Changes in Speed and Force after Power Training in Older Adults

A team of researchers at the University of Sydney, Australia sought to determine whether the intensity of explosive resistance training enhances the contribution that muscle force and contraction speed make to improving peak power.

Peak power is the power output produced for a relative intensity (as determined by a percentage of the maximum intensity someone can reach during resistance training–the so-called 1RM). Traditional resistance training is high-intensity but slow speed or velocity and has been proven to improve muscle strength. Explosive resistance-training, on the other hand, uses a high load as well but it is lifted as quickly as possible. This has also been determined to be effective in increasing muscle strength. The researchers studied 112 healthy older adults between ages 63 and 75 divided into 3 training intensity groups: low-, medium-, and high-intensity explosive training. All groups trained for 8-12 weeks, twice a week. They concluded that improvements in peak power resulted mainly from improvements in force rather than speed. Further, they corroborated their earlier findings, that high-intensity training best improved muscle strength and endurance but low-intensity best improved balance performance. All three levels of intensity seem to have the same relative effect on peak performance.

To your health,

Chris

References

de Vos, N.J., Singh, N.A., Ross, D.A., et al. (2008). Effect of Power-Training Intensity on the Contribution of Force and Velocity to Peak Power in Older Adults. Journal of Aging and Physical Activity, 16(4), 393-407.

Tango-dancing: a great way to improve your balance and confidence in walking. Olé!

People dancing the tangoArgentine Tango-dancing and traditional walking programs were compared recently in their effectiveness in improving balance and walking confidence in a group of older adults at risk of falling

The study at McGill University in Montreal randomly assigned 30 people aged 62 to 69 into two groups, all of whom had previously fallen and were at risk of falling again. One group underwent a 10-week walking program and the other took tango-dancing lessons for the same period of time. After completing their respective programs, the participants were assessed using an Activities-based Balance Confidence (ABC) scale, sit-to-stand test, and had their normal and fast walking speeds recorded to determine if improvements were made in their balance and walking confidence and which of the two programs was most effective.

Participants in both groups made improvements in all tests after the 10-week programs were finished and continued to maintain their improvements at the 1-month follow-up. However, greater gains were made in sit-to-stand speed (a measure of lower body strength) in the tango group. This also occurred in the results on the ABC scale. Normal and fast walking speeds improved for both groups where the improvement was about the same after the 10-week period but that benefit was slightly higher for the tango group when the participants were tested at the 1-month follow-up. The researchers could not assume, however, that the improvements in balance and confidence in the walking group would necessarily translate to lower risk of falling because their baseline scores were already higher than the cut-off point set for improvements to fall risk.

Still the researchers felt that adding tango classes to an arsenal of physical activity programs designed to improve balance and walking confidence was a good way to help reduce the risk of falls in older adults since the seniors who participated in the study continued to take the classes after the follow-up period. The classes were clearly popular with the participants.

To your health,

Chris

References

McKinley, P., Jacobson, A., Leroux, A., et al. (2008). Effect of a Community-Based Argentine Tango Dance Program on Functional Balance and Confidence in Older Adults. Journal of Aging and Physical Activity, 16(4), 435-453.

Helping Overcome Changes to Balance and Mobility As We Age

Yoga Tree PoseBack in the spring, I attended a seminar given at the Institute for Life Course and Aging at the University of Toronto, where the presenter, William McIlroy, Assistant Professor at the Graduate Department of Rehabilitation Science, spoke about age-related changes to our balance and mobility.

The presentation opened with a video showing two different individuals in a lab setting, each standing on a moveable floor, hooked up to electrodes in order to measure the degree of body sway as the platform moved.

In the first experiment, a 25 year-old male stood on the platform. When the floor moved quickly backward, he stepped forward slightly to regain his balance. The same disturbance caused the older subject, a 55 year-old male, to lose his balance entirely. He needed to recover sideways in response to the sudden backward movement. In the next experiment, the platform moved sideways to the left. The 25 year-old made a quick side step in the opposite direction to regain his balance. However, the 55 year-old had to make several corrections in order to steady himself. As the platform moved to the left, his right foot collided with his left and then he had to reach out his hand to the wall in order to regain his balance. The older subject had no physical impairments. He was a healthy, mobile, physically active individual with no history of falls. These videos were used to illustrate some of the changes to balance and mobility which occur as we age.

