Low-Load Prolonged Stretch vs. High-Load Brief

Low-Load Prolonged Stretch vs. High-Load Brief
Stretch in Treating Knee Contractures
KATHYE E. LIGHT,
SHARON NUZIK,
WALTER PERSONIUS,
and AUBYN BARSTROM
This study was designed to compare the results of a traditional method of
stretching knee flexion contractures by high-load brief stretch (HLBS) with the
results of an experimental method of prolonged knee extension by skin traction,
low-load prolonged stretch (LLCS). End range of passive knee extension was
measured by standard goniometry. Subjects were 11 nonambulatory residents of
a nursing home who had demonstrated gradually progressive bilateral knee
contractures. Each subject served as his or her own control with one lower limb
receiving LLPS and the other limb receiving HLBS and passive range of motion
(PROM). Sequential medical trials were used as the clinical research design.
Whether comparing the LLPS limb PROM measurements pretreatment and posttreatment (p ≤ .05) or the HLBS to the LLPS limb PROM recordings posttreatment
(p ≤ .05), the results demonstrated a preference for LLPS in the treatment of
knee contractures in the immobile nursing home resident.
Key Words: Contracture, Knee, Physical therapy.
Many elderly individuals demonstrate limited movement
abilities; a frequent consequence is the development of knee
contractures. Despite the efforts of an active physical therapy
maintenance program at a county nursing home, including
daily range of motion (ROM) and passive stretching tech­
niques, these chronic knee contractures continued to be a
problem. This study was designed to compare a more tradi­
tional method of stretching knee contractures, high-load brief
stretch (HLBS), with an experimental method of prolonged
knee extension, low-load prolonged stretch (LLPS).
LITERATURE REVIEW
Experimental and clinical data suggest that the tissue
changes, which may cause restricted joint motion in the
bedridden elderly, are physiological1-3 or morphological4-9
and involve intra-articular,5 periarticular4, 6, 9 and extra-artic­
ular structures.7, 8
Neuromuscular dysfunction appears to be a common cause
of extra-articular physiological joint restriction. This physio­
Ms. Light is Assistant Professor, Physical Therapy Program, University of
Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San
Antonio, TX 78284 (USA).
Ms. Nuzik is Research Physical Therapist, Medical College of Virginia
Hospitals, Virginia Commonwealth University, Richmond, VA 23298.
Mr. Personius is Assistant Professor, Department of Physical Therapy,
School of Allied Health Professions, Medical College of Virginia, Virginia
Commonwealth University.
Ms. Barstrom is a graduate student in the Department of Physical Therapy,
School of Allied Health Professions, Medical College of Virginia, Virginia
Commonwealth University.
The results of this study were presented in poster format at the Annual
Conference of the American Physical Therapy Association, Anaheim, CA, June
19-23, 1982, and at the 1982 State Meeting of the Virginia Chapter of the
American Physical Therapy Association, Williamsburg, VA, where Ms. Nuzik
was awarded Best Clinical Research Paper.
This article was submitted February 2, 1983; was with the authors for
revision 25 weeks; and was accepted October 24, 1983.
330
logical restriction of muscle length may be a consequence of
spinal segment and supraspinal inputs on the gamma loop
gain set mechanism.10-12 The result is an alteration of extrafusal muscle fiber resting length. Therapeutic exercise tech­
niques have been hypothesized to affect this mechanism
directly. The therapeutic techniques of contract-relax2 and
proprioceptive neuromuscular facilitation (PNF),3 as well as
the application offluorimethanespray and stretch,1 have all
been shown to assist a rapid improvement of restricted jointrange excursion.
