Components of Physical Conditioning - Rehabilitation Research

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COMPONENTS OF PHYSICALCONDITIONING

The main components of physical conditioningare cardiovascular endurance, flexibility, muscularstrength and endurance, and skill development . Thecardiovascular system is conditioned most effectivelyby active exercise such as running, swimming, orbicycling, and to a lesser degree, by weight resis-tance exercise and arm-cranking . Controlled passiveexercise using machines, temperature changes, medi-cation, or diets cannot replace active exercise.Flexibility, which also can be improved by weighttraining, is best achieved through stretching exer-cises that increase the body's range of motion.Muscular strength and endurance are developedthrough weight resistance exercise and, to a lesserdegree, through sports activities.

A great deal is known about muscle physiology.Recent studies and technological developments havechanged training techniques to verify certain prac-tices which, in the past, had been based on empiricobservations . The sports therapist, physiologist,trainer, and physical educator can adapt theirmethodology based on this new scientific informa-tion .

Computerized equipment accurately measuresand monitors cardiorespiratory function at rest andwhile exercising . Many of the advances in thetechniques of training and physical conditioninghave been stimulated by organized sports competi-tion. Biomechanical video analysis is useful tocoaches who are trying to improve team perfor-mance . Football players participate in aerobic danceclasses; weightlifting for strength and endurance is

used by athletes in every competitive sport toimprove performance.

A person with a lower limb amputation canexercise for fitness and train for sports in virtuallythe same ways as a nondisabled person . There maybe some modifications to the workout routinedepending on the level of amputation and theaccessibility of special facilities.

CARDIOVASCULAR ENDURANCE

The word "aerobic" refers to a state ofphysical well-being in which the heart and lungscombine to provide life-giving oxygen and nutritionto the body's cells. The heart, lungs, and circulatorysystem transport the gases and nutrients which reachevery body cell. In these cells, the complicatedprocess of energy conversion takes place and wasteproducts are discarded . We breathe and our heartsbeat continuously many trillions of times during thecourse of our lives . The more efficient our system,the greater our capacity to perform mechanically.

The efficiency of the cardiovascular system isimproved by the things that improve general health.These include diet, weight control, appropriate rest,and exercise . Several changes take place in thecardiovascular system once aerobic conditioningbegins. For example, stroke volume will increaseafter regular intervals of physical conditioning . Thismeans that every time the heart beats, more blood ismade available to the circulatory system . The heart

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RRDS Clinical Guide . Physical Fitness : A Guide for Individuals with Lower Limb Loss

JOHN WOODMANSEE/DVAMC, SEATTLE, WATreadmill Running Training on the treadmill is a form ofsteady state exercise . The speed of the treadmill can bevaried to achieve individual aerobic fitness levels . Thetreadmill provides an opportunity for a person with amputa-tion to run in a controlled environment on a regular basis.

will be able to beat fewer times to accomplish workat the same rate . The amount of work accomplishedis dependent upon the amount of time expended.Both at rest and against a given load, the heart rateis lower as one's stroke volume increases . Anotherimportant effect of conditioning is that more oxygencan be taken from the hemoglobin (the iron-containing pigment in the red-blood cell that carriesoxygen from the lungs to the tissues) . Tissueoxygenation is also improved by increasing thenumber and density of capillaries in the musclesbeing worked . Even in sedentary individuals, theseaerobic effects can begin to be realized after as littleas 3 weeks of regular aerobic exercise .

Dr . Kenneth Cooper in his book, The AerobicsProgram for Total Well-Being, defines aerobicexercises as activities "that demand large quantitiesof oxygen for prolonged periods and ultimatelyforce the body to improve those systems responsiblefor the transportation of oxygen . In other words,the exercise is being performed with the body in a`steady state' ." 1 The healthy body always maintainshomeostasis, a balance of its physiological systems.However, the level of energy expenditure needed tomaintain homeostasis is quite different if one issleeping or performing an active aerobic exercise.For aerobic conditioning, one must perform somekind of active training that brings oxygen into themuscular system (e .g ., running, slow jogging, bicy-cling, swimming, cross-country skiing, rowing, play-ing basketball) for sustained periods of time . Theopposite of this is anaerobic exercise during whichthe energy is provided without utilization of inspiredoxygen (i .e ., exercise that is limited to short burstsof vigorous activity, such as weight lifting).

