More than half of U.S. adults play video games with one in five playing daily or almost every day.¹  Video games are gaining popularity, especially those that use arm gestures and motions or force plates to control the system.  Sedentary individuals who like video games may find these more active types of video games attractive.  But is the intensity of these video games high enough to provide health benefits?

Japanese² researchers investigated the energy cost of theWii Fit Plus videos for yoga, resistance, balance and aerobic exercise and Wii Sports including golf, bowling, baseball, tennis and boxing.  They measured caloric expenditure in a special airtight room called a metabolic chamber while subjects performed each activity for eight minutes. 

Researchers measured the intensity of each video activity in units called metabolic equivalents (METs).  Resting energy expenditure is defined as 1 MET; if you are exercising at 3 METs then the intensity of the activity is three times resting.  According to the American College of Sports Medicine, an activity must reach a level of moderate intensity to provide health benefits.  Moderate intensity exercise is defined as an intensity of 3-6 METs.  Vigorous activities have an intensity >6 METs.

Results of the study showed that Wii balance exercises and yoga were below the minimum intensity of 3 METs.  These exercises produced only light activity levels which were not adequate to provide health benefits.  Many but not all the resistance training and aerobic exercises met the minimum 3 MET criteria and would be considered adequate to provide health benefits.  Of the Wii Sports activities, boxing had the highest energy expenditure averaging just over 4 METs.  Tennis and baseball averaged 3 METs with golf and bowling <3 METs.  None of the sports or fitness activities were considered vigorous activity. 

The activity guidelines for health benefits are 30 minutes of moderate intensity (3-6 METs) activity performed 5 days/week. Some of the Wii sports games and fitness activities are sufficient to meet these minimum guidelines and could be used to meet part of the recommended 150 minutes of activity per week.  However, many of the games (about 2/3 of those tested) provide only light activity (<3 METs) and do not meet the criteria.  For this reason it is important to choose games requiring the greatest energy expenditure.  It is also important to note that 150 minutes of moderate intensity activity is the amount recommended for health benefits like improving cholesterol, blood pressure, and blood sugar levels.  If an individual’s goal is weight loss, the recommendation for activity is 300 minutes of moderate intensity exercise per week. 

Worth noting, the Wii Sports games and Wii Fit Plus aerobic exercise videos expend fewer calories than performance of the actual sport or exercise itself.  There is not much horizontal movement involved in playing Wii games; the added movement increases energy expenditure when playing the real sport or aerobic exercise.  So if you get the opportunity select the actual activity or sport to get the most fitness improvements and the greatest caloric expenditure.

1.  Lenhart, A. Jones, S., and Macgill, A. (2008). Adults and video games. In: Pew  Internet and American Lift Project. 2008 [cited July 1, 2009]. Available from http://www.pewinternet.org/Reports/2008/Adults-and-Video-Games.aspx

2.  Miyachi, M, Yomamoto, K, Ohkawara, K, Tanaka, S. (2010). METs in Adults While Playing Active Video Games: A Metabolic Chamber Study. Med Sci Sports Exerc. 42(6), 1149-1153.

Just last week the 2010 Dietary Guidelines Advisory Committee (DGAC) released it's Advisory Report for the 2010 Dietary Guidelines (DG). Prepared by 13 national nutrition and health experts, this report provides the latest scientific evidence around a variety of food and nutrition topics. The public has 30 days to comment on the document, which will be used to develop the specific DG, set to be released by the end of 2010.

Updated every 5 years (since 1980), the DG are used for government nutrition programs and education, as well as by dietitians and health professionals to help educate people about eating healthier. So what's different about 2010?

1. The DGAC has recognized that it needs to address an American public of whom the majority are overweight or obese, yet undernourished in several key nutrients. Sound like an oxymoron?!?

2. The DGAC has recognized that change is needed in the overall food environment to support the efforts of all Americans to meet the 2010 DG.

Given these, the DGAC highlighted several necessary steps:

• Reduce overweight and obesity of the US population by cutting calorie intake and increasing physical activity.
• Shift food patterns to a more plant-based diet; but increase intake of seafood and fat-free and low-fat milk and milk products
• Reduce intake of sodium and refined grains, as well as foods with added sugars and solid fats
• Meet the 2008 Physical Activity Guidelines for Americans
• Improve cooking skills and empower Americans to prepare and consume healthy foods at home
• Increase health, nutrition, and PE programs/curricula in schools and preschools
• Provide financial incentives to purchase, prepare, and consume healthy foods
• Improve the availability of healthy foods like fresh produce and seafood
• Encourage restaurants and the food industry to offer healthy foods served in smaller portions
• Implement the US National Physical Activity Plan

So what do you think... if the 2010 DG released later this year reflect the above steps, will they make a difference in reducing weight and increasing diet quality in America? Will the food industry listen and become engaged in the process of improving American diets? What do you think needs to be done to improve Americans' eating habits?

