Therapeutic Exercise 

DeLateur defined therapeutic exercise as bodily movement prescribed to correct an impairment, improve musculoskeletal function, or maintain a state of well-being.^[1] It may vary from highly selected activities restricted to specific muscles or parts of the body, to general and vigorous activities that can return a convalescing patient to the peak of physical condition. Therapeutic exercise seeks to accomplish the following goals:

• Enable ambulation
• Release contracted muscles, tendons, and fascia
• Mobilize joints
• Improve circulation
• Improve respiratory capacity
• Improve coordination
• Reduce rigidity
• Improve balance
• Promote relaxation
• Improve muscle strength and, if possible, achieve and maintain maximal voluntary contractile force (MVC)
• Improve exercise performance and functional capacity (endurance)

The last 2 goals mirror an individual's overall physical fitness, a state characterized by good muscle strength combined with good endurance. No matter which types of exercise may be needed initially and are applied to remedy a patient's specific condition, the final goal of rehabilitation is to achieve, whenever possible, an optimal level of physical fitness by the end of the treatment regimen.

Types of therapeutic exercise

Therapeutic exercises aimed at achieving and maintaining physical fitness fall into the following major categories:

• Endurance training
• Resistance training
• Flexibility training

Patient education

For patient education information, see the Healthy Living Center, as well as Walking for Fitness and Resistance Training.

Decreased physical fitness may result from various diseases, especially when accompanied by prolonged recumbency, or from a sedentary lifestyle. Compared with a less fit individual, a physically fit person demonstrates the following physiologic profile:

• Higher oxygen consumption (mL/min)
• Greater cardiac output per minute
• Higher stroke volume and total blood volume
• Greater oxygen extraction by the tissues
• Greater cardiac volume
• Lower resting pulse rate
• Greater muscle strength
• Lower pulse rate on exercise
• Lower blood pressure on exercise
• Better adaptation of circulation and respiration to effort

The last 3 features above (ie, lower pulse rate and blood pressure on exercise and better adaptation of circulation and respiration to effort) are characteristic features of improved endurance.

Increased physical fitness is associated with a decreased incidence of hypertension and coronary artery disease (CAD) and with an improved long-term prognosis in patients with angina pectoris and in survivors of myocardial infarction (MI).^{[2, 3]} However, the duration, frequency, intensity, and type of therapeutic exercise that bring about these beneficial effects have not been established. Debate continues as to whether a better cardiac status allows for a higher level of physical activity and, consequently, better physical fitness, or vice versa.

Before a patient begins physical fitness training or other strenuous therapeutic training, he/she should undergo a medical evaluation by a physician, including a comprehensive medical history, a thorough physical examination, and an adequate laboratory screening. In cases involving cardiac conditions, it is important to exclude patients with valvular heart disease, ventricular hypertrophy, dangerous arrhythmias, and malignant hypertension.

Other cardiac cases, older and/or ill patients, and other patients at risk, such as those with exercise-induced asthma, hemoglobinopathies, diabetes, or obesity, should have an exercise stress test carried out under careful medical supervision. This test should include pulse and blood pressure monitoring and the administration of an electrocardiogram (ECG), prior to exercise. These individuals require especially close monitoring if they are included in any exercise program. Patients with musculoskeletal problems need an evaluation by a physical therapist before beginning an exercise regimen.

An endurance training program has 3 variables: frequency, intensity, and duration. The American College of Sports Medicine (ACSM) recommendations are as follows:

• Frequency - Aerobic exercise 3-5 days per week
• Intensity of training - 64/70-94% of maximum heart rate (HR max), or 40/50-85% of maximum oxygen uptake reserve (VO₂ R) or heart rate reserve (HRR)
• Duration of training - Continuous or intermittent aerobic activity for 20-60 minutes (minimum of 10min bouts accumulated throughout the day)

Duration is dependent on the intensity of the activity; thus, lower-intensity activity should be conducted over a longer period of time (≥30min), and, conversely, individuals training at higher levels of intensity should train at least 20 minutes or longer. Moderate-intensity activity of longer duration is recommended for adults not training for athletic competition, because total fitness is more readily attained with exercise sessions of longer duration and because potential hazards and adherence problems are associated with high-intensity activity.

