The impact of stretching on sports injury risk: a systematic review of the literature,”

. Purpose: We conducted a systematic review to assess the evidence for the effectiveness of stretching as a tool to prevent injuries in sports and to make recommendations for research and prevention. Methods: Without language limitations, we searched electronic data bases, including MEDLINE (1966), Current Contents (1997), Biomedical Collection (1993, the Cochrane Library, and SPORTDiscus, and then identified citations from papers retrieved and contacted experts in the field. Meta-analysis was limited to randomized trials or cohort studies for interventions that included stretching. Studies were excluded that lacked controls, in which stretching could not be assessed independently, or where studies did not include subjects in sporting or fitness activities. All articles were screened initially by one author. Six of 361 identified articles compared stretching with other methods to prevent injury. Data were abstracted by one author and then reviewed independently by three others. Data quality was assessed independently by three authors using a previously standardized instrument, and reviewers met to reconcile substantive differences in interpretation. We calculated weighted pooled odds ratios based on an intention-to-treat analysis as well as subgroup analyses by quality score and study design. Results: Stretching was not significantly associated with a reduction in total injuries (OR ϭ 0.93, CI 0.78 -1.11) and similar findings were seen in the subgroup analyses. Conclusion: There is not sufficient evidence to endorse or discontinue routine stretching before or after exercise to prevent injury among competitive or recreational athletes. Further research, especially well-conducted randomized controlled trials, is urgently needed to determine the proper role of stretching in sports. Key Words: ATHLETES, CONDITIONING, META-ANALYSIS, SYNTHESIS S tretching before participation in athletic activities is standard practice for all levels of sports, competitive or recreational. Athletes, coaches, trainers, physiotherapists, and physicians recommend stretching in an effort to both prevent injury and enhance performance; numerous journal articles and textbooks are devoted to the topic, providing a variety of approaches directed to different parts of the body and for specific sporting activities (1). As more people participate in sports and other recreational activities through social changes (e.g., Title IX) and increased recognition that physical activity is part of a healthy lifestyle, injury prevention becomes more important. However, some investigators have questioned the routine practice of stretching and contend that there is little evidence that stretching pre-or postparticipation prevents injury and that it might affect performance negatively We developed a logic model to illustrate the relations among stretching, flexibility, performance, and injury (Fig

The impact of stretching on sports injury risk: a systematic review of the literature,”

. Purpose: We conducted a systematic review to assess the evidence for the effectiveness of stretching as a tool to prevent injuries in sports and to make recommendations for research and prevention. Methods: Without language limitations, we searched electronic data bases, including MEDLINE (1966), Current Contents (1997), Biomedical Collection (1993, the Cochrane Library, and SPORTDiscus, and then identified citations from papers retrieved and contacted experts in the field. Meta-analysis was limited to randomized trials or cohort studies for interventions that included stretching. Studies were excluded that lacked controls, in which stretching could not be assessed independently, or where studies did not include subjects in sporting or fitness activities. All articles were screened initially by one author. Six of 361 identified articles compared stretching with other methods to prevent injury. Data were abstracted by one author and then reviewed independently by three others. Data quality was assessed independently by three authors using a previously standardized instrument, and reviewers met to reconcile substantive differences in interpretation. We calculated weighted pooled odds ratios based on an intention-to-treat analysis as well as subgroup analyses by quality score and study design. Results: Stretching was not significantly associated with a reduction in total injuries (OR ϭ 0.93, CI 0.78 -1.11) and similar findings were seen in the subgroup analyses. Conclusion: There is not sufficient evidence to endorse or discontinue routine stretching before or after exercise to prevent injury among competitive or recreational athletes. Further research, especially well-conducted randomized controlled trials, is urgently needed to determine the proper role of stretching in sports. Key Words: ATHLETES, CONDITIONING, META-ANALYSIS, SYNTHESIS S tretching before participation in athletic activities is standard practice for all levels of sports, competitive or recreational. Athletes, coaches, trainers, physiotherapists, and physicians recommend stretching in an effort to both prevent injury and enhance performance; numerous journal articles and textbooks are devoted to the topic, providing a variety of approaches directed to different parts of the body and for specific sporting activities (1). As more people participate in sports and other recreational activities through social changes (e.g., Title IX) and increased recognition that physical activity is part of a healthy lifestyle, injury prevention becomes more important. However, some investigators have questioned the routine practice of stretching and contend that there is little evidence that stretching pre-or postparticipation prevents injury and that it might affect performance negatively We developed a logic model to illustrate the relations among stretching, flexibility, performance, and injury (Fig

