Breathing through a diving snorkel; theory and experiment of air flow resistance and cost of breathing.

The snorkel allows a surface swimmer to observe the underwater world through the face mask without being disturbed by inhaling. The effect of a snorkel on breathing resistance and cost is widely held to be substantial. This study aims to model these parameters and to measure indirectly the actual increases. Further, resistances of differing designs and dimensions were assessed and recommendations were made concerning use and choice. Maximal voluntary ventilation in 12 seconds (MVV12) was measured in 19 volunteers seated on dry land with and without a classic J-type snorkel (inner diameter 20.5 mm). The extra and total resistances and costs were calculated using the MVV12 data and using estimated airways resistance extrapolated from subject's demography and spirometric literature data. MVV12 measurements with snorkel showed a minute volume of 152 ±38 L∙min-1, 6.0 ±3.7% lower than without snorkel (p = 7.0x10-6). The theoretical MVV12, calculated from snorkel and airways resistances, decreased by 3.2%. Experimental total breathing resistance (457±83 Pa∙s∙L-1) was 6.5 ± 3.2% higher than without snorkel (p = 2.6x10-7), but the total mechanical breathing cost was unaffected by the snorkel (13.58 Watts with; 13.64 Watts without). Divers' estimations of resistance increase were exaggerated (8.8% at rest, 23% swimming). Classical J-type snorkels with an inner diameter ≥19.5 mm add 3-16% resistance . There is no risk of hypercapnia. Scuba divers are recommended to use their snorkel to breathe more comfortably on the surface. It is recommended the snorkel be made a mandatory safety accessory. The best multipurpose snorkel (19-21 mm) has no top appendages and no water release valve.

Cricketers are not tickled pink by the new coloured ball.

OBJECTIVES: Cricket administrators have started scheduling long-form matches which finish at night and are played with a pink as opposed to a red ball. However, there are reports that the pink ball may introduce new dangers and alter performance. The aim of this study was to investigate professional cricketers' opinions about the visibility of the pink ball whilst playing in different lighting conditions (afternoon, dusk and night). DESIGN: Purposeful sampling of a cross-section of elite cricketers with pink ball experiences playing in the United Kingdom. METHODS: Eighty-eight international or first-class professional cricketers completed a questionnaire consisting of Likert scale and free text responses to questions covering perceptions of the pink ball, with a particular emphasis on visibility. RESULTS: The pink ball was reported as less visible than the red ball when batting (p<0.001) and fielding (p<0.001). Within the three lighting conditions the pink ball was significantly less visible at dusk under floodlights compared to afternoon and night both when batting and fielding (ps<0.001). Free text comments confirmed that visibility of the pink cricket ball was most challenging at dusk (coverage 0.37), and that players sometimes experienced a blurring sensation with the pink ball leaving a visual 'trail' when viewed under floodlights (coverage 0.24). CONCLUSIONS: Results advocate that governing bodies should consider the inclusion of a break in play during dusk to enhance player safety and performance. Empirical research is needed to quantify the risks to player safety in different lighting conditions.

A Saddle sores among female competitive cyclists: A systematic scoping review.

OBJECTIVES: Saddle sores are a prominent but an under investigated health issue among female competitive cyclists. To identify and describe existing evidence of the prevalence, prevention and treatment of saddle sores among female competitive cyclists. DESIGN: Systematic scoping review and expert consultation. METHODS: Primary studies and grey literature investigating saddle sores for competitive female cyclists were identified from six databases which were systematically searched (Medline; PubMed; Scopus; SPORTDiscus; Embase; Advanced Google Scholar) from 1990 onwards. An online survey was distributed to consultants in the female Australian competitive cycling community to obtain information and expert perspectives outside the published literature. RESULTS: Of the 401 studies identified, 10 met the inclusion criteria - 4 were case-series, 4 were cross-sectional, and 2 were brief intervention trials. There was limited empirical evidence to determine the prevalence, and identify prevention and treatment approaches for saddle sores. Handlebar positioning relative to the saddle and reducing perineal pressure had some evidence. Saddle sore treatments appear to be limited to antibiotics and surgical intervention when they worsen or become infected. Yet, three-quarters of the consultants (n=16) indicated saddle sores were frequent among female competitive cyclists, identifying prevention and management strategies as topical creams, maintaining good hygiene, wearing appropriate clothing, leg elevation and taking time off the bike. CONCLUSIONS: There is limited research investigating the prevalence, prevention and treatment of saddle sores among female competitive cyclists, although it has been described as a common occurrence by those in the cycling community. Research is required to understand its prevalence, along with trials to investigate prevention and management methods, so that evidence informed guidelines and/or protocols can be developed.

