Monitoring fitness,fatigue and running performance during a pre-season training camp in elite football players

ObjectivesTo examine the usefulness of selected physiological and perceptual measures to monitor fitness, fatigue and running performance during a pre-season, 2-week training camp in eighteen professional Australian Rules Football players (21.9 ± 2.0 years).DesignObservational.MethodsTraining load, perceived ratings of wellness (e.g. fatigue, sleep quality) and salivary cortisol were collected daily. Submaximal exercise heart rate (HRex) and a vagal-related heart rate variability index (LnSD1) were also collected at the start of each training session. Yo-Yo Intermittent Recovery level 2 test (Yo-YoIR2, assessed pre-, mid- and post-camp, temperate conditions) and high-speed running distance during standardized drills (HSR, >14.4 km h^?1, 4 times throughout, outdoor) were used as performance measures.ResultsThere were significant (P < 0.001 for all) day-to-day variations in training load (coefficient of variation, CV: 66%), wellness measures (6–18%), HRex (3.3%), LnSD1 (19.0%), but not cortisol (20.0%, P = 0.60). While the overall wellness (+0.06, 90% CL (?0.14; 0.02) AU day^?1) did not change substantially throughout the camp, HRex decreased (?0.51 (?0.58; ?0.45) % day^?1), and cortisol (+0.31 (0.06; 0.57) nmol L^?1 day^?1), LnSD1 (+0.1 (0.04; 0.06) ms day^?1), Yo-YoIR2 performance (+23.7 (20.8; 26.6) m day^?1, P < 0.001), and HSR (+4.1 (1.5; 6.6) m day^?1, P < 0.001) increased. Day-to-day ΔHRex (r = 0.80, 90% CL (0.75; 0.85)), ΔLnSD1 (0.51 (r = 0.40; 0.62)) and all wellness measures (0.28 (?0.39; ?0.17) < r < 0.25 (0.14; 0.36)) were related to Δtraining load. There was however no clear relationship between Δcortisol and Δtraining load. ΔYo-YoIR2 was correlated with ΔHRex (r = 0.88 (0.84; 0.92)), ΔLnSD1 (r = 0.78 (0.67; 0.89)), Δwellness (r = 0.58 (0.41; 0.75), but not Δcortisol. ΔHSR was correlated with ΔHRex (r = ?0.27 (?0.48; ?0.06)) and Δwellness (r = 0.65 (0.49; 0.81)), but neither with ΔLnSD1 nor Δcortisol.ConclusionsTraining load, HRex and wellness measures are the best simple measures for monitoring training responses to an intensified training camp; cortisol post-exercise and LnSD1 did not show practical efficacy here.     

Household illness is the strongest predictor of upper respiratory tract symptom risk in elite rugby union players

ObjectivesTo identify periods of increased risk for upper respiratory tract symptom (URTS) episodes, and examine whether biomarkers and/or self-reported lifestyle and wellness data can predict URTS risk in elite rugby union players.DesignProspective, longitudinal and repeated-measures study.MethodsSalivary secretory immunoglobulin A (SIgA), salivary cortisol, URTS, internal training load and self-reported lifestyle and wellness data including household illness, stress, mood, fatigue, muscle soreness and sleep quality were repeatedly measured in elite Southern hemisphere rugby union players (n = 28) throughout a season. Univariate frailty model analysis, which included 495 observations, was used to determine predictors of URTS risk.ResultsSurprisingly, the highest incidence of URTS occurred after rest weeks, namely the Christmas break and bye weeks (i.e., no scheduled trainings or matches); whereas URTS risk was reduced during weeks involving international travel (Hazard ratio (HR): 0.43, p < 0.001)). Household illness was the strongest predictor of URTS risk; players were almost three-fold more at risk for an URTS episode when illness in the household was present (HR: 2.90, p = 0.002). A non-significant, but potentially important trend for an inverse association between SIgA concentration and URTS incidence was also observed (HR: 0.99, p = 0.070).ConclusionsRest weeks were identified as periods of increased risk for URTS; while international travel did not appear to increase players risk for URTS. Incidence of household illness and SIgA concentration independently predicted URTS risk, with household illness being the strongest predictor. These findings can assist practitioners monitoring and management of athletes to potentially reduce URTS risk.     