According to William McIlroy, not all of the systems involved in balance follow the same rate of age-related decline. The sense of touch on the bottom of the feet, which is involved in maintaining an upright posture, decreases faster than the other balance systems. As well there is a slowing down of the “change-in-support” reaction time as we age. This reaction, which allows us to move quickly when there is a disturbance to our centre of support, involves recovery maneuvers such as stepping, reaching. or grasping. In a healthy young adult, there is a rapid onset of this reaction, less than 100 milliseconds (ms). However, in a healthy middle-aged adult, this can slow down to 100-150 ms. This may not seem like much, but it is that slight delay which can cause a fall, if one is not able to quickly step forward, reach, or grasp an object in time.

Researchers at the Centre for Studies in Aging at McGill University have been looking at the effectiveness of interventions such as balance and gait training, lower body strength training, types of footwear, environment and assistive technology, and changes in medication. Here’s what they learned:

  • strength training and balance training can’t improve your reaction time, but it will increase your ability to recover from losing your balance, especially laterally (side to side).
  • the ability to detect and react to a balance disturbance decreases with age.
  • we don’t fully understand where these slow-downs occur in the brain.
  • attention and cognitive state are important factors in the risk of falling. Those with Attention Deficit Disorder, Alzheimer’s Disease and dementia are at greater risk of losing their balance but they often avoid situations where they might fall in the first place.
  • lateral stability and muscle power will help reduce the risk of falling. (Muscle power is more than just strength — it takes into account the speed at which a muscle can exert force, not just the amount of force it can exert.)
  • rapid-strength training (using lower weight at higher speeds) is more beneficial for improving balance and mobility than the more standard strength training which uses higher loads but lower speed.
  • people have gotten into the habit of moving slowly during strength and aerobic training (especially treadmill walking and stationary cycling) and this has not allowed them to improve their speed of movement.
  • ping-pong is a good exercise because it requires fast action but is low load.
  • T’ai Chi is important — not because of speed of motion but because it challenges balance by shifting the centre of support.
  • strength training should focus on knee extension, hip flexion, and hip abduction, since these muscles weaken with age.
  • proper footwear is key to improving balance and decreasing risk of falls. Specifically:
    • avoid heavily-cushioned footwear, which detracts from sensory perception on the foot
    • avoid loose-fitting shoes and slippers.
    • wear special insoles to increase sensitivity by stimulating the soles of the feet.(Lack of foot sensitivity had a dramatic effect on the ability to balance. In one experiment, participants could not balance after having had their feet placed in ice water.)

Other recommendations included making environmental modifications, both at home and out-of-doors. For example:

  • adding handrails
  • lighting walking areas so that you can see obstacles in your path
  • removing scatter rugs and ensuring that carpet pile is not too thick
  • using cueing devices to help visually impaired individuals

The researchers noted that canes can be a hindrance as well as a help. The problem is that they constrain foot movement, so if you fall, the result can be much worse. However, a cane or a walker may be necessary to steady oneself to begin with. Where possible, one should opt for building lower body strength rather than relying on a cane for a crutch!

The researchers also regarded changes in medication as a factor in loss of balance. People who are taking sedatives or antidepressants should talk to their doctor if they are concerned about slowdowns in their reaction time.

McIlroy’s own conclusions were that better clinical tools are needed to assess one’s ability to stabilize and balance, not merely one’s risk of falling. He believed that physical training (balance and strength training) and medication control are the most important things we can do to improve our balance and avoid falls as we age.

What sorts of physical training can we do to improve our balance and avoid falls?

Phillip Page and Michael Rogers, who have published several articles on balance, suggest progressing gradually from less to more difficult exercises, just as you would for any other type of strength training. They suggest starting with simple one-leg stands and other challenges to the base of support, then gradually making the exercises more difficult by adding visual and vestibular challenges (closing the eyes, or looking from side to side). Also, progressing from hard, stable surfaces (such as a floor or thin mat) to a less stable surface (such as a foam pad or wobble board) will improve balance and mobility around the ankle.

