Summated Training and Match Load Predictors of Salivary Immunoglobulin-A, Alpha-Amylase, Testosterone, Cortisol and T:C Profile Changes in Elite-Level Professional Football Players:A Longitudinal Analysis

We examined how summated training and match load measures relate to salivary immunological and hormonal profile changes in professional football players. Data were collected from 18 elite-level professional male football players from one English Championship team across a complete 40 wk competitive season. Daily training (micro-technology) and match (computerised tracking) measures of total, high-speed and high-metabolic load running distance and sprint, acceleration, deceleration and sRPE load were converted into exponentially weighted moving average “acute” (7d), “chronic” (28d) and acute:chronic composite load measures. Bi-weekly morning saliva samples were analysed for immunoglobulin-A, alpha-amylase, testosterone, cortisol and testosterone:cortisol. A two-stage data reduction technique using partial least squares modelling and a backward stepwise selection procedure determined the most parsimonious model for each salivary variable. Testosterone had non-linear relationships with chronic total (P = 0.015; Cohen’s D: large), high-metabolic load (P = 0.001;small) and high-speed (P = 0.001;trivial) running distance and linear relationships with chronic sRPE (P = 0.002;moderate ↓) and acute:chronic high-speed running distance (P = 0.001; trivial ↑). Cortisol had a non-linear relationship with chronic high-speed running distance (P = 0.001;trivial). Testosterone:cortisol had non-linear relationships with chronic decelerations (P = 0.039;small) and chronic summated acceleration and deceleration load (P = 0.039;small). Non-linear relationships typically indicated optimal hormonal responses at squad mean loads. No load variables clearly related to salivary immunoglobulin-A or alpha-amylase changes. We conclude that chronic total and high-intensity load measures relate to hormonal changes and might be useful indicators of player readiness. Acute load variables were not related to immunological or hormonal changes and consequently, should not be used as surrogate measures of player readiness in isolation

The activity demands and physiological responses observed in professional ballet: A systematic review

The aim of this study was to systematically review research into the activity demands and physiological responses observed in professional ballet. PubMed, Web of Science, SPORTDiscus, and ProQuest were searched for original research relating to 1) the session- specific activity demands of professional ballet, 2) the general activity demands of professional ballet, 3) the immediate physiological responses to professional ballet, or 4) the delayed physiological responses to professional ballet. From an initial 7672 studies, 22 met the inclusion criteria. Methodological quality was assessed using the Mixed Methods Appraisal Tool and a modified Downs and Black Index. Professional ballet is intermittent; however, activity characteristics and intensity vary by session type and company rank. Performances involve high volumes of jumps (5.0 ± 4.9 jumps·min-1), pliés (11.7 ± 8.4 pliés·min-1), and lifts (men - 1.9 ± 3.3 lifts·min-1), which may result in near-maximal metabolic responses. Ballet classes are less metabolically intense than performance during both barre and centre ( 5 h·day-1), but half is spent at intensities below 3 METs. Evidence is mixed regarding the delayed physiological responses to professional ballet; however, metabolic and musculoskeletal adaptations are unlikely to occur from ballet alone. The mean Downs and Black score was 62%. Appraisal tools revealed that a lack of clarity regarding sampling procedures, no power calculation, and a poor quality of statistical analysis were common limitations of the included studies. Given the large working durations and high rates of jumps, pliés, and lifts, managing training loads and recovery may be a focus for strategies seeking to optimize dancer health and wellbeing. Ballet companies should provide dancers with opportunities and resources to engage in supplementary physical training. Further research is required into the physical demands of rehearsals and the longitudinal training loads undertaken by professional ballet dancers

Dance Exposure, Individual Characteristics, and Injury Risk over Five Seasons in a Professional Ballet Company

