Multiple studies in humans and animals have demonstrated the profound impact that exercise can have on the immune system. There is a general consensus that regular bouts of short-lasting (i.e. up to 45 minutes) moderate intensity exercise is beneficial for host immune defense, particularly in older adults and people with chronic diseases. In contrast, infection burden is reported to be high among high performance athletes and second only to injury for the number of training days lost during preparation for major sporting events. This has shaped the common view that arduous exercise (i.e. those activities practiced by high performance athletes/ military personnel that greatly exceed recommended physical activity guidelines) can suppress immunity and increase infection risk. However, the idea that exercise per se can suppress immunity and increase infection risk independently of the many other factors (e.g. anxiety, sleep disruption, travel, exposure, nutritional deficits, environmental extremes, etc.) experienced by these populations has recently been challenged. The purpose of this debate article was to solicit opposing arguments centered around this fundamental question in the exercise immunology field: can exercise affect immune function to increase susceptibility to infection. Issues that were contested between the debating groups include: (i) whether or not athletes are more susceptible to infection (mainly of the upper respiratory tract) than the general population; (ii) whether exercise per se is capable of altering immunity to increase infection risk independently of the multiple factors that activate shared immune pathways and are unique to the study populations involved; (iii) the usefulness of certain biomarkers and the interpretation of in vitro and in vivo data to monitor immune health in those who perform arduous exercise; and (iv) the quality of scientific evidence that has been used to substantiate claims for and against the potential negative effects of arduous exercise on immunity and infection risk. A key point of agreement between the groups is that infection susceptibility has a multifactorial underpinning. An issue that remains to be resolved is whether exercise per se is a causative factor of increased infection risk in athletes. This article should provide impetus for more empirical research to unravel the complex questions that surround this contentious issue in the field of exercise immunology.

Can exercise affect immune function to increase susceptibility to infection

Rugby Union, a popular full-contact sport played throughout the world, has one of the highest rates of concussion of all full-contact sports. The aim of the current review was to systematically evaluate the available evidence on concussion in Rugby Union and to conduct a meta-analysis of findings regarding the incidence of concussion. Articles were retrieved via a number of online databases. The current review examined all articles published in English up to May 2014 pertaining to concussion in Rugby Union players. The key search terms included ‘Rugby Union’, ‘rugby’, ‘union’, and ‘football’, in combination with the injury terms ‘athletic injuries’, ‘concussion’, ‘sports concussion’, ‘sports-related concussion’, ‘brain concussion’, ‘brain injury’, ‘brain injuries’, ‘mild traumatic brain injury’, ‘mTBI’, ‘traumatic brain injury’, ‘TBI’, ‘craniocerebral trauma’, ‘head injury’, and ‘brain damage’. The final search outcome following the eligibility screening process resulted in the inclusion of 96 articles for this review. The meta-analysis included a total of 37 studies. The results of the meta-analysis revealed an overall incidence of match-play concussion in men’s rugby-15s of 4.73 per 1,000 player match hours. The incidence of concussion during training was 0.07 per 1,000 practice hours. The incidence of concussion in women’s rugby-15s was 0.55 per 1,000 player match hours. In men’s rugby-7s match-play, concussion incidence was 3.01 per 1,000 player match hours. The incidence of concussion varied considerably between levels of play, with elite level play recording a rate of 0.40 concussions per 1,000 player match hours, schoolboy level 0.62 concussions per 1,000 player match hours, and the community or sub-elite level recording a rate of 2.08 concussions per 1,000 player match hours. The incidence of concussion in men’s rugby-15s as a function of playing position (forwards vs. backs) was 4.02 and 4.85 concussions per 1,000 player match hours, respectively. Concussion is a common injury sustained and reported in match play and to a lesser extent during practice by Rugby Union players. Based on the available published data, there appears to be a variation in risk of concussion across level of play, with the sub-elite level having the greatest incidence of injury. Future research focused on studying the acute consequences and best management strategies in current players, and the potential longer term outcomes of concussion in retired players, is needed. A focus on the areas of prevention, injury identification, and medical management, and risk for long-term outcomes will be of benefit to current athletes.

A Systematic Review and Meta-Analysis of Concussion in Rugby Union

The International Liaison Committee on Resuscitation (ILCOR) First Aid Task Force was formed in 2013 to review and evaluate the scientific literature on first aid in preparation for development of international first aid guidelines, including the 2015 American Heart Association (AHA) and American Red Cross Guidelines Update for First Aid . The 14 members of the task force represent 6 of the international member organizations of ILCOR. Before 2015, evidence evaluation for first aid was conducted by the International First Aid Science Advisory Board and the National First Aid Advisory Board. Although the group responsible for evidence evaluation has changed, the goals remain the same: to reduce morbidity and mortality due to emergency events by making recommendations based on an analysis of the scientific evidence.

