How much is too much? (Part 2) International Olympic Committee consensus statement on load in sport and risk of illness

Demystifying roles of exercise in immune response regulation against acute respiratory infections: A narrative review

The benefits of physical activity and exercise, especially those classified as moderate-to-vigorous activity (MVPA), have been well-established in preventing non-communicable diseases and mental health problems in healthy adults. However, the relationship between physical activity and exercise and the prevention and management of acute respiratory infection (ARI), a global high-burden disease, has been inconclusive. There have been debates and disagreements among scientific publications regarding the relationship between exercise and immune response against the causative agents of ARI. This narrative review aims to explore the theory that sufficiently explains the correlation between exercise, immune response, and ARI. The potential root causes of discrepancies come from research associated with the "open window" hypothesis. The studies have several limitations, and future improvements to address them are urgently needed in the study design, data collection, exercise intervention, subject recruitment, biomarkers for infection and inflammation, nutritional and metabolism status, and in addressing confounding variables. In conclusion, data support the clinical advantages of exercise have a regulatory contribution toward improving the immune response, which in turn potentially protects humans fromARI. However, the hypothesis related to its negative effect must be adopted cautiously.

Vertical Strength Transfer Phenomenon Between Upper Body and Lower Body Exercise: Systematic Scoping Review

BACKGROUND

There are a myriad of exercise variations in which upper body (UB) and lower body (LB) exercises have been intermittently used. However, it is still unclear how training of one body region (e.g. LB) affects adaptations in distant body areas (e.g. UB), and how different UB and LB exercise configurations could help facilitate physiological adaptations of either region; both referred to in this review as vertical strength transfer.

OBJECTIVE

We aimed to investigate the existence of the vertical strength transfer phenomenon as a response to various UB and LB exercise configurations and to identify potential mechanisms underpinning its occurrence.

METHODS

A systematic search using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) for Scoping Reviews protocol was conducted in February 2024 using four databases (Web of Science, MEDLINE, Scopus and CINAHL) to identify peer-reviewed articles that investigated the vertical strength transfer phenomenon.

RESULTS

Of the 5242 identified articles, 24 studies met the inclusion criteria. Findings suggest that the addition of UB strength training to LB endurance exercise may help preserve power-generating capacity for the leg muscle fibres. Furthermore, systemic endocrine responses to high-volume resistance exercise may beneficially modulate adaptations in precedingly or subsequently trained muscles from a different body region, augmenting their strength gains. Last, strength training for LB could result in improved strength of untrained UB, likely due to the increased central neural drive.

CONCLUSIONS

Vertical strength transfer existence is enabled by neurophysiological mechanisms. Future research should involve athletic populations, examining the potential of vertical strength transfer to facilitate athletic performance and preserve strength in injured extremities.

Mass Participation and Tournament Event Management for the Team Physician: A Consensus Statement (2022 Update)

ABSTRACT

Mass participation events include endurance events (e.g., marathon, triathlon) and/or competitive tournaments (e.g., baseball, tennis, football (soccer) tournaments). Event management requires medical administrative and participant care planning. Medical management provides safety advice and care at the event that accounts for large numbers of participants, anticipated injury and illness, variable environment, repeated games or matches, and mixed age groups of varying athletic ability. This document does not pertain to the care of the spectator.

Mass Participation and Tournament Event Management for the Team Physician: A Consensus Statement (2022 Update)

ABSTRACT

Mass participation events include endurance events (e.g., marathon, triathlon) and/or competitive tournaments (e.g., baseball, tennis, football (soccer) tournaments). Event management requires medical administrative and participant care planning. Medical management provides safety advice and care at the event that accounts for large numbers of participants, anticipated injury and illness, variable environment, repeated games or matches, and mixed age groups of varying athletic ability. This document does not pertain to the care of the spectator.

Sports and Immunity, from the recreational to the elite athlete

The pivotal role of the immune system in physical activity is well-established. While interactions are complex, they tend to constitute discrete immune responses. Moderate intensity exercise causes leukocytosis with a mild anti-inflammatory cytokine profile and immunoenhancement. Above a threshold of intensity, lactate-mediated IL-6 release causes a proinflammatory state followed by a depressed inflammatory state, which stimulates immune adaptation and longer term cardiometabolic enhancement. Exercise-related immune responses are modulated by sex, age and immunonutrition. At all ability levels, these factors collectively affect the immune balance between enhancement or overload and dysfunction. Excessive training, mental stress or insufficient recovery risks immune cell exhaustion and hypothalamic pituitary axis (HPA) stress responses causing immunodepression with negative impacts on performance or general health. Participation in sport provides additional immune benefits in terms of ensuring regularity, social inclusion, mental well-being and healthier life choices in terms of diet and reduced smoking and alcohol, thereby consolidating healthy lifestyles and longer term health. Significant differences exist between recreational and professional athletes in terms of inherent characteristics, training resilience and additional stresses arising from competition schedules, travel-related infections and stress. Exercise immunology examines the central role of immunity in exercise physiology and straddles multiple disciplines ranging from neuroendocrinology to nutrition and genetics, with the aim of guiding athletes to train optimally and safely. This review provides a brief outline of the main interactions of immunity and exercise, some influencing factors, and current guidance on maintaining immune health.

Acute Responses to Repeated-Sprint Training in Hypoxia Combined With Whole-Body Cryotherapy: A Preliminary Study

PURPOSE

This study aimed to investigate acute psychophysiological responses to repeated-sprint training in hypoxia (RSH) combined with whole-body cryotherapy (WBC).

METHOD

Sixteen trained cyclists performed 3 sessions in randomized order: RSH, WBC-RSH (WBC pre-RSH), and RSH-WBC (WBC post-RSH). RSH consisted of 3 sets of 5 × 10-second sprints with 20-second recovery at a simulated altitude of 3000 m. Power output, muscle oxygenation (tissue saturation index), heart-rate variability, and recovery perception were analyzed. Sleep quality was assessed on the nights following test sessions and compared with a control night using nocturnal ActiGraphy and heart-rate variability.

RESULTS

Power output did not differ between the conditions (P = .27), while the decrease in tissue saturation index was reduced for WBC-RSH compared to RSH-WBC in the last set. In both conditions with WBC, the recovery perception was higher compared to RSH (WBC-RSH: +15.4%, and RSH-WBC: +21.9%, P < .05). The number of movements during the RSH-WBC night was significantly lower than for the control night (-18.7%, P < .01) and WBC-RSH (-14.9%, P < .05). RSH led to a higher root mean square of the successive differences of R-R intervals and high-frequency band during the first hour of sleep compared to the control night (P < .05) and RSH-WBC (P < .01).

CONCLUSIONS

Inclusion of WBC in an RSH session did not modify the power output but could improve prolonged performance in hypoxia by maintaining muscle oxygenation. A single RSH session did not deteriorate sleep quality. WBC, particularly when performed after RSH, positively influenced recovery perception and sleep.

The meaning of injury to the elite athlete: A systematic review

In the pursuit of a successful career in elite sports, athletes mostly rely on their physical abilities. An injury can threaten such a career, thereby representing a potentially critical life event that carries considerable meaning to the affected athlete. Qualitative literature exploring injury experiences in elite athletes is therefore seeking to frame injury through the athlete's own voice. With this systematic review, we aimed to answer the research question What is the meaning of injuries to the elite athlete? by reviewing existing qualitative research exploring the meaning of injury as told from the athlete's perspective. We constructed five overarching themes of meaning through thematic synthesis of 29 original studies: (1) unwelcome disruption - Injury as potential career threat; (2) destruction - My life (as an athlete) is over; (3) reinforcement - Relighting the fire; (4) going through the motions - Injury as an inherent part of elite sport; and (5) time-out - Respite and perspective. These meanings were neither exclusive nor static but constructed according to the situation at the moment of injury and could later be adapted depending on social context and specific circumstances. To better support injured athletes, practitioners need to be aware of the importance of the subjective meaning that athletes construct for individual injuries. Understanding these meanings enables practitioners to aid athletes in changing previously negative meanings into more positive ones. Our findings therefore call for improvements in the individualized support of elite athletes that leaves space for open communication about the meanings that athletes attach to their injury experiences.

The reproducibility of dendritic cell and T cell counts to a 30-min high-intensity cycling protocol as a tool to highlight overtraining

Heavy training has been reported to be immunosuppressive in athletes and lead to blunted cortisol responses to exercise. Cortisol elevates the number of dendritic cells (DCs), key antigen-presenting cells that interact with T cells to initiate an immune response. Reproducible cortisol responses to a 30-min cycle test have been identified but were based on percentage of work rate maximum. To ensure physiological consistency, submaximal anchors, that is, ventilatory threshold (VT1 ) should prescribe intensity. This study aims to assess the reproducibility of the DC and T cell responses to an adapted stress test to assess its usefulness in assessing DC dysfunction with intensified training. Twelve males cycled for 1 min at 20% below VT1 and 4 min at 50% between VT1 andV ̇ O 2 max ${\dot{V}}_{{{\mathrm{O}}}_{\mathrm{2}}\max }$ , for 30 min (20/50), with blood samples pre-, post- and 30 min post-exercise. This was repeated twice, 2-7 days apart. Flow cytometry assessed total DCs, plasmacytoid DCs, myeloid DCs, total T cells, T helper cells and T cytotoxic cells. No significant trial or interaction effects were found for any variable. A significant main effect of time for all variables was found; immune cells increased from pre- to post-exercise and decreased to baseline 30 min post-exercise, apart from plasmacytoid DCs, which remained elevated 30 min post-exercise. Intraclass correlation coefficients showed overall good-to-excellent reliability for all immune cells, with smallest real difference and Bland-Altman analysis verifying high reproducibility between trials. These results suggest that the 20/50 exercise test induces reproducible DC and T cell count changes, which, implemented before and after a period of intensified training, may highlight the negative states of overtraining.

