Discrete time-series measurements collected at predefined timepoints are widely used in sport nutrition and exercise metabolism research, including tolerance tests, tracer studies, and physiological responses to experimental interventions. These data sets are commonly summarized using derived metrics such as area under the curve. The original Time Series Response Analyser, introduced in 2020 as a spreadsheet-based tool, aimed to standardize these calculations and reduced the risk of manual errors. However, spreadsheet implementations can be difficult to maintain, extend, and version control, and provide limited transparency regarding exactly how outputs are derived. Here, we present Time Series Response Analyser v2.0, a web-based successor designed to improve accessibility, usability, and long-term maintainability while preserving the analytical purpose of the original tool. The application runs in a standard web browser and guides users through a structured workflow consisting of data setup, file interpretation screening, interactive analysis, and export of results. It retains the core summary metrics of the original version while expanding visualization capabilities and export options. In summary, Time Series Response Analyser v2.0 is a free, open-source web-based application for researchers analyzing discrete time-series experiments across both repeated-measures and independent-groups designs, supporting transparent and reproducible analytical workflows while enabling future development through a code-based platform.

BACKGROUND:Personalized antioxidant supplementation is promoted to optimize redox balance and inflammation profile. OBJECTIVE:To quantify the short-term effects of vitamin C supplementation on redox and inflammatory outcome measures and explore the potential for supplement response heterogeneity in participants with vitamin C inadequacy through aggregated sets of multi-cycle n-of-1 trials. METHODS:Eight healthy young males (age 25.56 ± 3.15 years, body mass 68.24 ± 9.70 kg) completed four supplementation (vitamin C 1g) and four placebo trials administered on repeated occasions in randomized sequences following a 1-month run-in period. Vitamin C, F2-isoprostanes, interleukin-6, and tumor necrosis factor-α were assessed as primary outcomes. Separate within-participant linear mixed-effects modelling and meta-analytic models estimated replicate-averaged treatment effects and person-by-treatment response variation to vitamin C supplementation. RESULTS:Supplementation resulted in a statistically significant increase in plasma vitamin C of 20.6 μmol/L (95% confidence interval [CI]: 16.8 to 24.5). This mean treatment effect was lower than our selected clinically important threshold of 23 μmol/L. Vitamin C supplementation reduced F2-isoprostanes by 25.9 pg/mL (CI: 22.2 to 29.6 pg/mL), interleukin-6 by 1.2 pg/mL (CI: 0.7 to 1.7 pg/mL), and tumor necrosis factor-α by 0.5 pg/mL (CI: 0.2 to 0.9 pg/mL). The participant-by-treatment variance component from linear mixed-effects modelling was not statistically significant for all outcomes (P > 0.05), agreeing with the small τ-statistics for all outcomes. Shrinkage-adjusted estimates also showed strong shrinkage toward the mean, indicating that the observed response variation mainly reflected random within-person cycle-to-cycle variability rather than true inter-individual variability. CONCLUSIONS:Replicate-averaged treatment effects of vitamin C supplementation on our study outcomes were statistically significant, but heterogenous treatment effects were not detected between participants with baseline inadequacy. Cycle-to-cycle within-participant variation was larger than the observed inter-individual variability for each primary outcome response, suggesting that, if clinically relevant, "average treatment" may suffice for people prone to vitamin C inadequacy. CLINICAL TRIAL REGISTRY:Open Science Framework (osf.io/e567r). ETHICS:ERC-009/2024; #83059/2024.

Dietary nitrate supplementation increases nitric oxide (NO) bioavailability and reduces blood pressure (BP). Inter-individual differences in these responses are suspected but have not been investigated using robust designs, e.g., replicate crossover, and appropriate statistical models. We examined the within-individual consistency of the effects of dietary nitrate supplementation on NO biomarkers and BP, and quantified inter-individual response differences. Fifteen healthy males visited the laboratory four times. On two visits, participants consumed 140 ml nitrate-rich beetroot juice ( 14.0mmol nitrate) and, on the other two visits, they consumed 140 ml nitrate-depleted beetroot juice ( 0.03mmol nitrate). Plasma nitrate and nitrite concentrations were measured 2.5 h post-supplementation. BP was measured pre- and 2.5 h post-supplementation. Between-replicate correlations were quantified for the placebo-adjusted post-supplementation plasma nitrate and nitrite concentrations and pre-to-post changes in BP. Within-participant linear mixed models and a meta-analytic approach estimated participant-by-condition treatment response variability. Nitrate-rich beetroot juice supplementation elevated plasma nitrate and nitrite concentrations and reduced systolic (mean:-7mmHg, 95 https://clinicaltrials.gov/study/NCT05514821 .

