Parkinson's disease (PD) is one of the most common neurodegenerative diseases and presents numerous functional limitations (12). The accompanying Special Populations column includes a discussion of the epidemiology, symptoms, functional limitations, and benefits of exercise associated with PD. The cardinal symptoms of PD include resting tremor, rigidity, bradykinesis, and decreased postural reflexes (10), which can present many functional limitations such as abnormal gait patterns, decreased balance, and difficulty performing activities of daily living (ADLs). Exercise intervention has been shown to be an effective means to improve functional status (6,7,11). However, the limitations presented by PD can severely limit exercise performance and adherence. Because the major risk factor for PD is age (12), it is also advised that the exercise professional (EP) thoroughly examine any potential comorbidities and obtain medical clearance before working with persons with PD. Although exercise intervention is unable to positively modify the underlying pathology of PD, many associated functional limitations can be improved with regular exercise. An effective exercise program should consist of aerobic, resistance, flexibility, and functional training. The EP should be aware of the limitations of PD and appropriate exercise interventions (17).
Evaluation of PD severity is crucial before beginning an exercise program. Medical history information should include a physician evaluation including the Hoehn and Yahr stage rating (9) (see Special Populations column, Table 1) or Unified Parkinson's Disease Rating Scale score (13). The former system relies primarily on the evaluation of motor symptoms, whereas the latter evaluates the severity of both motor and nonmotor symptoms. These rating systems provide valuable information regarding functional limitations; however, additional functional evaluations by the EP can provide information regarding other areas to improve (Table 1). Additionally, because PD is a progressive disease process, functional status needs to be reevaluated at regular intervals. Zhao et al (21) demonstrated that the median rates of progression through stages 1, 2.5, 3, and 4 of the Hoehn and Yahr scale are 20, 25, 24, and 26 months respectively. Therefore, it is recommended that functional status be reevaluated every 2 years.
All 4 cardinal symptoms need to be evaluated before beginning an exercise program. Tremors can be classified as resting, postural, or intention tremors. Resting tremor is perhaps the most common and easily identifiable symptom of PD and usually presents as a pronation/supination of the wrist or “pill rolling” between the thumb and index finger. To elicit resting tremor, the EP should instruct the client to sit in a relaxed position with hands resting in the lap. The EP should then give the client a mentally challenging task (17) such as counting backward by 2s from 100 or reciting the alphabet backward. To assess postural tremor, the client should be instructed to suspend a limb against gravity (such as fully extending arms parallel to the floor). Because PD may present unilaterally, it is important to assess both sides. Intention tremors may be evaluated by having the client carefully touch the index finger to the nose. Noting the degree and amplitude of tremors during these tests gives an idea of the severity of PD. A more detailed discussion of tremor variations can be found in the review by Jankovic (10).
To assess rigidity, the EP should note muscular resistance and range of motion (ROM) while manually moving each major joint through its full ROM with the client in a relaxed position (17). This can be scored subjectively on a 1–5 scale according to the judgment of the EP because no scale has been established to objectively measure rigidity. Specifically, this test should be performed for the shoulders, elbow, hip, knee, and ankle. Caution should be used when performing these tests for the neck and trunk.
Bradykinesis can be evaluated by instructing the patient to rapidly pronate and supinate the forearm (17). If bradykinesis is present, the speed and coordination of the movement will be compromised as the duration of the activity increases. Finally, postural reflexes can be evaluated by the pull test (17). With the patient facing away, the EP reaches around to the front of the shoulders and pulls firmly. Two or more steps backward or failure to respond to the pull test are both indicative of compromised postural reflexes.
Additionally, it may be beneficial to use a walking test, such as the Timed Up and Go test (15). In this test, the client must stand from a seated position, walk 3 m (∼10ft), turn around, walk back to the start, and return to a seated position. Completing this task in less than 9 seconds indicates very low risk of fall, whereas a time of 20 seconds or more may indicate an increased risk of falls (20). Other authors have shown that in a non-PD population, persons requiring >10 seconds to complete this task have an 80% chance of falling (18). This test allows the EP to evaluate several ADLs: standing, turning, sitting, and balance as well as gait abnormalities, such as decreased stride length, festination (small shuffling steps), and/or freezing.
