|
참 이렇게 좋은 교과서도 있구나.
참으로 경이롭다.
문장이 간결하고, 핵심을 꿰뜷고..
언젠가는 이런 책을 이 세상에 몇권정도는 남겨야할텐데....
계획을 세워서 진행해봐야 할듯!!
치료적 운동과 마찬가지로 스트레칭, mobilization도 올바른 자세, 강도, 시간, 스피드, 빈도수, break time, 스트레칭의 방법 등 다양한 변수가 정확하게 고려되어야 함.
panic bird.....
DETERMINANTS, TYPES, AND EFFECTS OF STRETCHING INTERVENTIONS
- 스트레칭 치료의 결정인자, 형태와 효과
As with other forms of therapeutic exercise, such as strengthening exercises and endurance training, there are a
number of essential elements that determine the effectiveness of stretching interventions. The elements (determinants) of stretching, all of which are interrelated, include
1. alignment and stabilization of the body during stretching;
2. the intensity (magnitude)
3. duration,
4. speed
5. frequency
6. mode of stretch
7. and the integration of neuromuscular inhibition or facilitation and functional activities into stretching programs.
- 스트레칭의 변수들
1. 스트레칭동안 인체의 안정성과 정렬
2. 스트레칭의 강도
3. 스트레칭의 시간
4. 스트레칭 속도
5. 스트레칭 빈도수
6. 스트레칭 모드
7. 스트레칭 프로그램에서 기능적 활동과 신경근 억제 또는 촉진의 통합.
1. 배열 : 사지의 위치 또는 인체가 스트레치 힘이 적절한 근육그룹에 직접적이도록 배열
2. 안정성 : 근육 부착부의 고정으로 스트레치 힘이 뼈부착부에 적절하게 가해지도록 함.
3. 스트레치의 강도 : 적용되는 스트레치의 강도
4.스트레칭 시간, 스트레칭 속도, 빈도수
5. 스트레치의 방법들 : 정적 스트레칭, 동적 스트레칭, 사이클 스트레칭, 수동적 보조적 능동적 스트레칭
스트레칭의 형태
1. 정적 스트레칭
2. 순환 스트레칭
3. 동적 스트레칭
4. pnf 스트레칭
5. 수기 스트레칭
6. 자가 스트레칭
7. 수동적 스트레칭
8. 능동적 스트레칭
By manipulating the determinants of stretching interventions, which are defined in Box 4.3, a therapist has many options from which to choose when designing stretching programs that are safe and effective and meet many patients’ needs, functional goals, and capabilities. Each of these determinants is discussed in this section of the chapter.
There are four broad categories of stretching exercises:
1. static stretching
2. cyclic stretching
3. ballistic stretching,
4. and stretching techniques based on the principles of proprioceptive neuromuscular facilitation.19,35,44,
- 4가지 넓은 개념의 스트레칭 분류
1. 정적 스트레칭
2. 순환 스트레칭
3. 동적 스트레칭
4. pnf스트레칭
Each of these approaches to stretching can be carried out in various manners—that is, manually or mechanically, passively or actively, and by a therapist or independently by a patient—giving rise to many terms that are used in the literature to describe stretching interventions. The stretching interventions listed in Box 4.4 are defined and discussed in this section.
Extensive evidence from numerous research studies has shown that stretching interventions can improve flexibility and increase ROM, but recommended protocols vary substantially. Some of this research is highlighted in this section. Injury prevention or risk reduction, prevention or reduction of postexercise muscle soreness, and enhanced physical performance also are effects that have been attributed to stretching interventions. However, the evidence to support these claims, for the most part, is mixed.58,59,70,121
Focus on Evidence
Many of the investigations comparing the intensity, duration, frequency, and mode of stretching have been carried
out with healthy, young adults as subjects. The findings and recommendations of these studies are difficult to generalize
and apply to patients with long-standing contracture or other forms of tissue restriction. Therefore, many decisions, particularly those related to the type, intensity, duration, and frequency of stretching, must continue to be based on a balance of scientific evidence and sound clinical judgments by the therapist.
Alignment and Stabilization
Just as appropriate alignment and effective stabilization are fundamental components of muscle testing and goniometry as well as ROM and strengthening exercises, they are also essential elements of effective stretching.