Researchers in Australia found that older adults who trained with a wobble board at home saw an improvement in their ability to control the extent of ankle inversion, which is a large predictor of one’s ability to catch oneself when falling.

Rogers and Page recommend that the direction of movement begin in a forward and backward motion and then progress to lateral motion. As with all balance training, one must exercise caution by standing within easy grasp of a stationary object, or work with a qualified balance trainer.

Dean Smith, a physiotherapist who spoke at the 2006 Can-Fit-Pro conference in Toronto this past month, suggests a series of exercises to improve hip, foot and ankle stabilization as well as core (stomach and back) stability and increased upper trunk balance strength. He recommended that personal trainers assess their client’s balance ability through a series of tests, work to improve their balance through physical training, and then retest them. Dean also mentioned the importance of flexibility to ensure good balance. Among other things, Dean uses yoga to improve his clients’ flexibility and strength.

So, although we can expect to see changes that will challenge our balance as we get older, this does not mean that we are destined to experience a debilitating fall. The good news is that so many of these changes can be controlled through a regimen of physical activity and exercise designed to improve balance, mobility, and muscular strength. That, along with a careful check of our environment and ensuring that the effects of medications are being monitored, will reduce our chances of falling.

To your health,
Chris

References

McIlroy, W. (2006). Age related changes to balance and mobility. Institute for Life Course and Aging, March 23. Toronto, ON (unpublished presentation).

Rogers, M. & Page, P. (2003). Making sense of balance. Biomechanics, 0311.

Smith, D. (2006). Balance for healthy knees and feet. Can-Fit-Pro Conference, August 24-27.Toronto, ON (unpublished presentation).

Waddington, G. & Adams, R. The effect of a 5-week wobble-board intervention on ability to discriminate different degrees of ankle inversion, barefoot and wearing shoes: a study in healthy elderly. Journal of the American Geriatrics Society, 52.

Not in the Mood

EmoticonsObesity and physical inactivity are widely accepted as major health hazards. Older women in the United States have been counted as one of the most obese and sedentary segments of the population. Unfortunately, the combination of being post-menopausal, obese, and sedentary has been cited as being a high predictor of developing cardiovascular disease. Many women recognize this in their own lives and take steps to reduce their dietary intake and be more physically active by joining behavioural weight loss programs (BWLP – see note below). However, many of these women find it hard to stick to their programs, especially over time. Researchers decided to study whether a person’s mood could affect their chances of sticking to their exercise program. (This is called ‘compliance’ in research terms.)

The researchers studied 25 obese, sedentary, post-menopausal women over the course of an eight-week behavioural weight loss program (see Sidebar). The participants completed a graded exercise test (GXT) before beginning the program. They also completed a questionnaire to assess their mood before and after taking the initial exercise test. Exercise can evoke strong negative or positive feelings, and the researchers knew that many sedentary and obese people had reported feelings of embarrassment, fear, or apprehension related to exercising. Assuming that a person’s mood immediately before exercising would reflect their general attitude toward exercising, the researchers wanted to know if this attitude would affect participants’ adherence to the exercise component of the BWLP.

The first pattern to emerge from this study was that those who reported a positive mood before the initial exercise test tended to engage in more planned exercise during the weight loss program. Mood made no difference in the amount of non-exercise daily physical activity that occurred. In other words, people had to be in the mood to exercise in order to follow a program, whereas domestic and vocational tasks were performed out of necessity and duty.

The second pattern to emerge was that the relationship between mood and the amount of exercise performed grew stronger over the course of the BWLP. Women who reported greater vigor before and after the test and less post-exercise confusion spent more time in planned exercise during the middle and final stages of the BWLP. In contrast, those women who reported greater fatigue and confusion after the test spent less time exercising in the final weeks of the BWLP. One explanation for this finding is that at the beginning of the BWLP, all of the participants were excited about the new program and pushed themselves to exercise regularly, regardless of their moods. However, over time, as the novelty of the program wore off, many found it difficult to stick to the exercise program. Only those who showed an elevated mood at the initial test (and therefore presumably had better feelings about exercise) were able to stick to it.

