Finally Some Research on Crossfit!

High intensity, short duration exercise programs are growing in popularity. Evidence shows that such exercise programs lead to significant improvements in cardiorespiratory fitness (aka  aerobic fitness), body composition, muscular strength, and of course, health. Crossfit is a company that believes in this fitness principle and emphasizes programming focused on functional fitness. It has had much success and is continuing to grow in popularity. Unfortunately, there is no peer-reviewed research available on the effectiveness of Crossfit training. I am certain that anyone involved with Crossfit would happily provide anecdotal evidence that it has led to significant improvements in their fitness, health and quality of life. But for a program to be endorsed by professionals in the field, evidence is required.

As such, I was delighted to see a paper recently published in the Journal of Strength and Conditioning Research entitled “Crossfit-based high intensity power training improves maximal aerobic fitness and body composition” (doi: 10.1519/JSC.0b013e318289e59f); In Press).  I was particularly delighted to see that they used cardiorespiratory fitness as an outcome since the program consists primarily of strength and power based exercises. The study was a 10 week intervention with a total of 23 males and 20 females. The average age of this sample was approximately 32 years. Participants completed a maximal treadmill exercise test to determine VO2max; a measure of cardiorespiratory fitness that is considered to be the gold standard. The second main outcome assessed in the study was body composition as measured by the Bod Pod (air-displacement plethysmography). Unfortunately, this is not considered to be a highly reliable or valid method for assessing changes in body composition. The researchers would have been better off taking measures such as waist circumference, flexed bicep circumference or skinfolds at specific sites. These would have been more accurate in describing changes over the 10 week training period. Nonetheless, significant improvements in VO2max, body fat% and lean mass (i.e. muscle mass) were found. Another significant shortcoming of the present study is the lack of a control or comparison group. We know that exercise leads to improvements in fitness and body composition, but does Crossfit training provide additional benefit over other forms of exercise? We can’t answer that question with this data. More importantly, given the unreliable measure of body composition, the only take away from this study is that Crossfit training may lead to significant improvements in VO2max. Just in case I’m starting to sound cynical, I would like to emphasize that cardiorespiratory fitness or VO2max is the strongest predictor of health and mortality, so this is a very important finding.

TAKE HOME MESSAGE: There is no doubt that exercise is good for you and that high intensity exercise is better. For those of you interested in improving your health and cardiorespiratory fitness, Crossfit may be a great option. It provides a social support system, motivating coaches and a positive environment for exercise; all things that will really help you adhere to a Healthy, Active Lifestyle Forever!

NOTE: High intensity requires that you have a certain baseline level of fitness, so be sure to ease yourself into such a program; this will minimize your risk for injury and make for a much more enjoyable experience.

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How many times per week should older adults lift weights?

There is no doubt in the exercise science and health world that strength training (a.k.a. weight training or resistance training) is beneficial for older adults. In addition to increasing overall strength, it prevents bone and muscle wasting as you age. This is particularly important for older women. Women are at a higher risk of developing conditions such as sarcopenia (low muscle mass that increases risk of becoming dependent) and osteoporosis (low bone mineral density that increases risk of fractures) than men. In other words, they are more likely to require assistance to conduct activities of daily living such as cleaning, cooking and washing themselves, than are men. This is one of the reasons we see more women living in assisted living facilities (nursing homes) than men. Luckily, women can prevent this loss of independence if they routinely participate in strength training. While there are guidelines available on what you should do, there is some debate over “how much” you need to do to reap these health and fitness gains.

A recent study conducted by Farinatti et al. in the Journal of Strength and Conditioning Research set out to determine the difference in benefits from training once a week compared to training twice or even three times per week. Women over the age of 60 participated in 16 weeks of strength training and completed fitness assessments both before and after this training program. The training program consisted of 8-12 repetitions of 10 exercises conducted at an intensity of 60-80% of maximum measured strength. Only one set of these exercises was conducted at each session and weight (loads) was increased by 5% when the participant was able to perform more than 12 repetitions. Thus overall, participants who were in the group that exercised once per week conducted 8-12 repetitions of each of the 10 exercises at a weight that caused their muscles to fatigue completely.  Those in twice weekly and three times weekly groups did this same exercise routine on one or two other days of the week. The authors found that generally, more was better. When looking at gains in strength, those who exercised three times per week had the greatest gains. Furthermore, those in the group who exercised three times per week also had the greatest gains in functional fitness. However, it should be noted that ALL GROUPS had significant improvements in strength and functional fitness i.e. just one set of high intensity strength training per week led to significant gains in strength and thus health!

TAKE HOME MESSAGE: As we age we lose muscle mass and increase our risk of becoming dependent on others. In order to maintain our independence it is essential to include strength training in our weekly exercise program. Research indicates that one set of 8-12 repetitions of high intensity strength training is sufficient to improve strength and functional fitness, but that doing this on 2 or even 3 days of the week will lead to greater benefit. So, if you are crunched for time be sure to include at least one set of high intensity strength training to your weekly routine. If muscle loss is of concern to you, do your strength training exercises 3 days/week. Remember, strength training is essential in ensuring your HALF!

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