ChatGPT Generated Training Plans for Runners are not Rated Optimal by Coaching Experts, but Increase in Quality with Additional Input Information

ChatGPT may be used by runners to generate training plans to enhance performance or health aspects. However, the quality of ChatGPT generated training plans based on different input information is unknown. The objective of the study was to evaluate ChatGPT-generated six-week training plans for runners based on different input information granularity. Three training plans were generated by ChatGPT using different input information granularity. 22 quality criteria for training plans were drawn from the literature and used to evaluate training plans by coaching experts on a 1-5 Likert Scale. A Friedmann test assessed significant differences in quality between training plans. For training plans 1, 2 and 3, a median rating of <3 was given 19, 11, and 1 times, a median rating of 3 was given 3, 5, and 8 times and a median rating of >3 was given 0, 6, 13 times, respectively. Training plan 1 received significantly lower ratings compared to training plan 2 for 3 criteria, and 15 times significantly lower ratings compared to training plan 3 (p < 0.05). Training plan 2 received significantly lower ratings (p < 0.05) compared to plan 3 for 9 criteria. ChatGPT generated plans are ranked sub-optimally by coaching experts, although the quality increases when more input information are provided. An understanding of aspects relevant to programming distance running training is important, and we advise avoiding the use of ChatGPT generated training plans without an expert coach's feedback.

Is Problematic Physical Activity (PPA) a Uni- or Multi-Dimensional Concept? A Bifactor Analysis of the Exercise Dependence Scale-Revised (EDS-R)

The study of exercise dependence, or as we prefer, problematic physical activity (PPA), faces both theoretical and methodological challenges. Different factorial solutions were obtained for the widely used Exercise Dependence Scale-Revised (EDS-R), leading us to question both its latent underlying construct and the interpretation of its factor solutions. Through confirmatory factor analysis (CFA) and the use of a bifactor model (BCFA), we assessed the dimensionality of a French version of the EDS-R. We recruited 745 students from Paris Nanterre University, but we removed 88 responses (16.8%) to retain only those who (a) engaged in a moderate to high levels of physical activity, according to the Global Physical Activity Questionnaire (GPAQ; N = 494; 9.5%), and (b) completed the EDS-R. We used a final sample of 435 students (58.4% of the total population) for a factorial analysis of the EDS-R. We conducted a three-step CFA in Mplus, producing three models: (a) unidimensional, (b) second-order, and (c) bi-factor (BCFA). The results of the BCFA indicated that most EDS-R items were better indicators of a general factor than their respective group factors, except for the second factor measuring a withdrawal construct. These results add to an ongoing debate in the field of behavioral addiction as to how to better conceptualize and measure exercise dependence or PPA. Withdrawal appears to have a special position in this debate, since our BCFA suggested that it is the only specific sub-dimension of the EDS-R scale.

Combined Turmeric, Vitamin C, and Vitamin D Ready-to-Drink Supplements Reduce Upper Respiratory Illness Symptoms and Gastrointestinal Discomfort in Elite Male Football Players

Elite football is associated with the increased risk of illness, although targeted supplementation can reduce illness risk. This study assessed the effects of a supplement containing turmeric root within a black pepper and fat-soluble blend, vitamin C and vitamin D, on upper respiratory symptoms (URS), gastrointestinal symptoms (GIS), muscle soreness, and markers of inflammation and gut permeability in elite male footballers. Twenty-three footballers completed 3 weeks of no intervention (CON), followed by 16 weeks of daily consuming 60 mL of a commercially available supplement containing raw turmeric root (17.5 g, estimated to contain 700 mg of curcumin), vitamin C (1000 mg), and vitamin D3 (3000 IU/75 mcg) (SUP). URS and GIS were measured daily. Immediately (0 h), 40, and 64 h after six competitive matches (two in CON, four in SUP), the subjective soreness and plasma concentrations of creatine kinase [CK], c-reactive protein [CRP], and intestinal fatty-acid binding protein [I-FABP] were assessed. URS incidence (p < 0.001), GIS (p < 0.05), and plasma [I-FABP] at 0 h (p < 0.05) were greater during CON versus SUP. At 40 h, [CRP] was greater than 0 h during CON (p < 0.01) but not SUP (p = 0.204). There were no differences in soreness or [CK]. This study indicates that turmeric root, vitamin C, and vitamin D supplementation over 16 weeks can reduce URS, GIS, and post-match [I-FABP] in elite footballers.

Spanish Cross-Cultural Adaptation and Validation of the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score

CONTEXT

There are no available questionnaires in Spanish that assess the function and performance of shoulder and elbow in overhead sports. The Kerlan-Jobe Orthopaedic Clinic (KJOC) score is a reference tool for this purpose. We aimed to cross-culturally adapt and investigate its measurement properties in Spanish overhead athletes.

DESIGN

Cross-cultural adaptation followed the steps of direct translation, back translation, comprehensibility analysis, and review by the Committee of Experts. Then, symptomatic and asymptomatic overhead athletes were invited to complete an electronic version of the Spanish adaptation (KJOC-Sp). The structural validity was evaluated through an exploratory factor analysis with principal axis factoring. Hypotheses were tested for known-groups and convergent validity, studying the correlation with the Shoulder Pain and Disability Index and the Disabilities of the Arm, Shoulder, and Hand Sports Module questionnaires in symptomatic athletes. Cronbach alpha was calculated for internal consistency and intraclass correlation coefficient (ICC)2,1 for test-retest reliability. Floor and ceiling effects and time to completion were also calculated.

RESULTS

The KJOC-Sp maintained the content of the original version and was adapted to the new population. One hundred participants (41 females and 59 males) with a mean age of 22.4 (5.9) years participated in the study of measurement properties. The factor analysis revealed a 1-factor solution. Symptomatic participants scored significantly lower than asymptomatic, with a large effect size (P < .001; r = .67). Correlations were of -.60 (P < .05) with the Shoulder and Pain Disability Index questionnaire and -0.66 (P < .05) with the Disabilities of the Arm, Shoulder, and Hand Sports Module questionnaire. Cronbach alpha was .98 (95% confidence interval, .97-.98) and the ICC2,1 was .96 (95% confidence interval .93-.98). No floor or ceiling effects were observed among the symptomatic athletes, while mean time to completion was 121 seconds.

CONCLUSION

The KJOC-Sp is equivalent to the original score, aside from valid and reliable, without floor or ceiling effects in symptomatic athletes and with a low time consumption.

Overtraining Syndrome as a Risk Factor for Bone Stress Injuries among Paralympic Athletes

Background and Objectives: In this review, we have explored the relationship between overtraining syndrome (OTS) and bone stress injuries among paralympic athletes. OTS is a complex condition that arises from an imbalance between training volume, nutrition, and recovery time, leading to significant negative effects on paralympic athlete's performance and overall well-being. On the other hand, bone stress injuries occur when abnormal and repetitive loading is applied to normal bone, resulting in microdamage accumulation and potential. The prevalence of overtraining syndrome and bone stress injuries among athletes highlights the need for a better understanding of their relationship and implications for prevention and management strategies. Methods: A literature review from the PubMed, Web of Science, and Google Scholar databases including the MeSH keywords "overtraining syndrome", "bone", and "paralympic athletes". Results: Studies have consistently shown that athletes engaged in endurance sports are particularly susceptible to overtraining syndrome. The multifactorial nature of this condition involves not only physical factors, but also psychological and environmental determinants. In addition, the diagnosis and management of OTS and bone stress injuries present challenges in clinical practice. Conclusions: Currently, there are no definitive biochemical markers for overtraining syndrome. The diagnosis is based on a combination of subjective measures such as questionnaires, symptoms checklists, and objective biomarkers, including hormone levels, inflammatory markers, and imaging studies. However, these diagnostic approaches have limitations regarding their specificity and sensitivity.

Competence in Sports Pharmacy among Pharmacy Students in Norway

Pharmacists are competent to promote the proper use of medicines. According to the International Pharmaceutical Federation, pharmacists must develop competence in sports pharmacy and the contents of the World Anti-Doping Agency code. This explorative study aimed to identify the status of sports pharmacy in pharmacy education in Norway and competence in sports pharmacy among Norwegian pharmacy students. The study curricula of pharmacy education were examined for the content of sports pharmacy. An online questionnaire was also developed and distributed among pharmacy students. The anonymous survey collected demographic information and data on competence in sports pharmacy. Data from 122 participants were analyzed. Only 22.5% of pharmacy students had acquired a form of training in sports pharmacy and 91.7% wished to gain higher competence. In total, 40.2% of respondents were uncomfortable in advising athletes and trainers on medication use in sports. Study year was found to correlate with competence level with a significant difference between the 3rd year (bachelor) and 5th year (master) students. Age, institution, and number of years engaged in sports were not associated with competence level. The inclusion of sports pharmacy in pharmacy programs holds practical relevance for enhancing competency levels. This implementation can be realized through the integration of sports pharmacy modules and/or the incorporation of research-based activities.

