Tablet computers may be great for productivity or entertainment, but they can also be a pain in the neck. Researchers from Harvard School of Public Health, Microsoft Corporation and Brigham and Women's Hospital report that the best way to use a tablet is to place it higher (on a table rather than a lap), avoid low gaze angles, and use a case that gives steeper viewing angles. But steeper angles may be detrimental for continuous input with the hands, so the researchers say further studies are needed. The experts put 15 experienced tablet users through a set of tasks with two tablets, an Apple iPad 2 and a Motorola Xoom, and different viewing angles.

The bitter truth

Teens who consume a lot of fructose may have a higher risk of cardiovascular disease and diabetes, according to researchers from the Medical College of Georgia at Georgia Health Sciences University. Fructose is found in fruit and vegetables, but processed food and drink that contain high-fructose corn syrup are believed to produce bad metabolic byproducts. The study, published in The Journal of Nutrition, analysed 559 youths aged 14 to 18. High-fructose diets were linked to higher blood pressure, fasting glucose, insulin resistance and factors that contribute to heart and vascular disease. Also linked were lower levels of cardiovascular protectors such as HDL ('good') cholesterol and the protein hormone adiponectin. This dangerous high-fructose trend is exacerbated in teens who have fat around the midsection - another known risk factor for cardiovascular disease and diabetes.

Born to run?

What makes Usain Bolt (left) and other sprinters so fast? New research from Penn State University reveals these speedsters have different skeletal structures in the foot and ankle - a finding that may be useful in helping treat people who have difficulty walking. Magnetic resonance imaging of the feet of 16 men - half of them trained sprinters and half height-matched non-sprinters - showed that sprinters have significantly longer forefoot bones and shorter Achilles tendon lever arms. According to graduate student Josh Baxter, these allow sprinters to generate greater contact force between the foot and the ground and to maintain that force for a longer time. But he says it is unclear whether these structural differences are adaptations to sprint training or are hereditary. Other factors such as body type, limb dimensions and the presence of fast-twitch muscle fibres are also important in determining one's sprinting potential.