Application to healthy individuals

Exercises that use large muscle groups that can be maintained continuously and are aerobic in nature are recommended. These exercises include the following:

• Walking
• Running
• Jogging
• Dancing
• Stair climbing
• Cycling
• Swimming
• Rowing
• Skating
• Aerobic dance/exercise classes
• Jumping rope
• Cross-country skiing

The HR max can be determined by the following: HR max = 220 – age. The exercise session should consist of the following:

• A warm-up period of approximately 10 minutes - This should combine calisthenic-type stretching exercises and progressive aerobic activity that should increase the heart rate close to the prescribed heart rate for the session
• Endurance training (20-60min)
• A cool-down period of 5-10 minutes

Application to patients

For at-risk patients, especially those with cardiac or respiratory disease, a less intense training regimen must be used, with the training heart rate not exceeding that attained at 50-60% of maximum O₂ uptake (VO₂ max).

In the absence of data regarding maximum attained heart rate measurements, it is prudent not to allow a patient to exceed a heart rate of 130 beats per minute (bpm). In elderly patients and patients at risk, the intensity, frequency, and duration of therapeutic exercise should be established for each patient individually through prior medical evaluation.

Using the following equation, the HRR method, otherwise known as the Karvonen method, should be employed to determine the target heart rate for the ill or elderly patient: Target HR = (220 - age - resting heart rate × % intensity selected) + resting HR.

Progression

Progression must be a part of an exercise program to ensure continued results. With endurance training, progression can occur by increasing the duration or the intensity. Several factors contribute to the optimal rate of progression; current activity levels, exercise goals, age, and physiologic limitations should be considered. Most importantly, a rate of progression should be used that results in long-term participation. Being too aggressive with progression can lead to increased dropout rates as a result of injuries and/or perceived excessive discomfort.

Resistance training increases strength, walking speed, stair-climbing power, balance, and lean body mass and decreases regional and total fat mass. This type of exercise generally exists in 3 forms: isotonic, isometric, and isokinetic.

Resistance training has been shown to bring about favorable changes in risk factors for coronary artery disease, osteoporosis, diabetes mellitus, and cancer. For example, resistance training has been proven to lower systolic blood pressure, increase bone mineral density, increase mechanisms involved with blood glucose metabolism (glucose tolerance and insulin resistance), and increase bowel transit time, which decreases the risk of colon cancer in healthy men and women who are middle-aged or older. Back pain and work-related back injuries also have been shown to decrease with resistance training.

Isotonic exercise

Isotonic exercise consists of dynamic exercise combining a constant load (the amount of weight used) with uncontrolled speed of movement. Movement is through a range as the muscle shortens or lengthens. This type of exercise uses free weights and machines; it is what most people envision when they think of resistance training. DeLorme and Zinovieff were 2 of the first proponents of isotonic exercise.^{[4, 5]}

DeLorme recommended gradually building up to the 10 repetition maximum (RM; the maximum amount of weight lifted with correct technique for 10 repetitions) for each exercise with percentages of the 10 RM (ie, 50%, 75%, and then 100%). In contrast, Zinovieff's method, called the Oxford technique, starts at 10 RM and works down by a certain percentage (ie, 100%, 75%, and then 50%).

Both methods are effective because when the RM is reached, the progressive recruitment of muscle fibers has occurred and the muscle is at high intensity. Today, reaching the RM is still a crucial part of a resistance training program. More variables to a resistance training program exist, as described below.^[6]

Contraction

The fundamental components of most resistance training programs are dynamic repetitions of concentric contraction (in which the muscle is shortened) and of eccentric contraction (in which the muscle is lengthened), with an isometric contraction stabilizing the movement.

Load and volume

The load is the amount of weight used during the set and is the most important variable in program design. The load is best determined by the RM. Training volume is prescribed in terms of repetitions per set, number of sets per session, and number of training sessions per week. Resistance training programs designed for muscular strength and hypertrophy are best served by moderate to heavy loads (6-15 RM) and moderate volume (3-4 sets per exercise). The training load should be increased by 2-10% when the desired number of repetitions with the current load is surpassed by 1-2 repetitions.

Muscle groups and joints

Larger muscle groups (ie, thighs, back, chest) should be exercised before smaller muscle groups (ie, shoulders, arms, calves), and multijoint exercises (ie, squat, dead lift, bench press) should be performed before single-joint exercises (ie, leg extensions, curl, arm extension).

These approaches are important for 2 reasons: (1) multijoint, large muscle–group exercises require high levels of energy for optimal performance, and (2) small muscles limit the load during exercises for large muscles. For example, a bench press requires more energy than an arm extension; plus, the triceps limit the pectorals during the bench press. With regard to specific exercise selection, multiple exercises are available for each muscle group. This allows patients to perform those that they most enjoy, increasing compliance.