- 적절한 배열과 안정성이 스트레칭에서 가장 중요한 요소
Alignment
Proper alignment or positioning of the patient and the specific muscles and joints to be stretched is necessary for patient comfort and stability during stretching. Alignment influences the amount of tension present in soft tissue and consequently affects the ROM available in joints. Alignment of the muscles and joint to be stretched as well as the alignment of the trunk and adjacent joints must all be considered.
- 적절한 정렬을 위한 환자의 위치, 그리고 특정근육과 관절의 위치...
For example, to stretch the rectus femoris (a muscle that crosses two joints) effectively, as the knee is flexed and the hip extended, the lumbar spine and pelvis should be aligned in a neutral position. The pelvis should not tilt anteriorly nor should the low back hyperextend; the hip should not abduct or remain flexed (Fig. 4.8).
- 예를들어 대퇴직근 스트레칭을 효과적으로 하기 위해서 무릎 굴곡, 고관절 신전, 요추와 골반은 중립위치에 자리해야.. 골반은 전방으로 기울지 않아야 할분 아니라 허리는 과도하게 신전되지 않아야 함. 고관절은 외전되거나 굴곡되지 않아야 함.
When a patient is self-stretching to increase shoulder flexion, the trunk should be erect, not slumped (Fig. 4.9B).
Stabilization 스트레칭을 위한 안정성
To achieve an effective stretch of a specific muscle or muscle group and associated periarticular structures, it is imperative to stabilize (fixate) either the proximal or distal attachment site of the muscle-tendon unit being elongated. Either site may be stabilized, but for manual stretching it is common for a therapist to stabilize the proximal attachment and move the distal segment, as shown in Figure 4.10A.
- 특정한 근육을 효과적으로 스트레칭하기 위해서는 근육 기시-종지 부착부가 안정되는 것이 중요함.
For self-stretching procedures, a stationary object, such as a chair or a doorframe, or active muscle contractions by the patient may provide stabilization of one segment as the other segment moves. During self-stretching, it is often the distal attachment that is stabilized as the proximal segment moves (Fig. 4.10B).
- 자가 스트레칭 과전을 위해 의자 등 정지된 물체, 또는 환자에 의한 능동적 근육수축이 안정성을 제공함.
Stabilization of multiple segments of a patient’s body also helps maintain the proper alignment necessary for an
effective stretch. For example, when stretching the iliopsoas, the pelvis and lumbar spine must maintain a neutral
position as the hip is extended to avoid stress to the low back region. Sources of stabilization include manual contacts,
body weight, or a firm surface such as a table, wall, or floor.
- 인체의 다분절의 안정성은 효과적인 스트레칭을 위해 필수적임.
Intensity of Stretch 스트레칭의 강도
The intensity (magnitude) of a stretch force is determined by the load placed on soft tissue to elongate it. There is
general agreement among clinicians and researchers that stretching should be applied at a low intensity by means
of a low load.10,12,28,44,72,89,96,100,165
- 스트레치 힘의 강도는 연부조직이 늘어나게 하는 부하에 의해서 결정됨. 낮은 강도로 시행해야 한다는 것은 모든 임상의에 동의가 있음.
Low-intensity stretching in comparison to high-intensity stretching makes the stretching maneuver more comfortable for the patient and minimizes voluntary or involuntary muscle guarding so a patient can either remain relaxed or assist with the stretching maneuver.
- 고강도 스트레칭과 비교하여 저강도 스트레칭은 환자에게 좀더 편안함을 주고 자발적 또는 비자발적 근육 보호를 최소화하여 스트레칭과 이완을 도움.
Low-intensity stretching (coupled with a long duration of stretch) results in optimal rates of improvement in ROM without exposing tissues, possibly weakened by immobilization, to excessive loads and potential injury.89,96,100 Low-intensity stretching has also been shown to elongate dense connective tissue, a significant component of chronic contractures, more effectively and with less soft tissue damage and post-exercise soreness than a high-intensity stretch.2
- 저강도 스트레칭(오랜 기간 스트레칭과 동반된) rom증진에 적절한 비율을 야기하고 ....
- 저강도 스트레칭은 단단해진 결합조직을 늘리고, 만성 구축에 좀더 효과적인 ...... 대신 long duration으로 지속해라....
Duration of Stretch 스트레칭의 시간
One of the most important decisions a therapist must make when selecting and implementing a stretching intervention (stretching exercises or use of a mechanical stretching device) is to determine the duration of stretch that is expected to be safe, effective, practical, and efficient for each situation.