Gross anatomical, histological, and mechanical data impli­
cate abnormal intra-articular, periarticular, and extra-articu­
lar connective tissue structures as the cause of limited passive
ROM (PROM). These structures include intra-articular adhe­
sions,5 periarticular joint capsule stiffness,4,6,9 and shortened
extra-articular skeletal muscle.7, 8 After four weeks of immo­
bilization in a shortened position, cat soleus muscle demon­
strated a 40 percent decrease in the number of sarcomeres in
series7 and, therefore, a decrease in length of the parallel
elastic component.8 The decrease in cat soleus muscle length
resulted in a shift of its passive length-tension curve to the
left and a concomitant decrease in ankle ROM. After four
weeks release from immobilization (and normal activity by
the cats in their cages during the interim), muscle extensibility
and sarcomere number were restored to normal.7 In another
study, joints of monkeys immobilized in shortened positions
exhibited decreased ROM, decreased joint capsule length, and
loss of extensibility.6 Reduction of joint ROM and strength
of the medial posterior capsule was reported by Lavigne and
Watkins to be appreciable at 16 days and marked after 32
days of immobilization.6
The mechanism for immobilization-induced capsular re­
striction of ROM is not well understood and may be multi­
factorial. Histological studies of immobilized tissue have demPHYSICAL THERAPY
RESEARCH
onstrated capsular fibrofatty infiltrate,6 decreased matrix
water and glycosaminoglycans, increased major collagen
cross-links,4 and increased total amount of collagen.9
Warren et al used rat-tail tendons as an experimental model
for clinical stretching techniques.13 The rat-tail tendons were
used to compare two elongation methods similar to those
used in this study. Application of low-load, long-duration
tension at elevated temperatures, followed by cooling with
the load maintained, produced significantly greater residual
elongation with less tearing damage to the tissue than highload, short-duration tension at lower temperatures. The
present study included two of the four elements tested by
Warren et al: low-load and long-duration tension.
Existing literature supports LLPS as the preferred method
of lengthening immobilized, shortened tissues in animal
models. Because the very common clinical practice of stretching contractures with manual high loads for periods of a
minute or less was contradictory to findings in the literature,
this study sought to compare the PROM effects between the
clinical treatments of briefly applied manual high loads versus
prolonged low loads by skin traction. We hypothesized that if
chronic knee flexion contractures of at least 30 degrees in
nonambulatory geriatric nursing home subjects are treated
with LLPS instead of HLBS, then the passive knee extension
ROM will increase significantly.
METHOD
Subjects
Criteria for admission to this study were 1) the presence of
bilateral knee flexion contractures of at least three-months
duration and at least 30 degrees short of full passive extension
and 2) the inability to walk or pivot transfer without maximal
assistance. Eleven geriatric subjects who were nonambulatory
and who had demonstrated gradually progressive bilateral
chronic knee-flexion contractures ranging from 30 degrees to
132 degrees short of full passive end-range extension participated in this study. Subjects served as his or her own control
with one lower extremity receiving the LLPS and the other
receiving a traditional combination of both HLBS and
PROM. The choice of treatment for each limb was randomly
determined. Each treatment was performed twice daily, five
days a week for four weeks.
Procedures
The lower extremity not chosen to receive LLPS was treated
with a traditional regimen of 10 repetitions of passive lower
extremityflexion,adduction, and external rotation using PNF
diagonals that were followed by the HLBS. The HLBS procedure was considered to be a routine, forced, passive, manual-stretching technique. A maximum manual force was used
that did not cause injury. The muscles on stretch were palpably very tight. With the LLPS, this was not the case. The
patient's limb was moved manually at a force and velocity
that allowed the soft tissue structures to accommodate to the
change in ROM without resulting in excessive resistance, pain
on the part of the patient, or the possibility of injury. Once
the end range was achieved, this position was manually maintained for one minute. The force was then reduced for 15
seconds. The sequence of HLBS followed by a 15-second rest
was repeated three times each treatment session. The total
Volume 64/ Number 3, March 1984
Fig. 1. Modified Buck's skin traction apparatus applied to the lower
limb to provide LLPS.
treatment time required for the HLBS and PROM was approximately 15 minutes of patient-practitioner time.
