In the United States of America, the National Health and Nutrition Examination Survey (NHANES), using measured heights and weights, produced data on the prevalence of overweight children and adolescents between the ages 6 – 19 years. From the 1960s to 1980, the prevalence of overweight children and adolescents was relatively stable at 4 – 7% in the 6 – 11 year olds and 5 – 6% in the 12 – 19 year olds. However, from NHANES II (1976 – 1980) to NHANES III (1988 -1994), the rate had increased from 7% to 11% in the 6 – 11 year olds and 5% to 11% in the 12 – 19 year olds. Although the national health objectives were to bring the prevalence of overweight children and adolescents below 11% by 2010, the NHANES 1999 – 2002 estimates suggest that the overweight prevalence has increased to even higher levels, 16 % in both 6 -11 and 12 -19 year olds!

Increasing prevalence of overweight and obese children and adolescents is not confined to the USA. It is a global health issue. We know overweight adolescents are at increased risk of becoming overweight adults with the attendant health problems. Overweight and obesity in the child and adolescent populations are linked to increased food consumption and reduced physical activity. In recent years, many adolescents have mostly sedentary lifestyles for a variety of reasons. Increasing amount of time spent in front of television and computer screens has been causally linked to physical inactivity and obesity. Up until recently, the majority of computer games (PSP, Nintendo DS, PS2 and XBOX 360) have been sedentary games. With the introduction of the Nintendo Wii Sports, which requires players to move more than their fingers during play, it would be interesting to ask whether these active games (Wii Sports – tennis, bowling & boxing) will lead to a significant increase in expenditure of energy per unit time of gaming?

Researchers in Liverpool, UK, measured the energy expended in playing a sedentary computer game (Project Gotham Racing 3, XBOX 360) and active computer games (bowling, tennis and boxing in Wii Sports) in 5 girls and 6 boys aged 13 -15 years who regularly represented their school at hockey or netball (girls) and rugby and soccer (boys) (BMJ 2007; 335: 1282 1284). Normally, they played 4 hours of computer games per week at home. The study showed that all games significantly increased the energy expenditure above the resting energy expenditure in both sexes. The only significant difference in energy expenditure between boys and girls was seen during Wii Sports tennis. The boys expended significantly more energy than the girls while playing tennis. The energy expenditure while playing Wii Sports bowling, tennis and boxing was 190.6 kJ/kg/min, 202.5 kJ/kg/min and 198.1 kJ/kg/min respectively. The energy expended while playing sedentary games, 125.5 kJ/kg/min, was significantly less than while playing active games (See figure).

The above study showed that the energy expenditure during active gaming was at least 51% greater than during sedentary gaming. This translates into an extra 250 kJ of energy expended per hour during active gaming. In this group of children, active gaming would increase their total energy expenditure per week by less than 2%. For less physically active children, the contribution to energy expenditure from active gaming may be more.

The energy expended in active gaming in Wii Sports is less than actual bowling, tennis and boxing. The amount of exercise from active gaming is not intense enough to contribute significantly towards the recommendation that young people should take an hour of moderate to vigorous physical exercise each day. However, for overweight children and adolescents who spend significant amount of time playing computer games, the increased energy expenditure in playing active computer games may at least help with their weight management problem. You never know, the fun in playing Wii sports bowling may just encourage them to have a go at the real thing!

“Slide! Slide!” echoes round a baseball field as the player dashes from third base towards the home plate (meaning the home base). The player slides towards the home plate in an attempt to reach the base before the catcher receives the ball. My son plays baseball in school and has slid home a couple of times without problem. Unfortunately, this weekend when he slid home he sustained an intra-articular fracture of his ankle and had to have 2 screws put in to stabilise the joint.

Out of curiosity I searched Medline for medical literature on baseball injuries. In 2007 alone there were over 40 published articles on the study of various aspects of baseball injuries sustained by the players or pitchers. The National Electronic Injury Surveillance System of the United States Consumer Product Safety Commission estimated that softball and baseball are two of the main sports leading to emergency room visits in the United States. (Baseball and softball are very similar games.)

In a 1986 study which analysed sliding-related injuries in the recreational softball population, 71% of all softball-related injuries sustained were consequent to sliding. In another study on the causes of missed days in team sports within the military, softball injuries were found to be the leading cause and a large percentage of these were related to sliding. Biomechanical study of sliding has identified 4 phases to sliding – the sprint, attainment of the sliding position, the airborne phase and the landing phase. The study indicated that injuries occurred in the landing phase where a small area of the body was not only used to absorb the shock of the impact but also was subjected to high horizontal velocities as the bases were contacted.

A recent study examined 16 years of National Collegiate Athletic Association (NCAA) injury surveillance data for men’s baseball for the academic years 1988-89 through 2003-04. (Only 12.1% of the schools in US contributed data to this study. In the 1988-89 academic year, there were 19,670 participants. By the 2003-04 academic year, the number has increased to 27,262 participants.) The study identified 3 primary injury mechanisms in games and practices – player contact, other contact (eg walls, balls, ground) and no contact. About 45% of game injuries resulted from contact with something other than a competitor, such as the ground, base, ball, bat or wall. Another 42% of game injuries were from no-contact mechanisms such as throwing or pulling a muscle while running. Severe injury was defined as an injury which resulted in time loss of > 10 days. One quarter of all injuries in games and practices were severe injuries. Severe ankle injuries accounted for about 5 % of all severe injuries in games and practices. The most common injury mechanism for severe ankle injury is contact with the ground or with a base.

