Background: Sleep hygiene protocols (SHPs) have been shown to improve sleep and stress regulation; however, the role of cortisol in shaping downstream physiological and performance adaptations remains unclear. This study primarily examined the effects of a short-term SHP on sleep duration and salivary cortisol responses across resting, pre-exercise, and post-exercise states in female collegiate soccer players and, secondarily, whether cortisol statistically mediated selected aerobic and anaerobic performance outcomes. Methods: Fourteen players (22.1 ± 3.3 y; 157.8 ± 6.0 cm; 53.5 ± 3.9 kg) completed a randomised, counterbalanced crossover study comparing habitual sleep (no sleep hygiene protocol; nSHP) with a comprehensive SHP incorporating environmental, behavioural, and educational strategies. Salivary cortisol was sampled one hour post-waking and 30 min pre- and 15 min post-exercise during standardised testing sessions. Performance outcomes included vertical jump, sprint performance (40 m and repeated sprints [RAST]), and the Yo-Yo Intermittent Recovery Test Level 1. Linear mixed-effects models assessed cortisol responses, and mediation analyses explored cortisol–performance relationships. Results: After SHP, perceived (7.87 h vs. 6.5 h; p = 0.002, ESg = 1.0) and calculated sleep duration (8.5 h vs. 6.9 h; p = 0.004, ESg = 0.95) increased significantly. Cortisol was markedly lower following SHP at selected timepoints, including before RAST (−43.05%, p = 0.006, ESg = 0.84), with additional timepoint-specific, condition-dependent differences post-anaerobic and post-aerobic exercise (Δ = 7.37 and 5.98 nmol·L−1, respectively; p < 0.001). Vertical jump height demonstrated significant total (9.92 cm, p = 0.002) and direct effects (7.72 cm, p = 0.034), and peak repeated-sprint performance showed a significant direct effect (p = 0.026). Cortisol did not significantly mediate any performance outcomes (ACME p > 0.05). Conclusions: Short-term sleep hygiene is associated with increased sleep duration, timepoint-specific modulation of cortisol responses, and selected anaerobic performance benefits; however, these effects were not explained by measured cortisol responses and are unlikely to be sustained without ongoing reinforcement or support, particularly in athletic populations.
Background: Sleep is a critical recovery mechanism for athletes, supporting hormonal regulation, muscle repair, and cognitive function. Dual-career athletes are particularly vulnerable to sleep disruption, which may impair performance and stress regulation. This study examined the effects of a 14-day sleep hygiene intervention protocol (SHIP) on aerobic and anaerobic performance, as well as anticipatory cortisol responses, in university-level soccer players. Methods: Thirty athletes (females: n = 14, 22.1 ± 3.3 y, 157.8 ± 6.0 cm, 53.5 ± 3.9 kg, males: n = 16, 21.5 ± 1.7 y, 167.5 ± 5.9 cm, 62.7 ± 5.4 kg) completed the Pittsburgh Sleep Quality Index (PSQI), provided pre-test salivary cortisol samples, and performed the Yo-Yo Intermittent Recovery Test Level 1 (YYIR1) and Repeated Anaerobic Sprint Test (RAST) before and after the intervention (adhering daily to 10-18 individualized sleep hygiene). Results: The SHIP significantly reduced sleep latency (p = 0.04) and increased sleep duration (p = 0.03), and PSQI scores (p < 0.001) in both sexes. Females showed marked increases in sleep duration (p = 0.002), while males showed improved latency (p = 0.07). Five behaviourally coherent clusters derived from the SHIP adherence explained a substantial proportion of variance (74.99%). Stimulant and metabolic regulation, and bedroom light and thermal environment control consistently predicted sprint and physiological outcomes (p < 0.05). Anticipatory cortisol decreased before both tests (p = 0.03-0.04). YYIR1 performance improved for the full cohort (p = 0.001). RAST times slowed slightly (p = 0.02), though fatigue index improved (p = 0.05). Conclusions: A short-term SHIP effectively enhanced sleep, reduced physiological stress, and improved key performance outcomes in collegiate athletes.
