- Email: [email protected]
Exercise Following Burn Injury
E x e rci s e F o l l o w i n g Burn Injury Barbara J. de Lateur,
MD, MS
a
, Wendy S. Shore,
PhD
b,
*
KEYWORDS Burn injury Exercise Rehabilitation
A major barrier to return to work and full community reintegration for burned individuals is fatigue, a highly prevalent symptom. In an effort to determine the origin of this fatigue, a study of outcomes, in various domains, was conducted at Harborview Medical Center in Seattle on more than 100 survivors of major burns who had been hospitalized for 1 day or more (average length of stay 15 days) and age- and sexmatched, unburned controls. Data were collected that measured the strength and the relative endurance ratio of individual muscles, such as the quadriceps. (The relative endurance ratio is the ratio of the value of peak torque in the last of a series of contractions to the value of peak torque in the first contraction. Since the units of measure cancel out in this ratio, the result is a unit-free number.) Somewhat surprisingly, this ratio (approximately 0.7) was the same, on average, in the burned subjects as in the age- and sex-matched controls. The difference was in the strength of the subjects with burns, who were much weaker than the controls. This weakness applied to all muscles tested, regardless of whether there was a burn in the region of the given muscle or not; however, a burn in the region was associated with greater weakness. The strength of subjects with burns approached, as a limit, the strength of the controls, only at 2 years postburn.1 The common complaint of fatigue most likely resulted from the muscular weakness, which caused the subjects to operate at a higher percent maximal effort, even for their usual activities. Another, more recent, study found that patients with severe burns (>30% total body surface area) had weaker muscles even years (15–92 months) after the burn injury, suggesting either inability to fully recover muscle strength or insufficient rehabilitation. Interestingly, patients with less than 30% total body surface area showed no difference compared with controls.2 In an ongoing study of the effects of an augmented exercise program by de Lateur and colleagues3 (plus as-yet unpublished observations), some postburn subjects,
The authors have nothing to disclose. a Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institutions, AA Building, Room 1654, 4940 Eastern Avenue, Baltimore, MD 21224-2780, USA b Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institutions, 92 North Broadway, Suite 413, Baltimore, MD 21239, USA * Corresponding author. E-mail address: [email protected] Phys Med Rehabil Clin N Am 22 (2011) 347–350 doi:10.1016/j.pmr.2011.02.003 1047-9651/11/$ – see front matter Ó 2011 Elsevier Inc. All rights reserved.
pmr.theclinics.com
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de Lateur & Shore
independently ambulatory and able to walk on a treadmill, have very low baseline maximal aerobic capacities. In some of these, the values are so low (approximately 11 mL/kg/min) that if they were frail elderly subjects, they would be classified as fitting into a group considered to be unable to live independently in the community (the burned subjects were younger and were, in fact, living independently). Muscle wasting (catabolism) and hypermetabolism are prevalent in adult4 and pediatric5 burn survivors. In a study of severely burned children, hypermetabolism and catabolism remain elevated for at least 9 months after injury. The work of Alloju and colleagues6 has shown that severely burned children, compared with nonburned children, had significantly lower lean body mass and lower peak torque, as well as total work performance at 6 months post burn. These investigators, and Pereira and colleagues,5 comment on the hypermetabolic response to thermal injury and its marked catabolic effect. It is likely that this hypermetabolic response and its catabolism is the cause of muscle weakness. THE NATURAL COURSE
The studies cited above indicate that a slow return to normal or near-normal muscle strength (at 2 years postburn) is the natural course of recovery. With no special interventions, other than the “usual care” tailored to the needs of the individual, postburn patients will make gradual improvement in strength1 and aerobic capacity3; although, in the latter case, the improvement may not reach statistical significance. This is in marked contrast to the intervention group (usual care plus an augmented 12-week exercise program), which had a robust improvement in aerobic capacity. HOW SHOULD ONE DEVELOP A PROGRAM FOR PATIENTS AFTER A BURN INJURY?
