About Chris Moffett

Chris Moffett is a certified trainer, eductor, and older adult fitness specialist.

Can Nordic Walking increase your strength and cardio fitness?

nordic walkingResearchers in Finland recently studied the effects Nordic walking (or “pole walking”) had on functional capacity in older adults. Functional capacity reflects one’s ability to perform activities of daily living independently. Typical measurements for functional capacity are strength, flexibility, balance, and cardiovascular fitness (or endurance). The study examined whether a Nordic walking program contributed to improvements in these measures as well as walking gait, which plays a vital role along with balance in reducing instances of falls. A compromised walking gait is strongly associated with falls.

Participants were divided into two groups: 23 people were placed in a Nordic walking group and 14 were placed in the control group, which was sedentary. Beyond their current level of physical activity, members of the control group were asked not to participate in any new physical activity for the duration of the 9-week program.

Nordic walking or pole walking is a form of exercise that is very popular in Scandinavian countries and in Finland. In recent years, it has been gaining ground in North America, especially amongst older adults. It is a safe form of cardiovascular exercise, especially for those who like to walk as their main fitness routine. It also has benefits for strength gains, especially in the upper body. It involves walking with a set of poles, much like one would use for cross-country skiing, only participants walk in urban areas– along bike and walking trails, sidewalks, and in some cases, hiking trails (with special tips).

Previous studies have shown increases in heart rate and oxygen uptake, both of which are important for maintaining independence and assisting with activities of daily living (ADL). Most of the previous studies, however, have focused on younger people (middle age) and those with chronic conditions that would be improved with stronger cardiovascular fitness. Studies of Nordic pole walking in older adults are limited, although a previous study (2007) showed Nordic walking to be an appropriate exercise method for older people because it has beneficial cardiovascular benefits. A study such as this is important if improvements are going to be made to the general older adult population’s activity levels. Since walking is the most common leisure-time physical activity chosen by older adults, Nordic pole walking may be such an enhancement that could boost those activity levels. Another purpose of the study was to determine the effects Nordic walking had on the participant’s gait. The researchers hypothesized that a 9-week Nordic walking exercise program would increase functional capacity and improve walking balance in older adults. It generally takes two months for enough physical changes from exercise to show up in a test.

The 37 participants were male and female age 65 and older and the two groups were controlled for equal portion gender and age. The participants were given fitness and gait assessments using a common battery of tests before and after the study’s conclusion, one that I frequently use with my clients, called the Seniors’ Fitness Test (Rickli and Jones, 2001).

The 9-week Nordic walking program consisted of twice weekly hour-long sessions, which included a 5 minute warm up (stretching and slow walking), 40 minutes of Nordic walking with 10-min stretching mid-point, followed by a 5 minute cool-down of slow walking and stretching. For the Nordic walking portion, the participants were instructed to walk as fast as comfortable. Training intensity was based on the participants’ rate of perceived exertion. Participants also wore heart rate monitors during the first exercise session and had a target heart goal of 60% of the age-predicted maximum. The warm up and cool-down consisted of walking at low speed (without the poles) and stretching with the poles. All 23 participants in the Nordic walking group completed the 9-week program although there were some absences during the training period.

At the end of the nine weeks, both groups were re-assessed using the same test battery. Improvements were made across all measures in the Nordic walking group. Hip and leg strength as measured by the Chair Stand Test increased on average by 15.3% in the Nordic walking group whereas there was only a 2.2% increase in the control (sedentary) group. Arm strength as measured by the Arm Curl Test increased on average 19.7% vs. 1.9% in the control group. Other measures of functionality all showed significantly greater increases compared with the control group. The 2-Minute Step Test, which assesses cardiovascular fitness showed an average increase of 14.0% in the Nordic walking group vs. a 2.5% increase in the control group, the “Sit-and-reach” test, which assesses thigh and calf flexibility, showed a 92.5% increase vs. 2.9% increase in the control group. It was thought that the stretching exercises during warm-up and cool-down played a large role in contributing to this large increase in leg flexibility. However, since Nordic walking assumes a large stride length compared to regular walking, the walking pattern itself may have also been a large contributor to the increased flexibility.