The researchers concluded that although exercise is seen as one of the most important factors in successful weight maintenance after weight loss, many women who enter formal weight-loss or physical activity programs may have poor treatment outcomes. Women with negative feelings about exercise might exercise less than women who are in a positive frame of mind. Recognizing the role of mood to exercise compliance might reveal motivational and cognitive clues that could be used to identify and promote physical activity in reluctant adults more effectively. Some people may benefit from programs that help them overcome their negative feelings or ambivalence towards exercise. Motivational techniques geared to decreasing emotional obstacles and resolving ambivalence to exercise may go a long way to improving the effectiveness of BWLP, which appear to have reached a plateau in the last decade.

What the study did not address was how to motivate people who are reluctant or ambivalent towards exercise to get active. What can you do if you hate exercising?

The first thing I tell new clients is that it takes time to build that motivation. The motivation is usually external at first. This is why so many people like to join a class or hire a personal trainer–so that they feel obligated to show up to a class, a small group, or a session with their trainer. A good personal trainer or fitness instructor will help you get motivated and more importantly stay motivated. A good instructor or trainer will ensure that you are exercising safely and effectively. By making a class or a session challenging and fun, you will learn to associate exercise with good feelings instead of bad. Over time and with practice, motivation becomes more internally driven. Remember that it takes time to form habits–good or bad ones. Exercise is no different. As you become more regular with attending classes, meeting with your trainer, or exercising on your own, a habit will form and be reinforced every time you do it. It’s important to be regular with your exercise schedule–by choosing which days and times are most suitable–and sticking with it. If your schedule has to change because of work or domestic responsibilities, don’t give up. Make a new exercise schedule and stick with that one for as long as you can. Most of all, learn to roll with the punches. Don’t throw in the towel because of unforeseen circumstances. Get back in the ring!

To your health,
Chris


Behavioural Weight-Loss Program

Behavioural Weight-Loss Program (BWLP) is a program that tries to help people lose weight by attacking the problem on many fronts. Over a six-month period, participants attend 16 to 24 sessions with nurtitionists, behavioural therapists, and exercise physiologists. They learn not only how to eat better and exercise safely, but also how to change the environment around their home to make it easier for them to exercise and eat better. For example, they learn to remove high-fat foods from their environment; how to organize their space to remind them to exercise (and make it easy to do so), how to deal with social situations that require eating, how to modify their own recipes, and even how to get back to the program after a relapse. Participants are even taught problem-solving and assertiveness techniques, to help them get past unexpected problems that may arise.


References

Carels, R. A., Berger, B., Darby, L. (2006) The association between mood states and physical activity in post-menopausal, obese, and sedentary women. Journal of Aging and Physical Activity, 14(1), 12-28.

Can Exercise Help Prevent Alzheimer’s Disease?

Brain X-ray

A report published this week in the Annals of Internal Medicinesuggests that moderate levels of exercise may delay the onset of dementia. The study, which spanned 11 1/2 years, showed a remarkable 38% reduction in the chance of getting dementia for people who exercised three or more times a week, in comparison with those who exercised less than three times a week.

The study was extensive, involving 1,740 participants. To ensure that none of the participants showed any signs of dementia going into the study, they were given cognitive screening tests, and only the top 25 percent were accepted. Each participant was followed up every two years for an average of 6.2 years over the course of the study. By the end of the study, 158 people developed some form of dementia (107 of those developed Alzheimer’s Disease) and 1,185 remained dementia-free. Others either withdrew from the study or died during that period.

The findings support recent studies that suggest physical exercise can enhance cognitive function. Of those who exercised three or more times per week, an average of 13 people out of 1000 developed dementia in each year of the study. For those who exercised less, this ‘incident rate’ was 19.7 people out of 1000. Physical exercise was defined as lasting at least 15 minutes at a time and included such things as walking, hiking, bicycling, aerobics, swimming, weight training, and stretching.

Other factors were considered as well, such as smoking, drinking, using dietary supplements, as well as health conditions such as coronary heart disease, cerebral-vascular disease, hypertension, and diabetes. Surprisingly, these factors, along with gender and age differences were fairly consistent across the two groups: those with dementia and those without. In other words, the single most important difference was the frequency of exercise.