Crossover randomized controlled trials (RCTs) are common in exercise and nutrition sciences. Since researchers randomize participants to different sequences of the treatment and comparator/control conditions, crossover RCTs are powerful for detecting mean treatment effects under certain circumstances. We aim to review the information that can be derived from crossover RCTs about treatment response heterogeneity-a fundamental issue in precision medicine for tailoring treatments to individuals. After covering the fundamental design issues, we describe the variance components that underlie observed data. The crucial person-by-treatment variance component can be quantified from a repeated or "replicate" crossover RCT by exposing participants to multiple cycles of trial conditions. As a type of n-of-1 trial, replicate crossover RCTs have important design and statistical power considerations, which we describe. By synthesizing findings from our six published replicate crossover RCTs, we also compare various data analysis approaches. We find general agreement between these approaches, and a link between within-person consistency of response and the detection of person-by-treatment interactions. We postulate that a paired "variance comparison," for example, the Pitman-Morgan test, provides some preliminary information regarding response heterogeneity from a typical single-cycle crossover RCT. Nevertheless, underlying assumptions are critical, rendering these comparisons as merely exploratory until an n-of-1 or replicate crossover RCT is undertaken. Multiple-cycle n-of-1 trials and replicate crossover RCTs are underused but are informative for treatment response heterogeneity. However, these trials are still only one component of the process for predicting individual magnitude of response from any personal traits, which is the "holy grail" of personalized treatment.

Population-specific thresholds have not been defined for the levels of adiposity and systemic biomarkers that predict chronic health risks in people with restricted growth conditions. Here, anthropometric measures of adiposity, basal metabolic requirements, and fasted blood samples were obtained from adults with restricted growth (age 41 ± 14 years, height 1.30 ± 0.10 m, body mass 60.5 ± 18.3 kg, female: male n = 24:13, achondroplasia n = 26; mean ± SD). Basal metabolic rate was 6529 ± 1703 kJ·d-1 and total mass-normalized energy requirements were higher for females versus males. Plasma concentrations of glucose (5.55 ± 0.73 mmol·L-1), insulin (36.4 ± 19.9 pmol·L-1) and lipids (triacylglycerol 0.84 ± 0.37 mmol·L-1; total cholesterol 4.54 ± 0.85 mmol·L-1; high-density lipoprotein cholesterol 1.41 ± 0.31 mmol·L-1; low-density lipoprotein cholesterol 2.73 ± 0.69 mmol·L-1) were mostly within healthy clinical reference ranges. Sagittal abdominal diameter was positively correlated with plasma glucose and leptin concentrations (r = 0.85; 95% CI: 0.61, 0.95; p < 0.0001, and r = 0.85; 95% CI: 0.61, 0.95; p < 0.0001, respectively). Mean ± SD body mass index (BMI) was 36.1 ± 11.0 kg·m-2. However, we found that body mass scaled to height by the power of 1.4 (95% CI: 0.2, 2.6) rather than 2 associated with conventional BMI. Conventional biomarkers of cardiometabolic health are not substantially elevated in these individuals with restricted growth despite the classification of obesity using height-dependent references (e.g., traditional BMI).

Study Objectives Using the necessary replicate-crossover design, we investigated whether there is interindividual variability in home-assessed sleep in response to acute exercise.Methods Eighteen healthy men (mean [SD]: 26[6] years) completed two identical control (8 hour laboratory rest, 08:45-16:45) and two identical exercise (7 hour laboratory rest; 1 hour laboratory treadmill run [62(7)% peak oxygen uptake], 15:15-16:15) trials in randomized sequences. Wrist-worn actigraphy (MotionWatch 8) measured home-based sleep (total sleep time, actual wake time, sleep latency, and sleep efficiency) two nights before (nights 1 and 2) and three nights after (nights 3-5) the exercise/control day. Pearson's correlation coefficients quantified the consistency of individual differences between the replicates of control-adjusted exercise responses to explore: (1) immediate (night 3 minus night 2); (2) delayed (night 5 minus night 2); and (3) overall (average post-intervention minus average pre-intervention) exercise-related effects. Within-participant linear mixed models and a random-effects between-participant meta-analysis estimated participant-by-trial response heterogeneity.Results For all comparisons and sleep outcomes, the between-replicate correlations were nonsignificant, ranging from trivial to moderate (r range = -0.44 to 0.41, p >= .065). Participant-by-trial interactions were trivial. Individual differences SDs were small, prone to uncertainty around the estimates indicated by wide 95% confidence intervals, and did not provide support for true individual response heterogeneity. Meta-analyses of the between-participant, replicate-averaged condition effect revealed that, again, heterogeneity (tau) was negligible for most sleep outcomes.Conclusions Control-adjusted sleep in response to acute exercise was inconsistent when measured on repeated occasions. Interindividual differences in sleep in response to exercise were small compared with the natural (trial-to-trial) within-subject variability in sleep outcomes.Clinical trials information https://clinicaltrials.gov/study/NCT05022498. Registration number: NCT05022498.