The Nordic walking group experienced on average a 17.3% increase in upper body flexibility as measured by the “Back Scratch Test” compared with a 23% DECREASE in the control group. When it came to assessments of balance related capacity, there was only a 10% increase in the Nordic walking group as measured by the “Timed Up and Go” Test (a measure of dynamic balance) but there was no change observed in the control group. However, the results of the gait analysis tests, which measured ground-reaction forces (GRF) and walking speed, were disappointing. They showed no change in either group. Researchers had hoped to find an improvement in gait as a result of the pole walking program but any falls reduction benefit resulting from muscular strength increases may have been countered by reliance on the poles themselves as balance aids.

There were some limitations in the study. Because of early drop-out in a third group (a regular walking group), there were insufficient numbers to study them separately so they were combined with the Nordic walking group. Thus the test group was much larger than the control group (23 vs. 14). It also means that comparisons between the test group and the control group do not necessarily suggest that improvements were a result of Nordic walking in particular or regular walking in general which caused the greatest change. However, Nordic walking does require engagement of upper and lower body muscles that is not required with regular walking. As well, previous studies which compared Nordic walking with regular walking showed an increase in cardiovascular function, although these were done with a younger population. So there is no reason not to credit a portion of the cardiovascular increase to the Nordic walking program specifically. The cardiovascular benefits may have been the result of strength increases in upper body muscles, which improve lung functional capacity, circulation, and oxygen uptake, the researchers said.

Although no significant improvements in gait were corroborated by the exercise program, muscular strength, flexibility, cardiovascular capacity, and to an extent dynamic balance were all improved in the Nordic walking group after the 9-week program. It is safe to say that based on this study Nordic walking is a useful tool in an activity tool kit to keep vital and strong as one ages. Perhaps it is an exercise you’ll pick up and enjoy. It’s worth a try!

To your health,

Chris

References

Parkatti, T, Perttunen, J, and Wacker, P. (2012). Improvements in Functional Capacity from Nordic Walking: A Randomized Controlled Trial Among Older Adults, Journal of Aging and Physical Activity, 20 (1), 93-105.

I’d be a lot healthier if I only had the time!

clockA recent survey from the Heart & Stroke Foundation (HSFC) reported that a large number of Canadians say they do not have time to exercise regularly or eat healthy foods, both strong tools in the prevention of heart disease and stroke.

According to the survey, eighty percent of Canadians know that heart disease and stroke can largely be prevented, postponed, and even treated by living a healthier lifestyle and 75% say they would live a healthier life if it weren’t for a number of barriers. The biggest barrier cited is time.

According to the HSFC report, for some of these barriers, it may be more a matter of perception than reality. Let’s take a look at what they had to say:

No time because of a long commute: This is a tough one as it is well-known that commute times have grown longer over the years and this is especially the case in Canada’s large urban centres. However, commute times are often half as long in smaller cities and towns and yet those residents are not necessarily any more active. In fact obesity rates are higher in Canada’s smaller towns and rural areas, on average, than in the big cities.

No time because of family obligations: Driving the kids to soccer practice and piano lessons, taking care of a loved one, visiting aging parents, school involvement, helping kids with homework. These things all take time and are all a part of busy modern life. But let’s not forget some of the modern conveniences that have freed up time. For many, the internet has allowed them to shop and do banking online, stay in touch with friends and family through email and Facebook, get help with homework or research a paper, and a whole host of other activities that used to take much longer when one had to get up and go somewhere. And yet, spare time still seems to be a rare commodity, keeping us from doing things that will help prevent heart disease and stroke. So where is that time going if it’s not spent exercising or cooking a heart-healthy meal? HSFC cites Statistics Canada in reporting that about 30% of Canadian adults spend 2 or more hours a day watching television with half those people reporting they spend over 20 hours a week in front of the box. And what about that other box? 15% of Canadian adults report spending 90 minutes or more each day in front of their computers–and that’s not during work time!

So, clearly extra time is there for many of us. We just have to make healthy eating and physical activity priorities in our lives.

Some other barriers cited in the survey:

Lack of facilities: 25 % of the respondents to the HSFC survey cited this as a barrier.

Cost of exercise programs, too, was a factor cited.

But in both these cases, one doesn’t necessarily need access to a gym or community centre to be active. As long as there are well-maintained parks and safe streets to walk, many Canadians can take advantage of the cheapest form of exercise–a brisk walk or hike! Walking briskly can get your heart and lungs working more efficiently so that you reap the benefits–major benefits in the fight against heart disease and stroke!