- 가장 중요한 것이 스트레치의 시간임.
The duration of stretch refers to the period of time a stretch force is applied and shortened tissues are held in a lengthened position. Duration most often refers to how long a single cycle of stretch is applied. If more than one repetition of stretch (stretch cycle) is carried out during a treatment session (which is most often the case), the cumulative time of all the stretch cycles is also considered an aspect of duration.
In general, the shorter the duration of a single stretch cycle, the greater the number of repetitions applied during
a stretching session. Any number of combinations have been studied. For example, in a study by Cipriani et al.,25
two repetitions of 30-second hamstring stretches were found to be equally effective compared to six repetitions
of 10-second stretches.
- 30초 스트레칭과 10초 스트레칭..
However, Roberts and Wilson124 found that over the course of a 5-week period three 15-second hamstring stretches each day yielded significantly greater stretch-induced gains in ROM than nine daily 5-second stretches.
- 15초와 5초 스트레칭...
Despite numerous studies, there continues to be a lack of agreement on the “ideal” combination of the duration of a single cycle and the number of repetitions of stretch that should be applied in a daily stretching program to achieve the greatest and most sustained stretch-induced gains in ROM. The duration of stretch must be put in context with other stretching parameters, including intensity, frequency, and mode of stretch. Key findings from several studies are summarized in Box 4.5 on the following page.
- 많은 연구에도 불구하고, 스트레칭 주기와 시간, 반복수에 대한 완벽한 조합에 대한 동의는 없음.
- 스트레칭의 시간은 다른 스트레칭 변수인 강도, 빈도수, 스트레칭 모드와 조합해서 결정해야 함.
Numerous descriptors are used to differentiate between a long-duration versus a short-duration stretch. Terms such as static, sustained, maintained, and prolonged are all used to describe a long-duration stretch, whereas terms such as cyclic, intermittent, or ballistic are used to characterize a short-duration stretch. There is no specific time period assigned to any of these descriptors, nor is there a time frame that distinguishes a long-duration from a short-duration stretch.
- 오랜 시간 스트레칭 대 짧은 시간 스트레칭
- 정적, 지속적, 유지, prolonged와 같은 용어의 스트레칭은 long duration 스트레치임. 반면에 cyclic, intermittent, ballistic과 같은 용어의스트레칭은 short-duration임.
Static Stretching 정적 스트레칭
Static stretching* is a commonly used method of stretching in which soft tissues are elongated just past the point of tissue resistance and then held in the lengthened position with a sustained stretch force over a period of time. Other terms used interchangeably are sustained, maintained, or prolonged stretching. The duration of static stretch is predetermined prior to stretching or is based on the patient’s tolerance and response during the stretching procedure.
- 정적 스트레칭은 ...
In research studies the term “static stretching” has been linked to durations of a single stretch cycle ranging from as few as 5 seconds to 5 minutes per repetition when either a manual stretch or self-stretching procedure is employed.† If a mechanical device provides the static stretch, the time frame can range from almost an hour to several days or weeks. 15,68,76,79,96,100,106 (See additional information on mechanical stretching later in this section.)
Focus on Evidence
In a systematic review of the literature (28 studies) on hamstring stretching,35 a 30-second manual or self-stretching procedure performed for one or more repetitions was the most frequently used duration per repetition of stretch in static stretching programs. A 30-second stretch per repetition was also identified as the median duration of stretch in a review of the literature of studies on calf muscle stretching.163
Static stretching is well accepted as an effective form of stretching to increase flexibility19,35,44,71,72 and has been
considered a safer form of stretching than ballistic stretching (described in the next section on speed of stretch) for many years.39 Research has shown that tension created in muscle during static stretching is approximately half that created during ballistic stretching.148 This is consistent with our understanding of the viscoelastic properties of connective tissue, which lies in and around muscles, as well as the neurophysiological properties of the contractile elements of muscle.
As discussed in the previous section of this chapter, noncontractile soft tissues are known to yield more readily to a low-intensity, continuously applied stretch force, as used in static stretching.
Furthermore, during static stretching it is thought that the GTO, which monitors tension created by stretch of a
muscle-tendon unit, may contribute to muscle elongation by overriding any facilitative impulses from the primary afferents of the muscle spindle (Ia afferent fibers) and may contribute to muscle relaxation by inhibiting tension in the contractile units of the muscle being stretched.