Variability in exercise is linked to improved age-related dysfunctions: A potential role for the constrained-disorder principle-based second-generation artificial intelligence system

Objective: Regular physical activity (PA) promotes mental and physical health. Nevertheless, inactivity is a worldwide pandemic, and methods to augment exercise benefits are required. The constrained disorder principle (CDP) characterizes biological systems based on their inherent variability. We aimed to investigate the association between intra-individual variability in PA and disability among non-athlete adults. Methods: In this retrospective analysis of the longitudinal SHARE survey, we included non-disabled adults aged >50 with at least six visits over 14 years. Self-reported PA frequency was documented bi- to triennially. Low PA intensity was defined as vigorous PA frequency less than once a week. Stable PA was described as an unchanged PA intensity in all consecutive middle observations. The primary outcome was defined as a physical limitation in everyday activities at the end of the survey. Secondary outcomes were cognitive functions, including short-term memory, long-term memory, and verbal fluency. Results: The study included 2,049 non-disabled adults with a mean age of 53 and 49.1% women. In the initially high PA intensity group, variability in PA was associated with increased physical disability prevalence (23.3% vs. 33.2%, stable vs. unstable PA ; P<0.01; adjusted P<0.01). In the initially low PA intensity group, variability was associated with a reduced physical disability (45.6% vs. 33.3%, stable vs. unstable PA ; P=0.02; adjusted P=0.03). There were no statistically significant differences in cognitive parameters between the groups. Among individuals with the same low PA intensity at the beginning and end of follow-up, variability was associated with reduced physical disability (56.9% vs. 36.5%, stable vs. unstable PA ; P=0.02; adjusted P=0.04) and improved short-term memory (score change: -0.28 vs. +0.29, stable vs. unstable PA ; P=0.05). Conclusion: Incorporating variability into PA regimens of inactive adults may enhance their physical and cognitive benefits.

A novel approach for sports injury risk prediction: based on time-series image encoding and deep learning

The rapid development of big data technology and artificial intelligence has provided a new perspective on sports injury prevention. Although data-driven algorithms have achieved some valuable results in the field of sports injury risk assessment, the lack of sufficient generalization of models and the inability to automate feature extraction have made it challenging to deploy research results in the real world. Therefore, this study attempts to build an injury risk prediction model using a combination of time-series image encoding and deep learning algorithms to address this issue better. This study used the time-series image encoding approach for feature construction to represent relationships between values at different moments, including Gramian Angular Summation Field (GASF), Gramian Angular Difference Field (GADF), Markov Transition Field (MTF), and Recurrence Plot (RP). Deep Convolutional Auto-Encoder (DCAE) learned the image-encoded data for representation to obtain features with good discrimination, and the classifier was performed using Deep Neural Network (DNN). The results from five repeated experiments show that the GASF-DCAE-DNN model is overall better in the training (AUC: 0.985 ± 0.001, Gmean: 0.930 ± 0.007, Sensitivity: 0.997 ± 0.003, Specificity: 0.868 ± 0.013) and test sets (AUC: 0.891 ± 0.026, Gmean: 0.830 ± 0.027, Sensitivity: 0.816 ± 0.039, Specificity: 0.845 ± 0.022), with good discriminative power, robustness, and generalization ability. Compared with the best model reported in the literature, the AUC, Gmean, Sensitivity, and Specificity of the GASF-DCAE-DNN model were higher by 23.9%, 27.5%, 39.7%, and 16.2%, respectively, which confirmed the validity and practicability of the model in injury risk prediction. In addition, differences in injury risk patterns between the training and test sets were identified through shapley additivity interpretation. It was also found that the training volume was an essential factor that affected injury risk prediction. The model proposed in this study provides a powerful injury risk prediction tool for future sports injury prevention practice.

Sleep, Nutrition, and Injury Risk in Adolescent Athletes: A Narrative Review

This narrative review explores the impact of sleep and nutrition on injury risk in adolescent athletes. Sleep is viewed as essential to the recuperation process and is distinguished as an active participant in recovery through its involvement in growth, repair, regeneration, and immunity. Furthermore, the literature has shown that the sleep of athletes impacts elements of athletic performance including both physical and cognitive performance, recovery, injury risk, and mental well-being. For sleep to have a restorative effect on the body, it must meet an individual's sleep needs whilst also lasting for an adequate duration and being of adequate quality, which is age-dependent. The literature has suggested that athletes have increased sleep needs compared to those of the general population and thus the standard recommendations may not be sufficient for athletic populations. Therefore, a more individualised approach accounting for overall sleep health may be more appropriate for addressing sleep needs in individuals including athletes. The literature has demonstrated that adolescent athletes achieve, on average, ~6.3 h of sleep, demonstrating a discrepancy between sleep recommendations (8-10 h) and actual sleep achieved. Sleep-wake cycles undergo development during adolescence whereby adaptation occurs in sleep regulation during this phase. These adaptations increase sleep pressure tolerance and are driven by the maturation of physiological, psychological, and cognitive functioning along with delays in circadian rhythmicity, thus creating an environment for inadequate sleep during adolescence. As such, the adolescent period is a phase of rapid growth and maturation that presents multiple challenges to both sleep and nutrition; consequently, this places a significant burden on an adolescent athletes' ability to recover, thus increasing the likelihood of injury. Therefore, this article aims to provide a comprehensive review of the available literature on the importance of sleep and nutrition interactions in injury risk in adolescent athletes. Furthermore, it provides foundations for informing further investigations exploring the relation of sleep and nutrition interactions to recovery during adolescence.

Mid-Activity and At-Home Wearable Bioimpedance Elucidates an Interpretable Digital Biomarker of Muscle Fatigue

OBJECTIVE

Muscle health and decreased muscle performance (fatigue) quantification has proven to be an invaluable tool for both athletic performance assessment and injury prevention. However, existing methods estimating muscle fatigue are infeasible for everyday use. Wearable technologies are feasible for everyday use and can enable discovery of digital biomarkers of muscle fatigue. Unfortunately, the current state-of-the-art wearable systems for muscle fatigue tracking suffer from either low specificity or poor usability.

METHODS

We propose using dual-frequency bioimpedance analysis (DFBIA) to non-invasively assess intramuscular fluid dynamics and thereby muscle fatigue. A wearable DFBIA system was developed to measure leg muscle fatigue of 11 individuals during a 13-day protocol consisting of exercise and unsupervised at-home portions.

RESULTS

We derived a digital biomarker of muscle fatigue, fatigue score, from the DFBIA signals that was able to estimate the percent reduction in muscle force during exercise with repeated-measures Pearson's r = 0.90 and mean absolute error (MAE) of 3.6%. This fatigue score also estimated delayed onset muscle soreness with repeated-measures Pearson's r = 0.83 and MAE = 0.83. Using at-home data, DFBIA was strongly associated with absolute muscle force of participants (n = 198, p < 0.001).

CONCLUSION

These results demonstrate the utility of wearable DFBIA for non-invasively estimating muscle force and pain through the changes in intramuscular fluid dynamics.

SIGNIFICANCE

The presented approach may inform development of future wearable systems for quantifying muscle health and provide a novel framework for athletic performance optimization and injury prevention.

Adequate Interval between Matches in Elite Female Soccer Players

The present study compared four different intervals between three simulated soccer matches for changes in muscle damage and performance parameters. Thirteen well-trained female university soccer players performed three bouts of 90-min Loughborough Intermittent Shuttle Test (LIST) with four different intervals between bouts; one (1d), two (2d), three (3d) and four days (4d), with >12-weeks between conditions in a counterbalanced order. Heart rate, blood lactate, rating of perceived exertion and distance covered in each LIST were measured. Changes in several muscle damage markers (e.g., maximal voluntary isometric torque of the knee extensors: MVC-KE, muscle soreness), performance parameters (e.g., Yo-Yo intermittent recovery test level 1: Yo-Yo IR1), and blood measures (e.g., osmolality, high sensitivity cardiac troponin T) before the first LIST, 1 h after each LIST, and one to five days after the third LIST were compared among the conditions. The total distance covered during the first two LISTs was not different among the conditions, but that during the third LIST was shorter (P < 0.05) for the 1d (9,416 ± 885 m) and 2d conditions (9,737 ± 246 m) than the 3d (10,052 ± 490 m) and 4d conditions (10,432 ± 538 m). Changes in all measures were smaller (P < 0.05) in the 3d and 4d conditions (e.g., the decrease in MVC-KE at one day after the third LIST was -13 ± 4% and -10 ± 3%, respectively) when compared with the 1d and 2d conditions (-20 ± 7%, -18 ± 5%). Performance parameters showed smaller (P < 0.05) changes in the 4d (e.g., the decrease in Yo-Yo IR1 at one day after the third LIST was -9 ± 3%) and 3d (-13 ± 6%) conditions when compared with the 1d (-19 ± 4%) and 2d (-20 ± 8%) conditions. These results suggest that muscle damage and fatigue accumulate when soccer matches are performed three consecutive days or every other day, but if more than three days are inserted between matches, this could be minimized.