Currently, there are no established exercise guidelines specific to PD. However, aerobic training (AT) guidelines for PD may mirror those for healthy persons (15). Although treadmill exercise has been demonstrated to be effective in improving functional status (3,5,16), safety, disease stage, and functional limitations may dictate other AT modalities. Bicycle and arm ergometers have been shown to be safe and effective AT modalities (17). Bradykinesis presents a specific challenge to AT for persons with PD. Depending on the severity of bradykinesis, it may be difficult to achieve sufficient workloads to induce aerobic adaptations. Additionally, it is important to note that muscular strength is often compromised with increasing velocity of movement in PD (14). Considering these two limitations, persons with PD may respond better to AT using relatively lower velocity and higher resistance. It is important to note that PD may be accompanied by other age-associated comorbidities, such as hypertension, cardiovascular disease, arthritis, and cognitive decline/dementia, which may require modifications to the AT prescription (10,12,17). Typical AT guidelines for disease stage can be found in Table 2. Additionally, recommended modes of AT can be found in Table 3.
As with AT, there are minimal established exercise guidelines for resistance training (RT) for persons with PD. Tremor and rigidity offer substantial limitations with respect to coordination and ROM, respectively. Intention tremor usually decreases with cognitive movement strategies. This strategy may provide a safer atmosphere for RT by reducing tremor severity. Depending on the severity of tremor, free weight exercises may be an appropriate intervention. This is especially true of exercises that do not involve overhead lifting. However, free weights may become unsafe with increasing disease stage. Selectorized or plate loaded machines offer a safe alternative to free weights and have been shown to provide similar strength gains in healthy persons (20). Many selectorized and/or plate loaded machines allow unilateral use, which can be a good RT strategy because PD often presents with unilateral symptoms. Additionally, exercise modifications may be necessary to accompany decreased ROM associated with PD. Likewise, additional ROM training may improve exercise tolerance and improve ADLs. It is possible that RT with lower velocity may provide greater muscular recruitment and therefore greater strength gains and/or hypertrophy. However, training at greater velocities may improve speed-specific strength and therefore improve ADLs. Although this type of training has not been investigated in PD, it has been shown to improve functional performance and muscle power in elderly men without PD (4). A combination of both strategies may be necessary to elicit optimal benefits of RT. Recommended types of RT can be found in Table 3, and a typical RT program depending on disease stage can be found in Table 4.
FLEXIBILITY AND ROM
Flexibility training should consist of slow static stretches and passive ROM exercises for all major muscle groups and joints. Because PD symptoms are typically initially noted in the trunk and arms (17), flexibility and ROM exercises should emphasize these areas first to minimize the risk for complications, such as frozen shoulder and loss of spinal mobility. As with AT and RT, there are no established guidelines for flexibility exercise for persons with PD. One study showed that in persons with PD, flexibility is increased after 10 weeks of training 3 times per week (19).
Despite some skepticism of the functional benefits of exercise in PD, a recent meta-analysis by Keus et al. (11) demonstrated the efficacy of exercise in PD. These authors suggest using cueing and cognitive movement strategies as a means to improve daily functioning. Cues can effectively improve stride length and frequency and decrease instances or duration of freezing. Cueing strategies are thought to improve gait by providing external rhythmic or visual stimuli to compensate for the improper stimuli supplied by the basal ganglia (11). Cues can be external (from the surrounding environment) or internal (supplied by the person with PD) and can be divided into auditory, visual, tactile, and cognitive cues. Table 5 provides an outline for cueing strategies. These strategies can be implemented in exercise and normal living situations.
Cognitive movement strategies involve deconstructing complex movements into a series of smaller movements executed in a fixed order (11). For example, standing from a chair could be composed of placing hands on handrails (or table), leaning forward at the waist, extending the knees, and finally, extending the hips. This pattern should be practiced mentally (visualization of the proper movement pattern) before physically executing the task. Once the pattern is developed, it should remain under conscious control rather than becoming an automated movement. It is thought that in PD, the basal ganglia loses the ability to perform sequential movements. By consciously performing each task individually, sequential movements can be improved (11).
Functional training should also include balance exercises. Although balance exercise has been shown to be effective, some evidence suggests that it is more effective when combined with lower limb RT (8). It has previously been reported that improved balance is not necessarily associated with reduced incidence of falls (2). It should be noted, however, that the fear of falling, not just decreased balance, is a risk factor for falls (1). Successful functional training should not only improve ADL performance but also instill confidence. By improving confidence through exercise, it may be possible to reduce the fear of falls.
PD is a complex disease that can compromise physical performance. Additionally, depending on the symptom severity, PD can present many obstacles to traditional exercise programming. By understanding the disease process and appropriate exercise interventions, the EP is able to design safe, effective exercise programs and play an important role in improving exercise performance and physical functioning of the client.