Cost of healthy food: Income and location are major factors for many Canadians who would otherwise shop for better food to cook. This is a real problem for low-income Canadians who can not afford fresh fruits and vegetables and many Canadians live in areas where access to such food is limited. The HFSC urges government, industry, and non-governmental organizations to increase access to healthy food for Canadians who can not afford it or who do not live close to sources of healthy food.

Lack of motivation: Half of the HSFC survey respondents say they lack the motivation to be more active or eat healthier food. HSFC reminds us that even small steps count and suggests some practical things that can be done, such as meal planning, having some quick and easy healthy food in your cupboard, and making meals in advance on weekends. As for exercise, get out with a friend for a walk. As they say, “you don’t need to run a marathon–but you do have to get off the couch”.

For more on the HSFC survey and to learn more about their initiatives, see their new campaign at heartandstroke.ca/time. The Foundation has set an ambitious goal of reducing death from heart disease and stroke by 25% by 2020. Clearly Canadians get the message that heart disease and stroke can largely be prevented or at least assisted through diet and exercise. They just need help to find the time to do so.

To your health,

Chris

How Much Exercise Do You Need?

In the most recent issue of the British medical journal, The Lancet, a study of over 400,000 people in Taiwan followed for an average of eight years has shown that you don’t need to exercise a lot in order to reap the benefits — including a longer life. As little as 15 minutes of exercise a day or 90 minutes a week can add up to 3 years to your life! Men in the study lived on average 2.55 years longer than their non-exercising counterparts and for women, there was 3.10 years on average between the active and the sedentary group. This translates to a decrease in overall risk of dying by 14% with as little as 15 minutes of exercise a day with a further reduction of 4% for every additional 15 min of daily exercise beyond the minimum amount of 15 min a day.

What type of exercise and what level of intensity?

Researchers examined different types of exercise from regular walking to fast walking to jogging to running and found the benefits were there at all levels but they did confirm that there is a dose-response relationship, so that those who exercised for longer periods and at a higher intensity level reaped more benefits. Again, the participants in the study were compared with people who did no exercise at all. What this study shows is that there are benefits at even 90 minutes a week (6 days X 15 minutes), which is less than Canada’s new guidelines of 150 minutes a week at a moderate level or above. However, the study also showed that those who met the generally recommended guidelines of 30 minutes per day at a moderate level, life expectancy was even greater (4.21 years longer for men, on average, and 3.67 years longer for women).

To your health,

Chris

Can you be fit and fat?

measuring one's bellyJust released in the Canadian Medical Association Journal, a new study shows that overweight or obese people may not necessarily be considered unfit because they have a high weight to height ratio (commonly called the BMI or Body Mass Index). To be considered overweight, one must have a BMI greater than 25. To be considered obese, the number must be greater than 30.

Researchers at the University of Alberta analyzed data from over 8000 participants of the National Health and Human Nutrition Examination Surveys (NHANES) and conducted follow-up studies to determine death rates. Of those considered overweight or obese, they applied the Edmonton Obesity Staging System (EOSS) to determine if early death rates could be predicted based on high scores. Although it makes use of traditional body measurement tools such as BMI and hip to waist ratios, the Staging System goes beyond that by including other obesity related health factors which then rank the person on one of five stages of risk. Stage 0 means there are no health problems despite being overweight whereas someone in stage 4 would have severe diseases associated with obesity that put them at risk for early death.

The researchers determined that for the overweight and obese respondents to the survey, about 77% had a score of 1 or 2. Scores of 2 were associated with higher death rate versus scores of 0 or 1. A score of 1 translates to the presence of obesity-related risk factors, such as high blood pressure and elevated fasting blood sugar levels but at borderline levels, shortness of breath for moderate exertion, some aches and pains, and mild functional limitations. A score of 2 translates to the presence of chronic diseases clearly associated with obesity, such as high blood pressure, coronary heart disease, Type 2 Diabetes, sleep apnea, arthritis, and moderate limitation in activities of daily living. Death rates were not any higher for overweight and obese people over the 16 years of study for those rating 0 on the EOSS and only slightly higher for those who scored 1. But for those scoring 2 or more, there was a marked increase in death rate with only 50 to 70 % survival rate compared with those who scored 0. So, regardless of obesity level, it was the score on the EOSS that was the greater predictor of early death.

