Springer Science and Business Media LLC

Để tập luyện với tốc độ chạy nhanh hơn, nâng cao khối lượng đào tạo, ngăn ngừa chấn thương hoặc phục hồi sau chấn thương, máy chạy bộ áp lực dương thân dưới (LBPPT) đã trở nên phổ biến hơn trong cộng đồng vận động viên. Tuy nhiên, có nhiều bằng chứng mâu thuẫn và thiếu dữ liệu mô tả các phản ứng sinh lý và sinh cơ học khi chạy trên LBPPT của những vận động viên chạy bộ có chuyên môn cao hoặc có trình độ ưu tú với tốc độ chạy mà họ thường luyện tập, vốn nhanh hơn nhiều so với những vận động viên chạy giải trí. Hơn nữa, không có dữ liệu về phản ứng của vận động viên nữ khi chạy trên LBPPT. Do đó, nghiên cứu này được thiết kế để đánh giá các phản ứng sinh lý và sinh cơ học khi chạy trên LBPPT của các vận động viên nam và nữ chạy đường dài được đào tạo chuyên sâu. Mười lăm vận động viên chạy đường dài đã qua đào tạo chuyên sâu (bảy nam; tám nữ) đã hoàn thành một bài kiểm tra chạy đơn lẻ bao gồm 4 × chuỗi khoảng thời gian 9 phút với các tỷ lệ phần trăm trọng lượng cơ thể cố định, từ 0 đến 30% hỗ trợ trọng lượng cơ thể (BWS) theo các bước 10%. Khoảng thời gian đầu tiên luôn được thực hiện với 0% BWS; sau đó, các khoảng thời gian tại 10%, 20%, và 30% BWS được thực hiện một cách ngẫu nhiên. Mỗi khoảng thời gian bao gồm ba giai đoạn 3 phút, với các vận tốc 14.5, 16.1, và 17.7 km·h−1 cho nam và 12.9, 14.5, và 16.1 km·h−1 cho nữ. Các khí thải, thông khí, tần số hô hấp, nhịp tim (HR), cảm giác gắng sức (RPE), và các đặc điểm bước chạy được đo trong suốt mỗi tốc độ chạy và BWS. Các vận động viên nam và nữ đã có phản ứng sinh lý và sinh cơ học tương tự khi chạy trên LBPPT. Việc tăng BWS làm tăng chiều dài bước chạy (p < 0.02) và thời gian bay (p < 0.01) và giảm tần suất bước chạy (p < 0.01) và thời gian tiếp xúc (p < 0.01) trong các mức độ nhỏ đến lớn. Có sự giảm mạnh việc tiêu thụ oxy (VO2) liên quan đến BWS (p < 0.001), trong khi có sự giảm không đáng kể đến trung bình trong tỷ lệ trao đổi hô hấp, thông khí mỗi phút, và tần số hô hấp (p > 0.05), và ảnh hưởng nhỏ đến lớn lên HR và RPE (p < 0.01). Có sự khác biệt không đáng kể đến nhỏ trong VE, tần số hô hấp, HR, và RPE cho một VO2 nhất định giữa các BWS khác nhau (p > 0.05). Các kết quả chỉ ra rằng các vận động viên chạy đường dài nam và nữ có phản ứng sinh lý và sinh cơ học tương tự khi chạy trên LBPPT. Tổng thể, các thay đổi sinh cơ học trong suốt quá trình chạy trên LBPPT đều góp phần giảm chi phí trao đổi chất và những thay đổi sinh lý tương ứng.

Staphylococcus aureus (SA) is a leading cause of infectious diseases in sports teams. In recent decades, community-associated SA (CA-SA) strains have emerged worldwide and have been responsible for outbreaks in sports teams. There are very few data on the prevalence of these strains in France, and none on the carriage among athletes. We conducted a cross-sectional study to determine the SA carriage proportion among athletes practicing sports at risk for CA-SA infection in a French county, and determined the methicillin-resistant and/or CA-SA proportion. We also analyzed SA carriage according to risks factors and studied the SA clonality in a sample of our population. We included 300 athletes; SA carriage proportion was 61% (n = 183) and one was MRSA carrier (0.33%). The MRSA strain belonged to the clonal complex ST5. None of the strain produced Panton Valentine Leucocidin, and we did not find clonal distribution within the teams. Interestingly, we found a high throat-only carriage (n = 57), 31.1% of the SA carriers. We found a high SA carriage with a local epidemiology quite different than that reported in a similar population in the USA. Further studies on SA carriage should include throat sampling. The approved protocol was registered on ClinicalTrial.gov , NCT01148485.

The original article [1] mistakenly omits a grant acknowledgement; thus, the authors would like to acknowledge that the original article was supported by FAPESP 2015/20082-7.

Worldwide physical activity levels of adults are declining, which is associated with increased chronic disease risk. Wearables and smartphone applications offer new opportunities to change physical activity behaviour. This systematic review summarizes the evidence regarding the effect of wearables and smartphone applications on promoting physical activity. PubMed, EMBASE and Cochrane databases were searched for RCTs, published since January 2008, on wearables and smartphone applications to promote physical activity. Studies were excluded when the study population consisted of children or adolescents, the intervention did not promote physical activity or comprised a minor part of the intervention, or the intervention was Internet-based and not accessible by smartphone. Risk of bias was assessed by the Cochrane collaboration tool. The primary outcome was changed in physical activity level. Meta-analyses were performed to assess the pooled effect on (moderate-to-vigorous) physical activity in minutes per day and daily step count. Eighteen RCTs were included. Use of wearables and smartphone applications led to a small to moderate increase in physical activity in minutes per day (SMD = 0.43, 95% CI = 0.03 to 0.82; I2 = 85%) and a moderate increase in daily step count (SMD = 0.51, 95% CI = 0.12 to 0.91; I2 = 90%). When removing studies with an unclear or high risk of bias, intervention effects improved and statistical heterogeneity was removed. This meta-analysis showed a small to moderate effect of physical activity interventions comprising wearables and smartphone applications on physical activity. Hence, wearables and smartphone applications are likely to bring new opportunities in delivering tailored interventions to increase levels of physical activity.