1. Adkin A, Frank JS, Jog MS. Fear of falling and postural control in Parkinson's disease. Mov Disord 18: 496–502, 2003.
2. Allen N, Sherrington C, Paul SS, Canning CG. Balance and falls in Parkinson's disease: A meta-analysis of the effect of exercise and motor training. Mov Disord 26: 1605–1615, 2011.
3. Bergen J, Toole T, Elliott RG, Wallace B, Robinson K, Maitland CG. Aerobic exercise intervention improves aerobic capacity and movement initiation in Parkinson's disease patients. NeuroRehabilitation 17: 161–168, 2002.
4. Bottaro M, Machado SN, Nogueira W, Scales R, Veloso J. Effect of high versus low-velocity resistance training on muscular fitness and functional performance in older men. Eur J Appl Physiol 99: 257–264, 2007.
5. Cakit B, Saracoglu M, Genc H, Erdem HR. The effects of incremental speed-dependent treadmill training on postural instability and fear of falling in Parkinson's disease. Clin Rehabil 21: 698–705, 2007.
6. Ellis T, de Goede CJ, Feldman RG, Wolter EC, Kwakkel G, Wagenaar RC. Efficacy of a physical therapy program in patients with Parkinson's disease: A randomized controlled trial. Arch Phys Med Rehabil 86: 626–632, 2005.
7. Goodwin V, Richards SH, Taylor RS, Taylor AH, Campbell JL. The effectiveness of exercise interventions for people with Parkinson's disease: A systematic review and meta-analysis. Mov Disord 23: 631–640, 2008.
8. Hirsch M, Toole T, Maitland CG, Rider RA. The effects of balance training and high-intensity resistance training on persons with idiopathic Parkinson's disease. Arch Phys Med Rehabil 84: 1109–1117, 2003.
9. Hoehn MM, Yahr MD. Parkinsonism: Onset, progression, and mortality. Neurology 17: 427–442, 1967.
10. Jankovic J. Parkinson's disease: Clinical features and diagnosis. J Neurol Neurosurg Psychiatry 79: 368–376, 2008.
11. Keus S, Bloem BR, Hendriks EJM, Bredero-Cohen AB, Munneke M. Evidence-based analysis of physical therapy in Parkinson's disease with recommendations for practice and research. Mov Disord 22: 451–460, 2007.
12. Lees A, Hardy J, Revesz T. Parkinson's disease. Lancet 373: 2055–2066, 2009.
13. Martinez-Martin P, Gil-Nagel A, Gracia M, Gomez JB, Martinez-Sarries J, Bermejo F. Unified Parkinson's disease rating scale characteristics and structure. Mov Disord 9: 76–83, 1994.
14. Nogaki H, Kakinuma S, Morimatsu M. Movement velocity dependent muscle strength in Parkinson's disease. Acta Neurol Scand 99: 152–157, 1999.
15. Podsiadlo D, Richardson S. The timed “Up & Go”: A test of basic functional mobility for frail elderly persons. J Am Geriatr Soc 39: 142–148, 1991.
16. Protas E, Mitchell K, Williams A, Qureshy H, Caroline K, Lai EC. Gait and step training to reduce falls in Parkinson's disease. NeuroRehabilitation 20: 183–190, 2005.
17. Protas EJ, Stanley RK. Parkinson's disease. In: ACSM's Resources for Clinical Exercise Physiology: Musculoskeletal, Neuromuscular, Neoplastic, Immunologic, and Hematologic Conditions. Frey G, ed. Baltimore, MD: Lippincott Williams and Wilkins, 2010, pp. 44–57.
18. Rose D, Jones CJ, Lucchese N. Predicting the probability of falls in community-residing older adults using the 8-foot up-and-go: A new measure of functional mobility. JAPA 10: 466–475, 2002.
19. Schenkman M, Cutson TM, Kuchihhatla M, Chandler J, Peiper CR, Ray L, Laub KC. Exercise to improve spinal flexibility and function for people with Parkinson's disease: A randomized, controlled trial. J Am Geriatr Soc 46: 1207–1216, 1998.
20. Silvester L, Stiggins C, McGowan C, Bryce GR. The effect of variable resistance and free-weight training programs on strength and vertical jump. J Strength Cond Res 3: 30–33, 1982.
© 2012 National Strength and Conditioning Association
21. Zhao Y, Wee HL, Chan Y, Seah SH, Au WL, Lau PN, Pica EC, Li SC, Luo N, Tan LCS. Progression of Parkinson's disease as evaluated by Hoehn and Yahr stage transition times. Mov Disord 25: 710–716, 2010.