PURPOSE: To describe the relationships between dance exposure, dancer characteristics, and injury risk across five seasons in a professional ballet company. METHODS: Dance exposure time and clinician-reported time-loss and medical attention injury data were prospectively collected from 118 professional dancers of The Royal Ballet between 2015/16 and 2019/20. Cox proportional hazards and shared frailty models were fitted to overuse and traumatic injuries; individualized robust Z-scores for 7-day and 28-day accumulated exposure, and week-to-week change in exposure, age, sex, company rank, and injury history were included as time-varying covariates. RESULTS: Across 381,710 h of exposure, 1332 medical attention and 427 time-loss injuries were observed. Positive relationships were observed between week-to-week change in exposure and overuse time-loss (+1 Z-score hazard ratio (HR): 1.27, 95% confidence interval (CI): 1.06-1.53) and medical attention injury risk (+1 Z-score HR: 1.17, 95% CI: 1.06-1.28). A negative relationship was observed between 7-day accumulated exposure and overuse medical-attention injury risk (+1 Z-score HR: 0.74, 95% CI: 0.66-0.84). Overuse time-loss injury risk was greater in soloists compared to the corps de ballet (HR: 1.47, 95% CI: 1.01-2.15), and in dancers with a higher previous injury rate (+1 injury.1000 h-1 HR: 1.06, 95% CI: 1.02-1.10). Only age was associated with traumatic time-loss (+1-year HR: 1.05, 95% CI: 1.01-1.09) or medical attention injury risk (+1-year HR: 1.04, 95% CI: 1.01-1.07). CONCLUSION: Professional ballet companies should implement training principles such as periodization and progression, particularly in the case of senior-ranking dancers, older dancers, and dancers with high rates of previous injury. These findings provide a basis for future prospective investigations into specific causal injury pathways

The moderating effects of speed, strength and endurance capacities on match induced neuromuscular fatigue in U-18 English premier league academy football players: A hypothesis-generating case report

Purpose: To identify new hypotheses relating to the moderating effects of speed, strength and endurance capacities on match-induced neuromuscular fatigue. Methods 14 U-18 outfield players from one EPL academy team completed countermovement jump (CMJ) and isometric adductor (IADS) and posterior chain (IPCS) strength tests one day before match day (MD) (i.e., MD-1) and on MD + 2 around 8 competitive games. Explosive strength (CMJ), reactive strength (30 cm drop jump (DJ)), speed (10 m and 30 m), maximal strength (isometric mid-thigh pull (IMTP)) and endurance (1 km Time Trial (TT)) were measured at 4 time points across the season. Relationships between the average match induced change to each NMF measure and the average of each physical capacity measure were examined using Pearson's R ( r ) (when normally distributed) or Spearman's rank ( rho ) (when not normally distributed) correlation coefficients. Results: Moderate positive relationships were observed between CMJ-JH change ( δ ) and DJ-RSI ( rho = 0.36; p = 0.16) and IMPT ( r = 0.46; p = 0.06). Small negative relationships were observed between IADS-PF δ and 10 m speed ( rho = 0.27; p = 0.29), 30 m speed ( r = 0.22; p = 0.41), CMJ-JH ( rho = 0.29; p = 0.26) and DJ-RSI ( rho = 0.36; p = 0.16), and between IPCS-PF δ and 10 m speed ( rho = 0.20; p = 0.45) and 1kmTT ( rho = 0.26; p = 0.33). Conclusions: These results generate important hypotheses relating to the potential mitigating effects that reactive strength, maximal strength and endurance capacities might exert on match induced NMF in U-18 academy football players. These relationships warrant further investigation in larger research designs spanning both older and younger player age groups (i.e., across other youth development and professional development phase players) and competition levels (i.e., elite and sub-elite players)

Countermovement Jump and Isometric Strength Test-Retest Reliability in English Premier League Academy Football Players.

To examine the test-retest reliability of countermovement jump (CMJ) and isometric strength testing measures in elite-level under-18 and under-23 academy football players. A total of 36 players performed 3 maximal CMJs and isometric abductor (IABS), adductor (IADS), and posterior chain (IPCS) strength tests on 2 separate test days using dual force plates (CMJ and IPCS) and a portable strength testing device (IABS and IADS). Relative (intraclass correlation coefficient) and absolute (coefficient of variation, standard error of the measurement, and minimal detectable change [MDC%]) reliabilities for 34 CMJ, 10 IABS, 10 IADS, and 11 IPCS measures were analyzed using between-sessions best, mean, and within-session methods. For all methods, relative reliability was good to excellent for all CMJ and all IADS measures and poor to good for all IABS and IPCS measures. Absolute reliability was good (ie, coefficient of variation < 10%) for 27 (best) and 28 (mean) CMJ variables and for 6 (IABS and IADS) and 2 (IPCS) isometric measures. Commonly used CMJ measures (jump height, eccentric duration, and flight-time:contraction-time ratio) had good to excellent relative reliability and an MDC% range of 14.6% to 23.7%. Likewise, commonly used isometric peak force measures for IABS, IADS, and IPCS had good to excellent relative reliability and an MDC% range of 22.2% to 26.4%. Commonly used CMJ and isometric strength measures had good test-retest reliability but might be limited by their MDC%. Rate-of-force-development measures (for all isometric tests) and impulse measures (IPCS) are limited by poor relative and absolute reliability and high MDC%. MDC% statistics should be considered in the context of typical responsiveness