Objectives: Dietary nitrate supplementation increases nitric oxide (NO) bioavailability and reduces blood pressure (BP). Individual differences in these responses are suspected but have not yet been investigated using robust designs, e.g., replicate crossover trials, and appropriate statistical models. We examined the within-individual consistency of the effects of dietary nitrate supplementation on NO biomarkers and blood pressure, and quantified inter-individual response differences. Methods: Fifteen healthy men (age: 27 (5), BMI: 24 (4) kg/m2) visited the laboratory on four occasions. Two visits involved consumption of 140 ml nitrate-rich beetroot juice and two involved consumption of 140 ml nitrate-depleted beetroot juice. Plasma nitrate and nitrite concentrations were measured 2.5 hours post-supplementation, and BP was measured prior to and 2.5 hours post-supplementation. Correlations between replicates were quantified for the placebo-adjusted post-supplementation plasma nitrate and nitrite concentrations and pre-to-post supplementation changes in BP. Within-participant linear mixed models were used to quantify individual response heterogeneity via participant-condition interactions. Results: Consumption of nitrate-rich beetroot juice elevated plasma nitrate and nitrite concentrations and reduced systolic (-7 mmHg, 95% CI = -3 to -11 mmHg, p=0.001) and diastolic (-6 mmHg, 95% CI = -2 to -9 mmHg, p=0.003) BP versus placebo. Moderate-to-large positive correlations were observed between the two replicates of placebo-adjusted responses to nitrate supplementation for plasma nitrate (r=0.91) and nitrite (r=0.55) concentrations as well as for systolic BP (r=0.80) (all p< 0.05). Significant participant-condition interactions were present for plasma nitrate and nitrite concentrations and systolic BP (p< 0.02). Conclusions: In this seminal study involving a replicate crossover design, we have shown that effects of dietary nitrate supplementation on NO biomarkers and systolic blood pressure show good consistency within individuals, with reproducible inter-individual differences in these responses. The causes of this inter-individual variation deserve investigation. Funding Sources: Funded by the Newcastle Wellcome Trust Translational Partnership.

OBJECTIVES:To quantify the test-retest reliability of 3 patient-reported outcome measures of pain for people living with phantom limb pain (PLP) and assess the impact of test-retest errors on future research and clinical decisions. METHODS:Thirty-nine participants (30 males), mean (SD) age: 55 (16), mean (SD) years postamputation: 6.8 (8.3), reported their PLP levels on a visual analogue scale (VAS) for pain intensity, the revised short-form McGill Pain Questionnaire (SF-MPQ-2), and a pain diary, on 2 occasions 7 to 14 days apart. Mean systematic change, within-subjects SD, limits of agreement (LOA), coefficient of variation, and the intraclass correlation coefficient (ICC) were quantified alongside their respective 95% confidence intervals (95% CIs). RESULTS:Systematic learning effects (mean changes) were not clinically relevant across the VAS, SF-MPQ-2, and pain diary. Within-subject SDs (95% CI) were 11.8 (9.6-15.3), 0.9 (0.7-1.2), and 8.6 (6.9-11.5), respectively. LOA (95% CI) were 32.6 (26.5-42.4), 2.5 (2-3.3), and 23.9 (19.2-31.8), respectively. ICCs (95% CI) were 0.8 (0.6-0.9), 0.8 (0.7-0.9), and 0.9 (0.8-0.9), respectively, but may have been inflated by sample heterogeneity. The test-retest errors allowed detection of clinically relevant effect sizes with feasible sample sizes in future studies, but individual errors were large. DISCUSSION:For people with PLP, a pain intensity VAS, the SF-MPQ-2, and a pain diary show an acceptable level of intersession reliability for use in future clinical trials with feasible sample sizes. Nevertheless, the random error observed for all 3 of the pain outcome measures suggests they should be interpreted with caution in case studies and when monitoring individuals' clinical status and progress.