Rest periods

Rest periods are periods of time that are used for recovery between sets. The training goal, the training status of the individual, and the relative load lifted determine the rest period. Goal-specific rest periods are recommended as follows:

• For power (the ability to exert force at higher speeds) - 5-8 minutes
• For maximal strength (the greatest force that a muscle or muscle group can generate in a single maximum contraction) - 3-5 minutes
• For muscular hypertrophy - 1-2 minutes
• For muscular endurance - 30-60 seconds

Repetition velocity

The criterion standard repetition velocity that should maximize muscle tension and that may result in greater strength and hypertrophic changes is 2:1:4 (2s, concentric; 1s, pause; 4s, eccentric). However, for the average individual, 3:3 (3s, eccentric; 3s, concentric) is sufficient.

Frequency

Training frequency is the number of sessions during a given period of time (eg, 1/wk). Untrained individuals should perform a complete body workout 2-3 days per week. Changes in frequency to 3-4 days per week as training status increases may accompany program design changes (ie, splitting workouts into upper- and lower-body routines). For advanced training, workouts can take place 4-6 days per week (using workouts that focus on 1-2 body parts).

Isometric exercise

Isometric exercise is static exercise with muscle contraction but no movement of the load, resulting in no change in the total length of the muscle. These exercises involve the exertion of force against an immovable object or the holding of an object in a static position. They are relatively easy to perform and require little time. Isometric exercises are very effective on postural muscles and are useful when joint motion is painful or contraindicated. As is true with isotonic exercise, the force should be sufficient to fatigue all of the muscle fibers.

The strength gained during static exercise may not transfer to dynamic activities. Another disadvantage of isometric exercise is that it requires great caution, because it raises heart rate (due to decreased vagal tone and increased discharge of cardiac sympathetic nerves). Within a few seconds of the start of isometric exercise, the systolic and diastolic blood pressures rise.

Isokinetic exercise

In isokinetic exercise, movement is controlled so that it occurs through a range at a constant angular velocity as the muscle shortens or lengthens. However, the load or force exerted may be variable. Isokinetic exercise is performed using special equipment (eg, Cybex, Nautilus) that only permits movement at a preset angular velocity. This causes maximum tension at all angles.

The individual performing the exercises must be very motivated to recruit all of the muscle fibers, because the machine moves at the same rate no matter how much force is applied to it. Other disadvantages include the fact that strength gained at one particular velocity may not transfer to other velocities. In addition, the equipment is expensive and therefore is not readily available.

An allied technique for training of muscle strength

Proprioceptive neuromuscular facilitation (PNF), an excellent technique for muscle-strength training, is similarly based on applying resistance to muscle contraction in order to facilitate enhancement of muscle contractile force. PNF is suitable for patients with upper motor neuron lesions accompanied by spasticity, but it may also be used to initiate muscle contraction in cases of partial peripheral nerve damage and extreme muscle weakness.

Flexibility exercises can aid in improving and maintaining range of motion in a joint or a series of joints. They should be performed in a slow, controlled manner, with a gradual progression made to greater ranges of motion. There are 3 main types of stretching techniques: static, dynamic, and PNF.

Static

The muscle is stretched to a point of mild discomfort and then held at that position for an extended period of time (usually 15-30s). The characteristics of static flexibility exercise are as follows:

• Low injury risk
• Effective, with little time and assistance required
• Most commonly recommended method

Dynamic

Momentum created by repetitive bouncing movements produces a muscle stretch. However, dynamic flexibility exercises can cause muscle soreness or injury.

PNF

This involves the alternation of contraction and relaxation of agonists and antagonists through a designated series of motions. Characteristics of PNF are as follows:

• Produces the largest improvements in flexibility
• Typically causes some degree of muscle soreness
• Typically requires a partner trained in the technique and is time consuming

Stretching exercises

Stretching exercises should be performed a minimum of 2-3 days per week. For each stretch, 2-4 repetitions should be performed: 15-30 seconds of static stretching, as well as a 6-second contraction followed by 10-30 seconds of assisted stretching for PNF. These exercises can be effectively included in the warm-up and/or cool-down periods that precede and follow the endurance training exercise programs. A warm-up period should precede stretching exercises in order to elevate muscle temperature.

A systematic review examined the effect of acute static stretch on maximal muscle performance during preexercise routines. The authors found that stretch durations of less than 30 seconds (pooled estimate, -1.1% ± 1.8%) and 30-45 seconds (pooled estimate, -4.2% ± 2.7%) did not result in a meaningful reduction in muscular performance following these preexercise routines. However, they did find a moderate detrimental effect (61%) on peak performance with stretch durations of more than 60 seconds.^[7] Yoga, tai chi, and Pilates are techniques that can also be used to improve joint flexibility.

AAROM

Active assisted range-of-motion (AAROM) exercises are used when the patient has very weak muscles or when joint pain limits movement. During AAROM exercises, it is important to avoid forcing the joint and/or soft tissue beyond the point of pain.