Warm-up and Static Stretching Is a Common Routine Prior to Performance:
Stretching as part of warm up is commonly integrated as part of the pre-competition routine for competitive athletes and recreational fitness participants in order to reduce injury and improve muscular performance. Previous recent research ¹ suggests that acute stretching before maximal muscular performance may hinder the ability of the muscle to produce force.  Two theories to explain this include mechanical factors such as reduced stiffness on the musculotendinous unit and/or neural factors such as altered motor control or a greater autogenic inhibition.¹ However, this study investigated stretching volume, rest interval, and stretching method effects on the 1 Repetition Max bench press in resistance trained collegiate football players.

It was thought that static stretching would be detrimental to 1 RM performance. The investigators proposed that high volume static stretching (HVSS) and high volume Proprioceptive Neuromuscular Facilitation (HVPNF) stretching would have a significant detrimental effect on 1 RM bench press because of repeated high volume placed on the muscle.  A within–subject randomized repeated measures design was used. Fifteen athletes completed 5 different stretching protocols integrated with a 1RM dynamic warm-up routine followed by 1RM bench press testing in randomly assigned order.

5 Stretching Protocols:
The protocols included a) non-stretching (NS), b) low-volume  PNF stretching (LVPNFS), c) HVPNFS, d) low-volume static stretching (LVSS), and e) HVSS. The two stretches selected were the chest/shoulder partner stretch, and the overhead triceps partner stretch.

Types of Subjects and Conditions Important for Study Selection:
All of the subjects were injury free and able to perform stretching exercises and the 1RM bench press test without pain.  Furthermore none of the subjects had taken creatine or other performance-enhancing substances within the previous 90 days. Subjects refrained from vigorous upper body exercise for 48 hours before each testing session. Anthropometric measurements were taken before testing and the 3 site skin folds for body composition (chest, abdomen, thigh) and body weight to the nearest 10th of a kilogram.  The strength testing protocol was the American College of Sports Medicine guidelines for the Bench Press 1 RM.  The subjects assumed a supine position on a bench with the feet flat on the ground, the grip on the bar at slightly wider than shoulder width and the bar lowered to the chest in a smooth, controlled manner and lifted to a maximal upper limb length.

Results:
One way ANOVA analysis showed that there was no significant effect of any of the 5 stretching treatments on the 1 RM bench press performance.  Furthermore, repeated measures ANOVA revealed no significant differences among the testing days which indicates there was no testing order effects.  So, while the investigators expected a detrimental effect on the 1 RM results, no negative effects were determined. However, the rest interval after the stretching session and prior to the initial 1 RM attempt was 5 minutes.  This time interval may have been sufficient time to mitigate the effects of the stretching protocols on muscular performance.  This was consistent with the findings reported by Torres et al. ² on upper body performance by collegiate track throwers with 5 minutes of rest after stretching. 

Discussion:
This study and most comparative studies had trained collegiate athletes as subjects that performed regular stretching as part of the training warm-up routine and suggests that they have developed an adaptation of recovering from altered elastic properties of the musculotendinous unit within the 5 minutes of rest. Also, previous studies that reported decrements in performance was mostly studied in the lower body (Achilles tendons, hamstrings, calves) and suggest that acute stretching in the upper body may respond differently to acute stretching in the lower body. 

Student Questions:
1) Do you see how trained athletes versus untrained subjects might get different results?  There seems to be an adaptation to a set routine and regular warm-up and strength training.
2) What does the Law of Specificity have to do with this?
3) If you were conducting a follow up study, what would you alter to test subjects and get different results?

¹Zachary D. Molacek, Donovan S. Conley, Tammy K. Evetovich, and Kristi R. Hinnerichs. Effects of Low-and High-volume Stretching on Bench Press Performance In Collegiate Football Players. Journal of Strength and Conditioning Research 24:711-716, 2010.
²Torres, EM, Kraemer, WJ, Vingren, JL, Volek, JS, Hatfield, DL, Spiering, BA, Ho,JY, Fragala, MS, Thomas, GA, Anderson, JM, Hakkinen, K, and Maresh, CM. Effects of stretching on upper-body muscular performance. Journal of Strength and Conditioning Research 22:1279-1285,2008.