Abstract Background Following consumption of a meal, circulating glucose concentrations can rise and then fall briefly below the basal/fasting concentrations. This phenomenon is known as reactive hypoglycaemia but to date no study explored potential inter-individual differences in response to meal consumption. Objective We conducted a secondary analysis of existing data to examine inter-individual variability of reactive hypoglycaemia in response to breakfast consumption. Methods Using a replicate crossover design, 12 healthy men completed two identical control (continued overnight fasting) and two breakfast (444 kcal) conditions in randomised sequences. Blood glucose and lactate concentrations, serum insulin and non-esterified fatty acid concentrations, whole-body energy expenditure, carbohydrate and fat oxidation rates, and appetite ratings were determined before and 2 hours after the interventions. Inter-individual differences were explored using Pearson’s product-moment correlations between the first and second replicates of the control-adjusted breakfast response. Within-participant covariate-adjusted linear mixed models and a random-effects meta-analytical approach were used to quantify participant-by-condition interactions. Results Breakfast consumption lowered 2-h blood glucose 0.44 mmol/L (95%CI: 0.76 to 0.12 mmol/L) and serum NEFA concentrations, whilst increasing blood lactate and serum insulin concentrations (all p < 0.01). Large, positive correlations were observed between the first and second replicates of the control-adjusted insulin, lactate, hunger, and satisfaction responses to breakfast consumption (all r > 0.5, 90%CI ranged from 0.03 to 0.91). The participant-by-condition interaction response variability (SD) for serum insulin concentration was 11 pmol/L (95%CI: 5 to 16 pmol/L), which was consistent with the τ-statistic from the random-effects meta-analysis (11.7 pmol/L, 95%CI 7.0 to 22.2 pmol/L) whereas effects were unclear for other outcome variables (e.g., τ-statistic value for glucose: 0 mmol/L, 95%CI 0.0 to 0.5 mmol/L). Conclusions Despite observing reactive hypoglycaemia at the group level, we were unable to detect any meaningful inter-individual variability of the reactive hypoglycaemia response to breakfast. There was, however, evidence that 2-h insulin responses to breakfast display meaningful inter-individual variability, which may be explained by relative carbohydrate dose ingested and variation in insulin sensitivity of participants.

ABSTRACT Purpose Using a replicated crossover design, we quantified the response heterogeneity of postprandial cardiovascular disease risk marker responses to acute exercise. Methods Twenty men (mean (SD) age, 26 (6) yr; body mass index, 23.9 (2.4) kg·m−2) completed four 2-d conditions (two control, two exercise) in randomized orders. On days 1 and 2, participants rested and consumed two high-fat meals over 9 h. Participants ran for 60 min (61 (7)% of peak oxygen uptake) on day 1 (6.5 to 7.5 h) of both exercise conditions. Time-averaged total area under the curve (TAUC) for triacylglycerol, glucose, and insulin were calculated from 11 venous blood samples on day 2. Arterial stiffness and blood pressure responses were calculated from measurements at baseline on day 1 and at 2.5 h on day 2. Consistency of individual differences was explored by correlating the two replicates of control-adjusted exercise responses for each outcome. Within-participant covariate-adjusted linear mixed models quantified participant-by-condition interactions and individual response SDs. Results Acute exercise reduced mean TAUC-triacylglycerol (−0.27 mmol·L−1·h; Cohen’s d = 0.29, P = 0.017) and TAUC-insulin (−25 pmol·L−1·h; Cohen’s d = 0.35, P = 0.022) versus control, but led to negligible changes in TAUC-glucose and the vascular outcomes (Cohen’s d ≤ 0.36, P ≥ 0.106). Small-to-moderate, but nonsignificant, correlations were observed between the two response replicates (r = −0.42 to 0.15, P ≥ 0.066). We did not detect any individual response heterogeneity. All participant-by-condition interactions were P ≥ 0.137, and all individual response SDs were small with wide 95% confidence intervals overlapping zero. Conclusions Large trial-to-trial within-subject variability inhibited detection of consistent interindividual variability in postprandial metabolic and vascular responses to acute exercise.