Hart and colleagues7 have suggested that because there is substantial evidence that catabolic and metabolic responses to severe burn injuries linger many months after the injury, therapeutic attempts to address the catabolic and hypermetabolic response to severe injury should also be continued long after injury. There is little question that burn patients cannot only tolerate activity, they greatly benefit from it.8–10 In the initial phase, when the patient is in a catabolic state, the targeted physical and occupational therapies, with a gentle aerobic program, may be as much as the patient can tolerate. This rest of this article is devoted to exercise interventions for the patient well enough to be discharged to the community. SPECIFICITY VERSUS GENERALIZABILITY: THE PRINCIPLE OF INITIAL CONDITION
The principle of initial condition asserts that the worse the initial condition (barring a neuropathy or flexion contractures), the greater the response to exercise intervention and the more the response can be generalized. For example, in a study of frail elders, exercise on a treadmill, an aerobic intervention, resulted in increased strength.3,11 Likewise, one could predict up to 49% of the variance of treadmill performance by the relative strength (strength-to-weight-to-height ratio) of certain lower-body muscles. This seems counterintuitive because the aerobic and strength systems are so different. It is commonly understood that one should train for the specific task, such as resistance training for weight lifting and running sprints for track competitions. Indeed, in highly trained athletes, it is important to train on the performance task. However, in postburn patients, the principle of initial condition works in the patient’s favor and permits a number of options for exercise interventions, determined by patient preference and equipment availability. The therapist or trainer can be confident
Exercise Following Burn Injury
of increased strength, as well as aerobic performance, in response to treadmill or stationary bicycle exercise. HOW DOES ONE GO ABOUT IT?
There are many standard programs available, such as the DeLorme12 or the Oxford13 progressive resistive exercise programs. However, to avoid injury, or even an unpleasant experience, which might prompt the patient to discontinue the program, the authors suggest a very gradually progressive program, determined by the performance in a baseline work-to-tolerance period. An example is a very deconditioned person, with little or no recent experience with a regular exercise program and no equipment. This person could be asked to keep a record of minutes walked, for the sake of walking each day for 10 days. At the end of those 10 days, an average number of minutes walked would be found, being sure to include any zero-minute days. Ten percent of that average could be subtracted, and the resultant number would provide the quota for the daily minutes to be walked for the first week. Each week another minute would be added to the daily quota. Thus, if the baseline average was 10 minutes, the quota for the first week would be a daily walk of 9 minutes, the second week 10 minutes, the third 11 minutes, and so forth. The patient should keep a daily record, so that the person (physician, therapist, trainer) following him or her can check this. From a behavioral point of view, the physician (therapist, trainer) should show a high degree of enthusiasm and praise for the patient following this quota faithfully. The walking can be capped off at 30 minutes, as long as it is done every day, without fail, just as one would ordinarily not skip the daily shower. HOW LONG?
The typical exercise study is performed for 12 weeks (or, in some cases, 10 weeks). This is not a biological number. Rather, it is most often a period of convenience, such as the length of an academic quarter or semester, because many of the early exercise studies were performed on college students. This length of time is unlikely to be sufficient in the gradually progressive walking program for an extremely deconditioned subject, such as the example given above, and it should be extended beyond 12 weeks. If the subject’s initial condition permitted a vigorous progressive resistive exercise program, such as the DeLorme or Oxford techniques, three or four times a week, it should be sufficient. After the rehabilitation period, The American College of Sports Medicine’s guidelines indicate that shifting to a twice-a-week weight-training program is sufficient for maintenance. In addition, moderate aerobic activity should be continued at least 5 days a week.14 HOW FIT? FIT FOR WHAT?
