, there was a small effect in favor of FDS (standardized mean difference = 0.27, 95% confidence intervals [−0.07; 0.60], 95% prediction intervals [−1.01; 1.55]), but this was deemed not significant because of the wide-ranging prediction intervals. There is no distinguishable difference between HDS and FDS training on sprint performance. The wide-ranging prediction intervals suggest the variability is too great to determine whether one training type is more effective than the other. Practitioners should consider the individual needs of their athletes when deciding which training type to use for long-term sprint development.

Coaches utilise augmented feedback to help channel learning and skill acquisition in sports. However, the rationale and pedagogical approaches underpinning feedback (and technology) strategies employed by coaches remain poorly understood. The purpose of this study was to explore cricket coaches understanding towards the role of feedback, and how feedback (and technology) strategies are enacted within practice settings, viewed within pedagogical frameworks. An online questionnaire (Qualtrics) consisted of fixed-text and free-text questions. Fixed-text responses were analysed exploring associations (frequencies, chi-square) or differences (Mann-Whitney U) between coaching groups, with free-text questions examined through reflexive thematic analysis, exploring approaches to presenting athletes with feedback (and technology use). Overall, 134 coaches (94% male, 6% female) aged 18–69 years from 12 countries responded to the questionnaire. Following silhouette and k-modes cluster analysis, results were explored for two coaching groups: community cricket coaches (n = 84, 63%) and higher-performance coaches (n = 50, 37%). Significant differences showed greater coaching experience, qualifications, and time spent coaching per week for the higher-performance coaching group (p < 0.0125), in addition to higher self-efficacy around feedback, albeit with a small effect size (p < 0.001, r = 0.29). Community coaches showed a significant difference in manipulating feedback strategies on motivational factors (p < 0.0125). Reflexive thematic analysis identified different rationales for the perceived role of feedback and use of technology across coaching groups, underpinned by contrasting pedagogical approaches (coach-centred versus athlete-centred). Responses highlighted the co-adaptive properties of coach-athlete dyads (evident in how/why feedback was manipulated). Overall findings present opportunities to further coach education to improve understanding and operationalisation of feedback (and technology).

Purpose Understanding the test–retest reliability of physiological responses to load carriage influences the interpretation of those results. The aim of this study was to determine the test–retest reliability of physiological measures during loaded treadmill walking at 5.5 km h⁻¹ using the MetaMax 3B. Methods Fifteen Australian Army soldiers (9 male, 6 female) repeated two 12-min bouts of treadmill walking at 5.5 km h⁻¹ in both a 7.2 kg Control condition (MetaMax 3B, replica rifle) and a 23.2 kg Patrol condition (Control condition plus vest) across three sessions, separated by one week. Expired respiratory gases and heart rate were continuously collected, with the final 3 min of data analysed. Ratings of Perceived Exertion and Omnibus-Resistance Exercise Scale were taken following each trial. Reliability was quantified by coefficient of variation (CV), intra-class correlation coefficients (ICC), smallest worthwhile change (SWC), and standard error of the measurement. Results Metabolic and cardiovascular variables were highly reliable (≤ 5% CV; excellent-moderate ICC), while the respiratory variables demonstrated moderate reliability (< 8% CV; good-moderate ICC) across both conditions. Perceptual ratings had poorer reliability during the Control condition (12–45% CV; poor ICC) than the Patrol condition (7–16% CV; good ICC). Conclusions The test–retest reliability of metabolic and cardiovascular variables was high and relatively consistent during load carriage. Respiratory responses demonstrated moderate test–retest reliability; however, as the SWC differed with load carriage tasks, such data should be interpreted independently across loads. Perceptual measures demonstrated poor to moderate reliability during load carriage, and it is recommended that they only be employed as secondary measures. Graphical abstract