Pediatric Treadmill Friction Burns to the Hand: Outcomes of an Initial Nonoperative Approach.

Treadmill burns that occur from friction mechanism are a common cause of hand burns in children. These burns are deeper and more likely to require surgical intervention compared to hand burns from other mechanisms. The purpose of this study was to identify the factors associated with healing time using an initial nonoperative approach. A retrospective chart review was performed examining children (<15 years) who were treated for treadmill burns to the hand between 2012 and 2019. Patient age, burn depth, total body surface area of the hand injury, and time to healing were recorded. Topical wound management strategies (silver sheet, silver cream, non-silver sheet, and non-silver cream) and associated treatment durations were determined. For patients with burns to bilateral hands, the features, treatment, and outcomes of each hand were assessed separately. Cox regression analysis was used to evaluate the association between time to healing and patient characteristics and treatment type. Seventy-seven patients with 86 hand burns (median age 3 years, range 1-11) had a median total body surface area per hand burn of 0.8% (range 0.1-1.5%). Full-thickness burns (n = 47, 54.7%) were associated with longer time to healing compared to partial-thickness burns (HR 0.28, CI 0.15-0.54, P < .001). Silver sheet treatment was also associated with more rapid time to healing compared to treatment with a silver cream (HR 2.64, CI 1.01-6.89, P = .047). Most pediatric treadmill burns can be managed successfully with a nonoperative approach. More research is needed to confirm the superiority of treatment with silver sheets compared to treatment with silver creams.

A retrospective review of trampoline-related injuries presenting to a paediatric emergency department in Singapore.

INTRODUCTION: Trampolining is a popular activity. However, to our knowledge, no studies on paediatric trampoline-related injuries (TRIs) have been conducted in Asia. We aimed to provide an Asian perspective on paediatric TRIs and evaluate current safety measures. METHODS: Patients aged under 16 years who presented to the emergency department at KK Women's and Children's Hospital, Singapore, from March 2012 to June 2016 with a TRI were identified from the National Trauma Registry. Data was collated retrospectively focusing on age, location of the trampoline, mechanism and location of injury, treatment, disposition, and follow-up treatment. RESULTS: 137 children were seen for a TRI during this period. There was even representation across age groups (< 6 years, 6-11 years and 11-16 years). 60.6% of these injuries occurred in a public trampoline park, and a smaller proportion involved home and school trampolines. 61.3% of injuries occurred on the trampoline and 25.5% involved a fall off it, while the remaining were incurred by hitting the trampoline frame. The most common injury was soft tissue injury, followed by fractures and dislocations, of which 16.7% required surgical intervention. Most patients were discharged to an outpatient clinic. 14.6% of all patients required admission and 9.5% eventually required surgical intervention. There were three stable head injuries and no cervical spine injuries or deaths. CONCLUSION: The existence of trampoline parks has contributed to a rise in TRIs. We recommend measures such as general education, changes in the setup around the trampoline, increasing the age limit for trampolining, adult supervision and discouraging double bouncing.

Women Are at Higher Risk for Concussions Due to Ball or Equipment Contact in Soccer and Lacrosse.

