Effects of Recent Concussion and Injury History on Instantaneous Relative Risk of Lower Extremity Injury in Division I Collegiate Athletes.

BACKGROUND: Growing evidence suggests that concussion increases the risk of lower extremity (LE) musculoskeletal injury. However, it is unclear to how the effect of concussion on LE injury risk may be influenced by previous injuries. This study sought to examine the association between concussion, previous LE injuries, and the risk LE injury to the same previously injured limb (ipsilateral) or the opposite limb (contralateral). METHODS: This retrospective study examined medical records from 110 concussed athletes and 110 matched controls for LE injuries in the 365 days before and after the concussion event. The effect of concussion on time to injury was assessed with a Cox proportional hazard model after adjusting for injury history. Fine and Gray subdistribution models assessed the cumulative risk of ipsilateral and contralateral injury by group. RESULTS: Concussion was associated with an increased instantaneous relative risk of LE injury when adjusting for LE injury history [hazard ratio (HR) = 1.67, 95% confidence interval (CI) = 1.11-2.53], agreeing with previous results. Among individuals who had a history of LE injuries before the concussion event, a nonsignificant yet moderate effect of concussion on the instantaneous relative risk of ipsilateral injuries was found after adjusting for the competing risk of contralateral injuries and censored values (HR = 1.85, 95% CI = 0.76-4.46). CONCLUSIONS: This study provides independent confirmation of previous studies, reporting an association between concussion and LE injury risk. Furthermore, this study suggests that future large-scale studies should consider the competing risk of ipsilateral, contralateral, and new injuries in populations with an injury history.

Particle size distribution and atmospheric metals measurements in a rural area in the South Eastern USA.

Atmospheric particle mass concentrations were measured at a site adjacent to Lake Hartwell, GA, during six dry sampling events in February-March 2003. The overall average PM2.5 mass concentration was 9.5 microg/m3 and the overall average total suspended particles mass concentration was 19.1 microg/m3. Particulate matter was collected on a deposition plate mounted onto a specially designed wind vane and was subsequently analyzed to determine the particle size distribution. The average geometric particle diameter was found to be 2.8 microm. Particulate matter collected was found to be closely approximately at log-normal distribution, with a count median diameter of 1.5 mum and a geometric standard deviation of 1.8. Individual metal concentrations present in airborne particulate matter were determined for cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc using inductively coupled plasma-mass spectrometry analysis of samples collected on Teflon filters. Ambient metal concentrations were found to range from 0.8 ng/m3 for cadmium to 512 ng/m3 for iron. The dry deposition flux of metals was estimated to be in the range of 0.17 mg/(m2 year) for cadmium to 102 mg/(m2 year) for iron. More samples need to be collected and analyzed, both temporally and spatially, in order to establish atmospheric metals fluxes onto surfaces.

A review of return to play issues and sports-related concussion.

Mild traumatic brain injury in sports has become a significant public health concern which has not only received the general public's attention through multiple news media stories involving athletic concussions, but has also resulted in local, state, and national legislative efforts to improve recognition and management. The purpose of this article is to review the current literature for return to play (RTP) guidelines. State, regional, national, and professional legislation on sport-related concussion RTP management issues will be reviewed. This article will be helpful in developing a generalized systematic approach to concussion management and highlight specific RTP guidelines. The article will also touch upon specific contraindications to RTP, the role of neuropsychological testing in RTP, and other considerations and complications that affect an athlete's ability to return to competition. Finally, considerations for terminating an athlete's competitive season or ending a career after sustaining a concussion resulting in prolonged and protracted symptomatology or repeated concussions will be reviewed. PubMed and Google were searched using the key terms mentioned below. In addition, the author's library of concussion-related articles was reviewed for the relevant literature.

Precompetition manipulative treatment and performance among Virginia Tech athletes during 2 consecutive football seasons: a preliminary, retrospective report.

CONTEXT: One of the goals of providing manipulative treatment such as osteopathic manipulative treatment (OMT) is to restore maximal, pain-free movement of the musculoskeletal system and to enhance neuromuscular function. Anecdotally, some athletes have reported that their athletic performance improves after manipulative treatment. OBJECTIVE: To develop preliminary data to gain more understanding about the association between precompetition manipulative treatments provided to Division I football players and their athletic performance during each game for 2 consecutive football seasons. METHODS: The study design was a retrospective cohort study. Participants were football athletes at Virginia Polytechnic Institute and State University (Virginia Tech). Board-certified osteopathic physicians who were trained in osteopathic manipulative medicine and sports medicine performed OMT and determined the type of OMT techniques used and the spinal segments treated. One chiropractor provided chiropractic manipulative therapy. Prior to each game, the athletes who elected to receive precompetition manipulative treatment (ie, OMT or chiropractic manipulative therapy) underwent a focused physical examination and received manipulative treatment on the basis of clinical findings. After each game, the coaching staff "graded" the players by using a standard coaching algorithm. Offensive players received a percentile score (0 to 100) and defensive players received a numeric score (> 30 was considered "very good"). RESULTS: A total of 1976 manipulative treatments were provided to 115 football players in 2 consecutive football seasons. Sixty-two offensive players received 985 manipulative treatments, and 53 defensive players received 991 manipulative treatments. Treatments were applied to the affected regions of the spine: cervical, thoracic, lumbar, and sacral sections. Mean (standard deviation) performance scores were 67.8% (22.8%) and 11.1 (9.9) points among offensive and defensive players, respectively. The correlation coefficients between the numbers of the manipulative treatments and the performance scores were 0.107 (P = .407) among the offensive players and 0.218 (P=.117) among the defensive players. CONCLUSION: Precompetition manipulative treatment was positively associated with improved performance among both offensive and defensive Virginia Tech football players. Although the associations between these 2 factors were relatively small and not statistically significant, we found positive correlations in performance of the offensive and defensive players.