The word “fit” itself implies fit for something. In this case, if the patient can resume his or her usual activities, including bathing, dressing, household duties, work, recreation, and travel, then she or he can be considered to have a baseline level of fitness. It is important to note, however, that if no more activity than performance of activities of daily living is the norm, the individual will gradually lose both muscle mass and aerobic endurance, eventually ending up back in the “frail” category. The minimal activity recommendations from the American College of Sports Medicine, given above, are necessary for long-term ability to function independently. If the patient wishes to go beyond those guidelines, then more vigorous weight training of individual muscles,
349
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de Lateur & Shore
as well as treadmill, elliptical, and other aerobic practices should be employed, just as in the case of persons never burned. SOME PRECAUTIONS
Care should be taken in the case of impaired sensation (as in nerve entrapment) or grafted areas underneath shoes. The patient should be taught to inspect his or her skin after each exercise session and adjust the type or the duration of the exercise accordingly. As mentioned above, the generalizability of early exercise in very deconditioned patients permits options that avoid skin injury. REFERENCES
1. de Lateur BJ, Giaconi RM, Alquist AD. Fatigue and performance: data from normal adults, and from patients with neuromuscular and musculoskeletal syndromes; response to training. Proceedings AAEE Diagnostic Program, Thirty-fifth Annual Meeting; 1988. 2. St-Pierre DM, Choiniere M, Forget R, et al. Muscle strength in individuals with healed burns. Arch Phys Med Rehabil 1998;79(2):155–61. 3. de Lateur BJ, Magyar-Russell G, Bresnick MG, et al. Augmented exercise in the treatment of deconditioning from major burn injury. Arch Phys Med Rehabil 2007; 88(12 Suppl 2):S18–23. 4. Hasselgren PO. Burns and metabolism. J Am Coll Surg 1999;188(2):98–103. 5. Pereira C, Murphy K, Jeschke M, et al. Post burn muscle wasting and the effects of treatments. Int J Biochem Cell Biol 2005;37(10):1948–61. 6. Alloju SM, Herndon DN, McEntire SJ, et al. Assessment of muscle function in severely burned children. Burns 2008;34(4):452–9. 7. Hart DW, Wolf SE, Mlcak R, et al. Persistence of muscle catabolism after severe burn. Surgery 2000;128(2):312–9. 8. McEntire SJ, Herndon DN, Sanford AP, et al. Thermoregulation during exercise in severely burned children. Pediatr Rehabil 2006;9(1):57–64. 9. Suman OE, Mlcak RP, Herndon DN. Effect of exercise training on pulmonary function in children with thermal injury. J Burn Care Rehabil 2002;23(4):288–93 [discussion: 287]. 10. Whitney JD, Parkman S. The effect of early postoperative physical activity on tissue oxygen and wound healing. Biol Res Nurs 2004;6(2):79–89. 11. Buchner DM, Cress ME, Wagner EH, et al. The Seattle FICSIT/MoveIt study: the effect of exercise on gait and balance in older adults. J Am Geriatr Soc 1993; 41(3):321–5. 12. DeLorme TL, Watkins AL. Techniques of progressive resistance exercise. Arch Phys Med Rehabil 1948;29(5):263–73. 13. Zinovieff AN. Heavy-resistance exercises the “Oxford Technique”. Br J Phys Med 1951;14(6):129–32. 14. Haskell WL, Lee IM, Pate RR, et al. Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc 2007;39(8):1423–34.
MD, MS
a
, Wendy S. Shore,
PhD
b,
*
KEYWORDS Burn injury Exercise Rehabilitation
A major barrier to return to work and full community reintegration for burned individuals is fatigue, a highly prevalent symptom. In an effort to determine the origin of this fatigue, a study of outcomes, in various domains, was conducted at Harborview Medical Center in Seattle on more than 100 survivors of major burns who had been hospitalized for 1 day or more (average length of stay 15 days) and age- and sexmatched, unburned controls. Data were collected that measured the strength and the relative endurance ratio of individual muscles, such as the quadriceps. (The relative endurance ratio is the ratio of the value of peak torque in the last of a series of contractions to the value of peak torque in the first contraction. Since the units of measure cancel out in this ratio, the result is a unit-free number.) Somewhat surprisingly, this ratio (approximately 0.7) was the same, on average, in the burned subjects as in the age- and sex-matched controls. The difference was in the strength of the subjects with burns, who were much weaker than the controls. This weakness applied to all muscles tested, regardless of whether there was a burn in the region of the given muscle or not; however, a burn in the region was associated with greater weakness. The strength of subjects with burns approached, as a limit, the strength of the controls, only at 2 years postburn.1 The common complaint of fatigue most likely resulted from the muscular weakness, which caused the subjects to operate at a higher percent maximal effort, even for their usual activities. Another, more recent, study found that patients with severe burns (>30% total body surface area) had weaker muscles even years (15–92 months) after the burn injury, suggesting either inability to fully recover muscle strength or insufficient rehabilitation. Interestingly, patients with less than 30% total body surface area showed no difference compared with controls.2 In an ongoing study of the effects of an augmented exercise program by de Lateur and colleagues3 (plus as-yet unpublished observations), some postburn subjects,
The authors have nothing to disclose. a Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institutions, AA Building, Room 1654, 4940 Eastern Avenue, Baltimore, MD 21224-2780, USA b Department of Physical Medicine and Rehabilitation, Johns Hopkins Medical Institutions, 92 North Broadway, Suite 413, Baltimore, MD 21239, USA * Corresponding author. E-mail address: [email protected] Phys Med Rehabil Clin N Am 22 (2011) 347–350 doi:10.1016/j.pmr.2011.02.003 1047-9651/11/$ – see front matter Ó 2011 Elsevier Inc. All rights reserved.