Transmission of LLPS to the limb was accomplished by
applying a modified Buck's skin traction technique (Fig. 1)
with the patient in bed. A foam strip measuring 60 in by 3 in
by 1 in* was applied to the subject's lower extremity in a
stirrup-like fashion. The central portion of the foam strip was
placed at the subject's heel; its length extended alongside the
medial and lateral aspects of the limb. Taped to the center of
the foam and positioned at the subject's heel was a 3-in by 3in by 0.75-in padded wooden block. A screw eye extended
outward from the center of the block and served as an
attachment for the pulley rope. The foam strip and block
were secured to the limb by two or three 6-in ace bandages.
The rope was threaded through a single pulley and a weight
was attached to the end. Plastic milk cartons filled with sand
were used as weights. The length of each LLPS treatment was
one hour; the patient-practitioner setup time required only
two to five minutes. Each week the traction weight was
increased as follows: week one, 2.27 kg (5 lb); week two, 3.18
kg (7 lb); week three, 4.08 kg (9 lb); and week four, 5.44 kg
(121b).
In addition to the two methods of stretching described, each
subject received a standard upper extremity and trunk program of guided passive movements once daily. This program
included 10 repetitions of pelvis-on-trunk rotation and upper
extremity PNF diagonals bilaterally.
Standard manual goniometric measurements of the limbs
were taken before treatment began and after four weeks of
treatment. With the subject in the supine position, a physical
therapist moved one limb to its end range of knee extension
while also progressing toward maximal hip extension. This
end position was maintained for one minute. The kneeextension range was then measured by a second physical
therapist. The goniometer arms were aligned parallel to the
long axis of the femur and the tibia with the axis at midknee
joint. These two tasks were performed by the same individuals
throughout the experiment.
* One inch = 2.54 cm.
331
TEST # I: Increase in PROM of LLPS limb > 15°
ment (Fig. 2) or the increase in limb measurement of the
LLPS versus HLBS limbs posttreatment (Fig. 3), the results
demonstrated a preference (greater increase in PROM) for
LLPS in treatment of knee contractures of the immobile
nursing home resident. The Table offers a synopsis of the raw
data from this study.
DISCUSSION
A simple, noninvasive, nonstressful treatment is always
desirable, especially in an elderly group. In this sample, pa­
tients did not appear to experience pain while receiving LLPS
treatment. Trained physical therapy aides were instructed to
implement the exercise program and apply the traction ap­
paratus. Inconvenience to the nursing staff was minimal, and
the LLPS device did not impede primary care needs of the
patients, such as bathing and elimination.
Most of the subjects were characterized by a history of
progressive mental confusion, reduction of mobility, and
subsequent physical dependence. The use of traction as a
treatment for knee contractures in this patient group was
initiated long after the early physiological and possible mor­
phological effects of immobility had developed. The goals of
TEST# 2: PROM increase of LLPS limb at least 10° > PROM
Fig. 2. Sequential medical trials grid with a significance level of p ≤
.05 comparing pretreatment and posttreatment LLPS for Test 1
criterion. Statistical significance is established when the demarcation
lines are passed to the lower right or upper left of the grid.
increase of HLBS limb
Data Analysis
Sequential medical trials (SMT) were chosen to be the
method of experimental design and statistical analysis.14, 15
This sequential design was considered ideal because 1) sub­
jects could be admitted to the study as they became available,
2) comparisons could be made within the same subject, 3) no
statistical computations were necessary, and 4) the experiment
could be terminated as soon as statistical significance was
achieved (ie, a predetermined number of subjects was not
required).
The SMT plan was designed by Bross.14 Significance levels
were preestablished at the p ≤ .05 level. The outcome measure,
passive knee-extension end range, was assessed in two separate
test situations. Each test had its own criterion for improve­
ment: Test 1, difference between pretreatment and posttreat­
ment PROM recordings of the LLPS leg must be ≥15°; Test
2, difference in PROM posttreatment change between LLPS
and HLBS limbs must be ≥10°.