Background: Polymerized polyphenols (PP) found in oolong tea can inhibit pancreatic lipase activity in vitro, and pilot work indicates that this may reduce postprandial lipemia. Since tea contains caffeine and catechins, the interactions between these ingredients and PP warrant investigation. Objectives: To assess whether PP ingested alone or with caffeine and catechins lowers postprandial lipemia. Methods: Fifty healthy adults [mean (SD) age: 26 (7) y; BMI (in kg/m2): 24.0 (2.7); female: n = 16] completed 4 oral lipid tolerance tests in a placebo controlled randomized, crossover design. Participants ingested 40 g of fat with either 1) placebo, 2) 100 mg PP, 3) 150 mg PP, or 4) 100 mg PP plus 50 mg caffeine and 63 mg catechins (PP + CC). Blood was sampled for 3 h postprandially to assess concentrations of serum and plasma triacylglycerol and plasma markers of lipid (NEFA; glycerol; LDL and HDL cholesterol; and ApoA-I, A-II, B, C-II, C-III, and E) and glucose metabolism (glucose, insulin, and C-peptide). Results: Serum and plasma triacylglycerol concentrations and lipid metabolism variables generally increased following any test drink ingestion (main effect of time, p < 0.001). Nevertheless, for the lipid metabolism responses, there were no statistically significant condition-time interactions and no statistically significant differences in incremental or total area under the curve between conditions, apart from HDL cholesterol (p = 0.021). Ingesting 100 mg PP + CC lowered peak plasma glucose, insulin, and C-peptide concentrations compared with all other conditions 30 min postingestion (p < 0.001), with persistent alterations in glucose concentrations observed for 90 min compared with placebo and 100 mg PP conditions. Conclusions: PP ingested at doses <150 mg does not clearly alter early-phase postprandial triacylglycerol concentrations in healthy adults, irrespective of the presence or absence of caffeine and catechins. Nevertheless, caffeine and catechins added to PP lowered postprandial glucose and insulin concentrations. This trial was registered in ClinicalTrials.gov as NCT03324191 (https://clinicaltrials.gov/ct2/show/NCT03324191).

Injuries are common in adult recreational athletes. Exercise-based injury prevention programmes offer the potential to reduce the risk of injury and have been a popular research topic. Yet, syntheses and meta-analyses on the effects of exercise-based injury prevention programmes for adult recreational athletes are lacking. We aimed to synthesise and quantify the pooled intervention effects of exercise-based injury prevention programmes delivered to adults who participate in recreation sports. Studies were eligible for inclusion if they included adult recreational athletes (aged > 16 years), an exercise-based intervention and used a randomised controlled trial design. Exclusion criteria were studies without a control group, studies using a non-randomised design and studies including participants who were undertaking activity mandatory for their occupation. Eleven literature databases were searched from earliest record, up to 9 June, 2022. The Physiotherapy Evidence Database (PEDro) scale was used to assess the risk of bias in all included studies. Reported risk statistics were synthesised in a random-effects meta-analysis to quantify pooled treatment effects and associated 95

AIMS:The physiologic challenges related to performances in hot conditions calls for dedicated consideration when planning athlete training, although complete amelioration of the effects of heat may not be possible. We aimed to quantify within-subject correlations between different measures of environmental temperature and performance changes over multiple elite soccer competitions. METHODS:Thirty-seven elite male soccer players (age: 26 ± 3.4 years, height: 171 ± 2 cm, body mass: 78 ± 7.1 kg) competed in North America over four seasons (range: 3 to 98 matches). Players wore global positioning system devices during games and reported differential-RPE immediately post game. Temperatures at kick-off, week average temperature, the difference between game-day and week average (DiffTemp), and heat index at kick-off were obtained. Within-player correlations were calculated using general linear models to quantify associations between fluctuations in temperature measures and physical and perceived outputs. RESULTS:Correlations between total distance and the various temperature measures were trivial to small (range: -0.08 to 0.13, p=<0.001-0.02). Small negative correlations were found between all temperature measures except DiffTemp and high-speed running (HSR) (range: -0.17 to -0.14, p=<0.001). Most correlations between differential-RPE and temperature measures were trivial to small and not significant (r = 0.06 to 0.18 p = 0.03-0.92) although breathlessness-RPE and heat index showed a small significant association (P = 0.018). CONCLUSION:Decrements in HSR appear to be associated with increased environmental temperature, however, these associations are small in magnitude.

