Upper Respiratory Tract Infections (URTI) are amongst the most common illnesses reported in athletes. An URTI can result in missed training days, which in turn may lead to performance decrements. The purpose of this study was to investigate the use of salivary Immunoglobulin A (sIgA) as a predictor of URTI whilst also exploring the relationship to weekly training load in elite Rugby Union players. Nineteen male elite Rugby Union players provided morning saliva swabs, bi-weekly (Monday and Friday), over a 10-week training period. Participants completed an illness log documenting symptoms of URTI. Session Rate of Perceived Exertion (sRPE) was collected to determine training load (sRPE x session duration). Weekly training load was also calculated. Logistic regression was used to analyze the relationship between incidences of URTI with sIgA and training load. Multi-level regression was conducted to compare associations between sIgA and training load.The results found that the likelihood of suffering from an URTI increased when sIgA significantly decreased (p=0.046). Where sIgA decreased by 65% or more, a player was at a greater risk of contracting an URTI within the following 2-weeks. No association was found between sIgA and training load.In conclusion, sIgA may be a useful predictor for determining the likelihood of players contracting an URTI. This will allow the coach to make informed decisions on training status, helping reduce the risk of players missing training, which may have performance decrements.Coaches will benefit from the fast, easy and instant results available, to analysis a player's immune function.

Purpose: Insufficient recovery can lead to a decrease in performance and increase the risk of injury and illness. The aim of this study was to evaluate salivary cortisol as a marker of recovery in elite rugby union players. Method: Over a 10-wk preseason training period, 19 male elite rugby union players provided saliva swabs biweekly (Monday and Friday mornings). Subjective markers of recovery were collected every morning of each training day. Session rating of perceived exertion (sRPE) was taken after every training session, and training load was calculated (sRPE × session duration). Results: Multilevel analysis found no significant association between salivary cortisol and training load or subjective markers of recovery (all P > .05) over the training period. Compared with baseline (wk 1), Monday salivary cortisol significantly increased in wk 4 (14.94 [7.73] ng/mL; P = .04), wk 8 (16.39 [9.53] ng/mL; P = .01), and wk 9 (15.41 [9.82] ng/mL; P = .02), and Friday salivary cortisol significantly increased in wk 5 (14.81 [8.74] ng/mL; P = .04) and wk 10 (15.36 [11.30] ng/mL; P = .03). Conclusions: The significant increase in salivary cortisol on certain Mondays may indicate that players did not physically recover from the previous week of training or match at the weekend. The increased Friday cortisol levels and subjective marker of perceived fatigue indicated increased physiological stress from that week’s training. Regular monitoring of salivary cortisol combined with appropriate planning of training load may allow sufficient recovery to optimize training performance.

To investigate the association between contact injuries, non-contact injuries and training load indices, across different lag periods in elite soccer players. Internal load (session rate of perceived exertion) was collected from 15 elite soccer players over one-season (40-weeks). Acute (7-days), chronic (28-days), Acute:Chronic Workload Ratio (ACWR) (uncoupled), Exponentially Weighted Moving Averages (EWMA) ACWR and 2-, 3-and 4-week cumulative load were calculated on a rolling weekly basis. Multilevel logistic regression was used to analyze the associations between contact, non-contact injuries and training load indices, across different lag periods (5-and 7-days). A player was at a significantly higher risk of a non-contact injury 5-days' later, if week-to-week acute load changes increased (Odds Ratio, OR=1.97). An increase in EWMA ACWR was associated with an increased risk of both a contact (OR=1.30) and non-contact injury (OR=1.35), 5-days' later. An increase in 2-week cumulative load (OR=1.77) was associated with an increased risk of a contact injury 7-days' later and 3-week cumulative load (OR=1.55) 5-days' later. These findings suggest that in order to reduce the potential risk of a non-contact injury, training load should be gradually increased avoiding an increase in week-to-week acute load change (≥9%) or EWMA ACWR (>1.20). Findings indicated that EWMA ACWR may be a more sensitive measure for detecting a player at a higher risk of an injury than ACWR. Furthermore, a high 2-and 3-week cumulative load was associated with an increased risk of a contact injury, which may indicate accumulated fatigue.Practitioners must note this study investigated associations with injury risk and not injury prediction.