ABSTRACT:Prevoo, M, Broodryk, A, and Kramer, M. Effects of a sleep hygiene intervention period on the internal and external, inter- and intra-match demands of male university-level soccer players during a tournament. J Strength Cond Res 39(6): e798-e805, 2025-Soccer is a physiologically and psychologically demanding sport, requiring players to optimize their sleep to enhance their recovery and ensure optimal performance during a match. Therefore, this study aimed to determine the effect of a sleep hygiene intervention period (SHP) on the internal and external match demands during an 8-match tournament. Sixteen male university-level soccer players' (average age: 22.2 ± 3 years; stature: 167.6 ± 6.4 cm; mass: 62 ± 6.6 kg) movement patterns, heart rate, RPE, and sleep quality (Pittsburgh Sleep Quality Index-PSQI) were compared over an intervention period consisting of 2 matches (no-sleep hygiene period: no-SHP), 4 matches (sleep-hygiene period-SHP, adhering to 10 SHP principles over 4 weeks), and again 2 matches of no-SHP. A significantly improved global PSQI score ( p = 0.03), sleep latency ( p = 0.05), and sleep hours ( p = 0.004) were seen following the SHP. Comparing the match halves of the no-SHP and SHP, significant differences were found for total distance ( p < 0.001), distances completed while jogging ( p < 0.001), running ( p < 0.001), and sprinting ( p = 0.03), as well as distances covered in the medium ( p = 0.05) and high-velocity ( p < 0.001) zones, and low ( p < 0.001) and medium ( p < 0.001) decelerative zones and for all accelerative zones ( p < 0.001). Participants were able to surpass their work rates after the SHP with no RPE increases observed, hence demonstrating the usefulness of putting organized sleep into practice. Therefore, it is recommended that players and coaching staff implement sleep hygiene guidelines more regularly, as it may result in noteworthy performance improvements.
Abstract Broodryk, A, Pienaar, C, Edwards, D, and Sparks, M. Effects of a soccer tournament on the psychohormonal states of collegiate female players. J Strength Cond Res 35(7): 1873–1884, 2021—A gap exists in the literature concerning the connection between soccer players' hormonal and psychological responses when playing a tournament, or even a match, and its outcome (victory or defeat). This study evaluates the effects of a week-long tournament on the psychohormonal states of collegiate female soccer players. Eight players' cortisol (saliva sample), mood states (Incredibly Short Profile of Mood States [ISP]), and state-anxiety (state subscale of the State-Trait Anxiety Inventory) were assessed 1 hour before and 15 minutes after every game. Cortisol increased significantly after most matches, with intramatch differences observed (p < 0.05, d > 1.2). Match intensity influenced cortisol secretion, with greater secretion as intensity increased. The ISP demonstrated intramatch differences for the subscales' fatigue, depression, tension, and vigor (p < 0.05). Matches lost produced a higher total mood disturbance (TMD) index compared with matches won (p = 0.001, d = 1.4). Cortisol correlated with the TMD and various mood subscales before a winning outcome, with the ISP correlating at all times with the anxiety scores (p < 0.05). In conclusion, these results indicate that physiological and psychological variables combine to contribute to the stress response during a tournament. Focusing on high-intensity activities and minimizing fatigue are important, as both are associated with raised cortisol and negative mood states. Finally, implementing a mood questionnaire over a tournament can be beneficial, as sensitive information on players' hormonal and perceived anxiety states, which subsequently affect physical performance, can be obtained.
Background. Anxiety plays a major role when it comes to sports performance, not only mentally, but physically as well. Objectives. The study aimed to examine the effect of a soccer tournament on baseline anxiety [Spielberger State-trait anxiety inventory questionnaire (STAI), mood [Incredible Short POMS questionnaire (ISP)] and cortisol (saliva sampling) states. Methods. Eight sportswomen’s (age: 23.1 ± 3.2 y, playing experience: 10.6 ± 5.6 y) data were collected an hour after waking, two weeks prior to, and each morning during, a five-day tournament. Results. Overall, a small relationship was seen between true cortisol values and presence of state-anxiety (r = 0.3, P = < 0.05). On mornings prior to a match lost, a significant relationship was seen between cortisol and the current- (r = 0.7, P = 0.005) and total trait-anxiety scores (r = 0.7, P = 0.008). Following multiple regression analysis, the TAI questionnaire was demonstrated to be adequate to predict possible cortisol surges (r2 = 0.3, P = 0.04). Measuring the innate anxiety characteristic can be a positive measure to anticipate both psychological (presence of anxiety, r2 = 0.88, P = 0.001) and physiological (cortisol surges, r2 = 0.4, P = 0.008) stress. Conclusion. Therefore, an anxiety questionnaire might provide sensitive information regarding the unconscious physiological and psychological stress plausibly altering performance. It is recommended that a player’s state of anxiety (innate and current) be measured prior to a competition to adopt a strategy to overcome its negative consequences.