For these reasons clinicians believe that static stretching, if applied at a low intensity, generates less tissue trauma and less post-exercise muscle soreness than ballistic stretching.
Static Progressive Stretching
Static progressive stretching is another term that describes how static stretch is applied for maximum effectiveness.
The shortened soft tissues are held in a comfortably lengthened position until a degree of relaxation is felt by the patient or therapist. Then the shortened tissues are incrementally lengthened even further and again held in the new end-range position for an additional duration of time.15,79,112
This approach involves continuous displacement of a limb by varying the stretch force (stretch load). This approach to stretching capitalizes on the stress relaxation properties of soft tissue107,112,131 (see Fig. 4.7B).
Most studies that have explored the merits of static progressive stretching have examined the effectiveness of a dynamic orthosis (see Fig. 4.13, below), which allows the patient to control the degree of displacement of the limb.15,79 Manual stretching and self-stretching procedures are also routinely applied in this manner.
Cyclic (Intermittent) Stretching
A relatively short-duration stretch force that is repeatedly but gradually applied, released, and then reapplied is
described as a cyclic (intermittent) stretch.12,48,108,132 Cyclic stretching, by its very nature, is applied for multiple repetitions (stretch cycles) during a single treatment session.
With cyclic stretching the end-range stretch force is applied at a slow velocity, in a controlled manner, and at
relatively low intensity. For these reasons, cyclic stretching is not synonymous with ballistic stretching, which is characterized by high-velocity movements.
The differentiation between cyclic stretching and static stretching based on the duration that each stretch is applied
is not clearly defined in the literature. According to some authors, for cyclic stretching each cycle of stretch is held
between 5 and 10 seconds.48,132 However, investigators in other studies refer to stretching that involves 5- and 10-
second stretch cycles as static stretching.25,124
There is also no consensus on the optimal number of repetitions of cyclic stretching during a treatment session. Rather, this determination is often based on the patient’s response to stretching. Based on clinical experience, some therapists hold the
opinion that appropriately applied, end-range cyclic stretching is as effective and more comfortable for a patient than a static stretch of comparable intensity, particularly if the static stretch is appled continuously for more than 30 seconds. There is some evidence to support this opinion. Although there have been few studies on cyclic or intermittent stretching (aside from those on ballistic stretching), cyclic loading has been shown to increase flexibility as or more effectively than static stretching.108,132
Focus on Evidence
In a study of nonimpaired young adults, 60 seconds of cyclic stretching of calf muscles caused tissues to yield at slightly lower loads than one 60-second, two 30-second, or four 15-second static stretches, possibly due to decreased muscle stiffness.108 In another study that compared cyclic and static stretching,132 the authors speculated that heat production might occur because of the movement inherent in cyclic stretching and cause soft tissues to yield more readily to stretch. The authors of the latter study also concluded that cyclic stretching was more comfortable than a prolonged static stretch.
Speed of Stretch
Importance of a Slowly Applied Stretch
To ensure optimal muscle relaxation and prevent injury to tissues, the speed of stretch should be slow. 39,55,58,126,127 The stretch force should be applied and released gradually. A slowly applied stretch is less likely to increase tensile stresses on connective tissues95,102,103 or to activate the stretch reflex and increase tension in the contractile structures of the muscle being stretched.98,120
Remember, the Ia fibers of the muscle spindle are sensitive to the velocity of muscle lengthening. A stretch force applied at a low velocity is also easier for the therapist or patient to control and is therefore safer than a high-velocity stretch. In addition, a slow rate stretch affects the viscoelastic properties of connective tissue, making them more compliant.
Ballistic Stretching
A rapid, forceful intermittent stretch—that is, a high-speed and high-intensity stretch—is commonly called ballistic stretching.5–7,19,44,87,126,165 It is characterized by the use of quick, bouncing movements that create momentum to carry
the body segment through the ROM to stretch shortened structures.
Although both static stretching and ballistic stretching have been shown to improve flexibility equally, ballistic stretching is thought to cause greater trauma to stretched tissues and greater residual muscle soreness than static stretching.152
Consequently, although ballistic stretching has been shown to increase ROM safely in young, healthy subjects participating in a conditioning program,67 it is, for the most part, not recommended for elderly or sedentary individuals or patients with musculoskeletal pathology or chronic contractures.