The adductor squeeze strength test has become a popular training monitoring marker, particularly in team sports. The aim of this study was to investigate the relationship between adductor squeeze strength scores, subjective markers of recovery and training load in elite Rugby Union players, due to limited research in this area. Nineteen elite male Academy Rugby Union players completed daily monitoring markers (adductor squeeze strength and 5 selected subjective markers of recovery), over a 10-week pre-season training period. Rate of Perceived Exertion (RPE) was collected to determine training load (sRPE; RPE x session duration) and to calculate weekly training load. Spearman correlation was used to analyze the relationship between adductor squeeze strength scores, subjective markers of recovery and weekly training load. The results found that where adductor squeeze scores decreased, both perceived fatigue levels (r=-0.335, R 2 =11.2%, p<0.001) and muscle soreness (r=-0.277, R 2 =7.7%, p<0.001) increased. A weak correlation was found between Monday adductor squeeze strength scores and the previous week's training load (r=-0.235, R 2 = 5.5%, p<0.001) and Friday adductor squeeze strength scores and the same week's training load (r=-0.211, R 2 = 4.5%, p<0.05). These results show that adductor squeeze strength may provide coaches with a time-efficient, low-cost objective player monitoring marker. Additionally, the combination of adductor squeeze, with subjective markers, perceived fatigue and muscle soreness, and appropriately planned training load may help coaches to optimize training adaptations by determining a player's training status.

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Elite athletes are presented with significant challenges to their sleep due to the physiological and psychological demands of their sport (Nedelec et al., 2018). Sleep is considered crucial for recovery, overall wellness, and performance, especially among elite athletes (Halson, 2014; Knufinke et al., 2017). PURPOSE:The aim of this study was to investigate the relationship between sleep, subjective markers of recovery, and internal training load over a full soccer season (40 weeks). METHODS: Fifteen male elite soccer players provided 5 subjective markers of recovery (muscle soreness, fatigue, physical recovery, stress and energy levels), and sleep variables (quality and quantity), each morning before training on a purpose-built app. Daily, weekly, and chronic internal training load data were calculated, using session Rate of Perceived Exertion (sRPE). Pearson correlation was used to analyse the association between the previous night sleep with the next day's training load and subjective markers of recovery. RESULTS: The results found moderate to strong positive significant correlations (r=0.345-0.611 p=<0.001) between the previous night sleep quality and all 5 subjective markers of recovery, the following morning. A weak positive association was found between sleep quantity and energy levels (r=0.226 p <0.001). No associations were found between sleep quantity and the remaining subjective markers of recovery or between the sleep variables and training load indices. CONCLUSIONS:The results indicate that sleep quality rather than quantity associated with a player's subjective feelings of recovery. As a player's sleep quality improved, their reported subjective feelings of recovery were also improved (i.e. they felt less sore, more recovered, less stressed, more energized, and less fatigued). These results may help athletes and coaches understand the importance of sleep quality and the relationship with recovery, which in turn may help optimize training, preparation, and performance.

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This study aimed to investigate the association between training load indices and Upper Respiratory Tract Infection (URTI) across different lag periods in elite soccer players. Internal training load was collected from 15 elite soccer players over one full season (40 weeks). Acute, chronic, Acute:Chronic Workload Ratio (ACWR), Exponentially Weighted Moving Averages (EWMA) ACWR, 2, 3 and 4-week cumulative load, training strain and training monotony were calculated on a rolling weekly basis. Players completed a daily illness log, documenting any signs and symptoms, to help determine an URTI. Multilevel logistic regression was used to analyze the associations between training load indices and URTIs across different lag periods (1 to 7-days). The results found a significant association between 2-week cumulative load and an increased likelihood of a player contracting an URTI 3 days later (Odds Ratio, 95% Confidence Interval: OR = 2.07, 95% CI = 0.026-1.431). Additionally, a significant association was found between 3-week cumulative load and a players’ increased risk of contracting an URTI 4 days later (OR = 1.66, 95% CI = 0.013–1.006). These results indicate that accumulated periods of high training load (2- and 3-week) associated with an increased risk of a player contracting an URTI, which may lead to performance decrements, missed training sessions or even competitions.