The idea that increasing physical activity directly adds to TEE in humans (additive model) has been challenged by the energy constrained hypothesis (constrained model). This model proposes that increased physical activity decreases other components of metabolism to constrain TEE. There is a logical evolutionary argument for trade-offs in metabolism, but, to date, evidence supporting constraint is subject to several limitations, including cross-sectional and correlational studies with potential methodological issues from extreme differences in body size/composition and lifestyle, potential statistical issues such as regression dilution and spurious correlations, and conclusions drawn from deductive inference rather than direct observation of compensation. Addressing these limitations in future studies, ideally, randomized controlled trials should improve the accuracy of models of human energy expenditure. The available evidence indicates that in many scenarios, the effect of increasing physical activity on TEE will be mostly additive although some energy appears to “go missing” and is currently unaccounted for. The degree of energy balance could moderate this effect even further.

Objective To explore the association between baseline pain duration and the likelihood of re-referral of patients with low back pain (LBP) managed on the evidence-based North East of England Regional Back Pain and Radicular Pain Pathway (NERBPP).Study design Longitudinal, observational cohort study.Methods In all, 12,509 adults with LBP were identified as having been discharged from the pathway, between May 2015 and December 2019. To quantify any association between baseline pain duration and the likelihood of re-referral, two statistical modelling approaches, were used: logistic regression models for odds ratios and generalised linear models with a binomial link function in order to quantify risk differences.Results Twenty-five percent of patients with LBP, who were discharged, re-referred for management over a 4.5-year period. A large difference in pain duration of 2 SD days was statistically associated with re-referral, with an odds ratio of 1.22 (95% CI: 1.03, 1.44) and a risk difference of 3.6% (95% CI: 0.6, 6.6). Nevertheless, the predictive value of an individual's pain duration was found to be weak for re -referral. Higher baseline disability [odds ratio of 1.40 (95% CI: 1.07, 1.83)] and a younger age at baseline [odds ratio of 0.73 (95% CI 0.61, 0.86)] were also associated with an increased risk of re-referral.Conclusions Baseline pain duration, disability and younger age are statistically associated with re-referral onto the NERBPP. However, the value of these variables for predicting an individual's risk of re-referral is weak.Contribution of paper & BULL; The NERBPP is an evidence-based clinical pathway for low back pain and a forerunner to the National Back Pain Pathway.& BULL; Baseline pain duration, disability and younger participants have an association with re-referral onto the NERBPP, however, the predictive values of these variables are weak.& BULL; 25% of patients with low back pain, who were discharged, re-referred for management over a four-and-a-half-year period, re-referral rates onto the NERBPP have not previously been published.& COPY; 2023 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

ABSTRACT Introduction Valid and informed interpretations of changes in physical performance test data are important within athletic development programmes. At present, there is a lack of consensus regarding a suitable method for deeming whether a change in physical performance is practically relevant or not. Methods We compared true population variance in mean test scores between those derived from evidence synthesis of observational studies to those derived from practioner opinion (n = 30), and to those derived from a measurement error (minimal detectable change) quantification (n = 140). All these methods can help to obtain ‘target’ change score values for performance variables. Results We found that the conventional ‘blanket’ target change of 0.2 (between-subjects SD) systematically underestimated practically relevant and more informed changes derived for 5-m sprinting, 30-m sprinting, CMJ, and Yo-Yo Intermittent Recovery Level 1 (IR1) tests in elite female soccer players. Conclusions For the first time in the field of sport and exercise sciences, we have illustrated the use of a principled approach for comparing different methods for the definition of changes in physical performance test variables that are practically relevant. Our between-method comparison approach provides preliminary guidance for arriving at target change values that may be useful for research purposes and tracking of individual female soccer player’s physical performance.

The purpose of this study was to present reference standards for physical performance test outcomes relevant to elite female soccer players. We analysed mixed-longitudinal data (n = 1715 observations) from a sample of 479 elite youth and senior players as part of the English Football Association's national development programme (age range: 12.7 to 36.0 years). Semi-parametric generalized additive models for location, scale and shape (GAMLSS) estimated age-related reference centiles for 5-m sprinting, 30-m sprinting, countermovement jump (CMJ) height, and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) performance. The estimated reference centiles indicated that the median of the distribution of physical performance test scores varied non-linearly with advancing chronological age, improving until around 25 years for each performance variable. These are the first reference ranges for performance test outcomes in elite English female soccer players. These data can assist practitioners when interpreting physical test performance outcomes to track an individual's progress over time and support decision-making regarding player recruitment and development.