If you read Monday's blog you know that high outdoor temperatures and humidity (like we experience here in TX during the summer!) coupled with exercise can lead to extreme dehydration. But, it won't if you make a conscious effort to stay hydrated before, during, and after your physical activity. How do you do this? Here are the fluid recommendations again:

• Start hydrating 4 hours before activity by drinking 2-3 cups (16-24 ounces) of fluid.
• If signs of dehydration are present despite this (i.e. not needing to urinate), drink another 1-2 cups (8-16 ounces) 2 hours before activity.
• Drink 6-12 ounces every 15-20 minutes of activity.
• After activity, drink 3 cups (24 ounces) for each pound lost. 

Elite athletes and weekend warriors alike often believe that the best fluid replacement during exercise is a sports drink. After all, it has sodium and potassium to replace these electrolytes that are lost during exercise, right? While sports drinks do have their time and place, plain water is adequate under many (maybe most) circumstances. 

Choose PLAIN WATER: when your exercise is less than 1 hour and low to moderate in intensity.

Choose a SPORTS DRINK: when your exercise is greater than 1 1/2 hours and moderate intensity OR greater than 1 hour and high intensity OR you are exercising in extreme heat.

What's the advantage of a sports drink?

• Carbohydrates. A concentration of carbohydrates between 4 and 8 percent provide fuel for the muscles and brain without impairing gastric emptying.
• Electrolytes. Sodium increases fluid absorption and stimulates thirst, resulting in increased fluid intake. Contrary to popular belief, however, the amount of sodium in most commercial sports drink is low. So, salty foods are still encouraged to replace salt losses after intense exercise/sweating. In other words, sports drinks should be used as a fluid replacement, not an electrolyte replacement.
• Flavor. The more you enjoy the flavor of a drink, the more you will drink.

What's the disadvantage of a sports drink?

• Calories. If you follow the lower end of the fluid replacement recommendations and drink 24 ounces before exercise, 18 ounces during exercise, and 24 ounces after exercise that's 66 ounces and over 400 calories from your sport's drink (assuming 50 calories/8 fl ounces)!
• Cost. The cost of two 32 fl ounce sports drinks could be anywhere from two dollars to four dollars. While that doesn't seem like much, it adds up over time.

So what do you think? Do you see many people (including yourself?) drinking sports drinks when plain water would be recommended? How might you make plain water more palatable if you don't like it's taste?

American College of Sports Medicine; Sawka MN, et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 39:377-390, 2007.

I was out running a few Saturday’s ago and was plagued by extreme thirst. It was in the morning but as it turns out, unknown to me, it was the hottest day we had had this summer, hitting triple digits in the afternoon. So it was already pretty hot when I started out. How hot I didn’t realize until I later checked the temperature and humidity; 88°F, 70% humidity. This put the heat index at close to 100! Humidity, especially when combined with that high of a temperature, reduces the effectiveness of sweating to cool the body by reducing the evaporation of sweat from the skin. This causes us to sweat more in a further attempt to cool the body which is being stressed by both environmental heat and the heat being produced by our working muscles. No wonder I was thirsty! I was so thirsty that all I could think about was water. Every sprinkler I passed I swore was calling my name and eventually I gave in, not once, but twice. My first attempt didn’t yield very positive results. I got a few drops of water in my mouth but mostly just got drenched. My second attempt several minutes later was much better. The stream was more of a straight stream than a mist. The only downside was that I had to crouch low to the ground to get to it. But I didn’t care, I needed water and I was getting it! And no, I didn’t care who saw me or what they thought.

This incident served not only as a good laugh for me and the many others I shared it with but also as a wake up call that summer is indeed upon us and that I needed to pay better attention to my hydration status. So I thought this was a perfect opportunity to share some fluid guidelines with you so that you don’t wind up in the same predicament as me.

As was mentioned, evaporation of sweat is used to cool the body. If the fluid that is lost from sweating is not replaced, dehydration can occur. Even a slight level of dehydration (> 2% loss of body weight) can increase the strain on the cardiovascular system and significantly affect exercise performance¹. Many other factors can be affected by dehydration as well such as decision making skills, hand-eye coordination, and the ability to cool and deal with heat stress^1,2,3,4. Preventing significant loss requires consuming the proper amounts of fluid before, during, and after exercise. Here are some guidelines to follow⁴:
 
• Start hydrating 4 hours before activity by drinking 2-3 cups (16-24 ounces) of fluid.
• If signs of dehydration are present despite this (i.e. not needing to urinate), drink another 1-2 cups (8-16 ounces) 2 hours before activity.
• Drink 6-12 ounces every 15-20 minutes of activity.
• After activity, drink 3 cups (24 ounces) for each pound lost. 