The extramuscular connective tissue (ECT) has been shown to play a significant role in mechanical force transmission between musculoskeletal structures. Due to this and owing to its tight connection with the underlying muscle, the ECT may be vulnerable to excessive loading. The present study aimed to investigate the effect of eccentric elbow flexor exercise on the morphology of the biceps brachii ECT. In view of the high nociceptive capacity of the ECT, an additional objective was to elucidate the potential relationship between ECT damage and the occurrence of delayed onset muscle soreness (DOMS). Eleven healthy participants (♂ = 7; 24 ± 2 years) performed fatiguing dumbbell elbow flexor eccentric exercise (EE) for one arm and concentric exercise (CE) for the other arm in random order and with random arm allocation. Before, immediately after and 24–96 h post-exercise, maximal voluntary isometric contraction torque of the elbow flexors (dynamometer), pressure pain (algometer), palpation pain (100 mm visual analog scale), biceps brachii ECT thickness and ECT/muscle mobility during passive movement (both high-resolution ultrasound) were examined. Palpation pain, suggestive of DOMS, was greater after EE than CE, and maximal voluntary isometric contraction torque decreased greater after EE than CE (p < .05). Relative to CE, EE increased ECT thickness at 48 (+ 17%), 72 (+ 14%) and 96 (+ 15%) hours post-exercise (p < .05). At 96 h post-EE, the increase in ECT thickness correlated with palpation pain (r = .68; p < .05). ECT mobility was not different between conditions, but compared to CE, muscle displacement increased at 24 (+ 31%), 72 (+ 31%) and 96 (+ 41%) hours post-EE (p < .05). Collectively, these results suggest an involvement of the ECT changes in delayed onset muscle soreness.

Sports-related concussion remains a public health challenge due to its morbidity and mortality. One of the consequences of concussion is cognitive impairment (CI) and cognitive-related symptoms (CRS) which determine, to some extent, physical and behavioral functioning of children who sustain concussion. Despite the high prevalence of CI and CRS associated with concussion, the risk factors are not fully understood. We aimed to characterize CRS and to examine its relationship with race, ethnicity, age, insurance, and sex in a pediatric population. A retrospective cohort (case-only) design was used to assess CRS prevalence and its relationship with race and sex using a pediatric hospital’s electronic medical records. A consecutive sample was used with 1429 cases between 2007 and 2014. Study characteristics were examined using chi-square and log binomial regression for hypothesis-specific testing. Of the 1429 cases, 872 (61.0 %) were boys and 557 (39.0 %) were girls. The racial distribution indicated 1146 (80.2 %) Whites, 170 (11.9 %) Blacks/African Americans, and 113 (7.9 %) others. The prevalence of CRS was 78.0 %. Whereas boys had sustained more concussions, girls were more likely to present with CRS; prevalence risk ratio = 1.07, 95 % CI 1.01–1.13, p = 0.02. The crude analysis indicated no racial disparities in CRS prevalence, but the multivariable analysis did, comparing White to Black/African American children; adjusted prevalence risk ratio (aPRR) = 1.77, 99 % CI 1.02–3.08, p = 0.008. Racial disparities exist in CRS among children with sports-related concussion, and Black/African American children are more likely, relative to Whites, to suffer CRS. Due to uncertainty in causal inference, we caution the interpretation and application of these data in risk-adapted concussion prevention.

Debilitating gastrointestinal symptoms (GIS) and dermatological injuries (DI) are common during and after endurance events and have been linked to performance decrements, event withdrawal, and issues requiring medical attention. The study aimed to determine whether GIS and DI affect food and fluid intake, and nutritional and hydration status, of ultramarathon runners during multi-stage (MSUM) and 24-h continuous (24 h) ultramarathons. Ad libitum food and fluid intakes of ultramarathon runners (MSUM n = 54; 24 h n = 22) were recorded throughout both events and analysed by dietary analysis software. Body mass and urinary ketones were determined, and blood samples were taken, before and immediately after running. A medical log was used to monitor symptoms and injuries throughout both events. GIS were reported by 85 and 73 % of ultramarathon runners throughout MSUM and 24 h, respectively. GIS during MSUM were associated with reduced total daily, during, and post-stage energy and macronutrient intakes (p < 0.05), whereas GIS during 24 h did not alter nutritional variables. Throughout the MSUM 89 % of ultramarathon runners reported DI. DI during MSUM were associated with reduced carbohydrate (p < 0.05) intake during running and protein intake post-stage (p < 0.05). DI during 24 h were low; thus, comparative analyses were not possible. Daily, during running, and post-stage energy, macronutrient and water intake variables were observed to be lower with severity of GIS and DI (p < 0.05) throughout the MSUM only. GIS during the MSUM, but not the 24 h, compromised nutritional intake. DI presence and severity also compromised nutrient intake during running and recovery in the MSUM.