BACKGROUND: There is ample evidence to suggest sex- and gender-based differences in the incidence of sports-related concussions. The mechanisms of concussion may vary between male and female athletes and contribute to this observed difference. Understanding the underlying etiology by pooling data from primary studies across different settings and sport types will inform interventions that can reduce concussion rates. QUESTIONS/PURPOSES: Specifically, we asked: (1) In which sports are female athletes less likely to experience concussions from player contact? (2) In which sports are female athletes more likely to experience concussions because of ball or equipment contact? METHODS: PubMed, EMBASE, and Cochrane Library databases were searched to identify articles published from January 2000 to December 2018. Ten studies met the inclusion criteria, which were studies that reported concussion incidence by mechanism for both male and female athletes. Exclusion criteria included non-English studies, conference abstracts, and studies on non-sports related concussions. The sports represented by the 10 studies included ice hockey (n = 4), soccer (n = 5), basketball (n = 4), baseball/softball (n = 4), and lacrosse (n = 5). The rate ratio was calculated as the incidence rate in female athletes/male athletes for each concussion mechanism or activity. Data were pooled using the DerSimonian-Laird random-effects model. Study quality was assessed with the Newcastle-Ottawa Scale. RESULTS: Female athletes were at lower risk of player-contact-induced concussions in lacrosse (pooled rate ratio 0.33 [95% CI 0.25 to 0.43]; p < 0.001), basketball (pooled rate ratio 0.86 [95% CI 0.76 to 0.97]; p = 0.01), ice hockey (pooled rate ratio 0.64 [95% CI 0.56 to 0.73]; p < 0.001), soccer (pooled rate ratio 0.70 [95% CI 0.66 to 0.75]; p < 0.001), and soccer heading (pooled rate ratio 0.80 [95% CI 0.72 to 0.90]; p < 0.001); in these sports, men were at higher risk of concussions from player contact. Female athletes were more likely to experience concussions because of ball or equipment contact in lacrosse (pooled rate ratio 3.24 [95% CI 2.10 to 4.99]; p < 0.001), soccer (pooled rate ratio 2.04 [95% CI 1.67 to 2.49]; p < 0.001), and soccer heading (pooled rate ratio 2.63 [95% CI 1.84 to 3.77]; p < 0.001). CONCLUSIONS: The mechanism or activity underlying concussions differs between male and female athletes across different sports. This finding remains the same regardless of whether there are rule differences between the men's and women's games. The implementation of other interventions are required to further ensure player safety, including protective head equipment, concussion prevention training, or rules limiting player contact in the men's game. LEVEL OF EVIDENCE: Level III, retrospective study.

Wearing body armour and backpack loads increase the likelihood of expiratory flow limitation and respiratory muscle fatigue during marching.

The effect of load carriage on pulmonary function was investigated during a treadmill march of increasing intensity. 24 male infantry soldiers marched on six occasions wearing either: no load, 15 kg, 30 kg, 40 kg or 50 kg. Each loaded configuration included body armour which was worn as battle-fit or loose-fit (40 kg only). FVC and FEV1 were reduced by 6 to 15% with load. Maximal mouth pressures were reduced post load carriage by up to 11% (inspiratory) and 17% (expiratory). Increased ventilatory demands associated with carrying increased mass were met by increases in breathing frequency (from 3 to 26 breaths·min-1) with minimal changes to tidal volume. 72% of participants experienced expiratory flow limitation whilst wearing the heaviest load. Loosening the armour had minimal effects on pulmonary function. It was concluded that as mass and exercise intensity are increased, the degree of expiratory flow limitation also increases. Practitioner Summary: This study investigated the effect of soldier load carriage on pulmonary function, to inform the trade-off between protection and burden. Load carriage caused an inefficient breathing pattern, respiratory muscle fatigue and expiratory flow limitation during marching. These effects were exacerbated by increases in mass carried and march intensity.

Friction Blister by Climbing Harness: A Case Report.

An experienced 24-y-old climber on Mount Everest presented to the Base Camp medical clinic with a friction blister on his right flank. The blister was filled with clear fluid and was located about 3 cm posterior and 3 cm superior to the highest point of the right iliac crest, the site where a climbing harness would support the climber while hanging. A diagnosis of friction blister caused by a climbing harness used while traversing between Camp 2 and Camp 3 of Mount Everest was made. The blister was managed with hydrocolloid dressing, and the patient resumed climbing after 1 wk. The lesion healed with scarring at 2 wk. Friction blisters of the feet are common in climbers wearing ill-fitting shoes, but friction blisters caused by climbing harnesses are unusual and have not been reported in the literature as far as the authors are aware. All existing guidelines for blister management pertain to blisters of the feet, and there are inconsistencies in recommendations made by various authors. This unusual case in an extreme environment provides a good learning opportunity.