The researchers did not set out to determine a dose-response, that is, the amount of exercise needed to have a beneficial effect. But they did determine that the greatest reduction was in those who scored lower on fitness tests, as long as they exercised at least three times a week. Another study done a year earlier showed that moderate levels of physical activity (3-5 times per week) were associated with a greater delay in the onset of dementia than high exercise levels (more than 7 times per week)– a 45% reduction compared with a 28% reduction . This may mean that one only needs to do moderate amounts of exercise to realize these benefits, and that the frailest people are the most likely to see the benefits. The chief author of the article suggests that senior citizens may have even more reason to “use it even after (they) are losing it”

The researchers note that they did not take into consideration non-leisure and work activities of the participants, which may affect the results. But the results of the study are consistent with earlier ones which showed less tissue loss in the hippocampus in persons at higher levels of physical functioning than frailer older adults. The hippocampus is an area of the brain involved in cognitive functions and is damaged in Alzheimer’s patients.

The researchers concluded the study by suggesting that “physicians and health promotion programs might find this information valuable as our society works to find truly effective ways to promote physical activity for all its well-known benefits”. It would do society well to look into preventative measures such as exercise to help decrease the incidence of Alzheimer’s and other forms of dementia. This would allow seniors to live out their final years as independently as possible and curb what is often referred to as the greatest fear of aging.

To your health,
Chris

References

Larson, E.B., Wang, L., Bowen, J.D. et al (2006). Exercise is associated with reduced risk for incident dementia among persons 65 years of age and older. Annals of Internal Medicine,144, 1-20.

Brown, D.W., Brown, D.R., Heath, G.W. et al (2004). Associations between physical activity dose and health-related quality of life. Medicine & Science in Sports & Exercise,36:890-896.

Colcombe, S.J. Erickson, K.I., Raz, N. et al (2003). Aerobic fitness reduces brain tissue loss in aging humans. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences58:M176-M180.

Reducing Falls

Banana PeelAccording to a recent study, one third of adults 65 years of age and older suffers at least one fall each year. And nearly half of these people fall more than once. Falls are the leading cause of injury-related deaths. But even when the fall is less serious, it can still cause pain and suffering, and bring a tragic loss of independence. For many older adults, suffering a fall can mean the difference between remaining in your own home and having to go to a long-term care facility.

But there’s good news along with the bad. Studies have also shown that many falls can be prevented by a few simple changes you can make in your life. And it turns out that exercise is the most important thing you can do to help prevent falls.

How Not to Fall

Have you ever tried to stand a chair on two legs? It isn’t easy. But our bodies stand us up on two legs all the time, without our having to think about it. As it turns out, there is a lot happening.

Three systems have to be working properly to keep us balanced:

  • Our eyes tell the brain where we are in relationship to our environment and identify obstacles.
  • Our inner ears have special organs (the vestibular system) that tell the brain about the movement of our head in space.
  • Our muscles have special receptors (the somatosensory system) that tell the brain what position our body is in, and detect movement and contact with other objects (such as our feet on the floor).

With all this information, our brains send constant signals to our muscles that keep us standing in balance and that help us react to changes when we move around. So even with all the right information, we still need muscular strength to keep our balance.

Why does getting older increase our risk of falling?

Some age-related changes are inevitable, and ones that affect our vision, inner ears, receptors, brain, or muscular strength will of course affect our balance.

Vision can be affected by glaucoma, age-related macular degeneration, and cataracts. These compromise our ability to perceive hazards and anticipate changes in surfaces when walking. The inner ear starts to lose its motion-sensing “hairs” as early as age 30. Losing too many can result in postural sway. The receptors in our somatosensory system also decline with age, making it harder to sense contact and body position. The brain’s ability to control our muscles declines with age. We don’t react as fast to changes. Finally, our muscles can get weaker as we age, making it harder to recover balance when we lose it.

Can we reverse some of these changes, which increase our risk of falling?

The answer is yes!

Doing the right kinds of exercises — ones geared specifically for balance, strength, endurance, and flexibility — can improve balance, increase mobility, and reduce falls. Programs such as FallProofTM and Standing StrongTM target the sources of the impairments, which contribute to postural instability. However, there are a number of exercises you can do on your own, with a trainer, or in a class that can also help.