Impact of (long) COVID on athletes' performance: a prospective study in elite football players

OBJECTIVES

To investigate possible persistent performance deficits after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in elite athletes.

METHODS

A prospective cohort study in three Belgian professional male football teams was performed during the 2020 - 2021 season. Participants were submitted to strength, jump, and sprint tests and an aerobic performance test (the Yo-Yo Intermittent Recovery test (YYIR)). These tests were repeated at fixed time intervals throughout the season. Assessment of SARS-CoV-2 infection was performed by a polymerase chain reaction (PCR) test before each official game.

RESULTS

Of the 84 included participants, 22 were infected with SARS-CoV-2 during follow-up. At the first testing after infection (52.0 ± 11.2 days after positive PCR testing) significantly higher percentages of maximal heart rate (%HRmax) were seen - within the isolated group of infected players- during (p = .006) and after the YYIR (2 min after, p = .013), compared to pre-infection data. This increase in %HRmax was resolved at the second YYIR testing after infection (127.6 ± 33.1 days after positive PCR testing). Additionally, when comparing the first test after infection in formerly infected to non-infected athletes, significantly higher %HRmax were found during (p < .001) and after the YYIR test (p < .001),No significant deficits were found for the jump, muscular strength or sprint tests.

Aerobic performance seems compromised even weeks after infection. Simultaneously, anaerobic performance seemed to be spared. Because of the potential detrimental effects on the immune system, caution might be advised with high-intensity exposure until aerobic performance is restored.KEY MESSAGESElite football players' aerobic performance seems to be affected for weeks after they return to sports after a SARS-CoV-2 infection.Similarly, anaerobic performance tests showed no discernible changes between both before and after SARS-CoV-2 infections.Regular YYIR testing is recommended to monitor aerobic performance after SARS-CoV-2 infection.

Recovery Methods in Basketball: A Systematic Review

Although different strategies have been implemented to manage recovery-fatigue status in athletes, there is still a lack of consensus on which recovery protocols have the greatest impact and effectiveness when implemented with basketball players, including both physiological and psychological recovery methods. Thus, the purpose of this systematic review is to: (a) determine which recovery methods attain the greatest benefit in restoring the process of attenuating fatigue and (b) provide sports practitioners with guidelines on how some of the most effective recovery strategies can be used to optimize athletes' recovery and ultimately enhance their performance. Using the PRISMA guidelines, a total of 3931 research reports were obtained through four database searches (i.e., PubMed, Scopus, Cochrane, and Web of Science), from which only 25 met the inclusion and exclusion criteria. The recovery protocols analyzed in this systematic review were: sleep, nutrition, hydration, ergogenic aids, cold-water immersion, compression garments, massage, acupuncture, tapering, mindfulness, and red-light irradiation. The results revealed that all recovery strategies are capable of attenuating fatigue and enhancing recovery in basketball players to a certain degree. However, an individualized approach should be promoted, where a combination of proactive recovery modalities appears to result in the most rapid rates of recovery and athletes' ability to maintain high-level performance. Recovery should be programmed as an integral component of training regimens. Also, cooperation and communication between coaches, players, and the rest of the team staff members are essential in minimizing the risk of non-functional overreaching or injury and optimizing basketball players' on-court performance.

Vitamin D deficiency contributes to overtraining syndrome in excessive trained C57BL/6 mice

Overtraining syndrome is a condition resulting from excessive training load associated with inadequate recovery and poor sleep quality, leading to performance decrements and fatigue. Here we hypothesized that vitamin D (VitD) deficiency is a lead factor in the development of the overtraining syndrome. To test this hypothesis, two groups of 60-week-old C57BL/6 mice followed a 16-week excessive eccentric-based overtraining by excessive downhill running with or without dietary VitD depletion (EX and EX-D- groups). Two control groups were trained by uphill running at the same load with or without VitD depletion (CX and CX-D- groups). Handgrip strength decreased throughout the protocol for all groups but the decrease was sharper in EX-D- group (VitD × training, p = 0.0427). At the end of the protocol, the mass of Triceps brachii muscle, which is heavily stressed by eccentric contractions, was reduced in eccentric-trained groups (training effect, p = 0.0107). This atrophy was associated with a lower concentration of the anabolic myokine IL-15 (training effect, p = 0.0314) and a tendency to a higher expression of the atrogene cathepsin-L (training effect, p = 0.0628). VitD depletion led to a 50% decrease of the fractional protein synthesis rate in this muscle (VitD effect, p = 0.0004) as well as decreased FGF21 (VitD effect, p = 0.0351) and increased osteocrin (VitD effect, p = 0.038) concentrations that would lead to metabolic defects. Moreover, the proportion of anti-inflammatory Th2 lymphocytes was significantly decreased by the combination of eccentric training with VitD depletion (vitD × training, p = 0.0249) suggesting a systemic inflammation. Finally, exploratory behavior time of mice was decreased by VitD depletion (VitD effect, p = 0.0146) suggesting a cognitive dysfunction. Our results suggest that VitD deficiency exacerbates the effects of overtraining.

Olympic Games during nationwide lockdown: sports injuries and illnesses, including COVID-19, at the Beijing 2022 Winter Olympics

OBJECTIVE

The objective of this study is to describe the incidence of injuries and illnesses sustained during the Beijing Winter Olympic Games from 4 February 2022 to 20 February 2022.

METHODS

We recorded the daily number of athlete injuries and illnesses (1) through the reporting of all National Olympic Committee (NOC) medical teams and (2) in the polyclinic and medical venues by the Beijing 2022 medical staff.

RESULTS

In total, 2848 athletes (1276 women, 45%; 1572 men, 55%) from 91 NOCs were followed prospectively for the occurrence of injury and illness. NOC and Beijing 2022 medical staff reported 289 injuries and 109 illnesses, equalling 10.1 injuries and 3.8 illnesses per 100 athletes over the 17-day period. The injury incidence was highest in ski halfpipe (30%), ski big air (28%), snowboard slopestyle (23%) and ski slopestyle (22%), and lowest (1%-2%) in curling, alpine mixed team parallel slalom, Nordic combined and alpine super-G. The illness incidence was highest in ski aerials (10%), skeleton (8%), cross-country skiing (8%) and Nordic combined (7%). In the study period, COVID-19 affected 32 athletes, accounting for 29% of all illnesses affecting 1.1% of all athletes.

CONCLUSION

Overall, 10% of the athletes incurred an injury and 4% an illness during the Beijing Winter Olympic Games. The incidence of illnesses overall, which was the lowest yet recorded in the Winter Olympic Games, and COVID-19 was mitigated through comprehensive countermeasures.

A model for calculating the mechanical demands of overground running

An energy-based approach to quantifying the mechanical demands of overground, constant velocity and/or intermittent running patterns is presented. Total mechanical work done (Wtotal) is determined from the sum of the four sub components: work done to accelerate the centre of mass horizontally (Whor), vertically (Wvert), to overcome air resistance (Wair) and to swing the limbs (Wlimbs). These components are determined from established relationships between running velocity and running kinematics; and the application of work-energy theorem. The model was applied to constant velocity running (2-9 m/s), a hard acceleration event and a hard deceleration event. The estimated Wtotal and each sub component were presented as mechanical demand (work per unit distance) and power (work per unit time), for each running pattern. The analyses demonstrate the model is able to produce estimates that: 1) are principally determined by the absolute running velocity and/or acceleration; and 2) can be attributed to different mechanical demands given the nature of the running bout. Notably, the proposed model is responsive to varied running patterns, producing data that are consistent with established human locomotion theory; demonstrating sound construct validity. Notwithstanding several assumptions, the model may be applied to quantify overground running demands on flat surfaces.

Toward a New Conceptual Approach to "Intensity" in Soccer Player's Monitoring: A Narrative Review

ABSTRACT

Pillitteri, G, Clemente, FM, Petrucci, M, Rossi, A, Bellafiore, M, Bianco, A, Palma, A, and Battaglia, G. Toward a new conceptual approach to "intensity" in soccer player's monitoring: A narrative review. J Strength Cond Res 37(9): 1896-1911, 2023-In the last decade, monitoring physiological and match-related demands in soccer has become an increasingly common practice in sports sciences. One of the great challenges during monitoring process is the identification of key indicators that permit to generalize evidence and sustain decision-making process during training prescription. Actually, one of the major debates in the scientific community and among practitioners is the identification of the "intensity" concept. Defining a given training session or exercise based on "intensity" is difficult due to the fact that a huge amount of indicators are available (related both to the performed activities and to the athletes' psychophysiological responses). These indicators can lead to specific outcomes with different interpretations. The current narrative review aims to discuss the different measures approaches used in soccer to describe the intensity for both internal and external demands. In addition, a second purpose of this review is to propose general recommendations for combining intensity indicators with the aim of defining an overall intensity score of a training session or drill.

