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This material has been referenced before on the forums, but I had to go to the Way Back Machine to find the original version. Not all of it is relevant to PE, but a good deal is and there's some good information here regarding the application of heat in remodelling connective tissue. I thought it would be a good idea to post it here before it gets lost forever, and for easy reference.
Heat Application in Physiotherapy
Heat Application in Physiotherapy
Heat Application in Physiotherapy
Limitation of motion is a major area of concern in rehabilitation. Thus, one of the most relevant and important goals in Physiotherapy is the restoration of the client's full range of motion (ROM) in an attempt to maximize function. The shortening of connective tissue or the formation of new connective tissue often causes decreased motion. Superficial heat has been proven advantageous in the remodeling of connective tissue.
Connective tissue shortening or formation will result in several problematic conditions. Provided full ROM exercises are not performed following injury, connective tissue will gradually shorten with time and joint contractures will develop. In addition, adhesion formation, which is an abnormal adherence of collagen fibers to surrounding structures, restricts normal elasticity of the structures involved by preventing these structures form gliding past one another. Further limitations of mobility are due to formation of scar tissue from lacerations, burns and crush injuries.9
There are definite advantages to applying superficial heat to remodel connective tissue. Perhaps the most important is an increase in joint mobility. This is caused by three mechanisms. First, heat creates several physiologic changes through subsequent vascular changes, causing vasodilation. This dilation gives an analgesic effect which increases the client's pain threshold and results in greater tolerance of connective tissue stretching. Another physiologic effect of heat is an alteration of the viscous flow properties of collagen which results in the relief of joint stiffness.3 Lastly, there is an increase in the extensibility of collagen tissue, a major component of connective tissue, through changes in its viscoelastic properties following the application of heat. This is an important effect of heat due to the long-term remodelling of connective tissue.7,9
The main goal in the clinical treatment of adhesions, contractures, scar tissue or other connective tissue problems is the production of permanent collagenous tissue elongation. Numerous studies have concluded that the most effective means of attaining this result is through the combination of temperature elevation and the application of prolonged stretch thus altering the viscoelastic properties of connective tissue. 5,9,16 Collagen has viscous properties which allow a residual elongation after a load is applied then released. This phenomenon is known as plastic deformation. Furthermore, its elastic properties allow for recoverable deformation which is a return to its original length after stretch is applied then released. As mentioned above, elevated temperatures increase the extensibility of collagen. Therefore, when a load is applied to heated tissue then released, greater plastic deformation results (increased residual length) and thus permanent elongation of the connective tissue.9
Lehman and associates (1970) studied the effects of heat and stretching on rat tail tendons.6 The results indicated that heating alone produced no significant elongation and that stretching alone produced no residual elongation. Significant elongation occurred if heat and stretch were combined. A greater increase in length was maintained if the stretch was held during the period of cooling since “reorganization of the tissues is thought to occur during the cooling period.”6 Overall, the most effective method of producing a plastic deformation of connective tissue was to apply a sustained stretch during the application of heat and to maintain the stretch during the period of cooling.
Similar experiments using rat tail tendons have been conducted by Warren et al (1976) regarding permanent elongation of connective tissue at various temperatures.16 The data showed that the application of low force over a long duration was very effective in producing slow elongation in the viscous elements, resulting in increased residual elongation. Furthermore, elevating tissue temperature and maintaining it prior to applying force was found to cause significantly less tissue damage. Lastly, the lower loads applied at elevated temperatures for prolonged periods were found to produce significantly greater residual elongation.16 The clinical implications of this study are three fold: first, stretches used to increase ROM should be held for prolonged periods; second, warming tissue prior to ROM exercises will cause less tissue damage; and third, stretching should be accompanied with the highest possible therapeutic temperature for prolonged periods to most effectively increase joint mobility.
Although these therapeutic effects are beneficial, special consideration should be given to patients with rheumatoid arthritis. As Harris and McCroskery (1974) note, “excessive heat therapy harms joints by [increasing intrarticular temperature and thus] increasing the rate of collagen breakdown by specific collagenases.”1 It is for this reason that Oosterveld et al (1992, 1994) recommend that cold applications are most effective in the treatment of arthritis.10,11 They advise that if the patient nevertheless prefers heat, it should last no more than 5 to 10 minutes.10
It is evident that superficial heat is an effective modality that Physiotherapists can use in the remodelling of connective tissue. Studies have effectively shown that superficial heat therapy increases connective tissue elongation. Hence, its use is recommended to assist a patient maximize his or her mobility and functional capacity.
Reference List
1. Harris ED, McCroskery PA. The influence of temperature and fibril stability on degradation of cartilage collagen by rheumatoid synovial collagenase. The New England Journal of Medicine 1974 Jan 3; 290(1): 1-5.