A Toxin–Antitoxin System Promotes the Maintenance of an Integrative Conjugative Element

SXT is an integrative and conjugative element (ICE) that confers resistance to multiple antibiotics upon many clinical isolates of Vibrio cholerae. In most cells, this ∼100 Kb element is integrated into the host genome in a site-specific fashion; however, SXT can excise to form an extrachromosomal circle that is thought to be the substrate for conjugative transfer. Daughter cells lacking SXT can theoretically arise if cell division occurs prior to the element's reintegration. Even though ∼2% of SXT-bearing cells contain the excised form of the ICE, cells that have lost the element have not been detected. Here, using a positive selection-based system, SXT loss was detected rarely at a frequency of ∼1×10−7. As expected, excision appears necessary for loss, and factors influencing the frequency of excision altered the frequency of SXT loss. We screened the entire 100 kb SXT genome and identified two genes within SXT, now designated mosA and mosT (for maintenance of SXT Antitoxin and Toxin), that promote SXT stability. These two genes, which lack similarity to any previously characterized genes, encode a novel toxin-antitoxin pair; expression of mosT greatly impaired cell growth and mosA expression ameliorated MosT toxicity. Factors that promote SXT excision upregulate mosAT expression. Thus, when the element is extrachromosomal and vulnerable to loss, SXT activates a TA module to minimize the formation of SXT-free cells

Insect biodiversity of the Algodones Dunes of California.

Over a nine year period beginning in 2007 we surveyed the insects of the Algodones Dunes, Imperial Count, California, as part of a study undertaken for the U.S. Bureau of Land Management. In a series of 22 collecting trips ranging in duration from 2 to 8 days we thus far have accumulated records of 1,840 species, 21 orders and 244 families from the dunes. Hymenoptera constituted the most diverse order, comprising about 45% of all the species recovered. Insect diversity and abundance peaked during the hottest part of the year between the months of May and September. Life history traits of the insects sampled included herbivores (29.6%), parasitoids (28.7%), predators (18.1%), pollen/nectar feeders (10.9%), detritivores (6.2%) and scavengers (2.4%). Seventy-nine or 4% of the insect species collected in the dunes have been solely recorded from there, and 3% of the species almost certainly derive from adjacent aquatic habitats or agricultural ecosystems, as their life histories could not be completed in Algodones Dunes habitat. The insect fauna of the Algodones Dunes is unexpectedly rich and diverse

A microfluidic approach for hemoglobin detection in whole blood

Diagnosis of anemia relies on the detection of hemoglobin levels in a blood sample. Conventional blood analyzers are not readily available in most low-resource regions where anemia is prevalent, so detection methods that are low-cost and point-of-care are needed. Here, we present a microfluidic approach to measure hemoglobin concentration in a sample of whole blood. Unlike conventional approaches, our microfluidic approach does not require hemolysis. We detect the level of hemoglobin in a blood sample optically by illuminating the blood in a microfluidic channel at a peak wavelength of 540 nm and measuring its absorbance using a CMOS sensor coupled with a lens to magnify the image onto the detector. We compare measurements in microchannels with channel heights of 50 and 115 μm and found the channel with the 50 μm height provided a better range of detection. Since we use whole blood and not lysed blood, we fit our data to an absorption model that includes optical scattering in order to obtain a calibration curve for our system. Based on this calibration curve and data collected, we can measure hemoglobin concentration within 1 g/dL for severe cases of anemia. In addition, we measured optical density for blood flowing at a shear rate of 500 s-1 and observed it did not affect the nonlinear model. With this method, we provide an approach that uses microfluidic detection of hemoglobin levels that can be integrated with other microfluidic approaches for blood analysis