Bruce H. Jones

Mouthguards in sport activities : history, physical properties and injury prevention effectiveness

AbstractThree systematic reviews were conducted on: (i) the history of mouthguard use in sports; (ii) mouthguard material and construction; and (iii) the effectiveness of mouthguards in preventing orofacial injuries and concussions. Retrieval databases and bibliographies were explored to find studies using specific key words for each topic. The first recorded use of mouthguards was by boxers, and in the 1920s professional boxing became the first sport to require mouthguards. Advocacy by the American Dental Association led to the mandating of mouthguards for US high school football in the 1962 season. Currently, the US National Collegiate Athletic Association requires mouthguards for four sports (ice hockey, lacrosse, field hockey and football). However, the American Dental Association recommends the use of mouthguards in 29 sports/exercise activities.Mouthguard properties measured in various studies included shock-absorbing capability, hardness, stiffness (indicative of protective capability), tensile strength, tear strength (indicative of durability) and water absorption. Materials used for mouthguards included: (i) polyvinylacetate-polyethylene or ethylene vinyl acetate (EVA) copolymer; (ii) polyvinylchloride; (iii) latex rubber; (iv) acrylic resin; and (v) polyurethane. Latex rubber was a popular material used in early mouthguards but it has lower shock absorbency, lower hardness and less tear and tensile strength than EVA or polyurethane. Among the more modern materials, none seems to stand out as superior to another since the characteristics of all the modern materials can be manipulated to provide a range of favourable characteristics. Impact studies have shown that compared with no mouthguard, mouthguards composed of many types of materials reduce the number of fractured teeth and head acceleration. In mouthguard design, consideration must be given to the nature of the collision (hard or soft objects) and characteristics of the mouth (e.g. brittle incisors, more rugged occusal surfaces of molars, soft gingiva). Laminates with different shock absorbing and stress distributing (stiffness) capability may be one way to accommodate these factors.Studies comparing mouthguard users with nonusers have examined different sports, employed a variety of study designs and used widely-varying injury case definitions. Prior to the 1980s, most studies exhibited relatively low methodological quality. Despite these issues, meta-analyses indicated that the risk of an orofacial sports injury was 1.61.9 times higher when a mouthguard was not worn. However, the evidence that mouthguards protect against concussion was inconsistent, and no conclusion regarding the effectiveness of mouthguards in preventing concussion can be drawn at present. Mouthguards should continue to be used in sport activities where there is significant risk of orofacial injury.n

Injury Reduction Effectiveness of Selecting Running Shoes Based on Plantar Shape

Knapik, JJ, Swedler, DI, Grier, TL, Hauret, KG, Bullock, SH, Williams, KW, Darakjy, SS, Lester, ME, Tobler, SK, and Jones, BH. Injury reduction effectiveness of selecting running shoes based on plantar shape. J Strength Cond Res 23(3): 685-697, 2009-Popular running magazines and running shoe companies suggest that imprints of the bottom of the feet (plantar shape) can be used as an indication of the height of the medial longitudinal foot arch and that this can be used to select individually appropriate types of running shoes. This study examined whether or not this selection technique influenced injury risk during United States Army Basic Combat Training (BCT). After foot examinations, BCT recruits in an experimental group (E: n = 1,079 men and 451 women) selected motion control, stability, or cushioned shoes for plantar shapes judged to represent low, medium, or high foot arches, respectively. A control group (C: n = 1,068 men and 464 women) received a stability shoe regardless of plantar shape. Injuries during BCT were determined from outpatient medical records. Other previously known injury risk factors (e.g., age, fitness, and smoking) were obtained from a questionnaire and existing databases. Multivariate Cox regression controlling for other injury risk factors showed little difference in injury risk between the E and C groups among men (risk ratio (E/C) = 1.01; 95% confidence interval = 0.88-1.16; p = 0.87) or women (risk ratio (E/C) = 1.07; 95% confidence interval = 0.91-1.25; p = 0.44). In practical application, this prospective study demonstrated that selecting shoes based on plantar shape had little influence on injury risk in BCT. Thus, if the goal is injury prevention, this selection technique is not necessary in BCT.