Acute neuromuscular and perceptual responses to U‐18 English Premier League academy football match play

We examined the sensitivity and time‐course of recovery of neuromuscular and perceptual player monitoring measures to U‐18 English Premier League academy football match play. Eighteen players performed maximal posterior chain, hip adductor and abductor isometric strength tests, countermovement jumps (CMJ) and provided self‐report wellbeing scores around eight competitive league home games: 1 day before (MD‐1), pre‐match (MD‐PRE), post‐match (MD‐POST) and two (MD+2) and three (MD+3) days post‐match. A permutational multivariate analysis of variance and post hoc univariate analyses of variance were used to examine match‐induced responses to monitoring variables. Between MD‐1 and MD‐POST, we observed small to moderate reductions to the adductor and abductor peak force and maximal impulse and IPCS peak force; small reductions to CMJ jump height (JH) (flight time), eccentric peak force and eccentric deceleration rate of force development and moderate to large reductions to perceived fatigue, muscle soreness and mood. No match‐induced changes were observed for CMJ flight time: contraction time or eccentric duration. Posterior chain, abductor, CMJ and self‐report measures normalised by MD+3 but adductor peak force remained compromised at MD+3 (ES = small). Posterior chain, adductor and abductor peak isometric force and maximal impulse; CMJ JH, eccentric peak force and eccentric deceleration rate of force development and perceived fatigue, muscle soreness and mood are sensitive to match‐induced fatigue. Since adductor peak force remained compromised at MD+3, it is apparent that players might not achieve complete neuromuscular recovery within 3 days of match play, and that the adductor muscle group might be particularly vulnerable to match‐induced fatigue

Large Reductions in Match Play Physical Performance Variables Across a Professional Football Season with Control for Situational and Contextual Variables

This investigation examined match play physical performance across a professional football season using a multicamera computerized tracking system. A linear mixed-effects model, controlling for situational and contextual variables, identified decreases in team average total distance (TD): season quarter 1 (Q1) (11,047 m) &gt; season quarter 2 (Q2) (10,473 m) (P = 0.002; ES = Small), season quarter 3 (Q3) (10,449 m) (P &lt; 0.001; ES = Moderate), and season quarter 4 (Q4) (10,385 m) (P &lt; 0.001; ES = Moderate); work rate (WR): Q1 (115 m/min) &gt; Q3 (108 m/min) (P &lt; 0.001; ES = Moderate), Q4 (107 m/min) (P &lt; 0.001; ES = Moderate); Q2 (109 m/min) &gt; Q4 (107 m/min) (P = 0.003; ES = Small); high-speed running distance (HSR): Q1 (1,051 m) &gt; Q2 (813 m) (P = 0.006; ES = Small); number of high-speed runs (NHSR): Q1 (87) &gt; Q2 (65) (P &lt; 0.001; ES = Small), Q3 (64) (P = 0.002; ES = Small); sprint distance (SD): Q1 (202 m) &gt; Q4 (130 m) (P &lt; 0.001; ES = Moderate), Q2 (179 m) &gt; Q3 (165 m) (P = 0.035; ES = Small), Q4 (130 m) (P &lt; 0.001; ES = Moderate) and number of sprints (NS): Q1 (20.4) &gt; Q3 (10.2) (P &lt; 0.001; ES = Moderate), Q4 (8.3) (P &lt; 0.001; ES = Large); Q2 (14.9) &gt; Q3 (10.2) (P &lt; 0.001; ES = Moderate), Q4 (8.3) (P &lt; 0.001; ES = Large). Within-position changes were observed for WR: Q1 (122 m/min) &gt; Q4 (113 m/min) (P = 0.002; ES = Large) in central midfielders and for NS: Q1 &gt; Q3 in wide defenders (21.7 vs. 10.8) (P = 0.044; ES = Large) and central midfielders (18.1 vs. 8.3) (P = 0.002; ES = Large); Q1 &gt; Q4 in central defenders (13.1 vs. 5.3) (P = 0.014; ES = Large), wide defenders (21.6 vs. 7.1) (P &lt; 0.001; ES = Very Large), central midfielders (18.1 vs. 8.5) (P = 0.005; ES = Large), and wide midfielders (20.8 vs. 12.2) (P = 0.012; ES = Large); Q2 &gt; Q3 in central midfielders (16.9 vs. 8.3) (P = 0.002; ES = Large) and Q2 &gt; Q4 in wide defenders (16.3 vs. 7.1) (P = 0.005; ES = Very Large), central midfielders (16.9 vs. 8.5) (P = 0.004; ES = Large), and wide midfielders (20.8 vs. 12.2) (P = 0.007; ES = Large). The match-play physical performance was reduced across the competitive season. The most notable reductions were observed in wide defenders, central midfielders, and wide midfielders in sprint performance indices