To improve cardiovascular endurance, oneshould continually try to increase the length of timeand level of energy expenditure so that the cardio-vascular system can respond to the increased loads.Only by increasing the intensity, frequency, andduration of the exercise can the individual progressto higher levels of fitness . This is known as the"overload" principle because it requires the exerciseintensity to be near the maximum when applied toeither aerobic or anaerobic training programs . 2

For example, there are a variety of trainingprograms for running long- and short-distanceraces . Each varies with the length of the race . Manyof the techniques involved can be attributed torefinement of training methods used by coaches andathletes throughout the years . Anaerobic/sprint ca-pacities can be increased and aerobic/enduranceperformance can be improved . Interval training is asystem that involves several bouts of hard workalternating with periods of lighter work or rest,thereby allowing for maximum intensity during thework intervals. "Manipulation of the rate anddistance of the work interval, the number ofrepetitions, and the time and type of relief intervalprovides training programs that can meet the needsof many athletes and non-athletes ." 3

Research results have demonstrated the benefitsof aerobic conditioning for people with lower limbloss . In one study, 10 such people participated in a

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Physical Fitness Guidelines : Components of Physical Conditioning

15-week aerobic conditioning program to determinewhether it would improve cardiovascular fitness andreduce the effort required for walking . 4 Two of thesubjects had bilateral amputations, three had above-knee (AK) amputation, four had below-knee (BK)amputation, and one had a partial foot amputation.All had been sedentary prior to the program ; nonehad participated in any form of physical exercise orsport for several years . The average age of thesubjects was 39 . The program consisted of regularweekly exercise on a Schwinn ® Air-Dyne Ergometer.Subjects exercised at 60 to 80 percent of theirestimated maximum heart rate . Tests of maximumexercise on the ergometer and walking on a treadmillwere conducted before and after training . Resultsshowed a 25 percent increase in the maximumcapacity for exercise on the ergometer and notablylower values for heart rate and oxygen consumptionduring treadmill walking at various inclines.

In another study demonstrating the positiveeffects of aerobic conditioning in the early stages ofrehabilitation, subjects were middle-aged to elderlyand had unilateral AK or BK amputations . 5 Follow-ing 14 weeks of regular exercise on a SchwinnAir-Dyne Ergometer that was modified for com-bined lateral arm/unilateral leg training while seatedin their wheelchairs, all subjects showed improved

cardiovascular response. Moreover, preliminaryfindings suggest that a combined arm-leg ergometermay provide improved function in wheelchair pro-pulsion and prosthetic ambulation as well as aerobicconditioning and endurance training.

FLEXIBILITY

Flexibility is the ability to move without restric-tion during a normal range of movement : it is thequality of being bent without breaking . It is mea-sured by the range of motion present through theconnective tissues of ligaments and tendons thatsurround the joints between the bones and otherparts of the body . Natural flexibility decreases withage. A child's body is flexible because the skeletoncontains more cartilage, the bones are soft, and themuscles, ligaments, and tendons are more elastic.The loss of flexibility from childhood throughadulthood cannot be avoided . However, it can bedelayed by regularly performed exercises that stretchand improve the range of muscle and joint move-ment. Adults who maintain their flexibility throughstretching exercises feel better, have more energy foreveryday activities, and are less susceptible toinjuries during sports participation . Stretching exer-

Rowing While we normallythink of rowing a boat on a lake orriver, the benefits of this exerciseare accessible on stationary row-ing machines available for in-homeuse or in the gym. These ma-chines and computerized rowingmachines can provide good aero-bic conditioning.

JOHN WOODMANSEE/DVAMC, SEATTLE, WA

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RRDS Clinical Guide . Physical Fitness : A Guide for Individuals with Lower Limb Loss

Stationary Bicycle Riding Thestationary bicycle can be used athome as well as in the gym.Interval training can be done man-ually or on computer-driven exer-cise bicycles.

JOHN WOODMANSEE/DVAMC, SEATTLE, WA

cises done on a regular basis will help people whosuffer from chronic muscle "stiffness" to limber upand maintain a stretched-out feeling.

