Exercise: When, How and Why
Jacquelin Perry, M.D.
Chief, Pathokinesiology Service
Rancho Los Amigos Medical Center
Professor of Orthopedics
Biokinesiology and Physical Therapy
USC School of Medicine
Good morning. I want to talk to you today about exercise. First, I'd like
to give you a perspective of what exercise is and how it should be
considered with the polio and stroke muscles. Second, I'd like to tell you
things that you can do. It is critical that you appreciate that exercise is
a stress experience for the muscles. Basically, you have two levels of
stress, physiological stimulation and damage. The trick is staying in
between these two because exercise is an overload phenomenon which
challenges the tissues, causing a mild strain from which the muscles recover
and go on to be a little better than they were when it was a physiological
challenge. The commitment is to make sure that the exercise is physiological
and not damaging.
Why are polio patients so addicted to exercise? It's because of your initial
experience with acute post-polio. You got better with the help of exercise.
Why were you helped with exercise at that time? There are two contributing
factors. First, your exercise occurred at the time your nerves were
healing, and the exercise got the credit. If you did nothing, you also would
have healed. But it's nice to give exercise the credit.
Second, because you were acutely ill, you spent quite a bit of time in bed,
in wheelchairs. The resulting inactivity led to a lot of disuse weakness of
perfectly adequate musculature. Exercise did overcome that disuse
situation. Today neither situation exists. You do not have healing nerves,
you are well healed; that happened some 20, 30, 40, 50 years ago; and you
certainly don't have disuse unless you abruptly retired or had some major
change in life style. So your real problem is overuse, not underuse.
Therefore you have to be very careful when you think about exercise.
Why Limit Exercise?
The question is what should you polio survivors do today? Your muscles are
wearing out, but you want to keep them going. What does the stroke patient
do who has trouble making the muscles work? You need force to move the body
weight, and also to contain it so you don't fall. This requires muscle
How do you get muscle strength? First you have to have enough fibers. A
normal muscle would have 100%; post-polios have fewer (Figure 1).* Second,
you can whip the muscles up by making them contract a little faster, and
this is a natural physiological thing we do. But that of course means you
overuse them and you have less rest. Third, you can hypertrophy muscles, but
there's a limit to that because, after this physiological stress, the muscle
has to be able to respond, which means you have to have enough circulation
about the muscle fibers. You can do it to some extent.
During walking the person with normal muscles allows the knee to bend to
lessen the loading shock (Figure 2). This places the body weight line behind
the knee and creates a flexion demand on the quadriceps. That muscle
responds with about a 30% effort. Now, the common post-polio muscle which
still allows you to do things quite well is grade 4, also called a "good"
muscle, but it is only 40% of normal. (In strength testing a grade 4 holds
pretty well but still sags somewhat as the examiner pushes on the leg.) It
takes 30% of normal muscle to function, so the person with a 40% muscle
would overwork (75% effort) to meet the same demand. Instead he or she has
to go more slowly, walk less, or find some substitute posture. So the grade
4 muscle which seemed so great on a muscle test is really quite disabled and
has to be protected. The exercising you do must be limited.
How much can you do? Well, the intact muscle is commonly using about 20% to
30% of its capability. That means that only one-third or one-fourth of the
muscle is active, the rest is being relaxed, and that is lots of rest. If
you use it at a 50% effort, you have that much less rest, and if you use it
at exhaustive exercise at 80%, you're not going to last long. The best
example of that is the sprinter. A 100-yard dash lasts 10 seconds, and that
is all the runners can last, too. They are exhausted, having used every
muscle fiber they have for that 10 seconds. You don't ask them to go 200
yards at the same speed. On the other hand, the marathoner will go much more
slowly and will last longerÄhe'll be at the 50% effort.
What about hypertrophy? Dr. Gringsby, a neurologist, studied the anterior
tibialis muscle, which picks up your foot. In the group of patients with
grade 4-5 strength (which I labeled 4+), the muscle fibers (by biopsy)
showed slight enlargement. They were meeting the demand without too much
strain (Figure 3). A second group of patients with grade 3-4 muscles (which
I have called 3+) showed marked hypertrophy. Those muscles, just by living,
just by meeting the mechanics of walking, are getting their exercise into
hypertrophy. In addition, those muscles were working twice as fast, and so
they do not need additional stress from exercise. It's important that you
have a muscle test to learn the strength of your muscles. A grade 3+ or 3
muscle is working at a maximum effort just by living and doesn't need added
exercise. Muscles that are 4 and 5 can tolerate exercise, and these are the
ones that you can work on, but gently. The others you just want to keep
We have two populations in this room, those who had strokes and those who
had polio. You are as different as you can possibly be. My diagram shows a
brain, a spinal cord, and a leg with a muscle (Figure 4). The connection
from the brain to the spinal cord is the problem with stroke patients:
neural control is interrupted. There is nothing wrong with their muscles;
they just have trouble making them work. They can exercise as much as
possible without damage to the muscles. On the other hand, in polio there is
nothing wrong with the control. But the connection between your anterior
horn cell in your spinal cord and your muscle in the leg has been damaged.