Up to 95% of a soccer match entails aerobic actions that may cause fatigue. Little is known about the effects of fatigue on the hormonal and psychological states of female players. Cortisol values (saliva sample), state anxiety (Spielberger State-trait Anxiety Inventory) and mood scores (Incredibly Short Profile of Mood States [ISP], comprising six subscales and total mood disturbances [TMD]) of 43 female players (aged 22.0±2.7 years) were taken immediately prior to and 15 min after an aerobic fatiguing test (AFT: Yo-Yo Intermittent Recovery [YYIR] test). Cortisol increased (d=0.7, p=0.007) and ISP–confusion and ISP–vigour decreased (d=0.5, p=0.01–0.02). At pre-AFT, a slight positive relationship between cortisol and anxiety-absence (r=0.3, p=0.05) was seen. TMD consistently demonstrated a strong relationship with all ISP and anxiety scores (r>0.4, p<0.01). Post-AFT results demonstrated a positive relationship between cortisol and blood lactate (r=0.3, p=0.04), between ISP–anger with maximal heart rate (r=0.3, p=0.03), ISP–anger and YYIR level as well as ISP–fatigue (r=0.4, p=0.04), and between perceived exertion rate and ISP–vigour (r=-0.4, p=0.008) as well as ISP–fatigue (r=0.3, p=0.05). Fatigue caused by prolonged activity may be a greater physiological than psychological stressor, although both may affect soccer performance. We recommend training players to increase their aerobic capacity to ensure maximal quality match-time before fatigue and its subsequent adverse physiological and psychological effects set in. Significance: The YYIR-1 test is effective in producing significant changes in both the hormonal and psychological states of female soccer players. Conditioning staff can effectively implement a mood state questionnaire to predict possible psychological stress (increase in state or trait anxiety) prior to and after a stressor. A relationship exists between cortisol and the absenteeism of anxiety prior to this fatiguing test, as well as with blood lactate thereafter. Therefore, the State-trait Anxiety Inventory questionnaire can be administered and blood lactate samples can be collected as they may display sensitive information regarding hormonal state. A positive relationship exists between the maximal heart rate achieved following an aerobic fatiguing test and various mood subscales experienced. Thus, with an increase in heart rate (as frequently observed due to fatigue), it can be assumed that an increase in perceived negative mood state might take place.
Globally it is assumed that high-intensity activities are the general cause of fatigue experienced during a soccer match. However, little is known about the hormonal and psychological effects of fatigue due to these activities on semi-professional female soccer players. Forty-seven female players (22.0 ± 2.7 y) from a tertiary education institution volunteered for the study. Their cortisol values (saliva sample), anxiety [Spielberger State-trait anxiety inventory questionnaire (STAI)] and mood scores [Incredible Short Profile of Mood states questionnaire (ISP)] were taken an hour and immediately prior to, and 15 min after an anaerobic fatiguing test (AFT). During the AFT, subjects completed a 5-m multiple shuttle run test and their HRmax, blood lactate (BLa−) and rate of perceived exertion (RPE) taken afterwards. Anxiety scores were divided into three categories and mood scores into the Total Mood Disturbances (TMD) and six subscales. The results indicated an increase in cortisol, psychological fatigue and TMD from baseline and/or pre- to post-AFT (p < 0.05). Vigour and confusion decreased from baseline and/or pre- to post-AFT (p < 0.05). A relationship was seen between state-anxiety and TMD (r ≥ 0.63, p < 0.05) at all three time points, as well as between state-anxiety and HRmax (r = 0.37, p = 0.03). Cortisol and RPE (r = − 0.34, p = 0.03) demonstrated a correlation post-AFT. This is the first study to evaluate the effects of anaerobic fatigue on the hormonal and psychological states of female soccer players. The results suggest that an AFT can be perceived as a physiological and psychological stressor by female players, hence has the ability to influence performance. Altering a player's awareness and anaerobic fitness level might therefore influence both the hormonal and psychological consequences of the stressor, subsequently reducing the experience of fatigue and thereby enhancing performance.