Modelling the relationships between volume,intensity and injury-risk in professional rugby league players

ObjectiveThis study aimed to: (a) identify the association between external-workloads and injury-risk in the subsequent week; and (b) understand the effectiveness of workload variables in establishing injury-risk.DesignRetrospective cohort study.MethodsWorkload and injury data (soft-tissue) were collected from forty-eight professional male rugby league players. Load variables included duration (min), total distance (m), relative distance (m min⁻¹), high speed distance ([m]>20 km h⁻¹), very-high speed distance ([m]>25 km h⁻¹), acceleration and deceleration efforts (count) and PlayerLoad (Arbitrary Unit: AU). Cumulative two-, three- and four-weekly loads; Acute:Chronic Workload Ratio (ACWR); Mean-Standard Deviation Workload Ratio (MSWR) and strain values were calculated and divided into three equally-sized bins (low, moderate and high). Generalised Estimating Equations analysed relationships between workload variables and injury probability in the subsequent week.ResultsInjury-risk increased alongside increases in the ACWR for duration, total distance and PlayerLoad. Conversely, injury-risk decreased (Area Under Curve: 0.569–0.585) with increases in the four-weekly duration, total distance, accelerations, decelerations and PlayerLoad. For relative distance, high four-weekly workloads (high: >60 m min⁻¹) demonstrated a positive association with injury-risk, whilst high two-weekly loads (high: >82 m min⁻¹) were negatively associated.ConclusionsA range of external workload metrics and summary statistics demonstrate either positive or negative associations with injury-risk status. Such findings provide the framework for the development of decision-support systems in which external workload metrics (e.g. total or high speed distance) can be uniquely and routinely monitored across a range of summary statistics (i.e. cumulative weekly loads and ACWR) in order to optimise player performance and welfare.     

The efficacy of repetitions-in-reserve vs. traditional percentage-based resistance training: a 4-week pre-season randomized intervention in elite rugby league players

Sport Sciences for Health - This two-experiment study aimed to examine (1) the accuracy and reliability of repetitions-in-reserve and (2) using a randomized trial, the efficacy of...     

Injuries during transition periods across the year in pre-professional and professional ballet and contemporary dancers: A systematic review and meta-analysis

ObjectiveTo consider the association of injuries with transition periods in the dance year, i.e., when dancers return at the start of the year, and when they transition from rehearsal to performance periods.MethodsSix electronic databases were searched to November 2019. All English language peer-reviewed studies, of any study design investigating ballet and contemporary pre-professional and professional dance populations were included. Only those studies reporting on the timing of injury were included.ResultsFifteen cohort and two case-series studies were included. A meta-analysis of seven studies revealed the rate of injuries to be significantly higher for the second and third months (1.52; 95% confidence interval [CI]:1.11–2.08; 1.26; 95%CI:1.07–1.48 respectively) after the return to dance. Two further studies report more injuries up to Week 13 of the year. One study showed an increase in injured dancers at three and four weeks after transition from rehearsals to a performance season. Four studies show an increase in injuries at performance times.ConclusionsMeta-analyses of seven studies shows the second and third months after returning to dance have a significantly higher rate of injuries. More research is needed to quantify training loads in dance. Practitioners should be cognisant of the higher injury rates during periods of transition and consider modifying load, as it is a potential contributing factor.     