The rationale for this recommendation is33: Tissues, weakened by immobilization or disuse, are easily injured. Dense connective tissue found in chronic contractors does not yield easily with high-intensity, short-duration stretch; rather, it becomes more brittle and tears more readily.
High-Velocity Stretching in Conditioning
Programs and Advanced-Phase Rehabilitation
Although somewhat controversial, certain practitioners and authors believe there are situations when high-velocity stretching is appropriate for carefully selected individuals. 19,44 For example, a highly trained athlete involved in a sport such as gymnastics that requires significant dynamic flexibility may need to incorporate high-velocity stretching in a conditioning program. Also, a young, active patient in the final phase of rehabilitation who wishes to return to high-demand, recreational activities after a musculoskeletal injury may need to perform carefully progressed, high velocity stretching activities prior to beginning plyometric training or simulated, sport-specific exercises or drills.
If high-velocity stretching is employed, rapid, but low load (low-intensity) stretches are recommemded, paying close attention to effective stabilization. The following self-stretching sequence, referred to as a Progressive Velocity Flexibility Program, has been suggested for a safe transition and progression from static stretching to ballistic stretching to improve dynamic flexibility.165
1. Static stretching → Slow, short end-range stretching → Slow, full-range stretching → Fast, short end-range stretching → Fast, full-range stretching.
2. The stretch force is initiated by having the patient actively contract the muscle group opposite the muscle and connective tissues to be stretched.
Frequency of Stretch
Frequency of stretching refers to the number of bouts (sessions) per day or per week a patient carries out a stretching regimen.5,58 The recommended frequency of stretching is often based on the underlying cause of impaired mobility, the quality and level of healing of tissues, the chronicity and severity of a contracture, as well as a patient’s age, use of corticosteroids, and previous response to stretching.
Because few studies have attempted to determine the optimal frequency of stretching within a day or a week,5,58 it is not possible to draw evidence-based guidelines from the literature. As with decisions on the most appropriate number of repetitions of stretch in an exercise session, most suggestions are based on opinion. Frequency on a weekly basis ranges from two to five sessions, allowing time for rest between sessions for tissue healing and to minimize postexercise soreness. Ultimately, the decision is based on the clinical discretion of the therapist and the response and needs of the patient.
A therapist must be aware of any breakdown of tissues with repetitive stretch. A fine balance between collagen tissue breakdown and repair is needed to allow an increase in soft tissue lengthening. If there is excessive frequency of loading, tissue breakdown exceeds repair; and ultimate tissue failure is a possibility. In addition, if there is progressive loss of ROM over time rather than a gain in range, continued low-grade inflammation from repetitive stress can cause excessive collagen formation and hypertrophic scarring.
Mode of Stretch
The mode of stretch refers to the form of stretch or the manner in which stretching exercises are carried out. Mode of stretch can be defined by who or what is applying the stretch force or whether the patient is actively participating in the stretching maneuver. Categories include but are not limited to manual and mechanical stretching or self-stretching as well as passive, assisted, or active stretching.
Regardless of the form of stretching selected and implemented, it is imperative that the shortened muscle remains relaxed and that the restricted connective tissues yield as easily as possible to the stretch. To accomplish this, stretching procedures should be preceded by either low intensity active exercise or therapeutic heat to warm up the tissues that are to be lengthened.
There is no best form of stretching. What is important is that the therapist and patient have many modes of stretching from which to choose. Box 4.6 lists some questions a therapist needs to answer to determine which forms of stretching are most appropriate and most effective for each patient at different stages of a rehabilitation program.
Manual Stretching
During manual stretching a therapist or other trained practitioner or caregiver applies an external force to move the involved body segment slightly beyond the point of tissue resistance and available ROM. The therapist manually controls the site of stabilization as well as the direction, speed, intensity, and duration of stretch. As with ROM exercises (described in Chapter 3), manual stretching can be performed passively, with assistance from the patient, or even independently by the patient.