PROM

In patients who cannot exercise actively, passive range-of-motion (PROM) exercises, consisting of stretching immobile muscles and joint capsules to prevent joint stiffness and muscle contracture, are used. Joint flexibility is achieved by means of steady and slow manual stretching of large muscle groups and joint capsules or with the help of mechanical devices. As a preliminary exercise prior to endurance or resistance training, PROM should be performed during the first warm-up and the last cool-down phases.

Therapeutic exercise has numerous benefits for all patients. Therapeutic exercise programs should consist of endurance, resistance, and flexibility training. All 3 of these can be combined into 1 exercise session, or they can be divided up. The method that the patient will best comply with should be used.

Patients should be encouraged to progress with their exercise programs so that they can continue to benefit from them. When performing resistance training, patients should be encouraged to exercise the muscle group of interest until they reach their RM so that all of the muscle fibers in that group are recruited. In patients who are too debilitated to perform an independent therapeutic exercise program, AAROM and PROM should be performed by a therapist, a trained family member, or a caretaker.

Stroke

Therapeutic exercise has been shown in several studies to benefit poststroke patients.^{[8, 9, 10]} In one study, it improved function and the quality of life in patients with a subacute stroke, increasing their endurance, balance, and mobility.^[11] In a similar study in the same patient population, therapeutic exercise improved depressive symptoms.

A large, systematic review revealed that progressive resistance exercise can improve strength and activity in patients with acute or chronic stroke without increasing spasticity.^[12]

Peripheral arterial disease

Therapeutic exercise can improve symptoms of pain with increased walking distance, referred to as intermittent claudication, as well as improve the quality of life in patients with peripheral arterial disease (PAD). This includes resistance and endurance training. Resistance training, consisting of both lower extremity exercises, has improved walking distance, quality of life, and pain associated with intermittent claudication.^{[13, 14, 15]}

Endurance training, including low-intensity training,^[16] interval training,^[17] and upper extremity aerobic exercise,^[18] also improves quality of life, walking distance, and pain.^{[14, 19, 20]} In addition to improving symptoms, exercise can decrease cardiovascular morbidity and mortality in patients with PAD.^[21] The exercise programs do not have to be supervised. Home-based therapeutic exercise programs have also been shown to improve walking and quality of life.^{[22, 23]}

Multiple sclerosis

Several studies have shown that endurance and resistance training can reduce fatigue in patients with multiple sclerosis (MS).^{[24, 25]} Quality of life has been improved with endurance training. Studies have also shown improvements in VO₂ max and strength as a result of endurance and resistance training, respectively.^[26]

To allow MS patients to exercise safely, certain precautions should be taken. Close supervision is recommended. In addition, exercise should be graded so that the intensity of the exercise is reduced in proportion to the degree of disability. For individuals with mild to moderate disability, endurance training should be performed 2-3 times weekly for 20-30 minutes, with 65-75% of the HR max.

For previously untrained individuals, resistance training should be performed twice weekly. The sessions should consist of 1-2 exercises per body part for major muscle groups (legs, chest, back) and 1 exercise for the smaller muscle groups (shoulders, biceps, triceps, abdominals). Either 2 or 3 sets should be performed, with about 15 repetitions per set.

Symptoms in some patients with MS worsen in response to higher ambient temperatures. Interval training and/or precooling prior to the exercise session may be preferable for them.

Diabetes mellitus

Exercise is important in diabetes prevention and management. Exercise has been shown to decrease glycosylated hemoglobin, blood pressure, and diabetic medication doses in people with type 2 diabetes.^[27]

Exercise improves insulin sensitivity by acting directly on the muscle, causing autophosphorylation, glucose transporter 4 (GLUT-4) content, and glucose transport-phosphorylation to increase. Exercise reduces visceral obesity, which decreases free fatty acids. It also increases insulin-stimulated limb blood flow. Resistance training leads to muscular hypertrophy, which improves glycemic control by increasing the storage size for glucose disposal.

Exercise has also been shown to slow the development of diabetic peripheral neuropathy.^[28] The exact mechanism of this is unknown, but the authors of the study do propose some possible explanations. Exercise may cause cellular changes that result in increased endoneurial blood flow and greater oxygen delivery. Another mechanism could be an exercise-induced increase in the concentration of Na⁺/K⁺ –adenosine triphosphatase (ATPase) pumps. K-channel openers have been shown in experiments to improve nerve perfusion and function in patients with diabetic neuropathy.