Predicting Injury and Illness with Machine Learning in Elite Youth Soccer: A Comprehensive Monitoring Approach over 3 Months

The search for monitoring tools that provide early indication of injury and illness could contribute to better player protection. The aim of the present study was to i) determine the feasibility of and adherence to our monitoring approach, and ii) identify variables associated with up-coming illness and injury. We incorporated a comprehensive set of monitoring tools consisting of external load and physical fitness data, questionnaires, blood, neuromuscular-, hamstring, hip abductor and hip adductor performance tests performed over a three-month period in elite under-18 academy soccer players. Twenty-five players (age: 16.6 ± 0.9 years, height: 178 ± 7 cm, weight: 74 ± 7 kg, VO2max: 59 ± 4 ml/min/kg) took part in the study. In addition to evaluating adherence to the monitoring approach, data were analyzed using a linear support vector machine (SVM) to predict illness and injuries. The approach was feasible, with no injuries or dropouts due to the monitoring process. Questionnaire adherence was high at the beginning and decreased steadily towards the end of the study. An SVM resulted in the best classification results for three classification tasks, i.e., illness prediction, illness determination and injury prediction. For injury prediction, one of four injuries present in the test data set was detected, with 96.3% of all data points (i.e., injuries and non-injuries) correctly detected. For both illness prediction and determination, there was only one illness in the test data set that was detected by the linear SVM. However, the model showed low precision for injury and illness prediction with a considerable number of false-positives. The results demonstrate the feasibility of a holistic monitoring approach with the possibility of predicting illness and injury. Additional data points are needed to improve the prediction models. In practical application, this may lead to overcautious recommendations on when players should be protected from injury and illness.

Possible relationship between the gut leaky syndrome and musculoskeletal injuries: the important role of gut microbiota as indirect modulator

This article aims to examine the evidence on the relationship between gut microbiota (GM), leaky gut syndrome and musculoskeletal injuries. Musculoskeletal injuries can significantly impair athletic performance, overall health, and quality of life. Emerging evidence suggests that the state of the gut microbiota and the functional intestinal permeability may contribute to injury recovery. Since 2007, a growing field of research has supported the idea that GM exerts an essential role maintaining intestinal homeostasis and organic and systemic health. Leaky gut syndrome is an acquired condition where the intestinal permeability is impaired, and different bacteria and/or toxins enter in the bloodstream, thereby promoting systemic endotoxemia and chronic low-grade inflammation. This systemic condition could indirectly contribute to increased local musculoskeletal inflammation and chronificate injuries and pain, thereby reducing recovery-time and limiting sport performance. Different strategies, including a healthy diet and the intake of pre/probiotics, may contribute to improving and/or restoring gut health, thereby modulating both systemically as local inflammation and pain. Here, we sought to identify critical factors and potential strategies that could positively improve gut microbiota and intestinal health, and reduce the risk of musculoskeletal injuries and its recovery-time and pain. In conclusion, recent evidences indicate that improving gut health has indirect consequences on the musculoskeletal tissue homeostasis and recovery through the direct modulation of systemic inflammation, the immune response and the nociceptive pain.

Load Monitoring and Its Relationship with Healthcare in Sports

Load monitoring consists of training/match demand quantification as well as wellness and readiness to maximize the likelihood of optimal athletic performance [...].

Aerobic adaptations following two iso-effort training programs: an intense continuous and a high-intensity interval

The intensity of the training stimulus and the effort exerted (regarded as an index of internal load) to complete an exercise session are driving forces for physiological processes and long-term training adaptations. This study compared the aerobic adaptations following two iso-effort, ratings of perceived exertion (RPE)-based training programs, an intense continuous (CON) and a high-intensity interval (INT). Young adults were assigned to a CON (n = 11) or an INT (n = 13) training group to perform 14 training sessions within 6 weeks. The INT group performed running bouts (9.3 ± 4.4 repetitions) at 90% of peak treadmill velocity (PTV) with bout duration equal to 1/4 of time to exhaustion at this speed (134.2 ± 27.9 s). The CONT group ran (1185.0 ± 487.6 s) at a speed corresponding to -2.5% of critical velocity (CV; 80.1% ± 3.0% of PTV). Training-sessions were executed until RPE attained 17 on the Borg scale. VO2max, PTV, CV, lactate threshold velocity (vLT), and running economy were assessed pre-, mid-, and post-training. Both CONT and INT methods increased (p < 0.05) VO2max (INT: 57.7 ± 8.1-61.41 ± 9.2; CONT: 58.1 ± 7.5-61.1 ± 6.3 mL kg-1 min-1), PTV (INT: 14.6 ± 1.8-15.7 ± 2.1; CONT: 15.0 ± 1.7-15.7 ± 1.8 km h-1), CV (INT: 11.8 ± 1.4-12.8 ± 1.8; CONT: 12.2 ± 1.6-12.9 ± 1.7 km h-1), and vLT (INT: 9.77 ± 1.1-10.8 ± 1.4; CONT: 10.4 ± 1.4-11.0 ± 1.8 km h-1) with no differences (p > 0.05) between them; running economy remained unchanged. The continuous training method, when matched for effort and executed at relatively high intensity at the upper boundaries of the heavy-intensity domain (∼80% of PTV), confers comparable aerobic adaptations to those attained after a high-intensity interval protocol following a short-term training period.

Does Physical Activity Affect Clinical Symptoms and the Quality of Life of Mild-Infected Individuals with COVID-19 in China? A Cross-Sectional Study

BACKGROUND

Few studies have identified the links between physical activity (PA), clinical symptoms, and the quality of life (QoL) among mildly infected individuals with COVID-19. This cross-sectional study aims to evaluate how PA levels before infections affect the infectious symptoms and the QoL in mildly infected patients with COVID-19.

METHODS

An online questionnaire link including participants' sociodemographic and anthropometric characteristics, clinical symptoms during the COVID-19 infectious period, the QoL of the worst symptomatic day, and PA in the last seven days before COVID-19 infections was disclosed. Logistic regression and multiple linear regression analyses were applied to assess the relationships between PA levels in the last seven days before infections and COVID-19-related outcomes. The level of statistical significance was set at p < 0.05.

RESULTS

Compared to the low-PA-level group, the moderate-PA-level group presented a higher risk of headaches (OR = 1.34, 95% CI = 1.03 to 1.75, and p = 0.03) and the high-PA-level group presented a higher risk of muscle/body aches (OR = 1.42, 95% CI = 1.04 to 1.93, and p = 0.03). The adjusted linear regression analysis showed that no associations were found between PA levels in the last seven days before infections and the QoL index value on the worst symptomatic day (moderate-PA-level group: β = -0.04, and p = 0.08; high-PA-level group: β = -0.04, and p = 0.17). However, for the mobility and usual activities dimensions of EQ-5D-5L, the lower-PA-level group had a lower burden of QoL than the higher-PA-level group did on the worst-symptomatic day.

CONCLUSIONS

Among mildly infected patients with COVID-19, a higher PA level is associated with a higher risk of experiencing clinical symptoms and a lower QoL.

Mechanism and implications of pro-nature physical activity in antagonizing psychological stress: the key role of microbial-gut-brain axis

Appropriate physical activities and a biodiversity-rich environment are conducive to the relief of psychological stress, and pro-nature physical activities are a combination of the two, which has good application potential in antagonizing psychological stress, but the intervention mechanism is still unclear. The microbiota-gut-brain axis is cyclically associated with psychological stress, and psychological stress can affect the microbiota through the gut-brain pathway, and conversely, the microbiota can also affect the psychological stress-induced symptoms. It is suggested that the microbe-gut-brain axis may provide a new perspective and target for the treatment of psychological stress-related diseases. Pro-nature physical activity can improve the number of Firmicutes, short-chain fatty acids, Akkermansia bacteria, and the gut-brain barrier and further affect the HPA axis, BDNF, and serotonin pathways of gut-brain two-way communication, thereby maintaining the body's homeostasis and reducing antagonistic psychological stress. According to the comprehensive influence of physical activities on the microbiota-gut-brain axis, a "green + exercise prescription hypothesis" in line with the holistic medical concept is revealed, which is expected to be effective in the prevention, alleviation, and treatment of irritable bowel syndrome and neurodegenerative diseases. It provides new means for treating psychological stress-related diseases such as mental disorders and mood disorders. In addition, it enlightens the construction of green infrastructure that is conducive to the diversified contact of microorganisms in outdoor physical activities venues and induces healthy interaction between the human body and the microbial population in the natural ecology. However, the current research is still in its early stages, and the intervention effect and mechanism of pro-nature physical activities need further demonstration in the future.