RESULTS
A total of 11 subjects participated in this study before a p
≤ .05 significance level was attained with SMT. The SMT
grids for Test 1 (Fig. 2) and Test 2 (Fig. 3) demonstrate how
quickly and directly the LLPS was found to be the superior
treatment. In Test 1, when comparing pretreatment and posttreatment knee extension of the LLPS limb, 10 of the 11
subjects demonstrated greater than a 15-degree increase in
PROM. When comparing the HLBS with the LLPS limb in
Test 2, a 10-degree PROM difference in favor of LLPS was
demonstrated in the same 10 subjects. Whether comparing
the LLPS limb measurements pretreatment and posttreat­
332
Fig. 3. Sequential medical trials grid with a significance level of p ≤
.05 comparing posttreatment results of LLPS with HLBS for Test 2
criterion.
this treatment approach were to 1) reduce contractures to aid
in ease of nursing care and 2) increase active movement
abilities, including standing transfers.
Changes in activities of daily living (ADL) were not objec­
tively measured in this study. None of these subjects, however,
became ambulatory, and all continued to require maximal
assistance in transferring. Considering the severity and dura­
tion of the contractures, as well as the general mental and
PHYSICAL THERAPY
RESEARCH
physical debilitation of these subjects, the reduction in con­
tractures was probably inadequate to affect functional level.
With another group, ADL changes might have been used as
a criterion for improvement. Future investigations could con­
sider the effects of LLPS for early treatment of contractures
in mentally alert hospitalized patients.
Individuals with severe joint restrictions, subjects 2 and 11
in the Table, demonstrate greater improvement with the LLPS
treatment than those subjects whose initial restrictions were
less dramatic. The number of subjects and study procedures
cannot confirm this observation, but it does raise the question
of whether contractures of different degrees of severity re­
spond better to different stretching procedures. Other possible
explanations may lie in the morphological and physiological
changes specific to a given disease process. Patients in this
study had a variety of diagnoses, as do most geriatric nursing
home residents.
We presumed that the effects obtained in this study were
the direct result of connective tissue lengthening. Alterations
in neurophysiological input, and consequently, the gamma
loop, may also have been a factor. Neurological changes occur
rapidly and accommodate quickly, and, therefore, were not
measured or focused on in this study.12 The results of this
study are in accordance with those of Warren et al who used
a rat-tail tendon model to study the effects of load on tissue
elongation.13 Low-load, long-duration tension produced
greater elongation of tissues than high-load, short-duration
tension. Temperature, a variable not considered in this exper­
iment with humans, was found by Warren et al to enhance
tissue elongation in rats.13
Sapega et al have published a treatment protocol designed
to increase ROM in the postreconstructed and immobilized
knee.16 Their protocol was based on principles evolved from
the results of in vitro, connective-tissue studies in animals,
including the study of Warren et al, and involved the use of
heat in addition to low-load, long-duration tension. Their
recommended treatment sequence is 1) heating of the short­
ened tissues, 2) applying the load while maintaining the
elevated tissue temperature, 3) maintaining both the load and
heat throughout the treatment period, 4) cooling the tissue
below the normal body temperature before the load is re­
moved, and 5) removing the load. No experimental data were
presented. Sapega et al did not incorporate a traction com­
ponent into their stretching technique.16 We believed joint
mechanics to be an important consideration. We attempted
to apply the load in line with the tibia, so as to distract the
knee, and reduce compressive forces that may be created by
lengthening of imbalanced shortened tissues. The results of
this study may partially reflect the difference in treatment
times between the two groups. A future study is planned to
compare results of light-load versus heavy-load, skin-traction
progression with equal treatment time for groups.
CONCLUSION
Chronic knee flexion contractures are a familiar clinical
problem to most physical therapists. This study was per­
formed to compare the results of two methods of treatment
(LLPS vs HLBS) in increasing the passive knee extension
ROM of knee flexion contractures in a group of elderly,
nonambulatory, nursing-home patients. The SMT design al­
lowed the obvious preference for LLPS to be attained at the
Volume 64/ Number 3, March 1984
TABLE
Passive Range of Motion Changes of Each Subject
Sub­
ject
No.