Influence of intense training cycle and psychometric status on technical and physiological aspects performed during the small-sided games in soccer players

The study investigated the effect of intense training cycle (IT) of early season preparation period (SPP) and psychological status on technical and physiological parameters during small-sided games (SSG) and the relationships between these variables. Sixteen professional soccer players participated in the study (mean±SD: age: 24.5±4.1). Training load (TL), Total quality recovery (TQR) and well-being indices were performed daily. TL increased progressively (%TL=31.56 [AU]). Physiological variables did not change after IT and were not influenced by well-being indices and TQR. Technical aspects were negatively altered after IT (p<0.05). TL was significantly correlated with successful passes (r=-0.57, p=0.02), interceptions (r=-0.83, p<0.001) and lost balls (r=0.73, p=0.002). Well-being and TQR were related to successful passes, interceptions and lost passes [(r=-0.55, p=0.03; r=-0.75, p=0.001; r=-0.69, p=0.004); (r=0.54, p=0.03; r=-0.76, p=0.001; r=-0.69, p=0.004), respectively]. TL, Well-being indices and TQR represent a useful strategy for coaches to control technical aspects in soccer players during SPP.     

Daily and weekly training load and wellness status in preparatory,regular and congested weeks: a season-long study in elite volleyball players

The study aimed to assess the changes in the perceived internal load and wellness status of volleyball players in preparatory, regular (i.e. uncongested), and congested weeks during a full season. Thirteen elite volleyball players were studied (237 training sessions and 37 official matches). Session-RPE, muscle soreness, stress, fatigue, sleep quality, and the Hooper Index were measured daily using questionnaires. Training sessions were classified based on the number of matches per week and the days before or after a match: preparatory (no match), regular (one match), and congested weeks (two or more matches). Pairwise comparisons found significantly greater session-RPE scores (p < 0.05) one day before the match (304.74 A.U.), in regular weeks than in congested weeks (204.40 A.U.). Matches during the congested weeks (364.71 A.U.) had significantly higher session-RPE scores (p < 0.05) than regular weeks (252.97 A.U.). Three days before the match involved significantly higher values of muscle soreness, fatigue, stress, and sleep quality than regular weeks. Match accumulation increased the session-RPE training load of the matches. This study provides insights into the training load and well-being status before competition, for training the day of competition, and after the competition.     

Predictive modelling of the physical demands during training and competition in professional soccer players

ObjectivesThe present study aimed to predict the cut-off point-values that best differentiate the physical demands of training and competition tasks including friendly matches (FM), small sided games (SSG), large sided games (LSG), mini-goal games (MG) and ball circuit-training (CT) in professional soccer players.DesignExperimental randomized controlled trial.MethodsFourteen professional players participated in all tasks with the CT, SSG and MG consisting of 8 repetitions of 4-min game play, interspersed by 2-min of active recovery. The training data were compared to the first 32-min of the LSG and two competitive FM per player. All movement patterns from walking to sprint running were recorded using 10 Hz GPS devices while player perception of exertion was recorded via a visual analogue scale, post-task. Decision tree induction was applied to the dataset to assess the cut-off point-values from four training drills (SSG, LSG, MG, and CT) and FM for every parameter combination.ResultsDistance covered during jogging (2.3–3.3 m/s; >436 m), number of decelerations (≤730.5) and accelerations (≤663), and maximum velocity reached (>5.48 m/s) characterized the physical demands during competition (FM) with great variability amongst training drills.ConclusionThe use of these novel, cut-off points may aid coaches in the design and use of training drills to accurately prepare athletes for soccer competition.     

The concurrent validity and intrarater reliability of a hand-held dynamometer for the assessment of neck strength in semi-professional rugby union players

ObjectivesThe main objective of this study was to determine the concurrent validity between a hand-held (HHD) and mounted hand-held dynamometer (MHHD) for assessing isometric neck strength.DesignObservational design.SettingSemiprofessional rugby club.ParticipantsNineteen semi-professional rugby players (age = 26 ± 5 years, stature = 186.5 ± 6.5 cm, body mass = 98.7 ± 12.8 kg).Main outcome measuresConcurrent validity (limits of agreement, correlation) between HHD and MHHD, the intrarater reliability (intra-class correlation, ICC) and comparison between playing positions.ResultsAbsolute peak and mean peak force were systematically lower when using the HHD compared to MHHD, with the mean bias ranging from −1.8 to −3.8 kgf (P < 0.05). Differences were not evident for flexion when applying the correction equations (−0.5 to 2.1 kgf, P > 0.05) but remained for extension. Correlations between methods were large-to-very large; the ICCs for both methods were good (ICC = 0.72–0.89), with no difference between positions (P < 0.05).ConclusionThe concurrent validity of HHD was considered acceptable when compared to the MHHD and the correction equation applied. Both methods are reliable and useful for assessing neck strength in rugby players, though, caution is needed when determining strength during neck extension.     