Blood-Based Biomarkers for Managing Workload in Athletes: Considerations and Recommendations for Evidence-Based Use of Established Biomarkers

Blood-based biomarkers can provide an objective individualized measure of training load, recovery, and health status in order to reduce injury risk and maximize performance. Despite enormous potentials, especially owing to currently evolving technology, such as point-of-care testing, and advantages, in terms of objectivity and non-interference with the training process, there are several pitfalls in the use and interpretation of biomarkers. Confounding variables such as preanalytical conditions, inter-individual differences, or an individual chronic workload can lead to variance in resting levels. In addition, statistical considerations such as the detection of meaningful minimal changes are often neglected. The lack of generally applicable and individual reference levels further complicates the interpretation of level changes and thus load management via biomarkers. Here, the potentials and pitfalls of blood-based biomarkers are described, followed by an overview of established biomarkers currently used to support workload management. Creatine kinase is discussed in terms of its evidence for workload management to illustrate the limited applicability of established markers for workload management to date. We conclude with recommendations for best practices in the use and interpretation of biomarkers in a sport-specific context.

"Biofeedback-based return to sport": individualization through objective assessments

Elite athletes are regularly exposed to high and repetitive mechanical stresses and impacts, resulting in high injury rates. The consequences of injury can range from time lost from training and competition to chronic physical and psychological burden, with no guarantee that the athlete will return to preinjury levels of sport activity and performance. Prominent predictors include load management and previous injury, highlighting the importance of the postinjury period for effective return to sport (RTS). Currently, there is conflicting information on how to choose and assess the best reentry strategy. Treating RTS as a continuum, with controlled progression of training load and complexity, seems to provide benefits in this process. Furthermore, objectivity has been identified as a critical factor in improving the effectiveness of RTS. We propose that assessments derived from biomechanical measurements in functional settings can provide the objectivity needed for regular biofeedback cycles. These cycles should aim to identify weaknesses, customize the load, and inform on the status of RTS progress. This approach emphasizes individualization as the primary determinant of RTS and provides a solid foundation for achieving it.

Untangling risk factors including discipline-specific exposure for injuries in preprofessional and professional circus artists in the USA

Objective

This prospective cohort study quantified injury patterns related to specific circus discipline exposure in preprofessional and professional circus artists.

Methods

Circus artists (n=201; ages 13-69; 172 female, 29 male assigned sex at birth) were enrolled in 10 cities across the USA. Participants were followed for 1 year from enrolment, completing a weekly training log and undergoing a physical therapist evaluation for injuries. The circus-specific extension of the International Olympic Committee 2020 consensus on recording injury and illness in sports was used to analyse injury patterns.

Results

The study completion rate was 77% (n=155). Data were analysed by participant subgroup (age, professional status, sex at birth). The highest injury rates in participant subgroups were for males (5.69/1000 exposures) and related to discipline subgroups, were in aerial with ground elements (5.93/1000 exposures) and aerial (4.26/1000 exposures). Adults had more injuries related to aerial, whereas adolescents had more related to ground disciplines (χ² (2)=10.62, p=0.005) and non-time loss injuries (χ² (1)=5.45, p=0.02). Females had a higher proportion of repetitive injuries (70% vs 55%) than males (χ² (1) = 4.43, p=0.035). Individuals with an eating disorder history had more (p<0.004) injuries (mean 2.27±2.29) than those without (mean=1.48±0.96).

Conclusions

This study showed that intrinsic factors (age, sex at birth and history of eating disorder) and extrinsic factors (circus discipline exposure) affect injury risk. We need to account for the intersectionality of these factors to address risk management at an individual and group level.

Difference in Levels of Vitamin D between Indoor and Outdoor Athletes: A Systematic Review and Meta-Analysis

Vitamin D, its importance in different processes taking place in the human body, the effects of abnormal levels of this hormone, either too low or too high, and the need for supplementation have been extensively researched thus far. Variances in exposure to sunlight can cause vitamin D levels to fluctuate. Indoor activity can be a factor for these fluctuations and can lead to a decrease in vitamin D levels. We conducted a systematic review and meta-analysis aiming to identify whether indoor compared to outdoor training has a significant influence on vitamin D levels; we also performed subgroup analyses and multivariate meta-regression. The type of training has an impact on vitamin D levels that is influenced by multiple cofounders. In a subgroup analysis not considering cofounders, the mean serum vitamin D was 3.73 ng/mL higher in outdoor athletes, a difference which barely fails to achieve significance (p = 0.052, a total sample size of 5150). The indoor-outdoor difference is only significant (clinically and statistically) when considering studies performed exclusively on Asian athletes (a mean difference of 9.85 ng/mL, p < 0.01, and a total sample size of 303). When performing the analyses within each season, no significant differences are observed between indoor and outdoor athletes. To control for multiple cofounders (the season, latitude, and Asian/Caucasian race) simultaneously, we constructed a multivariate meta-regression model, which estimated a serum vitamin D concentration lower by 4.446 ng/mL in indoor athletes. While a multivariate model suggests that outdoor training is associated with slightly higher vitamin D concentrations when controlling for the season, latitude, and Asian/Caucasian race, the type of training has a numerically and clinically small impact. This suggests that vitamin D levels and the need for supplementation should not be decided based on training type alone.

Elbow Injuries Among MLB Pitchers Increased During Covid-19 Disrupted Season, But Not Other Baseball Injuries

Background

The 2020 Major League Baseball Season (MLB) demonstrated season disruptions due to the COVID-19 pandemic. Changes in training and seasonal time frames may be associated with higher rates of injury.

Purpose

To use publicly available data to compare injury rates during the 2015-2019 seasons, COVID-19 shortened season (2020), and the 2021 season stratified by body region and position (pitchers versus position players).

Study Design

A retrospective cohort study utilizing publicly available data.

Methods

MLB players who competed in 1+ seasons between 2015-2021 were included and stratified by position (pitcher, position player). Incidence rate (IR), reported by 1000 x Athlete-Game Exposures (AGEs), was calculated for each season, and stratified by position and body region. Poisson regressions were performed for all injuries and stratified by position to determine association between season and injury incidence. Subgroup analyses were performed on the elbow, groin/hip/thigh, shoulder.

Results

Four thousand, two hundred and seventy-four injuries and 796,502 AGEs across 15,152 players were documented. Overall IR was similar across seasons (2015-2019:5.39; 2020:5.85; 2021:5.04 per 1000 AGEs). IR remained high for the groin/hip/thigh for position players (2015-2019:1.7; 2020:2.0; 2021:1.7 per 1000 AGEs). There was no difference in injury rates between 2015-2019 and 2020 seasons [1.1 (0.9-1.2), p=0.310]. The 2020 season demonstrated a significant increase in elbow injuries [2.7 (1.8-4.0), p<0.001]; when stratified by position, this increase remained significant for pitchers [pitchers: 3.5 (2.1-5.9), p<0.001; position players: 1.8 (0.9-3.6), p=0.073]. No other differences were observed.

Conclusion

The groin/hip/thigh demonstrated the highest IR in 2020 among position players across all season time frames, indicating that continued injury mitigation for this region is necessary. When stratified by body region, elbow injury rates among pitchers demonstrated 3.5 times the rate of injury in 2020 compared to previous seasons, impacting injury burden for the most vulnerable body region among pitchers.

Level of Evidence

Level III.

Microbial bowel infections-induced biochemical and biological abnormalities and their effects on young Egyptian swimmers

Swimmers' personal hygiene affects the spread of microbes in pools. The present study aimed to determine the incidence of microbial infections among young Egyptian swimmers and its impact on swimmers' scores. From January 2020 to June 2021, 528 public club swimmers were examined cross-sectionally. Swimmers were divided into two groups according to their star tests and their scores in the competition (group 1 with a high score and group 2 with a low score). Stool samples, biochemical and biological parameters were assessed. Microbial infections were 54% for intestinal parasitosis and 2.8% for Helicobacter pylori. The rate of intestinal parasitosis was higher among Gp2 as compared to Gp1. The results also revealed higher prevalence of Cryptosporidium spp., Giardia lamblia, Entameba histolytica, and Cyclospora among Gp2 than Gp1. Swimming frequency, and duration influenced the infectious status that induced anemia, abnormal blood pressure, and heart rate. Infected swimmers with cryptosporidiosis had higher alanine transaminase levels, white blood cells, and differential cells but lower aspartate transaminase levels. Giardiasis showed higher reduction in the biochemical markers including ferritin, lactoferrin, iron, and transferrin among Gp 2, compared to Gp 1 and thus affected the swimmers' scores. Thus, raising swimmers' hygiene awareness and targeting health education is obliged.

Effects of physical, psychosocial and dual-career loads on injuries and illnesses among elite handball players: protocol of prospective cohort study

INTRODUCTION

Health problems in sport cause a major burden on several pillars: sport clubs, health and insurance system and mostly the individual athlete. There is limited knowledge in supporting dual-career athletes firmed on evidence-based research in injury/illness prevention, load and stress management. The main goal of this research approach is to determine how specific physical, psychosocial and dual-career loads affect the occurrence of injuries and illnesses in elite handball players and how much of a variation in the athlete's load leads to an occurrence of an injury/illness. A secondary aim is to determine the association between objective and subjective measures of stress as well as examine the benefits of certain biomarkers to monitor stress, load and injury/illness occurrence in athletes.

METHODS AND ANALYSIS

This prospective cohort study, as part of a PhD project, will be carried out on 200 elite handball players of first men's handball league in Slovenia during an entire handball season, lasting from July 2022 to June 2023. Primary outcomes, including health problems, loads and stress, will be assessed weekly on a player level. Other player-related outcomes will include anthropometry, life event survey and blood biomarkers (cortisol, free testosterone and Ig-A), which will be taken three to five times across the observation period according to the players' training cycle.