You have to be careful about doing too much. Neural control is a stroke
problem; muscle fiber strength and health is a polio problem.
In order to move we need three things. We need joint mobility; we need
strength, which is the capacity of muscles to create force; and we need
endurance to keep doing it. Therefore, we have three kinds of exercise.
When Is Exercise Indicated?
When is exercise indicated? Not at all if you have pain. Then exercise is
contraindicated. Pain means the joint or muscle is overused and you need to
protect it. Ice it, wrap it up, but don't exercise it for the moment. If
your complaints are weakness and fatigue, no one knows whether you have
overdone or underdone. There is no test to tell you. So, as your physician,
I will prescribe exercise as a clinical trial, if you ask me to. Usually I
don't volunteer it because most of you have overdone. But if you think you
need exercise, we'll try it.
And then we'll have a very "scientific" control: If you feel better, keep up
the exercise. If you feel worse, cut it in half. If you still feel worse,
stop. So if you feel better, you had some underuse, and some margin to
strengthen. If you feel worse, you had overuse. I don't want you to keep
exercising for the next month until you come back to see me. A week may be
more than you can stand.
Now why do we say that? I've already mentioned that muscles create force.
The muscle has a very elaborate anatomical chemical system that makes the
protein elements pull together and create a force (Figure 5) inside
themselves at the same time they are creating a force on your bones.
Therefore, they are doing a little damage to themselves and they need some
time for repair and time to refuel. If the muscle fibers don't have repair
time, you are going to have pain, and with pain you have more damage. So
remember that muscles are very elaborate and need protection.
What about stretching? Each muscle contains two elements. One is the red
contractile tissue. The other element is white fibrous tissue which acts as
a sheath to support the individual muscle fibers and to hold them together.
These sheaths have to be able to lengthen and shorten to allow full range of
motion. If you don't move it, it gets tight. There are two parts of the
fibrous sheath. There is the hard collagen, which is like a steel band, and
there is a gel that keeps these bands from sticking to each other and also
lubricates them. That gel is very active physiologically. If it isn't kept
moving it dries up and is like glue that stiffens. We want to keep the gel
loose so that the bands will keep their full length. So stretching is to
keep the fibrous tissue loose.
One of the biggest problems is tight heel cords. When you sit down, the one
muscle that crosses both your knee and your calf and your ankle
(gastrocnemius) is slack and it can tighten. If your feet are dangling, the
deep muscles also will get tight. So you want to stretch a little bit. You
can stand on a block or a wedge while working. Body weight stretches the
One of the problems, particularly in polio more than in stroke, is the foot.
There are two joints in the foot. One is the ankle joint and the other is
within the foot, just above the heel, called the subtalar joint, that allows
the foot to move in and out. Very often you borrow from the subtalar joint
when the ankle joint is tight and you will stretch the foot. Now your foot
tends to turn out (we call this valgus). Then you want to use a wedge to
keep the foot locked while you are stretching the heel, to ensure you are
not twisting the foot out (Figure 6). A stroke patient might want to do just
the opposite as the foot often turns in (called varus).
A Warning About Knee Injuries
Now I want to warn you about knees. When a knee is injured, it is going to
swell. If it swells, it will go into flexion. In a research project, fluid
was injected into the knee to learn what position would cause the least
joint pressure, which means in what position the joint space was largest.
The least pressure was found at 30ø to 60ø degrees flexion. After a
fracture of the knee, the joint swells and falls into 30ø of flexion. If
special effort is not made to prevent that knee from lying in that position
for more than three weeks, a permanent deformity can develop. Management is
tricky because you have to keep the bones together while you're trying to
move the joint. Any of you who don't have a normal quadriceps are prone to
this kind of deformity if you injure your knee.
I want you to nag your orthopedist or whoever takes care of you to make sure
to get your knee out straight quickly. They can't do it in the first ten to
twenty days because there is a lot of swelling and the knee won't do it. But
you can start working on it afterwards. You can lie on your face and let it
hang, or lie on the couch and put your heel on the arm of the couch and just
let it hang, put a little weight on it. But you want to get it straight
again; make that your commitment.