N O T E : Remember, stretching and ROM exercises are not synonymous terms. Stretching takes soft tissue structures beyond their available length to increase ROM. ROM exercises stay within the limits of tissue extensibility to maintain the available length of tissues. Figures 4.16 through 4.36 of this chapter depict manual stretching techniques of the extremities. Manual stretching usually employs a controlled, endrange, static, progressive stretch applied at an intensity consistent with the patient’s comfort level, held for 15 to 60 seconds and repeated for at least several repetitions. When compared to mechanical stretching, manual stretching could be categorized as a high-intensity, short-duration stretch.96
Despite widespread use in the clinical setting, the effectiveness of manual passive stretching for increasing the extensibility of range-limiting muscle-tendon units is debatable. Some investigators40,101,136 have found that manual passive stretching increases muscle length and ROM in nonimpaired subjects. However, the short duration of stretch that typically occurs with manual stretching may be why other investigators have reported that the effect of a manual passive stretching program is negligible,62 especially in the presence of long-standing contractures associated with tissue pathology.96
The following are points to consider about the use of manual stretching. Manual stretching may be most appropriate in the early stages of a stretching program when a therapist wants to determine how a patient responds to varying intensities or durations of stretch and when optimal stabilization is most critical. Manual stretching performed passively is an appropriate
choice for a therapist or caregiver if a patient cannot perform self-stretching owing to a lack of neuromuscular control of the body segment to be stretched.
If a patient has control of the body segment to be
stretched, it is often helpful to ask the patient to assist
the therapist with the manual stretching maneuver, particularly
if the patient is apprehensive and is having
difficulty relaxing. For example, if the patient concentrically
contracts the muscle opposite the short muscle
and assists with joint movement, the range-limiting
muscle tends to relax reflexively, thus decreasing
muscle tension interfering with elongation. This is
one of several stretching procedures based on proprioceptive
neuromuscular facilitation techniques that are
discussed later in this chapter.
Using procedures and hand placements similar to those
described for self-ROM exercises (see Chapter 3), a
patient can also independently lengthen range-limiting
muscles and periarticular tissues with manual stretching.
As such, this form of stretching is usually referred to as
self-stretching and is discussed in more detail as the next
topic in this section.
N O T E : Specific guidelines for the application of manual stretching, as well as descriptions and illustrations of manual stretching techniques for the extremities are presented in later sections of this chapter.
Self-Stretching
Self-stretching (also referred to as flexibility exercises or
active stretching) is a type of stretching procedure a patient
carries out independently after careful instruction and
supervised practice. Self-stretching enables a patient to
maintain or increase the ROM gained as the result of direct
intervention by a therapist. This form of stretching is often
an integral component of a home exercise program and is
necessary for long-term self-management of many musculoskeletal and neuromuscular disorders.
Teaching a patient to carry out self-stretching procedures
correctly and safely is fundamental for preventing reinjury
or future dysfunction. Proper alignment of the body
or body segments is critical for effective self-stretching.
Sufficient stabilization of either the proximal or distal
attachment of a shortened muscle is necessary but can be
difficult to achieve with self-stretching. Every effort should
be made to see that restricted structures are stretched specifically
and that adjacent structures are not overstretched.
The guidelines for the intensity, speed, duration, and
frequency of stretch that apply to manual stretching are
also appropriate for self-stretching procedures. Static
stretching with a 30- to 60-second duration per repetition is
considered the safest type of stretching for a self-stretching
program.
Self-stretching exercises can be carried out in several
ways.
Using positions for self-ROM exercises described in
Chapter 3, a patient can passively move the distal segment
of a restricted joint with one or both hands to elongate
a shortened muscle while stabilizing the proximal
segment (Fig. 4.11A).
If the distal attachment of a shortened muscle is fixed
(stabilized) on a support surface, body weight can be used as the source of the stretch force to elongate the
shortened muscle-tendon unit (Fig. 4.11B).
Neuromuscular inhibition, using PNF stretching techniques,
can be integrated into self-stretching procedures
to promote relaxation in the muscle that is being
elongated.
Low-intensity acitve stretching (referred to by some as
dynamic ROM6), using repeated, short-duration, endrange
active muscle contractions of the muscle opposite
the shortened muscle is another form of self-stretching
exercise.6,151,15
Mechanical Stretching
There are many ways to use equipment to stretch shortened
tissues and increase ROM. The equipment can be as simple
as a cuff weight or weight-pulley system or as sophisticated
as some adjustable orthoses or automated stretching
machines.* These mechanical stretching devices provide
either a constant load with variable displacement or constant
displacement with variable loads. Studies15,79 about
the efficacy of these two categories of mechanical stretching
devices base their effectiveness on the soft tissue properties
of either creep or stress-relaxation, which occur
within a short period of time, as well as plastic deformation,
which occurs over an extended period of time.
