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Comment on Passfield et al: Validity of the Training-Load Concept
Shaun J. McLaren, Tzlil Shushan, Christoph Schneider, and Patrick Ward
Programming High-Speed and Sprint Running Exposure in Football: Beliefs and Practices of More Than 100 Practitioners Worldwide
Antonio Dello Iacono, Marco Beato, Viswanath B. Unnithan, and Tzlil Shushan
Purpose: To gain knowledge on the beliefs and practices of football practitioners applying high-speed and sprint running exposure programming strategies. Methods: One hundred two football practitioners from 22 different countries participated in a study consisting of a survey including 5 domains: demographic and professional characteristics (Who); importance of high-speed and sprint running exposure for physical-capability development, preparation for competition, and injury-prevention strategies (Why); exposure timing (When); methodological procedures for exposure monitoring and training scheduling (What); and effectiveness of common training practices (How). Data were analyzed using a combination of descriptive statistics, generalized mixed effects, and multinomial logistic regression models. Results: Data revealed 5 main findings: (1) overall agreement on the importance of exposure for physical-capability development, preparation for competition, and injury-prevention strategies; (2) different exposure timing and selective training scheduling for starting and nonstarting players across typical and congested weeks; (3) lack of consensus on the conceptual constructs defining high-speed and sprint running metrics and the methodological procedures used for monitoring; (4) a probable association between match-related outcomes and exposure strategies used in training; and (5) a broad range of training methods considered effective to elicit exposure. Conclusions: This study provides actionable insights into the planning, implementing, and monitoring strategies for high-speed and sprint running exposure in football. While some conform with the evidence on high-speed and sprint running training in football, further research and professional debate are warranted to develop empirical knowledge and provide pragmatic recommendations to help practitioners in adopting evidence-informed decisions.
Can We Just Play? Internal Validity of Assessing Physiological State With a Semistandardized Kicking Drill in Professional Australian Football
Adriano Arguedas-Soley, Tzlil Shushan, Andrew Murphy, Nicholas Poulos, Ric Lovell, and Dean Norris
Purpose: To examine associations between exercise heart rate (HRex) during a continuous-fixed submaximal fitness test (CF-SMFT) and an intermittent-variable protocol (semistandardized kicking drill [SSD]) in Australian Football athletes, controlling for external intensities, within-session scheduling, and environmental conditions. Methods: Forty-four professional male Australian Football athletes (22.8 [8.0] y) were monitored over 10 sessions involving a 3-minute CF-SMFT (12 km·h−1) as the first activity and a SSD administered 35.7 (8.0) minutes after the CF-SMFT. Initial heart rate and HRex were collected, with external intensities measured as average velocity (in meters per minute) and average acceleration–deceleration (in meters per second squared). Environmental conditions were sampled. A penalized hierarchical linear mixed model was tuned for a Bayesian information criterion minima using a 10-fold cross-validation, with out-of-sample prediction accuracy assessed via root-mean-squared error. Results: SSD average acceleration–deceleration, initial heart rate, temperature, and ground hardness were significant moderators in the tuned model. When model covariates were held constant, a 1%-point change in SSD HRex associated with a 0.4%-point change in CF-SMFT HRex (95% CI, 0.3–0.5). The tuned model predicted CF-SMFT HRex with an average root-mean-squared error of 2.64 (0.57) over the 10-fold cross-validation, with 74% and 86% of out-of-sample predictions falling within 2.7%-points and 3.7%-points, respectively, from observed values, representing the lower and upper limits for detecting meaningful changes in HRex according to the documented typical error. Conclusions: Our findings support the use of an SSD to monitor physiological state in Australian Football athletes, despite varied scheduling within session. Model predictions of CF-SMFT HRex from SSD HRex closely aligned with observed values, considering measurement imprecision.
A Worldwide Survey on the Practices and Perceptions of Submaximal Fitness Tests in Team Sports
Tzlil Shushan, Dean Norris, Shaun J. McLaren, Martin Buchheit, Tannath J. Scott, Steve Barrett, Antonio Dello Iacono, and Ric Lovell
Purpose: To survey team-sport practitioners on current practices and perceptions of submaximal fitness tests (SMFTs). Methods: A convenience sample of team-sport practitioners completed an online survey (September to November 2021). Descriptive statistics were used to obtain information of frequencies. A mixed-model quantile (median) regression was employed to assess the differences between the perceived influence of extraneous factors. Results: A total of 66 practitioners (74 discrete protocols) from 24 countries completed the survey. Time-efficient and nonexhaustive nature were considered the most important features of implementation. Practitioners prescribed a range of SMFTs, administered mostly on a monthly or weekly basis, but scheduling strategies appeared to differ across SMFT categories. Cardiorespiratory/metabolic outcome measures were collected in most protocols (n = 61; 82%), with the majority monitoring heart-rate-derived indices. Subjective outcome measures (n = 33; 45%) were monitored exclusively using ratings of perceived exertion. Mechanical outcome measures (n = 19; 26%) included either a combination of locomotor outputs (eg, distance covered) or variables derived from microelectrical mechanical systems. The perceived influence of extraneous factors on measurement accuracy varied according to outcome measure, and there was a lack of consensus among practitioners. Conclusions: Our survey showcases the methodological frameworks, practices, and challenges of SMFTs in team sports. The most important features for implementation perhaps support the use of SMFTs as a feasible and sustainable tool for monitoring in team sports. The wide variety of protocols, scheduling strategies, and outcome measures, along with their associated collection and analytical techniques, may reflect the absence of robust evidence regarding the application of SMFTs in team sports.
A Methodological Comparison of Protocols and Analytical Techniques to Assess the Outcome Measures of Submaximal Fitness Tests
Tzlil Shushan, Ric Lovell, Shaun J. McLaren, Steve Barrett, Martin Buchheit, Tannath J. Scott, and Dean Norris
Background: Submaximal fitness test (SMFT) outcome measures are frequently collected with a wide array of technologies and methodological approaches. Purpose: To examine the test–retest reliability of various SMFT outcome measures derived from different protocols and analytical techniques. Methods: Twenty-six semiprofessional adult soccer players performed 3 SMFT protocols, including 2 continuous (3 min, 11 and 12.8 km·h−1) and 1 intermittent (4 × 50 m, 18 km·h−1) twice, each separated by 7 days. Heart-rate (HR) indices (exercise HR, HR recovery) and scapula-mounted (PlayerLoad vector magnitude) and foot-mounted (flight time and contact time, stride length) microelectrical mechanical system–derived variables were collected using different time frames and analytical approaches adopted in the literature and practice. Absolute reliability was quantified as the group mean difference, typical error of measurement, also expressed as the coefficient of variation (where appropriate) and standardized units (ie, d). Intraclass correlation coefficient was used to quantify relative reliability. Results: The highest degrees of reliability were evident for exercise HR (typical error: 1.0%–1.6% points), the vertical component of PlayerLoad (expressed in arbitrary units; coefficient of variation: 5.5%–7.0%), and contact time (coefficient of variation: 1.5%–3.0%). These estimates were not influenced by SMFT protocol or analytical approach. All other measures displayed poorer reliability and/or were different between protocols and analytical methods. Conclusions: SMFT protocols impact the test–retest reliability of various outcome measures; however, exercise HR, vertical PlayerLoad, and contact time (derived from foot-mounted micro-electrical mechanical systems) appear to have stable measurement properties to assist the assessment of aerobic capacity and lower-limb neuromuscular status, respectively.