In another study published recently in the journal Applied Physiology, Nutrition and Metabolism, 5400 men and 770 women who had BMIs of 30 or more (i.e. obese) were scored on the EOSS and were compared with 23,000 normal weight people also over a 16 year period. The lead researcher of this study, Prof. Jennifer Kuk at York University’s School of Kinesiology and Health Studies in Toronto, found that people in Stages 2 and 3 were at high risk of developing coronary heart disease but those in stages 0 and 1 were not. This study used a modified EOSS which excluded Stage 4. Surprisingly those obese people in stages 0 and 1 were at a lower risk for cardiovascular disease and coronary heart disease than normal-weight individuals but all obese patients were at an higher risk for death due to cancer but not for death caused by other factors besides cancer or heart related. Based on her data, Kuk suggests that up to one third of the 6000 people could be considered “healthy obese” based on her examination of the data. Being overweight by age 21, having low cardiovascular fitness, smoking status, and eating few fruits and vegetables were all associated with Stages 2 and 3. To be considered “healthy obese”, Kuk says, people must lead a healthy lifestyle, follow a good diet, and get regular exercise. Otherwise, these factors along with their obesity will put them at greater risk of early death.

This also shifts the focus away from an obsession with weight loss, especially for those who get caught in a viscous cycle of dieting, toward becoming healthier through a healthy diet, lifestyle, and regular physical activity.

 

Foot Sensitivity and Balance

(CBC Radio One Quirks and Quarks)

CBC Radio Host Bob McDonald interviewed researcher Dr. Leah Bent at the University of Guelph who measured skin sensitivity of astronauts before they visited the International Space Station. She will follow this up when they return. She is interested in how skin on the soles of feet and vestibular (inner ear) input relate to balance in seniors. Much research has been done on the effects on balance in older adults due to changes in what is believed to be the three components of balance: visual, vestibular, and proprioception. Proprioception is the body’s ability to sense where it is in relation to the environment through skin sensitivity, foot and ankle placement, and stability. Studies have shown that these three components are all compromised with age and thus older adults have a higher risk of falling. Dr. Bent’s research is concerned with pin-pointing which receptors in the feet are most affected by periods of weightlessness such as when astronauts are in flight. It is believed that since astronauts in flight have compromised vestibular input because of loss of gravity, skin sensitivity is increased, allowing them to maintain balance. It is Dr. Bent’s hope that by better identifying these skin receptors, she will be able to target them specifically to improve their sensitivity in seniors, thus decreasing the risk of falling. Exercise regimens which are used to improve balance in older adults tend to be quite generalized, by increasing muscular strength in the ankle and hip and enhancing the proprioception by shutting down or compromising the other two components, for example doing one legged stands with eyes closed (visual) or doing tandem walking while turning the head (vestibular). Instead, if specific proprioceptors in the feet can be identified and thus stimulated in further experiments, this may be a more effective way to balance-train older adults.

Speed of Behaviour in Older Adult Drivers

( from “Effect of Exercise on Speed of Behaviour in Older Drivers”, Journal of Aging and Physical Activity, 19.1, 48-61 (January 2011) ).

Researchers at the University of Évora in Portugal studied the effects of an exercise program on the speed of behaviour of older adults while driving. Speed of behaviour encompasses reaction time (RT) to environmental stimuli and speed of execution of a task. Speed of behaviour is known to decrease as we age and in driving, this can be especially detrimental for obvious reasons. Twenty-six community dwelling drivers aged between 55 and 78 were assigned to either a control (non-exercise group) or the study group who exercised for 1 hour, 3 times a week for 8 weeks. Baseline tests were performed to measure brake RT, peripheral RT (detecting a light beaming into the windshield at the side), choice RT (choosing between two external stimuli such as braking and detecting an outside light stimulus), and a dual task RT (where participants had to apply the brake while performing a mental calculation at the same time). The exercise intervention consisted of a program with a number of eternal stimuli being given which required a fast reaction while continuing to walk and other physical activities such as stepping, reaching, throwing, etc. Thus there was a physical as well as a cognitive element to the program. After 8 weeks during re-test, improvement to speed of behaviour was significant in all measures for the exercise group. For the control group, not only was there no improvement, but there was decline in speed in all but one measure. Thus the researchers concluded that older drivers’ speed of behaviour can be improved through exercise and that exercise programs should include activities that stimulate cognitive and perceptive abilities.