A critical review of the scientific literature by appointed ILCOR First Aid Task Force members and evidence evaluators resulted in consensus on science statements with treatment recommendations for 22 selected questions addressing first aid interventions. These findings are presented in “Part 9: First Aid” of the 2015 ILCOR International Consensus on First Aid Science With Treatment Recommendations ,1,2 and they include a list of identified knowledge gaps that may be filled through future research. The ILCOR treatment recommendations are intended for the international first aid community, with the understanding that local, state, or provincial regulatory requirements may limit the ability to implement recommended first aid interventions. The current AHA/American Red Cross First Aid guidelines are derived from this work. New topics found in the 2015 First Aid Guidelines Update include first aid education, recognition of stroke, recognition of concussion, treatment of mild symptomatic hypoglycemia, and management of open chest wounds. Other topics have been updated based on findings from the corresponding ILCOR reviews.

The roots of first aid have been recorded throughout …

Part 15: First Aid: 2015 American Heart Association and American Red Cross Guidelines Update for First Aid.

Upper respiratory illness is the most common reason for non-injury-related presentation to a sports medicine clinic, accounting for 35-65% of illness presentations. Recurrent or persistent respiratory illness can have a negative impact on health and performance of athletes undertaking high levels of strenuous exercise. The cause of upper respiratory symptoms (URS) in athletes can be uncertain but the majority of cases are related to common respiratory viruses, viral reactivation, allergic responses to aeroallergens and exercise-related trauma to the integrity of respiratory epithelial membranes. Bacterial respiratory infections are uncommon in athletes. Undiagnosed or inappropriately treated asthma and/or allergy are common findings in clinical assessments of elite athletes experiencing recurrent URS. High-performance athletes with recurrent episodes of URS should undergo a thorough clinical assessment to exclude underlying treatable conditions of respiratory inflammation. Identifying athletes at risk of recurrent URS is important in order to prescribe preventative clinical, training and lifestyle strategies. Monitoring secretion rates and falling concentrations of salivary IgA can identify athletes at risk of URS. Therapeutic interventions are limited by the uncertainty of the underlying cause of inflammation. Topical anti-inflammatory sprays can be beneficial for some athletes. Dietary supplementation with bovine colostrum, probiotics and selected antioxidants can reduce the incidence or severity of URS in some athletes. Preliminary studies on athletes prone to URS indicate a genetic predisposition to a pro-inflammatory response and a dysregulated anti-inflammatory cytokine response to intense exercise as a possible mechanism of respiratory inflammation. This review focuses on respiratory infections and inflammation in elite/professional athletes.

/pdf/respiratory-inflammation-and-infections-in-high-performance-37p13oyz3f.pdf

Respiratory inflammation and infections in high-performance athletes.

Background Injury risk in youth rugby has received much attention, highlighting the importance of establishing evidence-based injury reduction strategies. Aim To determine the efficacy of a movement control exercise programme in reducing injuries in youth rugby players and to investigate the effect of programme dose on injury measures. Methods In a cluster-randomised controlled trial, 40 independent schools (118 teams, 3188 players aged 14–18 years) were allocated to receive either the intervention or a reference programme, both of which were to be delivered by school coaches. The intervention comprised balance training, whole-body resistance training, plyometric training, and controlled rehearsal of landing and cutting manoeuvres. Time-loss (>24 hours) injuries arising from school rugby matches were recorded by coaches and medical staff. Results 441 time-loss match injuries (intervention, 233; control, 208) were reported across 15 938 match exposure-hours (intervention, 9083; control, 6855). Intention-to-treat results indicated unclear effects of trial arm on overall match injury incidence (rate ratio (RR)=0.85, 90% confidence limits 0.61 to 1.17), although clear reductions were evident in the intervention arm for concussion incidence (RR=0.71, 0.48 to 1.05). When trial arm comparisons were limited to teams who had completed three or more weekly programme sessions on average, clear reductions in overall match injury incidence (RR=0.28, 0.14 to 0.51) and concussion incidence (RR=0.41, 0.17 to 0.99) were noted in the intervention group. Conclusion A preventive movement control exercise programme can reduce match injury outcomes, including concussion, in schoolboy rugby players when compared with a standardised control exercise programme, although to realise the greatest effects players should complete the programme at least three times per week.

https://bjsm.bmj.com/content/bjsports/51/15/1140.full.pdf

Reducing musculoskeletal injury and concussion risk in schoolboy rugby players with a pre-activity movement control exercise programme: a cluster randomised controlled trial.

A prospective epidemiological study of injuries to New Zealand premier club rugby union players

Background: Ground hardness is considered one of the possible risk factors associated with rugby injuries. Objectives: To examine the contribution of ground hardness, rainfall and evapotranspiration to the incidence of injury, and to investigate seasonal injury bias throughout one full season of rugby union. Methods: A prospective epidemiological study of rugby injuries was performed on 271 players from rugby union teams involved in the premier grade rugby competition in Dunedin, New Zealand. Ground hardness was measured before each match over 20 rounds with an industrial penetrometer, and local weather information was collected through the National Institute of Weather and Atmospheric Research and the Otago Regional Council. Poisson mixed models were used to describe injury incidence as a function of ground hardness throughout the season. Results: The overall injury incidence during the season was 52 injuries per 1000 match player-hours (95% CI 42 to 65). Although injury incidence decreased gradually by round with a rate ratio of 0.98 (95% CI 0.96 to 0.99) (p = 0.036), and the hardness of match grounds decreased significantly over the season (0.16 MPa/round, 95% CI 0.12 to 0.21, p Conclusions: Seasonal change in ground hardness and an early-season bias of injuries was demonstrated. Although the contribution of ground hardness to injury incidence was not statistically significant, match round and injury incidence were highly correlated, confirming a seasonal bias, which may confound the relationship of injury to ground condition.