2. Henley, Dr. E. Henley Health Company, Sugar Land, Texas. Personal interview. Oct 31, 1997.
3. Irrgang JJ, Delitto A, Hagen B, Huber F, Pezzullo D. Rehabilitation of the injured athlete. Orthopedic Clinics of North America 1995 July; 26(3): 561-77.
4. Kisner C, Colby LA. Therapeutic Exercise. Philadelphia: F.A. Davis Company, 1996.
5. Lehmann JF, DeLateur BJ. Therapeutic heat. In: Lehmann JF, editor. Therapeutic heat and cold. 4th rev. ed. Baltimore: Williams and Wilkons, 1990: 417-59.
6. Lehmann JF, Masock AJ, Warren CG, Koblanski JN. Effect of therapeutic temperatures on tendon extensibility. Archives of Physical Medicine & Rehabilitation 1970 Aug; 51(8): 481-7.
7. Low J, Reed A. Electrotherapy Explained: Principles and Practice. London: Butterworth-Heinemann Ltd., 1990.
8. McClure PW, Flowers KR. Treatment of limited shoulder motion: a case study based on biomechanical considerations. Physiotherapy 1992 Dec; 72(12): 929-36.
9. Michlovitz SL. Thermal Agents In Rehabilitation. 3rd rev. ed. Philadelphia: F.A. Davis Company, 1996.
10. Oosterveld FG, Rasker JJ. Treating arthritis with locally applied heat or cold. Seminars in Arthritis and Rheumatism 1994 Oct; 24(2): 82-90.
11. Oosterveld FG, Rasker JJ, Jacobs JW, Overmars HJ. The effect of local heat and cold therapy on the intraarticular and skin surface temperature of the knee. Seminars in Arthritis and Rheumatism 1992 Feb; 35(2): 146-51.
12. Rivenburgh DW. Physical modalities in the treatment of tendon injuries. Clinics in Sports Medicine 1992 July; 11(3): 645-51.
13. Strickler T, Malone T, Garrett WE. The effects of passive warming on muscle injury. The American Journal of Sports Medicine 1990 Mar-Apr; 18(2): 141-5.
14. Taylor BF, Waring CA, Brasher TA. The effects of therapeutic heat or cold followed by static stretch on hamstring muscle length. Journal of Orthopedics & Sports Physiotherapy 1995 May; 21(5): 283-6.
15. Taylor LP. Taylor’s Manual of Physical Evaluation and Treatment: Volume II. Thorofare: SLACK Incorporated, 1990.
16. Warren CG, Lehmann JF, Koblanski JN. Heat and stretch procedures: an evaluation using rat tail tendon. Archives of Physical Medicine & Rehabilitation 1976 March; 57(3): 122-6.
Limitation of motion is a major area of concern in rehabilitation. Thus, one of the most relevant and important goals in Physiotherapy is the restoration of the client's full range of motion (ROM) in an attempt to maximize function. The shortening of connective tissue or the formation of new connective tissue often causes decreased motion. Superficial heat has been proven advantageous in the remodeling of connective tissue.
Connective tissue shortening or formation will result in several problematic conditions. Provided full ROM exercises are not performed following injury, connective tissue will gradually shorten with time and joint contractures will develop. In addition, adhesion formation, which is an abnormal adherence of collagen fibers to surrounding structures, restricts normal elasticity of the structures involved by preventing these structures form gliding past one another. Further limitations of mobility are due to formation of scar tissue from lacerations, burns and crush injuries.9
There are definite advantages to applying superficial heat to remodel connective tissue. Perhaps the most important is an increase in joint mobility. This is caused by three mechanisms. First, heat creates several physiologic changes through subsequent vascular changes, causing vasodilation. This dilation gives an analgesic effect which increases the client's pain threshold and results in greater tolerance of connective tissue stretching. Another physiologic effect of heat is an alteration of the viscous flow properties of collagen which results in the relief of joint stiffness.3 Lastly, there is an increase in the extensibility of collagen tissue, a major component of connective tissue, through changes in its viscoelastic properties following the application of heat. This is an important effect of heat due to the long-term remodelling of connective tissue.7,9
The main goal in the clinical treatment of adhesions, contractures, scar tissue or other connective tissue problems is the production of permanent collagenous tissue elongation. Numerous studies have concluded that the most effective means of attaining this result is through the combination of temperature elevation and the application of prolonged stretch thus altering the viscoelastic properties of connective tissue. 5,9,16 Collagen has viscous properties which allow a residual elongation after a load is applied then released. This phenomenon is known as plastic deformation. Furthermore, its elastic properties allow for recoverable deformation which is a return to its original length after stretch is applied then released. As mentioned above, elevated temperatures increase the extensibility of collagen. Therefore, when a load is applied to heated tissue then released, greater plastic deformation results (increased residual length) and thus permanent elongation of the connective tissue.9
Lehman and associates (1970) studied the effects of heat and stretching on rat tail tendons.6 The results indicated that heating alone produced no significant elongation and that stretching alone produced no residual elongation. Significant elongation occurred if heat and stretch were combined. A greater increase in length was maintained if the stretch was held during the period of cooling since “reorganization of the tissues is thought to occur during the cooling period.”6 Overall, the most effective method of producing a plastic deformation of connective tissue was to apply a sustained stretch during the application of heat and to maintain the stretch during the period of cooling.