ETHICS AND DISSEMINATION

The project was approved by the National Medical Ethics Committee of Slovenia (number: 0120-109/2022/3) and will be conducted in compliance with the most recent version of Helsinki Declaration. The study results will be published as peer-reviewed articles, congress presentations and as a Doctoral thesis. The results will not only be of importance for the medical and sports community for development of new injury prevention and rehabilitation strategies but also for structuring the correct policy recommendations for athletes' general health.

TRIAL REGISTRATION NUMBER

NCT0547129.

The influence of physical activity level and cytomegalovirus serostatus on the cytokine levels of young individuals

The practice of physical activity (PA) is a non-pharmacological variable that alters the immune response through changes in cytokines and cellular immunity. Inversely latent cytomegalovirus (CMV) infection prematurely ages the immune system and contributes to the chronic inflammatory condition in several diseases and in aging. This study aimed to compare the association of the PA level and CMV serostatus on whole blood mitogen-stimulated cytokine production of young individuals. The resting blood samples were collected from 100 volunteers of both sexes assigned to one of six groups according to the degree of PA and CMV serostatus: sedentary CMV- (n = 15), moderate physical activity CMV- (moderate PA CMV -, n = 15), high physical activity CMV- (high PA CMV-, n = 15), sedentary CMV+ (n = 20), moderate physical activity CMV + (moderate PA CMV+, n = 20) and high physical activity CMV + (high PA CMV +, n = 20). The collected peripheral blood got diluted in supplemented RPMI-1640 culture medium and incubated for 48 hours with a 2% concentration of phytohemagglutinin at 37ºC and CO2 at 5%. The supernatants were collected and used for the IL-6, IL-10, TNF-α, and INF-γ analysis by the ELISA method. The IL-10 concentration was higher in the Moderate PA and High PA groups when compared to the sedentary group, regardless of CMV status. The physically active (moderate and high PA) CMV+ individuals presented lower concentrations of IL-6 and TNF-α compared to CMV+ sedentary individuals, and the sedentary CMV+ subjects had a higher concentration of INF-γ compared to Sedentary CMV- subjects (p < 0.05). In summary, it is possible to infer that PA is key to controlling inflammation related to CMV infection. The stimulation of physical exercise is an important factor in controlling many diseases at the populational level.

The design and evaluation of an integrated training load and injury/illness surveillance system in competitive swimming

OBJECTIVE

To design and evaluate an integrated training load monitoring and injury/illness surveillance system in a competitive swimming environment.

DESIGN

Descriptive/mixed methods.

SETTING

Swim Ireland National Training Centres.

PARTICIPANTS

Fourteen competitive athletes and seven coaches/medical data collectors participated in the evaluation process.

OUTCOME MEASURES

System satisfaction, usefulness and burden were evaluated. Barriers to the implementation and effectiveness of the system were explored.

RESULTS

Most athletes were 'extremely' or 'very' satisfied with the overall data collection process and also found it to be 'extremely' or 'very' useful in the training centre environment. All practitioners were 'extremely satisfied with the system and found it to be either 'extremely' or 'very' useful in their role. Process constraints and data access and control were significant themes related to the athletes, while practitioners highlighted communication and cooperation amongst stakeholders, layering context to the data, maintaining data integrity and the coach's influence in the monitoring process as being important to the monitoring/surveillance process.

CONCLUSIONS

Training load monitoring and injury/illness surveillance are necessary to elevate the standard of prospective injury/illness prevention research. Integrated systems should be designed in line with key consensus statements, while also being implemented in a way that counteracts the challenges within the real-world training environment.

Combined use of dasatinib and quercetin alleviates overtraining-induced deficits in learning and memory through eliminating senescent cells and reducing apoptotic cells in rat hippocampus

Excessive physical exercise (overtraining, OT) charactered by long-term and excessive training results in the damage of multiple vital tissues including hippocampus which plays a critical role in learning and memory. A combination of dasatinib (D) plus quercetin (Q) (D+Q) belongs to senolytic drugs which selectively kill senescent cells in vitro and vivo. In this study, the rats that suffered a five-week excessive swimming training were subjected to the oral administration of D+Q. D+Q alleviated the decline in exercise performance of OT rats during the swimming training, and prevented learning and memory deficits in Morris water maze, Y-maze and novel object recognition tests after excessive swimming training. Analytical results by SA-β-gal staining and western blotting showed that D+Q significantly reduced senescent cells with repressed expression of senescence-related proteins, p53 and p21, in hippocampus. Nissl and immunohistochemical staining showed that D+Q significantly attenuated neuronal loss caused by apoptosis. Interestingly, we observed elevated level of cleaved caspase 3, an apoptosis executor protein, in p21 positive hippocampus cells by D+Q treatment in immunofluorescent staining, suggesting that senescent cells were induced to apoptosis in D+Q-treated rats. The positive control drug, silibinin, showed similar protective effect against OT, but did not induce the apoptosis of senescent cells, suggesting a difference in the protective mechanisms. These results indicated that D+Q alleviates overtraining-induced deficits in learning and memory through elimination of senescent cells and reduction of apoptotic cell number.

In silico study of potential immunonutrient-based sports supplements against COVID-19 via targeting ACE2 inhibition using molecular docking and molecular dynamics simulations

Use of some sports supplements can inhibit angiotensin-converting enzyme II (ACE2), a receptor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as reviewed through molecular docking and sequent molecular dynamics (MD) simulations against this condition. The crystal structures of ACE2 receptors of SARS-CoV-2 and SARS-CoV, applied in docking analysis, were taken from the Protein Data Bank (PDB). The receptors were then prepared using the Molecular Operating Environment (MOE), as a drug-discovery software platform for docking. Supplements such as quercetin and beta glucan (β-glucan) were the top docked compounds to ACE2 receptor though they strongly interacted with CoV target protein. The study data showed that immune responses to immunonutrient-based sports compounds (viz. quercetin and β-glucan) in Coronavirus disease 2019 (COVID-19) were essential in mounting successful immune responses by athletes. While awaiting the development of an effective vaccine, there is a need to focus on immunonutrient-based sports supplements as preventive and therapeutic options that can be implemented in a safe and quick manner to bolster immune responses in athletes.Communicated by Ramaswamy H. Sarma.

Strength and Conditioning Practices of Brazilian Olympic Sprint and Jump Coaches

Olympic coaches are likely to have adequate knowledge and implement effective training programs. This study aimed to describe and critically examine the strength and conditioning practices adopted by Brazilian Olympic sprint and jump coaches. Nineteen Olympic coaches (age: 50.2 ± 10.8 years; professional experience: 25.9 ± 13.1 years) completed a survey consisting of eight sections: 1) background information; 2) strength-power development; 3) speed training; 4) plyometrics; 5) flexibility training; 6) physical testing; 7) technology use; and 8) programming. It was noticed that coaches prioritized the development of explosiveness, power, and sprinting speed in their training programs, given the specific requirements of sprint and jump events. Nevertheless, unexpectedly, we observed: (1) large variations in the number of repetitions performed per set during resistance training in the off-season period, (2) a higher volume of resistance training prescribed during the competitive period (compared to other sports), and (3) infrequent use of traditional periodization models. These findings are probably related to the complex characteristics of modern competitive sports (e.g., congested competitive schedule) and the individual needs of sprinters and jumpers. Identification of training practices commonly used by leading track and field coaches may help practitioners and sport scientists create more effective research projects and training programs.

"Is the focus in professional rugby ever really on health?": A qualitative study on the uptake of illness prevention guidelines in rugby

Illness prevention is essential for athlete health management, but little is known about its uptake in sport. Prior to the pandemic, the International Olympic Committee (IOC) published a consensus statement recommending illness prevention guidelines are implemented in sports. Yet, little is known about guideline uptake. Therefore, this study aimed to explore the (1) illness experiences of rugby players and athlete support personnel and (2) barriers and enablers to illness prevention guideline uptake in rugby, using the lens of behaviour change theory. In a bid to inform and enhance athlete welfare, we sought to amplify the voices of participants through qualitative inquiry. Between August 2020 and May 2021, 16 semi-structured interviews were undertaken with players and athlete support personnel working across rugby. Analysis was conducted using Braun and Clarke's reflexive thematic analysis. Prior to COVID-19, participants deemed illness to be of little concern, with experience of illnesses and the global pandemic critical enablers to guideline uptake. The rugby environment was a barrier to illness prevention, particularly in women's and academy teams where resource deficiency was highlighted. 'Rugby identity' acted as both a barrier and enabler with participants' passion for rugby driving both guideline adherence and non-adherence. Tackling resource inequalities between men's and women's cohorts is critical to effectively implement guidelines. Coach and player education is essential, and emphasis must be placed on continuing preventative behaviours adopted due to COVID-19. Our findings offer new insight into illness prevention, moving away from prevailing quantitative research, and instead voicing players' experiences.