/pdf/association-of-ground-hardness-with-injuries-in-rugby-union-1walwy8nfe.pdf

Association of ground hardness with injuries in rugby union

Epidemiological studies suggest that highly trained athletes are more susceptible to upper respiratory tract infections (URTI) compared with the general population. Upper respiratory symptoms (URS) often appear as either primary invasion of pathogenic organisms and/or reactivation of latent viruses such as Epstein-Barr virus (EBV). The purpose of this study was to examine the relationship between EBV reactivation and the appearance of URS during intensive training in collegiate rugby football players. We evaluated EBV-DNA expression in saliva and examined the relationship between onset of URS and daily changes in EBV-DNA as well as secretory immunoglobulin A (SIgA) levels among 32 male collegiate rugby football players during a 1-month training camp. The EBV-DNA expression tended to be higher in subjects who exhibited sore throat (p=0.07) and cough (p=0.18) than that of those who had no symptoms, although their differences were not significant. The SIgA level was significantly lower 1 day before the EBV-DNA expression (p<0.05). The number of URS increased along with the EBV-DNA expression and decrease of SIgA levels. These results suggest that the appearance of URS is associated with reactivation of EBV and reduction of SIgA during training.

Virus activation and immune function during intense training in rugby football players.

Background/Aim During competitive diving, divers jump up from 1 to 3 m springboards or 5 to 10 m platforms and dive into the water. The impact forces are very large in the water entry phase, and, as such, microtraumatic injuries are common due to the tremendous physical stress placed on the diver. Low-back pain (LBP) is the most frequently reported symptom in divers. This study aimed to extract possible risk factors related to LBP from physical and technical characteristics in Japanese elite junior divers. Methods Eighty-three elite junior divers (42 men and 41 women) in Japan were included in this study. LBP was assessed by a questionnaire, interview and physical examination during a national training camp. Morphological data, physical fitness and diving skills were also evaluated. The factors related to LBP were extracted by using logistic-regression analysis and the forward-selection method (likelihood ratio). Results A total of 37.3% (31 reports) of back pain occurred in the lumbar region. Shoulder flexibility (OR 0.919; 95% CI 0.851 to 0.992) and age (OR 0.441; 95% CI 0.239 to 0.814) were recognised as factors related to LBP in male-elite junior divers, whereas only age (OR 0.536; 95% CI 0.335 to 0.856) was a factor in female-elite junior divers. Conclusions Our results suggest that shoulder flexibility is important for preventing LBP in elite-male junior divers, since they require full shoulder flexion during the water entry phase. Limited shoulder flexibility could cause lumbar hyperextension when adjusting for the angle of water entry.

https://bjsm.bmj.com/content/bjsports/48/11/919.full.pdf

Critical factors for the prevention of low back pain in elite junior divers

Background Neurocognitive function may be a risk factor for anterior cruciate ligament (ACL) injury by changing neuromuscular control such as muscle activities. However, the effect of differences in neurocognitive function on biomechanics and neuromuscular control related to ACL injury risk is not clear. The purpose of this study was to examine the effect of differences in neurocognitive function on biomechanics and neuromuscular control during an unanticipated side-step cutting motion. Method The subjects were 15 collegiate female athletes who were divided into two groups using the Symbol Digit Modalities Test (SDMT). The experimental task was an unanticipated side-step cutting motion from a 30 cm high box. We calculated joint angles and moments using a 3-dimensional motion analysis system from the dominant leg, and measured muscle activities using a surface electromyography. We calculated the co-contraction ratio (CCR) as relative muscle activity of the quadriceps to the hamstring. Results As a result, subjects with a lower SDMT score had significantly increased quadriceps activity before and after ground contact and decreased CCR only after ground contact. Conclusion In the lower SDMT score group, the quadriceps showed stronger muscle activity than the hamstring during an unanticipated side-step cutting motion. This dominant quadriceps muscle activity has been reported to increase the load on the ACL, and there was a possibility of increasing the risk of the ACL injury. Considering these factors, subjects with lower neurocognitive function could have a high risk of ACL injury due to alterations in muscle activities surrounding the knee.

Masahiro Takemura

Papers

A prospective epidemiological study of injuries to New Zealand premier club rugby union players

Association of ground hardness with injuries in rugby union

Virus activation and immune function during intense training in rugby football players.

Critical factors for the prevention of low back pain in elite junior divers

The influence of differences in neurocognitive function on lower limb kinematics, kinetics, and muscle activity during an unanticipated cutting motion