1
2
3
4
5
6
7
8
9
10
11
PROM
(° from 180°)
Rx
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
LLPS
HLBS
Pre Rx
Post Rx
- 50
- 75
-132
-113
- 95
-102
- 99
- 80
- 45
- 48
- 82
- 70
- 92
- 60
- 69
- 68
- 75
- 60
- 53
- 54
-112
-105
- 46
- 57
-102
- 99
- 80
- 97
- 70
- 67
- 27
- 40
- 64
- 67
- 57
- 56
- 50
- 74
- 58
- 70
- 20
- 36
- 80
-108
Post Rx
Change
Difference
Between
Between
PreRx
LLPS
and
and
Post Rx
HLBS
4
18
30
14
15
5
29
13
18
8
18
3
35
4
19
- 6
17
-10
33
18
32
3
-14
16
10
16
10
12
31
25
27
12
29
p ≤ .05 significance level after only 11 subjects were assessed.
The LLPS was found to be the more effective, acceptable,
nonstressful treatment to the patient over a four-week period.
REFERENCES
1. Halkovich LR, Personius WJ, Clamann HP, et al: Effect of fluorimethane
spray on passive hip flexion. Phys Ther 61:185-189,1981
2. Medeiros JM, Smidt GL, Burmeister LF, et al: Influence of isometric
exercise and passive stretch on hip joint motion. Phys Ther 57:518-523,
1977
3. Tanigawa MC: Comparison of the hold-relax procedure and passive mo­
bilization on increasing muscle length. Phys Ther 52:725-735,1972
4. Akeson W, Amiel D, Woo S: Immobility effects on synovial joints: The
pathomechanics of joint contracture. Biorheoiogy 17:95-110,1980
5. Enneking WF, Horowitz M: The intra-articular effects of immobilization on
the human knee. J Bone Joint Surg [Am] 54:973-985,1972
6. Lavigne AB, Watkins RP: Preliminary results on immobilization-induced
stiffness of monkey knee joints and posterior capsules. In Perspectives in
Biomedical Engineerings: Proceedings of a Symposium. Biological Engi­
neering Society, University of Strathyclyde, Glasgow, Scotland, Baltimore,
MD, University Park Press, 1972, pp 177-179
7. Tabary JC, Tabary C, Tardieu C: Physiological and structural changes in
the cat's soleus muscle due to immobilization at different lengths by plaster
casts. J Physiol 224:231-244,1972
8. Tardieu C, Tabary JC, Tabary C, et al: Adaptation of connective tissue
length to immobilization in the lengthened and shortened positions in cat
soleus muscle. J Physiol 78:214-220,1982
9. Peacock E: Comparison of collagenous tissue surrounding normal and
immobilized joints. Surgical Forum 14:440-441,1963
10. Granit R, Burke RE: The control of movement and posture. Brain Res
53:1-28,1973
11. Kots YM: The Organization of Voluntary Movement: Neurophysiological
Mechanisms. New York, NY, Plenum Publishing Corp, 1977, pp 5-25
12. Matthews PBC: Mammalian Muscle Receptors and Their Central Actions.
Baltimore, M D, Williams & Wilkins, 1972, pp 143-192, 481-606
13. Warren CG, Lehman JF, Koblanski JN: Heat and stretch procedures: An
evaluation using rat tail tendon. Arch Phys Med Rehabil 57:122-126,1976
14. Bross I: Sequential medical plans. Biometrics 8:189-205,1952
15. Gonnella C: Designs for clinical research. Phys Ther 53:1276-1283,1973
16. Sapega AA, Quedenfeld TC, Moyer RA, et al: Biophysical factors in rangeof-motion exercise. Physician and Sports Medicine 9:57-65,1981
333