Selected immunoendocrine measures for monitoring responses to training and match load in professional association football: A review of the evidence

Biomarkers relating to player stress balance, immunological (ie, immunoglobulin-A), and hormonal (ie, testosterone and cortisol [T : C]) status are now commonly used in football. This article is our critical review of the scientific literature relating to the response of these measures to player load and their relationships with player health. The commonly reported relationship between immunoglobulin-A and training or match load highlights its sensitivity to changes in psychophysiological stress and the increased risk of compromised mucosal immunity. This is supported by its close relationship with symptoms of upper respiratory tract infection and its association with perceived fatigue in football players. Testosterone and cortisol concentrations and the testosterone-cortisol ratio are sensitive to changes in player load, but the direction of their response is often inconsistent and is likely influenced by player training status and non-sport-related stressors. Some evidence indicates that sustained periods of high training volume can increase resting testosterone and that sustained periods of low and high training intensity can increase resting cortisol, compromising the testosterone-cortisol ratio. These findings are noteworthy, as recent findings indicate interrelationships between testosterone, cortisol, and testosterone:cortisol and perceived measures of fatigue, sleep quality, and muscle soreness in football players. Variability in individual responses suggests the need for a multivariate and individualized approach to player monitoring. Overall, we consider that there is sufficient evidence to support the use of salivary immunoglobulin-A, testosterone, cortisol, and testosterone:cortisol measures as part of a multivariate, individualized player monitoring system in professional football

Summated Training and Match Load Predictors of Salivary Immunoglobulin-A, Alpha-Amylase, Testosterone, Cortisol and T:C Profile Changes in Elite-Level Professional Football Players: A Longitudinal Analysis.

We examined how summated training and match load measures relate to salivary immunological and hormonal profile changes in professional football players. Data were collected from 18 elite-level professional male football players from one English Championship team across a complete 40 wk competitive season. Daily training (micro-technology) and match (computerised tracking) measures of total, high-speed and high-metabolic load running distance and sprint, acceleration, deceleration and sRPE load were converted into exponentially weighted moving average “acute” (7d), “chronic” (28d) and acute:chronic composite load measures. Bi-weekly morning saliva samples were analysed for immunoglobulin-A, alpha-amylase, testosterone, cortisol and testosterone:cortisol. A two-stage data reduction technique using partial least squares modelling and a backward stepwise selection procedure determined the most parsimonious model for each salivary variable. Testosterone had non-linear relationships with chronic total (P = 0.015; Cohen’s D: large), high-metabolic load (P = 0.001;small) and high-speed (P = 0.001;trivial) running distance and linear relationships with chronic sRPE (P = 0.002;moderate ↓) and acute:chronic high-speed running distance (P = 0.001; trivial ↑). Cortisol had a non-linear relationship with chronic high-speed running distance (P = 0.001;trivial). Testosterone:cortisol had non-linear relationships with chronic decelerations (P = 0.039;small) and chronic summated acceleration and deceleration load (P = 0.039;small). Non-linear relationships typically indicated optimal hormonal responses at squad mean loads. No load variables clearly related to salivary immunoglobulin-A or alpha-amylase changes. We conclude that chronic total and high-intensity load measures relate to hormonal changes and might be useful indicators of player readiness. Acute load variables were not related to immunological or hormonal changes and consequently, should not be used as surrogate measures of player readiness in isolation