Cold water immersion (CWI) is a popular recovery modality used in the sporting arena. However, there are discrepancies in the results regarding the post-exercise effects of CWI over a 48-hour recovery period. Therefore, the objective of this study was to determine the post-exercise effects of CWI and passive recovery (PAR) on the physical and haematological parameters of male university-level rugby players over a 48-hour recovery period. A cross-sectional, pre-posttest experimental study design with convenience sampling was used. Six haematological [blood lactate (BLa - ), partial O 2 pressure (PO 2 ), blood glucose, sodium (Na + ), haematocrit and haemoglobin] and four physical parameters (vertical jump test (VJT) -height, VJT-speed and VJT-power as well as grip strength) were evaluated at baseline, after a 15-minute fitness session, and at 0, 24 and 48 hours post-recovery in 23 male university rugby players. The CWI group sat in a cold water pool (8°C) for 20 minutes whereas the PAR group remained seated in a laboratory. At 0 hours post-CWI, BLa - , Na + and haemoglobin returned to baseline values whereas VJT-height decreased compared to post-PAR values which improved. From 0 to 24 and/or 48 hours, PO 2 , VJT-height, plasma glucose, and Na + significantly increased ( p ≤ 0.05) in either and/or both groups. Significant intragroup differences ( p ≤ 0.05) were noticed for BLa - and grip strength at 0 and 24 hours. VJT-height, -speed and -power were worse at 0 hours post-CWI compared to PAR. However, CWI was superior over 24 hours post-recovery to improve haemoglobin, haematocrit, Na + and grip strength. Therefore, in cases where recovery over a longer period is required (48 hours), CWI is superior compared to PAR to restore the body’s physiological parameters and enhance recovery. Keywords: Cryotherapy, haematological, physical, recuperation, hydrotherapy
Cold water immersion (CWI) is a popular recovery modality used in the sporting arena. However, there are discrepancies in the results regarding the post-exercise effects of CWI over a 48-hour recovery period. Therefore, the objective of this study was to determine the post-exercise effects of CWI and passive recovery (PAR) on the physical and haematological parameters of male university-level rugby players over a 48-hour recovery period. A cross-sectional, pre-posttest experimental study design with convenience sampling was used. Six haematological [blood lactate (BLa - ), partial O 2 pressure (PO 2 ), blood glucose, sodium (Na + ), haematocrit and haemoglobin] and four physical parameters (vertical jump test (VJT) -height, VJT-speed and VJT-power as well as grip strength) were evaluated at baseline, after a 15-minute fitness session, and at 0, 24 and 48 hours post-recovery in 23 male university rugby players. The CWI group sat in a cold water pool (8°C) for 20 minutes whereas the PAR group remained seated in a laboratory. At 0 hours post-CWI, BLa - , Na + and haemoglobin returned to baseline values whereas VJT-height decreased compared to post-PAR values which improved. From 0 to 24 and/or 48 hours, PO 2 , VJT-height, plasma glucose, and Na + significantly increased ( p ≤ 0.05) in either and/or both groups. Significant intragroup differences ( p ≤ 0.05) were noticed for BLa - and grip strength at 0 and 24 hours. VJT-height, -speed and -power were worse at 0 hours post-CWI compared to PAR. However, CWI was superior over 24 hours post-recovery to improve haemoglobin, haematocrit, Na + and grip strength. Therefore, in cases where recovery over a longer period is required (48 hours), CWI is superior compared to PAR to restore the body’s physiological parameters and enhance recovery. Keywords: Cryotherapy, haematological, physical, recuperation, hydrotherapy