Muscle Mass and Middle Age

(“Canadian Health” (Winter 2011).

Dr. Greg Wells, a Toronto-based sports scientist was recently interviewed in Canadian Health magazine on his views of the importance of lean muscle mass through weight training in improving the health of middle aged men. Some of the benefits he cited were:

  • Increase in metabolic rate allowing you to burn more calories and thus reduce risk of obesity, cardiovascular disease and diabetes. Fat is inert but muscle is active even at rest so calories have to be burned just to keep that muscle alive.
  • Protection of joints by stabilizing them, thus relieving them of having to do all the work when carrying loads. Stronger joints will also reduce risk of osteoarthritis, falls and fractures that can increase with age. Muscle mass itself provides a protective layer to the bones if you do fall, lessening the chance or severity of fractures.
  • Look and feel better by reducing flab and wasting appearance of aging. Says Dr. Wells: “Exercise is proven to prevent almost every chronic disease. If you want to be healthy and fit over your whole life, a combination of strength, cardio and flexibility is the ticket.”
  • Increased stamina and can potentially give you a better sex life. “At least you’ll be less likely to fall asleep from exhaustion afterwards”, says Wells.

Can Exercise Keep You Young?

(from the New York Times, March 2, 2011)

Researchers at McMaster University in Hamilton, ON are attempting to answer the question, “Can Exercise Keep You Young?” Dr. Mark Tarnopolsky was surprised when he and his students discovered that exercise kept a strain of mice from becoming grey prematurely. They studied mice whose cell mitochondria were altered to lack the inherent repair mechanism so that they aged prematurely. Things like muscle shrinkage, decrease in brain volume, fur loss and greying, enlarged hearts, frailty, and even shrivelling gonads were all markers of an early aging process in the mice. However, they divided these genetically altered mice into two groups, a sedentary group and an exercising group. At 8 months (or about age 60 in human terms), the sedentary group showed the age-related markers and were all dead before they reached their 1st birthday. The exercising group on the other hand, remained youthful at 8 months. They maintained their dark fur, which was still full, their muscle mass had only shown a slight decrease as did their brain volume, their balance was good, and even their hearts were normal size as were their gonads. Even though they still had the genetic mutation that inhibited mitochondrial repair, they had more mitochondria and less damage than their sedentary cousins. All were still alive at age 1.

What was their key to the fountain of youth? A vigorous exercise regimen. They ran on a wheel for 45 minutes, 3X per day beginning at their 3rd month. This is the human equivalent of running a 50-55 minute 10K. Thus the exercise was of a cardio or aerobic nature and considered much more vigorous than what the general recommendations for exercise are. The researchers admitted that there is probably a threshold of exercise that needs to be reached in order to slow down physiological aging and this study was not meant to determine that threshold. Still, they believe that even following a less rigorous regimen humans can still reap some benefit. Besides prior studies has shown an improvement in mitochondrial function in older adults who did weight training at a moderate level. As Tarnopolsky has said, “Anything is better than nothing.” “If you havent been active in the past”, he continued, “start walking five minutes a day, then begin to increase your activity level”.

Happy New Year 2011!

dart hitting targetHappy New Year!

There’s nothing like the turn of a new year to remind us to take stock of our lives this past year and set some goals for the new. For many of us, it’s a time to reflect on what things we accomplished, what worked and what didn’t. Hopefully it’s a time when we’re not too hard on ourselves — after all, we can only do our best. For many of us, this is a time of year when we want to get our health and fitness back on track from the “mini-vacation” we’ve been on over the Holiday season.

Tips for starting the New Year off right:

1. Set a Date. Let’s face it, your “New You” New Year will probably start AFTER January 1st. If you have slipped in your healthy eating and not looked at the treadmill in weeks, chances are you will still be in that holiday mode until the last party or holiday visit is over and the last shortbread cookie is eaten! So, make those changes when you get some routine back in your life so that you’re not trying to swim upstream. For most of us, that starts a day or two after New Year’s Day.

2. Don’t just resolve, set a goal. Resolving to lose some weight, work out more regularly, put more activity in your life are all good resolutions but they won’t amount to anything unless you state them as goals. Better yet, write out your goal. “I will lose 10 lb in 10 weeks!”