Osteoporosis

Multiple trials in postmenopausal women have shown improvements in bone-mineral density as a result of resistance training. These studies have also shown improvements in strength and muscle mass, which can help with functional activities.^{[29, 30, 31, 32, 33, 34, 35]}

However, despite the importance of resistance training, a conservative approach should be taken when designing an exercise program. The exercise routines can be simple and should have no jarring motions or sudden changes in direction, which may result in a fall. Patients should start with a light weight that allows them to perform 8-12 repetitions in a specific muscle group without the assistance of other muscle groups. Erect trunk alignment with back and head support, along with proper positional alignment, is important. High loads through the vertebral bodies should be avoided because they can produce compression fractures.

Progression should occur gradually, with sets added before weight is increased. The exercises should be performed 3-4 times weekly. Over time, those exercises that increase strength in the spine and extremities will increase the patient’s sense of balance and stability, which may decrease the individual's risk of falling.

Parkinson disease

Several studies have shown that therapeutic exercise can increase function and quality of life in people with Parkinson disease. Researchers found that an exercise program consisting of flexibility, endurance, and resistance training improved patients' perceptions of quality of life by increasing physical activity and social interaction.^[36] Another study demonstrated that high-intensity resistance training could result in muscular hypertrophy; more important, it led to improvements in stair descent times and 6-minute walk distances.^[37] High-intensity resistance training has also been shown to increase balance.^[38] In another study, endurance training improved movement initiation times and increased VO₂ max.

Neuromuscular disease

Strength can be increased in children with Duchenne muscular dystrophy and in adults with slowly progressive neuromuscular disease. The exercise needs to begin when the muscle groups have significantly more than simply antigravity strength. Exercising muscles that do not have antigravity strength may cause them to become weaker. The exercises need to be performed on a routine basis because any discontinuation will result in a rapid decrease in the strength gained. They also need to be performed at a submaximal level. There is no clinical evidence, however, that exercising muscles in individuals with neuromuscular disease will result in long-term improvements.

There have been only a few studies pertaining to endurance training and neuromuscular disease. Most of these have shown a positive effect from the training. Individuals have had variable responses to the training, probably in relation to their level of conditioning at the time their study participation began and to the effects of individual diseases. The cardiopulmonary adaptations to submaximal training in persons with neuromuscular disease are similar qualitatively to those in individuals without this type of illness. Short-term adaptations may be made, but the long-term effect of the training is unknown and may be limited by loss of muscle mass.

Balance disorders

Therapeutic exercise, including resistance training, flexibility training, multicomponent exercise, and tai chi, for the treatment of balance disorders and balance confidence has been studied extensively in older adults.^{[39, 40, 41, 42, 43, 44]} Resistance and endurance training programs incorporating jumping and mini-trampoline exercise have also been shown to improve balance in elderly persons.^{[45, 46]}

A meta-analysis of randomized, controlled trials on exercise and balance confidence in adults aged 60 years and older without a neurologic condition demonstrated low-significant effects for exercise and multifactorial interventions and medium-significant effects for tai chi.^[47]

Recumbent and convalescing patients

Recumbent and convalescing patients require maintenance by means of AAROM or PROM exercises, aided or performed by a therapist, to preserve full joint mobility and prevent joint stiffness and muscle contractures.

During or immediately after a patient's hospital stay, the patient should be referred to a physical training program. Otherwise, an individual therapeutic regimen appropriate to the patient's physical capacity should be designed in order to maintain and, whenever possible, improve his/her level of physical fitness. Thus, physical fitness maintenance or training can be performed either by means of an individual program carried out by the patient at home or by participation in a group training program.

Additional patient populations

Therapeutic exercise can also be used in many diagnoses other than those specified above. See Table 1 (below) for more diagnoses and pertinent exercise recommendations.

Table 1. Some Therapeutic Exercise Routines for Specific Patient Populations (Open Table in a new window)

The Swedish Back School, mentioned in the above table, is a systematic training regimen aimed at teaching patients with back problems to use movement patterns that diminish the load on the low back. For example, among persons studied it was found that when an individual lifted a load of 20kg with bent knees, his measured intradiscal pressure was 250kp/cm², whereas when he lifted the same load with the knees straight, the pressure rose to 380kp/cm². Consequently, the Swedish Back School trains patients in the use of the former technique, allowing for keeping the back straight, thereby diminishing the load by 130 kp/cm².

Mechanical aids in physical fitness

Examples of mechanical aids used in physical fitness maintenance and training include the following:

• Electrically braked cycle ergometers
• Treadmills
• Rowing apparatuses
• Bed bicycles
• Arm cycles
• Pulleys
• Free weights
• Weight-training machines
• Indoor stair steppers
• Medicine balls
• Pools