The trouble is that for your orthopedist, you represent a tenth of a tenth
of a tenth percent of society. You have a very critical problem, but
nevertheless you are not the typical patient. The majority of patients can
ignore that knee for a longer period and it still gets better because the
person is vigorous. But you are not vigorous, and so you have to make this
your own commitment, to keep your knees out straight. A 10ø deformity
with no quadriceps threatens standing stability; 30ø is horrible. If you
don't have any muscle, you're going to need to keep that knee straight so
that body weight can lock that knee and not overtax the muscles.
How much stretching do you want? You don't want to overstretch your ankles.
Go to 5ø, just
enough to put your body weight over your forefoot. You can use the remaining
tightness as a substitution for muscle. But you want to have enough range to
do it. On the other hand, you want the knee to go fully straight, even back
5ø if you can for passive stability. In one case you are getting passive
stability by slight tightness of the calf and in the other you are getting
passive stability by having the knee joint fully out. I want to make you
sensitive to those two situations.
How do you do it? You tease it, you don't cause pain, because if you cause
pain, you are tearing that connective tissue. If you tear it, the fibrous
tissue is going to swell, to get stiffer, and then you have made it worse.
You just tease the edges.
Stretching actually is more important in stroke patients because they have
spasticity which tends to pull the muscles a little bit short, and this
allows the connective tissue to get short. It also is very good to stretch
the hand so that the muscle that are active can work without resistance. If
you're working on the shoulder, the important thing is to push it out and
get external rotation. Family members can help.
If you have the rotation range, the arm will go up. If you don't have the
rotation range, there will be impingement of the shoulder if you go up, and
you'll have pain. You are really jamming the joint because the shoulder
joint capsule is a very elaborate little scheme. It takes a certain amount
of rotation to let the arm be raised. A common practice is to give you a set
of pulleys. Just pulling up and down can make the shoulder sore. What you
really want to do is to roll the forearm out (external rotation). With this
range the arm will come up if you have the strength to raise it.
Why do we do aerobics? It's the national rage. The purpose is to condition
your heart and develop endurance. The lungs breathe in the air, the heart
pumps the oxygen to the muscles, which extract it. This is a physiological
system that works very well. The general concept of aerobics is to run, to
take a long bicycle ride, or race. It is said that you have to have a
sustained effort of at least 20 minutes or you don't get an aerobic
What is the limitation of aerobics to the polio patient? The problem is that
the heart is a response organ; it doesn't make itself go except just to
beat, but it doesn't beat any harder than it has to. You create that demand
by your arms and legs. If your arms and legs are weak, you'll wear them out
trying to develop the heart to a level it doesn't need to be because the
arms and legs can't make that demand. So don't sacrifice your arms and legs
to build up a heart. You have to watch your cardiologist. In fact, I had one
man who lost leg strength permanently. He had a heart attack and the only
answer was exercise. But that isn't the only answer. I know another
cardiologist who prefers using aspirin instead of exercise.
I like swimming. You can interrupt it, you can do it as little as you want,
you can paddle around the warm water, you can swim vigorously, you can do
whatever you can physically, you can moderate. The only trouble is you get
your hair wet. The other good exercise is using a stationary bicycle. Why
stationary rather than mobile? Well, if you have a street bicycle, you have
to come back from wherever you went. If you have a stationary bike, you can
get off any time. You can have an activity program of one or two minutes (I
like one minute myself), then rest for 30 seconds and then do the next
minute or two. It really adds up. You can do your five or ten minutes or
whatever is comfortable. Interrupted bicycling, interrupted swimming, or
interrupted anything that doesn't force you to go beyond what you are
comfortable doing is a good aerobic exercise.
One of the common recommended exercises is walking. This is great for stroke
patients because they have plenty of muscle so are not worried about
overdoing their muscles. Walking is not as good for polio patients unless
they really have enough strength because it creates a high demand on the
calf muscles, which tend to be overused. Also a common substitution for a
weak quadriceps is to lock the knee, which makes more impact on the joints.
I'd rather have you use a bicycle.
Aerobics is only for asymptomatic muscles. Don't use painful muscles because
it's a long-term demand activity. How much? Remember that a normal muscle
has 100% fibers, a grade 4 muscle has only 40% (Figure 1), so there is
significant weakness that has to be recognized. Use them but respect them.
If you have grade 3+ muscles, they are already working too hard, so you
don't need extra exercise.