Litigation involving sports-related spinal injuries: a comprehensive review of reported legal claims in the United States in the past 70 years

BACKGROUND CONTEXT

Sports-related spinal injuries can be catastrophic in nature. Athletes competing in collision sports (eg, football) may be particularly prone to injury given the high-impact nature of these activities. Due to the oftentimes profound impact of sports-related spinal injuries on health and quality-of-life, they are also associated with a substantial risk of litigation. However, no study to date has assessed litigation risks associated with sports-related spinal injuries. A better understanding of the risk factors surrounding these legal claims may provide insights into injury prevention and other strategies to minimize litigation risks. In addition, it may allow the spine surgeon to better recognize the health, socioeconomic, and legal challenges faced by this patient population.

PURPOSE

To provide a comprehensive assessment of reported legal claims involving sports-related spinal injuries, including a comparative analysis of legal outcomes between collision and non-collision sports. To discuss strategies to prevent sports-related spinal injuries and minimize litigation risks.

STUDY DESIGN/SETTING

Retrospective review.

PATIENT SAMPLE

Athletes experiencing spinal injuries during sports.

OUTCOME MEASURES

Outcomes included verdict outcome (defendant vs. plaintiff), legal claims, injuries sustained, clinical symptoms, and award payouts.

METHODS

The legal research database Westlaw Edge (Thomson Reuters) was queried for legal claims brought in the United States from 1950 to 2021 involving sports-related spinal injuries. Verdict or settlement outcomes were collected as well as award payouts, time to case closure, case year, and case location. Demographic data, including type of sport (ie collision vs. non-collision sport) and level of play were obtained. Legal claims, spinal injuries sustained, and clinical symptoms were also extracted. Furthermore, the nature of injury, injured spinal region, and treatment pursued were collected. Descriptive statistics were reported for all cases and independent-samples t-tests and chi-square tests were used to compare differences between collision and non-collision sports.

RESULTS

Of the 840 cases identified on initial search, 78 met our criteria for in-depth analysis. This yielded 62% (n=48) defendant verdicts, 32% (n=25) plaintiff verdicts, and 6% (n=5) settlements, with a median inflation-adjusted award of $780,000 (range: $5,480-$21,585,000) for all cases. The most common legal claim was negligent supervision (n=38, 46%), followed by premises liability (n=23, 28%), and workers' compensation/no fault litigation (n=10, 12%). The most common injuries sustained were vertebral fractures (n=34, 44%) followed by disc herniation (n=14, 18%). Most cases resulted in catastrophic neurological injury (n=37, 49%), either paraplegia (n=6, 8%) or quadriplegia (n=31, 41%), followed by chronic/refractory pain (n=32, 43%). Non-collision sport cases had a higher percentage of premises liability claims (41% vs. 11%, p=.006) and alleged chronic/refractory pain (53% vs. 28%, p=.04). Conversely, collision sport cases had a higher proportion of workers' compensation/no fault litigation (23% vs. 4%, p=.03) and cases involving disc herniation (29% vs. 9%, respectively; p=.04).

CONCLUSION

Sports-related spinal injuries are associated with multiple and complex health, socioeconomic, and legal consequences, with median inflation-adjusted award payouts nearing $800,000 per case. In our cohort, the most commonly cited legal claims were negligent supervision and premises liability, emphasizing the need for prevention guidelines for safe sports practice, especially in non-professional settings. Cases involving athletes participating in non-collision sports were significantly associated with claims citing chronic/refractory pain, highlighting the importance of long-term care in severely injured athletes.

Assessment of fatigue and recovery in elite cheerleaders prior to and during the ICU World Championships

Introduction

Little is known about the demands of competitive cheerleading. Therefore, the objective of this study was to assess fatigue and recovery during preparation for world championships.

Methods

Fifteen participants from the German senior "All-Girl" and "Coed" national teams (nine males and six women) were recruited. Data were collected during the final preparation (T1 -T7) and competition days (C1 -C2). Heart rate variability (HRV) and resting heart rate (HR) were measured every morning. Data on training load, recovery, and stress (Short Scale for Recovery and Stress) were surveyed after training. Countermovement jump height (CMJ), sit-and-reach, and exercise-induced muscle damage (EMID) scores were taken in the afternoon.

Results

There was a practically relevant decrease in CMJ (T2, T6). A trend for HR to increase (T5-C2) and HRV to decrease (T4, T6-C2) was evident. Through training, recovery decreased and recovered as C1 approached (mental performance: T2-T4 p = 0.004; T2-C1 p = 0.029; T3-T4 p = 0.029; emotional balance: T3-T4 p = 0.023; T3-C1 p = 0.014; general recovery status T1-T3 p = 0.008; T3-T4 p = 0.024; T3-C1 p = 0.041), whereas stress increased during the first days and returned to normal before C1 (emotional dysbalance: T2-T4 p = 0.014; T2-C1 p = 0.009; T3-T4 p = 0.023; T3-C1 p = 0.014). EMID scores increased for the upper and lower body between T3, T5-T7 (p ≤ 0.036) and T3, T6-T7 (p ≤ 0.047), respectively.

Discussion

Pre-competition training led to substantial fatigue, and most markers indicate that athletes do not compete fully recovered. This could possibly be avoided by optimizing the training load or implementing recovery strategies.

Rat Mucosal Immunity following an Intensive Chronic Training and an Exhausting Exercise: Effect of Hesperidin Supplementation

Stressful situations such as a high-intensity exercise or exhausting training programs can act as immune disruptors leading to transitory immunodepression status, which can be accompanied by alterations of the gastrointestinal functions. Hesperidin intake has demonstrated ergogenic activity and is able to influence the intestinal ecosystem and immunity. We aimed to investigate the effect of hesperidin consumption in rats submitted to an intense training and a final exhaustion test, focusing on the functionality of the intestinal immune system and on the cecal microbiota. Rats, supplemented or not with hesperidin, were intensively trained on a treadmill for 5 weeks. Samples were obtained 24 h after a regular training session, and immediately and 24 h after a final exhaustion test. Cecal microbiota and composition and function of mesenteric lymph node (MLN) lymphocytes and mucosal immunoglobulin A (IgA) were determined. Results showed that chronic intense exercise followed by an exhausting test induced changes in the intestinal immune compartment such as the distribution and function of MLN lymphocytes. Although the hesperidin supplementation did not prevent these alterations, it was able to enhance IgA synthesis in the intestinal compartment. This could be important in enhancing the immune intestinal barrier in this stressful situation.

Evaluation of Supplement Use in Sport Climbers at Different Climbing Levels

The lack of specific recommendations on the use of supplements for sport climbers may be the reason for their misuse by athletes of this discipline. This study aimed to evaluate choices of dietary supplementation, the reasons for taking them, and the source of information on supplementation among sport climbers at different levels. In addition, how climbers subjectively evaluated the impact of their diets in supporting selected aspects of climbing training was evaluated. We enrolled 110 regular sport climbers (40 women and 70 men) from Wroclaw, Poland, who completed a validated questionnaire, assessing their use of dietary supplements, attitudes towards the influence of diet on sports performance, and climbing level. Their anthropometric measurements were also collected. Participants regarded diet as an important element of sports performance. Sport climbers indicated the Internet to be the main source of information on supplements. Health maintenance and improvement of recovery were the most frequently chosen reasons for taking dietary supplements. The most common supplements were isolated protein, vitamin C, vitamin D, magnesium, and amino acid blends. However, participants rarely used supplements suggested as beneficial for sport climbing performance. Therefore, developing recommendations for supplementation in sport climbing and promoting this should be an elementary part of the preparation for climbing training.

Incidence and burden of injury at the Tokyo 2020 Paralympic Games held during the COVID-19 pandemic: a prospective cohort study of 66 045 athlete days

OBJECTIVE

To describe the epidemiology of injuries at the Tokyo 2020 Paralympic Games, including injuries sustained in the new sports of badminton and taekwondo.

METHODS

Injury data were obtained daily via the established web-based injury and illness surveillance system (WEB-IISS; 81 countries, 3836 athletes) and local organising committee medical facilities (81 countries, 567 athletes). Univariate unadjusted incidences (injuries per 1000 athlete days with 95% CIs), injury proportion (IP, %) and injury burden (days lost per 1000 athlete days) are reported.

RESULTS

A total of 4403 athletes (1853 women, 2550 men) from 162 countries were monitored prospectively during the 3-day pre-competition and 12-day competition periods (66 045 athlete days). 386 injuries were reported in 352 athletes (IP=8.0%) with an incidence of 5.8 per 1000 athlete days (95% CI 5.3 to 6.5). Football 5-a-side (17.2), taekwondo (16.0), judo (11.6) and badminton (9.6) had the highest incidence. There was a higher incidence of injuries in the pre-competition period than in the competition period (7.5 vs 5.4; p=0.0053). Acute (sudden onset) injuries and injuries to the shoulder (0.7) and hand/fingers (0.6) were most common. Injury burden was 10.9 (8.6-13.8), with 35% of injuries resulting in time loss from training and competition.

CONCLUSION

Compared with previous Paralympic Games, there was a reduction in injury incidence but higher injury burden at the Tokyo 2020 Paralympic Games. The new sports of taekwondo and badminton had a high injury incidence, with the highest injury burden in taekwondo, compared with other sports. These findings provide epidemiological data to inform injury prevention measures for high-risk sports.