Allergic Contact Dermatitis to Shin Pads in a Hockey Player: Acetophenone Is an Emerging Allergen.

Acetophenone azine (AA) has recently been identified as a new allergen in shin pads and sports shoes. We report the case of a boy with allergic contact dermatitis of the shins caused by AA present in his shin pads. High-performance liquid chromatography of samples of shin pads was performed to help identify potential contact allergens. Patch tests revealed strongly positive reactions to pieces of his shin pads and to AA down to a concentration of 0.001% in acetone. To our knowledge, this is the first reported case of allergic contact dermatitis to AA in the United Kingdom. Here we recommend the optimal concentration of AA for patch testing at 0.1% in acetone and summarize previous relevant published cases.

Is ski boot sole abrasion a potential ACL injury risk factor for male and female recreational skiers?

OBJECTIVES: To evaluate the potential impact of ski boot sole abrasion on the ACL injury risk of recreational skiers. METHODS: During the past two winter seasons 2016/17 and 2017/18, this retrospective case-control study was conducted in one Austrian ski area. Among a cohort of 148 ACL-injured (51.4% females) and 455 uninjured recreational skiers (43.3% females), age, sex, height, weight, and self-reported skill level were collected by questionnaire, ski length and sidecut radius were notated and sole abrasion of the toe and heel piece of the ski boot was measured using a digital caliper. RESULTS: ACL-injured skiers showed a higher proportion of female (51.4% vs 43.3%, P < 0.001) and less skilled skiers (48.6% vs 20.9%, P < 0.001), and ski length to height ratio was higher (94.7 ± 3.7 vs 93.8 ± 5.0%, P = 0.019) compared to uninjured skiers. ACL-injured skiers used ski boots of greater abrasion at the toe (4.8 ± 1.8 vs 2.4 ± 2.5 mm, P < 0.001) and heel piece (5.4 ± 1.8 vs 3.3 ± 2.3 mm, P < 0.001) compared to controls. Multivariate regression analysis revealed, beside female sex (OR 6.0, 95% CI, 3.1-11.5, P < 0.001), lower skill level (OR 3.2, 95% CI, 1.9-5.4, P < 0.001) and ski length to height ratio (OR 1.1, 95% CI, 1.0-1.2, P < 0.001), sole abrasion at the toe (OR 1.8, 95% CI, 1.5-2.1, P < 0.001) and heel piece (OR 1.4, 95% CI, 1.2-1.6, P < 0.001) to be independently associated with an ACL injury among recreational alpine skiers. CONCLUSIONS: Based on the underlying findings, ski boot sole abrasion was found to be an independent risk factor and may contribute to an increased ACL injury risk.

Abrasion injuries on artificial turf: A systematic review.

OBJECTIVES: To review the incidence of abrasion injuries sustained on artificial turf playing fields and the level of evidence existing on player perceptions of abrasion injuries on these surfaces. DESIGN: Systematic review. METHOD: A systematic search was performed using SPORTDiscus, Medline, Web of Science, Scopus and Science Direct databases. Inclusion criteria included: abrasion type injuries measured; conducted on artificial/synthetic turf; type of sport reported; peer-reviewed original research; English language search terms, but no language restrictions. A quality assessment was conducted using the Newcastle-Ottawa quality scale. RESULTS: The search yielded 76 potential articles, with 25 meeting all inclusion criteria. Twenty articles were injury-based and five were perception-based. The differences in injury definition and the lack of details of the playing surfaces produced varying results on the rate of injuries on artificial turf. Regardless of the condition of the surface, the level of play, or the sport, players perceived the fear of abrasion injuries as a major disadvantage of artificial turf surfaces. CONCLUSIONS: The review highlighted the current disparity that exists between players' perceptions of abrasion injuries and the level of evidence of abrasion injury risk on artificial turf playing surfaces. There is a need for the inclusion of greater detail of playing surfaces' specifications and condition, and an injury definition sufficiently sensitive to better measure abrasion injury incidence and severity. Without this more detailed information, it is likely that the strongly perceived risk of abrasion injuries will continue as a barrier to the adoption of artificial playing surfaces.