And important to note is that thirst can be an unreliable mechanism for detecting fluid loss. So the fact that I was thirsty during my run probably meant that I was significantly dehydrated, and had been so before I had even started out that day. There are several ways to determine your level of fluid loss so that you can be certain to replace the proper amount.
 
• Weigh yourself before and after you exercise. This will tell you how much weight you have lost in the form of water or sweat.
• Check the color and quantity of your urine*. If your urine is dark in color and only in a small volume, you need to drink more fluids. When it is pale yellow and of substantial volume, you have returned to normal water balance. Remember that dehydration is accumulative so this may take several days. 
 
*Urine is not a good indicator of hydration status if diuretics are present in the body.

Remember that many fluids can be used to replace sweat losses including water, seltzer, juice, sports drinks, milk, soft drinks, even foods with liquid in them (i.e. soups, fruit). Check back next week for a discussion on sports drinks.

What do you do to stay hydrated? Do you have a sprinkler story of your own? Or maybe just the opposite, you drank too much water in a short period of time and suffered from water poisoning? Has your performance ever been affected by dehydration? Do tell.

1 Armstrong, L.E., D.L Costill, and W.J. Fink. Influence of diuretic-induced dehydration on competitive running performance. Med. Sci. Sports Exerc.17 (4): 456-461, 1985.

2 Casa, D. J., P. M. Clarkson, and W. O. Roberts. American College of Sports Medicine roundtable on hydration and physical activity: consensus statements. Curr. Sports Med. Rep. 4:115–127, 2005.

3 Cheuvront, S. N., R. Carter III, and M. N. Sawka. Fluid balance and endurance exercise performance. Curr. Sports Med. Rep. 2:202–208, 2003.

4 American College of Sports Medicine; Sawka MN, et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 39:377-390, 2007.

As a "neat freak" research presented last week at the annual meeting of the American College of Sports Medicine (6/2/2010; Baltimore, MD) made me smile.

Researchers in the physical education department at Indiana University-Purdue University in Indianapolis set out to determine the major factor(s) affecting physical activity levels of almost 1,000 residents of St. Louis, aged 49-65, who were participants of the African American Health longitudinal study. Measures included: neighborhood desirability, measured with a self report of the neighborhood as a place to live, general feelings, attachment, and safety from crime; interviewer block face assessments of the streets, yards, sidewalks, noise, air quality and condition of other houses and buildings in the neighborhood; and interviewer in-home assessments that rated furnishings, cleanliness of the dwelling interior, physical conditions of the interior of the home, condition of the outside of the dwelling, and a global rating of the dwelling. These factors were then compared to physical activity levels assessed with an adjusted Yale Physical Activity Scale. Unexpectedly, increased physical activity was only associated with interviewer global ratings of the dwelling and ratings of the condition of houses and other buildings in the neighborhood.

So what is the connection between a clean home and increased physical activity? Here are three possibilities:

1. A clean home drives physical activity.

2. People with a clean home spend time dusting, mopping, and doing in-home maintenance, which increases their time spent being active.

3. People who take care of their homes are the same people that take care of their bodies.

What do you think? If #2, then maybe we should focus less attention on the "built environment" like improving sidewalks, lighting, and other outside environmental factors, and more on helping people increase physical activity inside their homes including things like vigorous sweeping, mopping, and vacuuming. The Cooper Institute is a long-time believer in (and has done quite a bit of research on) lifestyle physical activity, which includes things like cleaning house, shoveling snow, planting flowers, and raking leaves. These activities can be moderate-to-vigorous in intensity when done with vigor; can be fun; and can create a sense of accomplishment when completed.

Share your thoughts on this research as well as lifestyle physical activity. Do you see the value of promoting lifestyle activities as a means toward achieving the recommended 150-minutes a week of moderate-intensity or 75-minutes a week of vigorous-intensity aerobic physical activity?

NiCole R. Keith, FACSM, Daniel O. Clark, Douglas K. Miller. Environmental Correlates of Physical Activity in Middle-Aged, Urban Dwelling African Americans. 2010 American College of Sports Medicine Annual Meeting. Baltimore, MD. June 2, 2010.