pmr.theclinics.com
348
de Lateur & Shore
independently ambulatory and able to walk on a treadmill, have very low baseline maximal aerobic capacities. In some of these, the values are so low (approximately 11 mL/kg/min) that if they were frail elderly subjects, they would be classified as fitting into a group considered to be unable to live independently in the community (the burned subjects were younger and were, in fact, living independently). Muscle wasting (catabolism) and hypermetabolism are prevalent in adult4 and pediatric5 burn survivors. In a study of severely burned children, hypermetabolism and catabolism remain elevated for at least 9 months after injury. The work of Alloju and colleagues6 has shown that severely burned children, compared with nonburned children, had significantly lower lean body mass and lower peak torque, as well as total work performance at 6 months post burn. These investigators, and Pereira and colleagues,5 comment on the hypermetabolic response to thermal injury and its marked catabolic effect. It is likely that this hypermetabolic response and its catabolism is the cause of muscle weakness. THE NATURAL COURSE
The studies cited above indicate that a slow return to normal or near-normal muscle strength (at 2 years postburn) is the natural course of recovery. With no special interventions, other than the “usual care” tailored to the needs of the individual, postburn patients will make gradual improvement in strength1 and aerobic capacity3; although, in the latter case, the improvement may not reach statistical significance. This is in marked contrast to the intervention group (usual care plus an augmented 12-week exercise program), which had a robust improvement in aerobic capacity. HOW SHOULD ONE DEVELOP A PROGRAM FOR PATIENTS AFTER A BURN INJURY?
Hart and colleagues7 have suggested that because there is substantial evidence that catabolic and metabolic responses to severe burn injuries linger many months after the injury, therapeutic attempts to address the catabolic and hypermetabolic response to severe injury should also be continued long after injury. There is little question that burn patients cannot only tolerate activity, they greatly benefit from it.8–10 In the initial phase, when the patient is in a catabolic state, the targeted physical and occupational therapies, with a gentle aerobic program, may be as much as the patient can tolerate. This rest of this article is devoted to exercise interventions for the patient well enough to be discharged to the community. SPECIFICITY VERSUS GENERALIZABILITY: THE PRINCIPLE OF INITIAL CONDITION
The principle of initial condition asserts that the worse the initial condition (barring a neuropathy or flexion contractures), the greater the response to exercise intervention and the more the response can be generalized. For example, in a study of frail elders, exercise on a treadmill, an aerobic intervention, resulted in increased strength.3,11 Likewise, one could predict up to 49% of the variance of treadmill performance by the relative strength (strength-to-weight-to-height ratio) of certain lower-body muscles. This seems counterintuitive because the aerobic and strength systems are so different. It is commonly understood that one should train for the specific task, such as resistance training for weight lifting and running sprints for track competitions. Indeed, in highly trained athletes, it is important to train on the performance task. However, in postburn patients, the principle of initial condition works in the patient’s favor and permits a number of options for exercise interventions, determined by patient preference and equipment availability. The therapist or trainer can be confident
Exercise Following Burn Injury
of increased strength, as well as aerobic performance, in response to treadmill or stationary bicycle exercise. HOW DOES ONE GO ABOUT IT?
There are many standard programs available, such as the DeLorme12 or the Oxford13 progressive resistive exercise programs. However, to avoid injury, or even an unpleasant experience, which might prompt the patient to discontinue the program, the authors suggest a very gradually progressive program, determined by the performance in a baseline work-to-tolerance period. An example is a very deconditioned person, with little or no recent experience with a regular exercise program and no equipment. This person could be asked to keep a record of minutes walked, for the sake of walking each day for 10 days. At the end of those 10 days, an average number of minutes walked would be found, being sure to include any zero-minute days. Ten percent of that average could be subtracted, and the resultant number would provide the quota for the daily minutes to be walked for the first week. Each week another minute would be added to the daily quota. Thus, if the baseline average was 10 minutes, the quota for the first week would be a daily walk of 9 minutes, the second week 10 minutes, the third 11 minutes, and so forth. The patient should keep a daily record, so that the person (physician, therapist, trainer) following him or her can check this. From a behavioral point of view, the physician (therapist, trainer) should show a high degree of enthusiasm and praise for the patient following this quota faithfully. The walking can be capped off at 30 minutes, as long as it is done every day, without fail, just as one would ordinarily not skip the daily shower. HOW LONG?