The independent effects of match location,match result and the quality of opposition on subjective wellbeing in under 23 soccer players: a case study

This study examined if subjective wellbeing in soccer players was affected by match location, match result and opposition quality before a match (PRE), 1 day after (POST-1), and 3 days after a match (POST-3). Eleven professional male soccer players from the under 23 squad playing in the Premier League 2 division completed a wellbeing questionnaire before and after 17 matches. Match training load (session-rating perceived exertion) was not different, regardless of the location, result, or quality of opposition faced (P > 0.05). Subjective wellbeing was not different at PRE (P > 0.05); however, at POST-1 and POST-3, stress and mood were ≥20% lower after playing away from home or losing (P < 0.05). Stress, mood and sleep were ≥12% worse after playing against a higher-level opposition at POST-1. Coaches need to be aware that match location, match result and the quality of the opposition can influence post-match wellbeing, irrespective of match load.     

Changes in inflammation markers after a 10-week high-intensity combined strength and endurance training block in women: The effect of hormonal contraceptive use

ObjectivesThe influence of hormonal contraceptives (HC) on inflammation and body composition after high-intensity combined strength and endurance training was investigated.DesignActive healthy women formed two training groups: HC users (HCU, n = 9) and those who had never used HC (NHC, n = 9). Training included two strength training sessions and two high-intensity interval training sessions per week for 10 weeks.MethodsBefore (PRE) and after (POST) the training intervention, high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1beta (IL-1β) concentrations were measured. Dual-energy X-ray absorptiometry was used to estimate fat mass (FM), abdominal fat mass (aFM), and lean mass (LM).ResultsCirculating concentrations of hs-CRP decreased significantly in the NHC from pre to post with −0.46 mg l⁻¹ (95% CI: −0.78, −0.14, p = 0.009, ES = 0.434), whereas a significant increase was observed in HCU from pre to post with 0.89 mg l⁻¹ (95% CI: 1.66, 0.12, p = 0.048, ES = 1.988) with a significant between-group difference (p = 0.015). In addition, hs-CRP concentration was significantly higher in HCU than in NHC after training (p = 0.036) at post. Lean mass increased significantly more in NHC than in HCU (p = 0.049).ConclusionsHigh-intensity combined strength and endurance training can modify inflammation and body composition of women. The present study showed that inflammation, in terms of hs-CRP was higher post training in HCU than NHC, which may be associated with smaller gains in lean mass in response to training.     

Analysis of landing performance and ankle injury in elite British artistic gymnastics using a modified drop land task: A longitudinal observational study

ObjectivesTo determine whether differences in landing force and asymmetry of landing force exist between gymnasts at the time of data collection versus those that subsequently experienced an ankle injury 12-months later.Study designProspective longitudinal observational design with baseline measures and 12 month follow up.SettingBritish Gymnastics National Training Centre.ParticipantsThirty-two asymptomatic elite level gymnasts from three artistic gymnastic squads (n = 15 senior female, n = 10 junior female and n = 7 senior male).Main outcome measuresA modified drop land task was used to quantify measures of landing performance. Peak Vertical Ground Reaction Force (PVGRF) was used to measure landing force. The level of inter-limb asymmetry of landing force was calculated using the Limb Symmetry index (LSI). Other measures included injury incidence and percentage coefficient of variation (% CV).ResultsThere was no statistical difference for landing force (p = 0.481) and asymmetry of landing force (p = 0.698) when comparing injured and non-injured gymnasts. Most participants (69%) demonstrated inter-limb asymmetry of landing forces.ConclusionsOur findings observed inter-limb asymmetry of landing force in injured gymnasts, although uninjured gymnasts also exhibited asymmetry of landing force. Both magnitude of landing force and inter-limb asymmetries of landing force failed to identify the risk of ankle injury.