Stretching is a simple and painless method ofpreparing for vigorous physical activity withoutcausing undue strain upon the body. Anyone canlearn to stretch and regain some of the flexibilitylost through the aging process . Athletic ability, pastor present, is not necessary . However, before begin-ning stretching exercises, it is important that thepotential exerciser carefully assess his or her physicalcondition, health, and capacity for muscle tensionand flexibility, since stretching exercises should beindividually tailored . A physician should be con-sulted and advised about any existing physicalproblems, recent surgery (particularly pertaining tothe joints and muscles), or prolonged inactivity.

Stretching exercises must be performed cor-rectly with the exerciser focusing on the range ofmotion of a particular muscle group and stretchingonly far enough to feel tension—not pain . Thosewho have been involved in other forms of condition-ing have been told, "No pain, no gain ." Thisphilosophy does not hold true for stretching becausemuscles need to be relaxed in order to stretchfurther . People who stretch incorrectly have atendency to bounce up and down until the exercisecreates pain, which should be the signal to stop .

Muscle strain activates the protective stretchmechanism called the "stretch reflex ." Each timemuscle fibers are stretched too far by either bounc-ing or over-stretching, a nerve reflex sends a signalto the muscle to contract . This involuntary contrac-tion keeps the muscle from being injured or over-stretched. When over-stretched, muscles actuallytighten and the body's natural defense mechanismprotects them from injury . However, repeated incor-rect methods of stretching can cause not only pain,but microscopic tearing of the muscle fibers . Thistearing eventually causes the formation of scar tissuewhich gradually results in the loss of elasticity andflexibility.

MUSCULAR STRENGTH AND ENDURANCE

Physical strength is achieved through muscledevelopment . Muscular strength is defined as theforce or tension of a muscle group which can beexerted against a resistance in one maximal effort.Muscle strength and increase in muscle size areacquired by muscles working against a resistantforce which is gradually increased as the musclesbecome stronger.

A strength conditioning program usually con-sists of progressively resistive weight exercises . The

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Physical Fitness Guidelines : Components of Physical Conditioning

exercises can concentrate on specific goals such asbuilding muscle bulk, power weightlifting, muscledefinition, muscle tone, endurance for a specificsport, or skills . The muscle groups of the body canbe isolated and trained. Nutrition, amount of rest,and genetics also play a part in achieving thesegoals.

Endurance is acquired by repetitive exerciseagainst a constant level of resistance . Light resis-tance exercises repeated many times produces endur-ance . However, muscle exercise for endurance af-fects muscle bulk only slightly and does not increasemuscle strength . For that reason, it is necessary tocombine endurance and strength exercises in acoordinated program.

Increases in strength and endurance are accom-panied by physiological changes, that is, increasedmuscle size (hypertrophy), biochemical alterations,and adaptations in the nervous system. A muscleshortens while lifting, and lengthens while lowering,a constant load. The tension developed over therange of motion depends upon the length of themuscle, the angle of the pull of the muscle on theskeleton, and the speed of the shortening.

Muscular strength and endurance are developedby practicing the overload principle . Strength, en-durance, and hypertrophy of a muscle will increase

Stretching Exercise

Greg Mannino works to touch hishead to his knee .

only when that muscle performs for given periods oftime at its maximal capacity to work againstresistance and loads that are above those normallyencountered.

As one develops strength and endurance, partic-ipation in aerobic and sports activities becomeseasier . Strength gains can be specifically orientedtoward sports performance by focusing on exercisesthat simulate movement patterns used in the skill ofa particular sport . Most exercise physiologists feelthat it takes from 6 to 12 weeks of progressive,organized, muscle-resistance exercise to build up anoptimum level of strength for the performance ofmany competitive sports activities . For outdoorseasonal sports, the program can be combined formaintenance-conditioning during the sport seasonand for strength-conditioning during the off-season.

Muscle Soreness

Muscle soreness is common to beginners in astrengthening program. Two types of soreness canresult from muscle strain : acute and delayed.