2008 Physical Activity Guidelines for Americans

One of the popular trends in fitness, functional training was recently discussed. Another popular trend in fitness is the usage of boot camps and other type of fitness classes. Many of these classes use untraditional exercises and functional exercises.

One exercise that is sometimes used is the tire flip. This is an exercise that is sometimes seen in strongman events. The exercise normally uses large tires. Many times the tires are from a tractor or other big truck. Individuals crouch down into a low squatted position in front of the tire. Then grab the bottom of one side of the tire.

Next, while keeping a flat back and good posture, the individual stands up with the tire. This step is done through forceful extension of the ankle, knee, hip and spine. As the individual begins to bring the tire to a high level, it often requires a re-positioning of the hands. Finally, the individual pushes the tire over to complete a flip.

The article¹ in the Journal of Strength & Conditioning Research looked at the tire flip in regard to the physiological stress, such as heart rate is affected by the exercise. They found that two sets of 6 tire flips resulted in a high degree of stress based on an average heart rate of 180 beats per minute at the end. In addition they found elevated blood lactate levels.

More research may be needed to determine to determine the exact energy expenditure of this type of exercise. Comparatively, other heavy vigorous callisthenic conditioning such as push-ups and sit-ups were shown to have an energy cost of 8.0 METs² or eight times as much energy as at rest. This article¹ does suggest that the tire flip, among other exercises, could be used to improve anaerobic conditioning and increase energy usage.

Have you ever thought about mimicking any of the other strongman type of exercises in an exercise session?

Just remember, regardless of where you have seen it done or how great of an idea it is, every exercise should have form and safety as the most important factor. What other type of safety cues, other than the flat back and good posture that were mentioned earlier, would you suggest for someone performing a tire flip?

¹Keogh, J., Payne, A., Anderson, B., & Atkins, P. (2010). A Brief description of the biomechanics and physiology of a strongman event: the tire flip. Journal of Strength & Conditioning Research, 24(5), 1223-1228.

²Ainsworth BE. (2002, January) The Compendium of Physical Activities Tracking Guide. Prevention Research Center, Norman J. Arnold School of Public Health, University of South Carolina. Retrieved [02/25/10] from the World Wide Web. http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf

Food manufacturers and restaurants are under increasing pressure to eliminate trans fats, or partially hydrogenated oils from foods. Trans fats, fats created by adding hydrogen to vegetable oil to make it firmer, are heart unhealthy as they raise "bad" LDL-cholesterol, lower "good" HDL-cholesterol, and induce an inflammatory response at even low levels of intake (e.g., 2 to 4% of total calories). 

But removing trans fats isn't a simple feat. Trans fats make food products look bigger and better, last longer, and cost less. Cakes, cookies, crackers, bread, and margarine rely heavily on the functionality of partially hydrogenated oils for texture and appearance. So what's the easiest solution? Replace trans fats with saturated fats to give pastries and cookies their light, crispy, and flaky texture. However, since saturated fats are also hazardous to the heart, this doesn't make the food much healthier. But does the food industry care? In the past we've seen many food reformulations where an undesirable component (like fat) was removed only to be replaced with another undesirable component (like sugar). Remember the fat-free phenomena when everyone thought they could eat a whole package of fat-free cookies unaware that the amount of calories in the cookies were just as high because fat was replaced with sugar?

To determine whether the removal of trans fats is resulting in foods with higher saturated fat content, researchers from the Harvard School of Public Health analyzed 83 reformulated products from supermarkets and restaurants. They found that trans fat content was reduced to less than 0.5 g per serving in 95% of the supermarket products analyzed and 80% of the restaurant products analyzed. And after the reformulation, 65% of the supermarket products and 90% of the restaurant products had levels of saturated fat that were lower, unchanged, or only slightly higher than before reformulation. So the food industry does care!

This doesn't me you don't have to read food labels anymore - 65% and 90% isn't 100%. Furthermore, many foods on the market are still undergoing reformulation so looking out for partially hydrogenated oils and saturated fats that may be used as replacements like palm, palm kernel, and coconut oil on the ingredient list is still very important. No ingredient list to look at? Ask your server if trans fat-free oils are used. Or... order a dish that is baked instead of fried!

Mozaffarian, D. (2010). Food reformulations to reduce trans fatty acids. The New England Journal of Medicine, 362(21), 2037-2039.