These should include balance specific exercises, which train your centre of gravity, the three sensory systems, posture, and gait to help maintain and improve your balance.

  • Centre of Gravity Training will reduce your body sway and help you move more quickly. Some of the exercises are done while seated on a stability ball while others are done standing on the floor, a step, a foam pad, or an uneven surface.
  • Multi-sensory training will help each of the sensory systems to work more efficiently: the eyes, inner ears, and muscle receptors. Some of these exercise are performed standing, while other are performed sitting on a stability ball or a chair.
  • Postural Training will help to improve the strategies you use subconsciously to correct your posture while you are moving such as ankle and hip correction and your ability to step out quickly to prevent a fall. These exercises are done standing and require a trainer to support you or move you through space using resistance bands placed around your waist.
  • Gait Training will help improve your walking gait pattern so that it is more efficient, flexible, and adaptable to environmental changes. The exercises are designed to increase the length of your stride length and help you get around obstacles better.

No exercise program is complete without including strength, endurance, and flexibility training. Of all of the systems that decline with age, the musculoskeletal system is one which benefits the most from exercise and can be improved at any age.

Muscles are made stronger by resistance training. You don’t have to lift heavy weights, operate complicated machinery, or join a gym. You can strengthen your muscles with simple exercises using everyday props, stability balls, and elastic bands or tubing in the comfort of your own home. Strong muscles will cause your bones to become stronger as well and reduce wear and tear on your joints. A strong musculo-skeletal system will serve you well in reacting and responding to a situation that may otherwise cause you to fall.

Your muscles don’t just need to be strong, they must also be kept supple and flexible. Any falls reduction program must also include flexibility training to stretch muscles that have been worked. This will allow you to reach and move with ease without pulling a muscle or causing a painful spasm.

A strong heart is also important by giving you the energy you need to react and move quickly in order to avoid falling when something startles you or you trip and lose your balance. So, aerobic activity should be included in any falls reduction program.

I highly recommend that you begin a falls reduction program that you can do at home, with a friend, or at a gym or recreational facility. If you decide to work with a trainer, make sure he or she is qualified to prescribe a falls prevention program. Many recreation facilities and gyms offer programs. Whatever you decide to do, remember that through exercise you can help reduce the risk of falling and the number of falls you experience. Having a strong body, good posture, and balance will go a long way to help keep you on your feet and not on your rear-end!

To your health,

Chris

References:

Belfry, S. et al. (2004). The project to prevent falls in veterans: a multifactoral risk factor screening and intervention study. Scientific Proceeding from the 6th World Congress on Aging and Physical Activity. London, ON: Canadian Centre for Activity and Aging, 157-164.

Brown, R. (2004). How to start and sustain a falls prevention program for seniors led by seniors.Scientific Proceeding from the 6th World Congress on Aging and Physical Activity. London, ON: Canadian Centre for Activity and Aging, 147-149.

Freiberger, E. (2004). Prevention of falls – an ongoing longitudinal research project. Scientific Proceeding from the 6th World Congress on Aging and Physical Activity. London, ON: Canadian Centre for Activity and Aging, 150-153.

Islam, M.M., et al. (2004) Improvement in body sway after 12-wk of customized balance training versus tai chi exercise in older adults. Scientific Proceeding from the 6th World Congress on Aging and Physical Activity. London, ON: Canadian Centre for Activity and Aging, 57-64.

Islam, M.M., et al. (2004) Improvement in fitness after 12-wk of well-rounded exercises in older adults. Scientific Proceeding from the 6th World Congress on Aging and Physical Activity. London, ON: Canadian Centre for Activity and Aging, 78-81.

Rogers, M.E. & Page, P. (2005). Standing StrongTM: a strength and balance program for older adults. Can-Fit-Pro Annual Conference, August 18-21. Toronto, ON (unpublished paper).

Rose, D. (2003). Fall Proof!: A Comprehensive Balance and Mobility Training Program. Champaign, IL: Human Kinetics.

Westlake, K.P. & Gulham, E.G. (2004) Activity level, proprioception, postural sway, and fear of falling in older adults. Scientific Proceeding from the 6th World Congress on Aging and Physical Activity.London, ON: Canadian Centre for Activity and Aging, 43-57.