3. Be SMART. Make sure your goals are SMART ones: Specific, Measurable, Attainable, Realistic, and Timed. So often when we make resolutions that fail because there is nothing to back them up. With a SMART goal in mind, you can then set up a plan and a schedule to reach that goal.

4. Make a Plan. To help you reach your goals, be sure to have a plan. If your goals is to lose 10 pounds, how will you do it? As long as your goal is SMART, your plan will be more effective. The plan is where the details lie. Or thought of in a different way, the Goal is the WHAT, the plan is the HOW.

“I will lose 10 lb. in 10 weeks by fast walking on the treadmill 5 days a week with an expenditure of 300 kcal. I will cut out 200 calories from my daily intake. I will set aside a specific time to go on the treadmill. I will cut out those 200 calories by having water instead of juice or pop for my afternoon break. I will have only a cup of coffee without a muffin on my morning break.”

Find an online calorie counter and look for the foods that are easiest to give up. Find an exercise activity that you enjoy or at least can endure for 30 minutes! The devil is in the detail.

5. Forgive yourself if you slip up. If you set goals instead of making resolutions, then it is much easier to get back on track if you do slip up. You may have taken a detour or slowed down a bit but you don’t have to lose sight of your goal. If your goal is still firmly in sight, then you can look at other paths to reach it if what you are doing isn’t working.

So, as you begin this New Year, think Goal instead of Resolution. Have a plan. And be SMART about it.

To your health,

Chris

Use it or Lose it!

Senior couple on cycle rideWe all like holidays. Not only is it good to take a break from work, home, or the winter weather, but it’s good to give yourself a break from routine. However, what happens when you have been working out regularly for about 4 months and then take a month off from your exercise routine? You might be surprised to find out!

Researchers in Queensland, Australia designed a 20-week study of men in their 70s to determine just that. Studies have shown for years the positive effects of resistance training on muscle strength and power. (Musclestrength is used when you try to lift a heavy box. Muscle power is when you run up a flight of stairs as fast as you can.) Numerous studies have also shown the positive effects of aerobic training on cardio-vascular fitness. But instead of resistance training, this study set out to determine if a particular type of aerobic exercise could also benefit thigh muscle strength and power. They used a cycle ergometer, which is an exercise bicycle where the resistance can be controlled.

Here’s how the study worked:

The scientists measured the fitness of 24 men in their 70s. Then the men were randomly assigned to one of two groups. The first group followed an aerobic exercise program of increasing intensity. The other group (the “control” group) did no formal exercise. The fitness of all 24 men was measured every four weeks, and then four weeks after the training program ended.

Here’s what they found out:

In the first 8 weeks of training, the men in the exercise group showed no significant change in thigh strength. However by the end of 12 weeks, there was a significant increase and by the end of the training period their strength was up an average of 21%. Their thigh muscle power and aerobic capacity (how efficiently the body uses oxygen) increased continuously throughout the training. Plus, they lost fat and gained lean muscle mass in the thigh.

As expected the control group showed no change, except for a slight decrease in muscle power — not surprising, since people in their 70s can lose 5% of their muscle power per year.

But what happened to the men in the exercise group when they stopped exercising?

What a difference a month makes…

After 4 weeks of no exercise, their thigh muscle strength decreased to the levels shown at week 8 of the exercise program. Their muscle power decreased the most, ending up even lower than at the start of the study. Body composition (proportion of fat and muscle) returned to pre-training levels. Aerobic capacity also went down, but still remained well above the pre-training levels even 4 weeks after exercise stopped. This was unexpected by the researchers.

How does this apply to me?

Whether you’re a man or a woman in your 70s, older or younger, this study shows that one type of aerobic exercise can provide a host of improvements to your strength, power, aerobic capacity, and body composition. But you have to keep at it — if you stop exercising for a month, you will lose most of your hard-earned gains.

So, the message is keep your holidays from exercise short. Keep what you’ve gained after all that hard work. Use it or lose it! Sure, take a little break now and again but don’t wait too long before getting back on track!

To your health,

Chris


References

Lovell, D., Cuneo, R, and Gass, G. (2010). Can Aerobic Training Improve Muscle Strength and Power in Older Men? Journal of Aging and Physical Activity, 18, 14-26.
Spriduso, W. (2005). Physical Dimensions of Aging. 2005. Champaign, IL: Human Kinetics.