Similar experiments using rat tail tendons have been conducted by Warren et al (1976) regarding permanent elongation of connective tissue at various temperatures.16 The data showed that the application of low force over a long duration was very effective in producing slow elongation in the viscous elements, resulting in increased residual elongation. Furthermore, elevating tissue temperature and maintaining it prior to applying force was found to cause significantly less tissue damage. Lastly, the lower loads applied at elevated temperatures for prolonged periods were found to produce significantly greater residual elongation.16 The clinical implications of this study are three fold: first, stretches used to increase ROM should be held for prolonged periods; second, warming tissue prior to ROM exercises will cause less tissue damage; and third, stretching should be accompanied with the highest possible therapeutic temperature for prolonged periods to most effectively increase joint mobility.
Although these therapeutic effects are beneficial, special consideration should be given to patients with rheumatoid arthritis. As Harris and McCroskery (1974) note, “excessive heat therapy harms joints by [increasing intrarticular temperature and thus] increasing the rate of collagen breakdown by specific collagenases.”1 It is for this reason that Oosterveld et al (1992, 1994) recommend that cold applications are most effective in the treatment of arthritis.10,11 They advise that if the patient nevertheless prefers heat, it should last no more than 5 to 10 minutes.10
It is evident that superficial heat is an effective modality that Physiotherapists can use in the remodelling of connective tissue. Studies have effectively shown that superficial heat therapy increases connective tissue elongation. Hence, its use is recommended to assist a patient maximize his or her mobility and functional capacity.
Reference List
1. Harris ED, McCroskery PA. The influence of temperature and fibril stability on degradation of cartilage collagen by rheumatoid synovial collagenase. The New England Journal of Medicine 1974 Jan 3; 290(1): 1-5.
2. Henley, Dr. E. Henley Health Company, Sugar Land, Texas. Personal interview. Oct 31, 1997.
3. Irrgang JJ, Delitto A, Hagen B, Huber F, Pezzullo D. Rehabilitation of the injured athlete. Orthopedic Clinics of North America 1995 July; 26(3): 561-77.
4. Kisner C, Colby LA. Therapeutic Exercise. Philadelphia: F.A. Davis Company, 1996.
5. Lehmann JF, DeLateur BJ. Therapeutic heat. In: Lehmann JF, editor. Therapeutic heat and cold. 4th rev. ed. Baltimore: Williams and Wilkons, 1990: 417-59.
6. Lehmann JF, Masock AJ, Warren CG, Koblanski JN. Effect of therapeutic temperatures on tendon extensibility. Archives of Physical Medicine & Rehabilitation 1970 Aug; 51(8): 481-7.
7. Low J, Reed A. Electrotherapy Explained: Principles and Practice. London: Butterworth-Heinemann Ltd., 1990.
8. McClure PW, Flowers KR. Treatment of limited shoulder motion: a case study based on biomechanical considerations. Physiotherapy 1992 Dec; 72(12): 929-36.
9. Michlovitz SL. Thermal Agents In Rehabilitation. 3rd rev. ed. Philadelphia: F.A. Davis Company, 1996.
10. Oosterveld FG, Rasker JJ. Treating arthritis with locally applied heat or cold. Seminars in Arthritis and Rheumatism 1994 Oct; 24(2): 82-90.
11. Oosterveld FG, Rasker JJ, Jacobs JW, Overmars HJ. The effect of local heat and cold therapy on the intraarticular and skin surface temperature of the knee. Seminars in Arthritis and Rheumatism 1992 Feb; 35(2): 146-51.
12. Rivenburgh DW. Physical modalities in the treatment of tendon injuries. Clinics in Sports Medicine 1992 July; 11(3): 645-51.
13. Strickler T, Malone T, Garrett WE. The effects of passive warming on muscle injury. The American Journal of Sports Medicine 1990 Mar-Apr; 18(2): 141-5.
14. Taylor BF, Waring CA, Brasher TA. The effects of therapeutic heat or cold followed by static stretch on hamstring muscle length. Journal of Orthopedics & Sports Physiotherapy 1995 May; 21(5): 283-6.
15. Taylor LP. Taylor’s Manual of Physical Evaluation and Treatment: Volume II. Thorofare: SLACK Incorporated, 1990.
16. Warren CG, Lehmann JF, Koblanski JN. Heat and stretch procedures: an evaluation using rat tail tendon. Archives of Physical Medicine & Rehabilitation 1976 March; 57(3): 122-6.
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