Injuries from participation in sports are par for the course. However, it may be possible to mitigate some of the injuries seen during sports. In the late 80s preventative techniques were introduced as an attempt to change the sliding injury scenario. Instructional courses were offered but this failed because there was a lack of attendance by the league participants. Attempts to institute a no sliding rule failed because participants were concerned that this would alter the game to a drastic degree.

Surely, the atmosphere and excitement of a recreational or school baseball game does not rest on ‘the slide’ alone. Providing instructional courses on how to avoid sliding injury at an earlier age would most likely be more fruitful if introduced to children in 6th grade rather than at college level. It is interesting to note that the authors of the 2007 study on the NCAA injury surveillance data stated “Athletic trainers covering practices and games should be prepared to deal with serious, life-threatening injuries from batted balls and other injury mechanisms. The use of breakaway bases to prevent sliding injuries should be supported in college baseball.” Perhaps we can help to reduce the incidence of baseball injuries by teaching our young baseball players good techniques in order to reduce their chances of injuring themselves in practice and in games.

Gum chewing is a common habit for young and old. While it is more common in the West, gum chewing has become much more popular in Asia over the last 10 years. The ancient Greeks chewed mastic gum (or mastiche), which is a resin from the bark of the mastic tree. It is a shrub-like tree found on the island of Chios, Greece. Greek women chewed the gum to clean their teeth and sweeten their breath. The ancient Mayans chewed chicle which is the sap from the sapodilla tree. The American colonists learned to chew the gum-like resin that formed on spruce trees when the bark was cut from the Indians of New England. During the early 1800s, lumps of spruce gum were sold in the eastern United States. In 1850, sweetened paraffin wax became popular and eventually became more popular than spruce gum. The present day gum had its beginning in 1869 when the Mexican General Antonio Lopez de Santa Anna introduced Thomas Adams to chewing chicle. Two years later, Thomas Adams patented a machine for manufacturing gum. In 1914, Wrigley Doublemint brand was created by William Wrigley Jr. and Henry Fleer who added the popular mint and fruit extracts to a chicle chewing gum.

Could such an innocuous product cause health problems? Apparently so!

A report (BMJ 2008; 336: 96 – 97) from the Charite Universitatsmedizin in Berlin described two patients who were referred to them for investigations because of unexplained gastrointestinal (GI) symptoms and weight loss of unknown cause. The first patient was a 21 year old lady who had had diarrhea and diffuse abdominal pain for 8 months. She had lost 11 kg over that time and weighed only 40.8kg. Extensive blood investigations only showed low albumin level due to malabsorption. Endoscopic examination of the intestine and extensive X-ray scanning did not reveal any abnormality. The patient produced a large amount of stool – up to 1900 gm daily (normal <250 gm)! Analysis of the stool electrolytes raised the suspicion that the diarrhea could be due to the action of an osmotic purgative. On close questioning the patient admitted to chewing large amounts of sugar-free gum. Her daily intake of sorbitol was 18 – 20 gm (one stick of gum contains about 1.25 gm of sorbitol). After starting on a sorbitol-free diet, her diarrhea stopped. One year later she was back to having a normal GI function and had gained 7 kg in weight. The second case involved a 46 year old man who had diarrhea and a weight loss of 22 kg in the previous year. He complained of abdominal gas, bloating and 7 – 10 watery stools daily. Again extensive blood, endoscopic and X-ray investigations turned up nothing abnormal. Stool analysis again showed the diarrhea could be secondary to an osmotic purgative. On questioning, he admitted to chewing 20 sticks of sugar-free gum and eating up to 200 gm of sweets per day. This equates to an intake of about 30 gm of sorbitol. After he started a sorbitol-free diet, his diarrhea stopped and he gained 5 kg over 6 months.

Sorbitol belongs to the family of polyalcohol sugars, like mannitol and xylitol, some of which are used as laxatives. Sorbitol is also used as a sweetener in many sugar-free foods and drug products. People with diabetes often eat dietetic foods containing sorbitol. Sorbitol is poorly absorbed by the small intestine and it can act as an osmotic agent. Ingestion of relatively small amounts (5-20 gms) causes GI symptoms such as gas, bloating and abdominal cramps in a dose dependent manner. Higher doses (20-50 gms) may cause osmotic diarrhea which over a prolonged period can lead to severe weight loss and low albumin level due to malabsorption. Consumption of just 20 gms of sorbitol has been found to produce diarrhea in about half of normal people.

The next time you start developing symptoms of bloating, gas and loose motion, have a think whether you are chewing too many sticks of chewing gum or eating too many sugar-free products with sorbitol as a sweetener. You might just save yourself from a sticky situation!