The typical exercise study is performed for 12 weeks (or, in some cases, 10 weeks). This is not a biological number. Rather, it is most often a period of convenience, such as the length of an academic quarter or semester, because many of the early exercise studies were performed on college students. This length of time is unlikely to be sufficient in the gradually progressive walking program for an extremely deconditioned subject, such as the example given above, and it should be extended beyond 12 weeks. If the subject’s initial condition permitted a vigorous progressive resistive exercise program, such as the DeLorme or Oxford techniques, three or four times a week, it should be sufficient. After the rehabilitation period, The American College of Sports Medicine’s guidelines indicate that shifting to a twice-a-week weight-training program is sufficient for maintenance. In addition, moderate aerobic activity should be continued at least 5 days a week.14 HOW FIT? FIT FOR WHAT?
The word “fit” itself implies fit for something. In this case, if the patient can resume his or her usual activities, including bathing, dressing, household duties, work, recreation, and travel, then she or he can be considered to have a baseline level of fitness. It is important to note, however, that if no more activity than performance of activities of daily living is the norm, the individual will gradually lose both muscle mass and aerobic endurance, eventually ending up back in the “frail” category. The minimal activity recommendations from the American College of Sports Medicine, given above, are necessary for long-term ability to function independently. If the patient wishes to go beyond those guidelines, then more vigorous weight training of individual muscles,
349
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de Lateur & Shore
as well as treadmill, elliptical, and other aerobic practices should be employed, just as in the case of persons never burned. SOME PRECAUTIONS
Care should be taken in the case of impaired sensation (as in nerve entrapment) or grafted areas underneath shoes. The patient should be taught to inspect his or her skin after each exercise session and adjust the type or the duration of the exercise accordingly. As mentioned above, the generalizability of early exercise in very deconditioned patients permits options that avoid skin injury. REFERENCES
1. de Lateur BJ, Giaconi RM, Alquist AD. Fatigue and performance: data from normal adults, and from patients with neuromuscular and musculoskeletal syndromes; response to training. Proceedings AAEE Diagnostic Program, Thirty-fifth Annual Meeting; 1988. 2. St-Pierre DM, Choiniere M, Forget R, et al. Muscle strength in individuals with healed burns. Arch Phys Med Rehabil 1998;79(2):155–61. 3. de Lateur BJ, Magyar-Russell G, Bresnick MG, et al. Augmented exercise in the treatment of deconditioning from major burn injury. Arch Phys Med Rehabil 2007; 88(12 Suppl 2):S18–23. 4. Hasselgren PO. Burns and metabolism. J Am Coll Surg 1999;188(2):98–103. 5. Pereira C, Murphy K, Jeschke M, et al. Post burn muscle wasting and the effects of treatments. Int J Biochem Cell Biol 2005;37(10):1948–61. 6. Alloju SM, Herndon DN, McEntire SJ, et al. Assessment of muscle function in severely burned children. Burns 2008;34(4):452–9. 7. Hart DW, Wolf SE, Mlcak R, et al. Persistence of muscle catabolism after severe burn. Surgery 2000;128(2):312–9. 8. McEntire SJ, Herndon DN, Sanford AP, et al. Thermoregulation during exercise in severely burned children. Pediatr Rehabil 2006;9(1):57–64. 9. Suman OE, Mlcak RP, Herndon DN. Effect of exercise training on pulmonary function in children with thermal injury. J Burn Care Rehabil 2002;23(4):288–93 [discussion: 287]. 10. Whitney JD, Parkman S. The effect of early postoperative physical activity on tissue oxygen and wound healing. Biol Res Nurs 2004;6(2):79–89. 11. Buchner DM, Cress ME, Wagner EH, et al. The Seattle FICSIT/MoveIt study: the effect of exercise on gait and balance in older adults. J Am Geriatr Soc 1993; 41(3):321–5. 12. DeLorme TL, Watkins AL. Techniques of progressive resistance exercise. Arch Phys Med Rehabil 1948;29(5):263–73. 13. Zinovieff AN. Heavy-resistance exercises the “Oxford Technique”. Br J Phys Med 1951;14(6):129–32. 14. Haskell WL, Lee IM, Pate RR, et al. Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc 2007;39(8):1423–34.