Background Repeated-sprint training (RST) is a common training method for enhancing physical fitness in athletes. To advance RST prescription, it is important to understand the effects of programming variables on physical fitness and physiological adaptation. Objectives This study (1) quantifies the pooled effects of running RST on changes in 10 and 20 m sprint time, maximal oxygen consumption (VO2max), Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) distance, repeated-sprint ability (RSA), countermovement jump (CMJ) height and change of direction (COD) ability in athletes, and (2) examines the moderating effects of program duration, training frequency, weekly volume, sprint modality, repetition distance, number of repetitions per set and number of sets per session on changes in these outcome measures. Methods Pubmed, SPORTDiscus and Scopus databases were searched for original research articles up to 04 July 2023, investigating RST in healthy, able-bodied athletes, between 14 and 35 years of age, and a performance calibre of trained or above. RST interventions were limited to repeated, maximal running (land-based) sprints of ≤ 10 s duration, with ≤ 60 s recovery, performed for 2–12 weeks. A Downs and Black checklist was used to assess the methodological quality of the included studies. Eligible data were analysed using multi-level mixed-effects meta-analysis, with standardised mean changes determined for all outcomes. Standardised effects [Hedges G (G)] were evaluated based on coverage of their confidence (compatibility) intervals (CI) using a strength and conditioning specific reference value of G = 0.25 to declare an improvement (i.e. G > 0.25) or impairment (i.e. G < − 0.25) in outcome measures. Applying the same analysis, the effects of programming variables were then evaluated against a reference RST program, consisting of three sets of 6 × 30 m straight-line sprints performed twice per week for 6 weeks (1200 m weekly volume). Results 40 publications were included in our investigation, with data from 48 RST groups (541 athletes) and 19 active control groups (213 athletes). Across all studies, the effects of RST were compatible with improvements in VO2max (G 0.56, 90% CI 0.32–0.80), YYIR1 distance (G 0.61, 90% CI 0.43–0.79), RSA decrement (G − 0.61, 90% CI − 0.85 to − 0.37), linear sprint times (10 m: G − 0.35, 90% CI − 0.48 to − 0.22; 20 m: G − 0.48, 90% CI − 0.69 to − 0.27), RSA average time (G − 0.34, 90% CI − 0.49 to − 0.18), CMJ height (G 0.26, 90% CI 0.13–0.39) and COD ability (G − 0.32, 90% CI − 0.52 to − 0.12). Compared with the reference RST program, the effects of manipulating training frequency (+ 1 session per week), program duration (+ 1 extra training week), RST volume (+ 200 m per week), number of reps (+ 2 per set), number of sets per session (+ 1 set) or rep distance (+ 10 m per rep) were either non-substantial or comparable with an impairment in at least one outcome measure per programming variable. Conclusions Running-based RST improves speed, intermittent running performance, VO2max, RSA, COD ability and CMJ height in trained athletes. Performing three sets of 6 × 30 m sprints, twice per week for 6 weeks is effective for enhancing physical fitness and physiological adaptation. Additionally, since our findings do not provide conclusive support for the manipulation of RST variables, further work is needed to better understand how programming factors can be manipulated to augment training-induced adaptations. Study Registration Open Science Framework registration https://doi.org/10.17605/OSF.IO/RVNDW.

Background: Maximal lower-body strength can be assessed both dynamically and isometrically; however, the relationship between the changes in these 2 forms of strength following resistance training is not well understood. Purpose: To systematically review and analyze the effects of resistance training on changes in maximal dynamic (1-repetition-maximum back squat, deadlift, and power clean) and position-matched isometric strength (isometric midthigh pull and the isometric squat). In addition, individual-level data were used to quantify the agreement and relationship between changes in dynamic and isometric strength. Methods: Databases were systematically searched to identify eligible articles, and meta-analysis procedures were performed on the extracted data. The raw results from 4 studies were acquired, enabling bias and absolute reliability measures to be calculated using Bland-Altman test of agreement. Results: Eleven studies met the inclusion criteria, which resulted in 29 isometric-dynamic change comparisons. The overall pooled effect was 0.13 in favor of dynamic testing; however, the prediction interval ranged from g = -0.49 to 0.75. There was no evidence of bias (P = .825) between isometric and dynamic tests; however, the reliability coefficient was estimated to be 16%, and the coefficient of variation (%) was 109.27. Conclusions: As a range of future effects can be expected when comparing isometric to dynamic strength changes following resistance training, and limited proportionality exists between changes in these 2 strength qualities, there is strong evidence that isometric and dynamic strength represent separate neuromuscular domains. These findings can be used to inform strength-assessment models in athlete populations.