Interventions to prevent softball related injuries: a review of the literature

Objectives: To examine the published evidence on interventions to prevent softball related injuries among adults, and to encourage more epidemiologic research as a foundation for future softball injury prevention efforts. Methods: The authors reviewed literature identified from six electronic databases for studies on softball related injuries. The search was limited to studies written in the English language, published between 1970 and 2002, and involving adult populations. Research was excluded that evaluated baseball (“hard ball”) related injuries or was aimed at injury treatment. Identified studies were categorized by study design. Intervention/prevention papers were evaluated further and described in detail. Results: The search strategy identified 39 studies specifically related to softball. Most studies were case reports/case series (nu200a=u200a13) or descriptive studies (nu200a=u200a11); only four were analytic or intervention/prevention studies. Studies collected data in a variety of ways, often without denominator data to permit calculation of injury rates. Studies also did not differentiate between slow or fast pitch softball activities and most did not mention the type of softball that was used. Conclusions: Surprisingly few studies exist on interventions to reduce injuries during softball, one of the most popular recreational sports in the US. Of the existing literature, much attention has been on sliding related injuries, which comprise only a segment of softball injuries. Basic epidemiologic studies describing the nature, severity, and risk factors for softball injuries in a variety of populations are needed, followed by additional intervention evaluation studies aimed at modifiable risk factors.

The Army Health Hazard Assessment Program's Medical Cost-Avoidance Model

BACKGROUNDnThe Logistics Management Institute initially developed a medical cost-avoidance model (MCAM) to estimate the costs associated with the failure to eliminate or control health hazards of army materiel systems during 1997.nnnMETHODSnPresented is an updated version of the MCAM that uses cost factors for individual health hazard categories. The earlier MCAM calculated army materiel acquisition-life cycle medical costs based on a single cost factor for all hazard categories.nnnRESULTSnThe Armys Health Hazard Assessment (HHA) Program, which uses the MCAM while assessing 18 types of health hazards commonly found in materiel undergoing the acquisition process, recognized the need to refine the MCAM to be hazard-type specific. These hazard types have unique cost factors and serve as the basis for the revised model.nnnCONCLUSIONSnThe revision will assist the HHA program in targeting health hazards that have the potential to affect soldier health and readiness.

Tobacco Use Prevalence and Factors Associated with Tobacco Use in New U.S. Army Personnel

ABSTRACT This study examined the prevalence of tobacco use and factors associated with pre-military service cigarette and smokeless tobacco use. From January 2000 to December 2006, military students arriving for Advanced Individual Training at the U.S. Army Ordnance School completed a questionnaire that asked about their use of tobacco products. The prevalence of smokeless tobacco use from 2000 to 2006 for women generally decreased, as did the number of cigarettes smoked per day by men. For men and women, factors associated with cigarette use included younger age, Caucasian race, and use of smokeless tobacco. Factors associated with smokeless tobacco use among men included younger age, Caucasian race, and cigarette use. For women, cigarette use was the only factor associated with smokeless tobacco use. The identified factors in this study could be used to establish strategies in the future to reduce tobacco use in the military.

Associations of age, aerobic fitness, and body mass index with injury in an operational Army brigade

OBJECTIVESnTo investigate the effects of age, aerobic fitness, and body mass index (BMI) on injury risk in operational Army soldiers.nnnDESIGNnRetrospective cohort study.nnnMETHODSnMale soldiers from an operational Army brigade were administered electronic surveys regarding personal characteristics, physical fitness, and injuries occurring over the last 12 months. Injury risks were stratified by age, 2-mile run time, and BMI. Analyses included descriptive incidence, a Mantel-Haenszel χ2 test to determine trends, a multivariable logistic regression to determine factors associated with injury, and a one-way analysis of variance (ANOVA).nnnRESULTSnForty-seventy percent of 1099 respondents reported at least one injury. A linear trend showed that as age, 2-mile run time, and BMI increased, so did injury risk (p<0.01). When controlling for BMI, the most significant independent injury risk factors were older age (odd ratio (OR) 30years-35years/≤24years=1.25, 95%CI: 1.08-2.32), (OR≥36years/≤24years=2.05, 95%CI: 1.36-3.10), and slow run times (OR≥15.9min/≤13.9min=1.91, 95%CI: 1.28-2.85). An ANOVA showed that both run times and BMI increased with age.nnnCONCLUSIONSnThe stratified analysis and the multivariable logistic regression suggested that older age and poor aerobic fitness are stronger predictors of injury than BMI.