Strengthening exercise is working to change the physiology of the muscles
directly. You can use light weights, and you can do one or two or three
cycles. It doesn't take much time. Generally, we use about five or ten
repetitions for about 50% of your strength. Whatever weight you can lift
once, use about 50% of that effort. Do what is comfortable. You will feel
that you are exerting yourself, but don't have it hurt. Exertion and hurt
are different things. When you get up to ten repetitions, add a little
weight and go back to five and build it up again. On the shoulder, you have
two muscle groups: the deltoid, which lifts the arm, and the rotator cuff
muscles, which stabilize the joint. Actually, the cuff muscles hold the
humeral ball into the socket, which is built for lots of motion and
therefore is very shallow. The shoulder joint is like a cup and saucer on
edge and it's very unstable. It takes muscles to hold it in place.
The key to shoulder exercise is really to work on the cuff muscles. This
involves three key muscles. Supraspinatus is the muscle deep to the deltoid
that helps raise the arm. It is best exercised by having the arm turned in
when the arm is raised to the side. The infraspinatus crosses the back of
the shoulder joint. It is exercised by turning the arm out. Using both hands
to stretch large rubber bands (they are called Therabands and there are
different densities) is the easiest way to exercise the infraspinatus. Or
you can lie on your side and lift a weight. Find out what is comfortable for
you, what will allow exertion without pain, and what you can do at least
The third muscle, called subscapularis, crosses the front of the shoulder
joint. Its action is internal rotation. One can exercise this muscle by
pulling down on a weight hung over a door while keeping the elbow level. You
also can lie on your side and lift the weight with the underarm. To exercise
the scapular muscles, you can push against a wall for the serratus (that's a
light demand). The best thing for the trapezius is to pull the arms back.
The common sitting posture causes posterior shoulder muscle strain. Lean
back to protect these muscles from overuse.
In the lower extremities, the quadriceps is the key muscle for walking. You
can exercise this muscle with a Theraband tied to the wheelchair or you can
lift weights. Lying on your face, you can have weights on your ankle and
work on the knee flexors. Basically, you can use any device that gives some
resistance. Gravity is often enough just for the hip muscles. Sitting with
a Theraband tied around both thighs allows you to exercise the abductors of
both hips by pulling the legs apart against the Theraband. You can do all
sorts of clever tricks. For your hip extensors, you can lie on your face
and raise your thigh, or you can lie on your back and raise your buttocks.
To exercise your calf muscles, you want to lift your body weight. If they
are not very strong, use both legs. If you are strong, rise up on one leg at
How effective is exercise? In a study conducted at Rancho Los Amigos Medical
Center, the results from patients' home exercise were graded "Improved," "No
change," and "Worse." About one-third of the patients fell into each
category (Figure 7). The ones who felt better had a good program; the ones
with no change probably didn't have enough resistance; and the patients who
felt worse had too much. How much was better? Half of the patients who felt
better gained 1/2 muscle grade, felt they could walk better, and had more
endurance and less fatigue. But none of them regained the strength to lift
their body weight up a stair.
In another strengthening program a very conscientious group of people worked
for a year. For six months they gained strength and for the next six months
they lost strength. The leg that wasn't exercised lost 5%. In the aerobics
program, the gain was about 15%. So a little bit of exercise is good, but
don't expect a lot. It keeps your muscles toned, but don't wear them out.
Remember: No Pain
So, no pain. Pain is always a sign of injury. You may say sports people put
up with pain. The smart athletes are not doing it any more. Overuse is a
tremendous problem in athletics. As to fatigue: if your exertion makes you
tired for about ten minutes, that's no problem. If you are wiped out and
have to go to bed, you've done too much.
The most important thing in a post-polio program is life style modification
to reduce strain. If you reduce the strain so you have a little bit less
than maximum effort, then you have a margin for exercise. That's the ideal
program because then you have a non-stressful life and you have some margins
to keep your muscles up to prime. So listen to your body. Be a
hypochondriac. Listen to it. But don't complain; do something about it.
Remember that every time you do excessive exercise, you are causing
scarring. There is further damage and some permanent injury to the muscle if
you get scarring. Athletes get it sometimes and that's why they have these
groin pulls that never heal. They overdid it and they keep overdoing it. You
have athletes who lose a million dollar job because they pulled a groin
muscle doing too much.
Now I want to talk a little bit about therapeutic electrical stimulation.
That's the latest thing to hit the fan. The theory is that a low electric
activity will improve the circulation to the muscles. It does not cause a
contraction. The stimulus feels like a little buzz. It's supposed to
improve the circulation of the muscle; then by having better circulation,
the muscle has a change to hypertrophy. The program developer is Dr. Pape.
Her strongest advocate is Drake in Arizona. Dr. Drake was "cured" by a
combination of life style management and therapeutic electric stimulation.