Acute muscle soreness is often caused byinadequate blood flow. Tension created in a muscu-lar contraction occludes blood flow to the musclesbeing worked thereby causing ischemia . Metabolic

JOHN WOODMANSEE/DVAMC, SEATTLE, WA

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RRDS Clinical Guide . Physical Fitness : A Guide for Individuals with Lower Limb Loss

Strength Conditioning Pulling

against resistance and liftingweights strengthens the mus-

cles of the arms and upper back.JOHN WOODMANSEE/DVAMC, SEATTLE, WA

waste products like potassium and lactic acid cannotbe removed from the blood because of the build-upof ischemia . This build-up can actually stimulate thepain receptors in the muscles, causing soreness . Thepain or soreness will subside when the exercise pro-ducing the contraction of the muscles is reduced orcompletely stopped. The blood can then flow in anormal manner, creating an environment for theremoval of lactic acid and potassium . The completeremoval of these waste products can take manyhours, but a majority are removed within the first15-60 seconds after the contraction of the musclehas ceased . For this reason, a 30- to 60-second restperiod between each set of weightlifting exercise isalways recommended to allow any soreness tosubside.

Delayed muscle soreness is usually caused by adisruption of the connective tissues . This form ofsoreness is commonly noticed between 24-48 hoursafter exercising . Several theories exist regarding thecause of delayed muscle soreness and some observa-tions have been made pertaining to prevention . Forexample, controlled stretching before and after anactivity has been found to be helpful . Stretching isalso effective in soothing existing muscle soreness. Acarefully graduated exercise program can help pre-vent delayed muscle soreness .

SKILL DEVELOPMENT

Being skilled in sports implies the ability toexcel. Time, distance, and accuracy objectivelymeasure skillful performance . Competition is also ameasure of skill ; as are coordination, balance, andspeed.

Skill also can be expressed in terms of grace,beauty, and aesthetics . The ballet dancer, eques-trian, basketball player, and gymnast perform withvarying degrees of artistry . While these qualities arenot easy to measure objectively, they represent trueforms of physical and artistic skill . Thus, manyathletic skills are both physical and artistic.

Skillful physical performance is also the resultof neuromuscular coordination . Finely-tuned coor-dination can be both inborn and acquired . Certainvoluntary and involuntary movements can be de-scribed as being clumsy, awkward, and poorlycoordinated . On the other hand, trained and coordi-nated movements are usually graceful and precise.Young children playing active physical games duringa school recess exhibit a wide variety of inbornneuromuscular coordination.

Acquired skills are the result of physical condi-tioning, fitness, and practice . No matter how muchnatural physical ability a person possesses, proper

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Physical Fitness Guidelines : Components of Physical Conditioning

DALE TILLY/DVAMC, SEATTLE, WASkill at Work Basketball combines skill and concentrationwith enjoyable exercise.

coaching and training will develop skill . Successfulathletes continually improve their skills through theapplication of more refined techniques, and notnecessarily by building greater strength and endur-ance. Precision sports, such as golf, constantlyexemplify the need for perfecting technique .

For the person with lower limb loss, there arealways compensations to be made when participat-ing in physical activities . However, the compensa-tions can be reduced by effective prosthetic substitu-tion and/or adaptations . It also becomes natural forsuch individuals to enhance their performancethrough creative use of other parts of their body.Participating in activities wherein the physical lossof a limb can be successfully compensated for willresult in maximum enjoyment and potential for skilldevelopment.

NOTES

1. K.H. Cooper, The Aerobics Program for Total Well-Being.New York : Bantam Books, 1982, p . 112.

2. E .L . Fox and D .K. Mathew, Physiological Basis of PhysicalEducation and Athletes. Philadelphia : CBS College Publishing,1981, pp . 273-291.

3. Ibid., p . 162.

4. K .H. Pitetti, P .G. Snell, J . Stray-Gundersen, and FAGottschalk, "Aerobic Training Exercises for Individuals WhoHad Amputation of the Lower Limb ." Journal of Bone andJoint Surgery, 69-A(6), 1987, pp . 914-921.

5. A.G. Bostom, E . Bates, N . Mazzarella, E . Block, and J.Adler, "Ergometer Modification for Combined Arm-Leg Useby Lower Extremity Amputees in Cardiovascular Testing andTraining ." Archives of Physical Medicine and Rehabilitation,68(April), 1987, pp . 244-247 .

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RRDS Clinical Guide . Physical Fitness : A Guide for Individuals with Lower Limb Loss

Greg Mannino demonstrates a muscle strengthening exercise.

All photographs in Chapters 5 through 12 (unless otherwise credited) were taken by Dale Tilly or John Woodmansee of theMedical Media Service, Department of Veterans Affairs Medical Center, Seattle, WA .