Is Helmet and Faceguard Modification Common in Hurling and Camogie and Why Is It Done?

Aims Despite no previous research, it is anecdotally reported that hurling and camogie players modify their helmet and faceguard, which is against GAA regulations and can potentially increase injury risk. This study aimed to establish the prevalence and rationale behind modifications in hurling and camogie. Methods An online questionnaire was completed by 304 players aged over 18 (62% hurlers, 38% camogie players) which consisted of 27 questions. Results Appearance (43%) was the primary reasons for helmet brand choice, with just 1.6% citing safety as a main reason for choice. Surprisingly, 8% of helmets were already modified when purchased and 31% of participants made further modifications, primarily switching faceguards and removal of bars. Restricted vision, comfort and perceived poor quality of the helmet/faceguard were the most common reasons for modification. Players predominantly (75.8%) agreed that further education on modifications is required. Conclusion Future research on the relationship between helmet/faceguard modification and injury risk is required.

Childhood trampoline injuries.

INTRODUCTION: With the increasing use of recreational trampolines, more injuries are seen in emergency depart-ments (ED). Little is known about the relationship between adherence to safety precautions and injuries. This retro-spective study aims to describe the types of injuries and the precautions taken when using trampolines, and to investigate the relationship between injuries and safety precautions. METHODS: We reviewed patient lists and the medical records of children younger than 18 years who were treated between 1 April and 30 September 2014 at the ED of Hospital Unit West, Denmark. Demographic data and type of injury were recorded. Patients or guardians were contacted for a structured telephone interview to describe the safety precautions they had taken before the injury occurred. A total of 113 patients were identified, and 100 patients were included in the phone interviews. A total of 13 patients were excluded due to incorrect/missing phone numbers or lack of a Danish home address. RESULTS: 6% of all children treated in the ED had trampoline-related injuries. A total of 58 (51.3%) patients had fracture injuries, and 55 (48.7%) patients had non-fracture injuries. 4% had complied with all five recommended safety precautions. CONCLUSIONS: This study describes types of injuries and safety precautions related to trampoline use. 6% of all children in the ED had an injury related to trampoline use. 4% complied with all five recommended safety precautions. FUNDING: none. TRIAL REGISTRATION: not relevant.

Effects of a lighter, smaller football on acute match injuries in adolescent female football: a pilot cluster-randomized controlled trial.

BACKGROUND: The high injury incidence during match-play in female adolescent football is a major concern. In football, males and females play matches with the same football size. No studies have investigated the effect of football size on injury incidence in female adolescent football. Thus, the aim of the present study was to investigate the effects of introducing a lighter, smaller football on the injury pattern in female adolescent football. METHODS: We conducted a pilot cluster randomized controlled trial including 26 football teams representing 346 adolescent female football players (age 15-18 years). The teams were randomized to a new lighter, smaller football (INT, N.=12 teams) or a traditional FIFA size 5 football (CON, N.=14 teams) during a full match-season. Acute time-loss injuries and football-exposure during match-play were reported weekly by text-message questions and verified subsequently by telephone interview. RESULTS: In total, 46 acute time-loss injuries were registered (5 severe injuries), yielding an incidence rate of 15.2 injuries per 1000 hours of match-play (95% CI: 8.5-27.2) in INT and 18.6 injuries per 1000 hours of match-play (95% CI: 14.0-24.8) in CON. The estimated 22% greater injury incidence rate risk (IRR: 1.22 [95% CI: 0.64-2.35]) in the CON group was not significant. With an IRR of 1.22, a future RCT main study would need to observe 793 acute time-loss injuries during match-play, in order to have a power of 80%. CONCLUSIONS: A large-scaled RCT is required to definitively test for beneficial or harmful effects of a lighter, smaller football in adolescent female football.