Questions and Answers
Question: How do you lose weight without losing muscle?
Perry: The weight you want to lose is fat. You don't have to lose muscle to
lose fat. They're entirely different organs. Pick low fat foods. Most all
our protein foods have fat along with the protein. The recommendation is for
He now has documented about ten people. About half of them feel better; the
other half haven't noticed any change or are worse. So it is not a panacea.
If your muscles are better than 3+ and have some capacity to hypertrophy
with better circulation, it will help. But don't expect too much.
The Most Important Exercise
The most important exercise you can do is to lose weight. When you go up a
stair, the quadriceps has to lift the entire body weight. My diagram of
stair-climbing shows that the distance between that muscle and the tendon
across the knee is about 2 inches (Figure 8). If you look at the line
between the center of the tire around the trunk and the knee joint, you can
see there is a good 10 to 14 inches. Therefore, that tire has an advantage
of at least 5:1 over that quadriceps. If you got rid of the spare tire, your
quadriceps would have that much more strength because it wouldn't have to do
that much work. I have two patients who have lost 100 pounds sitting in a
wheelchair, with no exercise. One woman wears a neck brace and a back brace.
So actually the most important thing you can do is get rid of the spare tire
by watching what you eat.
The second most important thing to do is keep yourself busy, distract
yourself. One of my most successful patients, with mostly grade 2+ muscles,
is our volunteer chaplain at Rancho. She is busy, she is charming and she
is happy. Volunteer to do something and keep your mind going, so you don't
think about food. Those are your two most important exercises.
Question: Is there a theory or a reason why most stroke survivors have
built-in fatigue regardless of what they do?
Perry: The problem with a stroke is the control error causing more than the
essential muscles to act, resulting in overwork. Spasticity is the other
problem, that creates an antagonistic force for whatever you do. So you work
inefficiently. So keep things stretched out and exert yourself at a moderate
Question: Why do I have most of my pain at night?
Perry: Look at the postures you use when you relax. Are you lying in a poor
posture so it adds more strain? The other thing is that you get your pain at
night after a busy day; that's very common because you've interrupted your
distraction and can feel the overuse.
Dr. Hilary Siebens: I just want to add a comment about stroke patients who
don't have muscle weakness. Having a stroke somehow affects your mentation,
so that you have to concentrate extra hard to do certain things; that does
cause a kind of mental fatigue, not a physical fatigue.
Question: Do you use external rotation for a shoulder with a rotator cuff
problem? What about a rowing machine for a post-polio's upper body and back?
Perry: If your muscles are grade 4 and 5 and your back is not painful, it's
great. If the muscles hurt when you do it and your back hurts with it, it's
Question: What about the external rotation for a shoulder?
Perry: I showed you a rotator cuff exercise series which also is good when
you have a rotator cuff injury because you need to strengthen the other
muscles besides the supraspinatus. The external rotators are one of the cuff
group. But again, don't do anything that hurts. If you're irritating that
torn area, then you're doing too much. Work closely with a therapist.
Question: How long did it take those two patients to lose 100 pounds, and
was it diet only?
Perry: It was diet only and it took them about a year. It's a lot of weight.
Question: What are the implications of a grade 3 versus a grade 4 muscle?
Perry: With an EMG study, we demonstrated that for normal walking, the calf
muscles work at a grade 3 (20% of our long-term ability). That leaves a
margin between a grade 3 muscle, which fatigues with its 100% effort, and
grade 4 to do something extra. You can walk at a low level, and then you do
something extra to keep the muscle strong. But you don't do an awful lot if
you are a 4 instead of a 5. You have to make sure there is no pain nor
long-term fatigue. I do have these two very critical rules. No pain, and no
fatigue more than 10 minutes. My patients can do anything they want within
Question: If you are having a lot of fatigue and some muscle pain, does deep
Perry: It seems to. I used not to believe that, but an orthopedic surgeon
colleague who got Parkinsonism had a lot of muscle tightness; his wife was a
physical therapist, and he used to survive by massage. I knew he was a valid
person so I started believing it. What I think you do is you massage out the
edema from the damage of overuse. The common assumption is that one removes
the exudate, but muscle studies showed that the lactate is gone ten minutes
after the exercise. Your first reaction to anything is swelling and that
creates its own tensions and it takes a while to work that out. Now you can
hang your arm or leg up and drain out the swelling, but it's probably easier
to have somebody to push it out. So the answer is yes, it helps.
Question: What good is the commercial electric stimulation as a substitute
Perry: Well, you can read a book at the same time. But don't overdo.