Abstract: Gastrointestinal cancers account for 37% of all cancer deaths worldwide, underlining the need to further investigate modifiable factors for gastrointestinal cancer risk and prognosis. This review summarizes the corresponding evidence for physical activity (PA), including, briefly, possible biological mechanisms. Despite high public health relevance, there is still a scarcity of studies, especially for tertiary prevention. Besides the convincing evidence of beneficial effects of PA on colon cancer risk, clear risk reduction for gastroesophageal cancer was identified, as well as weak indications for pancreatic cancer. Inverse associations were observed for liver cancer, yet based on few studies. Only for rectal cancer, PA appeared to be not associated with cancer risk. With regard to cancer-specific mortality of the general population, published data were rare but indicated suggestive evidence of protective effects for colon and liver cancer, and to a lesser extent for rectal and gastroesophageal cancer. Studies in cancer patients on cancer-specific and total mortality were published for colorectal cancer only, providing good evidence of inverse associations with post-diagnosis PA. Overall, evidence of associations of PA with gastrointestinal cancer risk and progression is promising but still limited. However, the already available knowledge further underlines the importance of PA to combat cancer.
Abstract: The aim of the present study was to examine and measure high intensity, intermittent upper body performance, in addition to identifying areas of the body that affect the variance in total work done during the 5 × 6 s sprint test. Fifteen males completed an upper body 5 × 6 s sprint test on a modified electro-magnetically braked cycle ergometer, which consisted of five maximal effort sprints, each 6 s in duration, separated by 24 s of passive recovery. A fly wheel braking force corresponding to 5% of the participants’ body weight was used as the implemented resistance level. Body composition was measured using dual-energy X-ray absorptiometry (DEXA). Percent (%) decrement was calculated as 100 − (Total work/ideal work) × 100. Significant (P < 0.05) differences were found between sprints for both absolute and relative (W, W·kg−1, W·kg−1 Lean body mass (LBM) and W·kg−1 Upper body lean body mass (UBLBM)) peak (PP) and mean (MP) power. The % decrement in total work done over the five sprints was 11.4%. Stepwise multiple linear regression analysis revealed that UBLBM accounts for 87% of the variance in total work done during the upper body 5 × 6 s sprint test. These results provide a descriptive analysis of upper body, high intensity intermittent exercise, demonstrating that PP and MP output decreased significantly during the upper body 5 × 6 s sprint test.
Abstract: Sleep is crucial to the physiological and psychological development of youth. The implications of insufficient sleep on learning and school performance are well documented. However, adequate sleep often goes unmet due to a combination of biological, societal, and environmental factors, especially during adolescence. In the present review, the changes to adolescent sleep patterns, and its consequences on cognition and learning are briefly explored. We then review the empirical literature of the role of exercise in regulating adolescent sleep patterns, and its potential mechanisms.
Abstract: This paper analyses the performances of lower-limb amputees in the 100, 200 and 400 m running events from the 2004, 2008 and 2012 Paralympic Games. In this paper, four hypotheses are pursued. In the first, it investigates whether the running performance of lower-limb amputees over three consecutive Paralympic Games has changed. In the second, it asks whether a bi-lateral amputee has a competitive advantage over a uni-lateral amputee. In the third, the effect of blade classification has been considered and we attempt to see whether amputees in various classifications have different level of performance. Finally, it is considered whether the final round of competition obtains different levels of performance in comparison to the qualification heats. Based on the outcomes of these investigations, it is proposed that future amputee-based running events should be undertaken with separate and not combined events for the T42, T43 and T44 classifications at the Paralympic Games.
Abstract: The aim of this study was to analyse the effect of forces applied to pedals and cranks on the strain imposed to an instrumented bicycle motocross (BMX) frame. Using results from a finite element analysis to determine the localisation of highest stress, eight strain gauges were located on the down tube, the seat tube and the right chain stay. Before the pedaling tests, static loads were applied to the frame during bench tests. Two pedaling conditions have been analysed. In the first, the rider was in static standing position on the pedals and applied maximal muscular isometric force to the right pedal. The second pedaling condition corresponds to three pedaling sprint tests at submaximal intensities at 150, 300 and 550 W on a cycle-trainer. The results showed that smaller strain was observed in the pedaling condition than in the rider static standing position condition. The highest strains were located in the seat tube and the right chain stay near the bottom bracket area. The maximum stress observed through all conditions was 41 MPa on the right chain stay. This stress was 11 times lower than the yield stress of the frame material (460 MPa). This protocol could help to adapt the frame design to the riders as a function of their force and mechanical power output. These results could also help design BMX frames for specific populations (females) and rider morphology.
Abstract: Aim: To describe lower extremity injuries for badminton in New Zealand. Methods: Lower limb badminton injuries that resulted in claims accepted by the national insurance company Accident Compensation Corporation (ACC) in New Zealand between 2006 and 2011 were reviewed. Results: The estimated national injury incidence for badminton injuries in New Zealand from 2006 to 2011 was 0.66%. There were 1909 lower limb badminton injury claims which cost NZ$2,014,337 (NZ$ value over 2006 to 2011). The age-bands frequently injured were 10–19 (22%), 40–49 (22%), 30–39 (14%) and 50–59 (13%) years. Sixty five percent of lower limb injuries were knee ligament sprains/tears. Males sustained more cruciate ligament sprains than females (75 vs. 39). Movements involving turning, changing direction, shifting weight, pivoting or twisting were responsible for 34% of lower extremity injuries. Conclusion: The knee was most frequently injured which could be due to multi-planar loading. Turning or cutting movements typically involve motion in the frontal and transverse planes that may place the knee at greater risk of injury than movement in the sagittal plane alone. Further research on badminton specific movements is warranted to better understand the mechanisms of lower extremity injuries in the sport. Sports medicine and support personnel should take into account the susceptibility of the knee to injury when designing training and injury prevention programmes given the large number of change of direction movements during badminton.