It is often the responsibility of a therapist to recommend
the type of stretching device that is most suitable and
teach a patient how to safely use the equipment and monitor
its use in the home setting. A therapist may also be
involved in the fabrication of serial casts or splints.
Mechanical stretching devices apply a very lowintensity
stretch force (low load) over a prolonged period
of time to create relatively permanent lengthening of soft
tissues, presumably due to plastic deformation.
N O T E : Be cautious of studies or product information that report “permanent” lengthening as the result of use of mechanical stretching devices. Permanent may mean that length increases were maintained for as little as a few days or a week after use of a stretching device has been discontinued. Long-term follow-up may indicate that tissues have returned to their shortened state if the newly gained motion has not been used regularly in daily activities. Each of the following forms of mechanical stretching has been shown to be effective, particularly in reducing long-standing contractures.
An effective stretch load applied with a cuff weight (Fig. 4.12) can be as low as a few pounds.96
Some devices, such as the Joint Active Systems™
adjustable orthosis (Fig. 4.13), allow a patient to
control and adjust the load (stretch force) during a
stretching session.15,79
With other devices the load is preset prior to the application
of the splint, and the load remains constant
while the splint is in place.68
Duration of Mechanical Stretch
Mechanical stretching involves a substantially longer
overall duration of stretch than is practical with manual
stretching or self-stretching exercises. The duration of
mechanical stretch reported in the literature ranges from
15 to 30 minutes15,79 to as long as 8 to 10 hours at a time68
or continuous throughout the day except for time out of
the device for hygiene and exercise.10 Serial casts are
worn for days or weeks at a time before being removed
and then reapplied.76 The time frame is dependent on
the type of device employed, the cause and severity of
impairment, and patient tolerance. The longer durations
of stretch are required for patients with chronic contractures
as the result of neurological or musculoskeletal
disorders than for healthy subjects with only mild hypomobility.
15,76,79,96,100,107,112
Focus on Evidence
Light and colleagues96 studied nonambulatory, elderly nursing home residents with long-standing bilateral knee flexion contractures and compared the effects of mechanical and manual stretching. Over a 4-week period twice daily stretching sessions occurred 5 days per week.
Low-intensity, prolonged mechanical stretching (a 5-
to 12-lb poundstretch force applied by a weight-pulley
system for 1 hour each session) was applied to one knee,
and manual passive stretching was applied to the other
knee by a therapist (three repetitions of 1-minute static
stretches per stretching session). At the conclusion of
the study, the mechanical stretching procedure was found to be considerably more effective than the manual stretching
procedure for increasing knee extension. The patients
also reported that the prolonged mechanical stretch was
more comfortable than the manual stretching procedure,
which tended to be applied at a higher intensity. The
investigators recognized that the total duration of mechanical
stretch (40 hours) was substantially longer over
the course of the study than the total duration of manual
stretch (2 hours) but believed that the manual stretching
sessions were typical and practical in the clinical
setting.
Proprioceptive Neuromuscular Facilitation Stretching Techniques
Proprioceptive neuromuscular facilitation techniques used
for stretching (PNF stretching),19,29,72,117,165 also referred
to as active stretching158 or facilitative stretching,119 integrate
active muscle contractions into stretching maneuvers
purportedly to facilitate or inhibit muscle activation
and to increase the likelihood that the muscle to be lengthened
remains as relaxed as posssible as it is stretched.
It is believed that when muscle fibers are reflexively
inhibited through autogenic or reciprocal inhibition,
there is less resistance to elongation by the contractile
elements of the muscle.134,147 However, inhibition techniques
are designed to relax only the contractile structures
of muscle, not the connective tissue in and around
shortened muscles.
N O T E : The PNF stretching techniques described in
this section require normal innervation and voluntary
control of either the shortened muscle or the muscle
on the opposite side of the joint. As such, these techniques
cannot be used effectively in patients with
paralysis or spasticity resulting from neuromuscular
diseases or injury. Furthermore, because PNF stretching
procedures are designed to affect the contractile elements
of muscle, not noncontractile connective tissues,
they are more appropriate when muscle spasm limits
motion and less appropriate for stretching fibrotic contractures.
The PNF stretching techniques, most of which have
been adapted from the PNF techniques originally described
by Knott and Voss,134,147 have been used for many years in
the clinical setting as an adjunct to manual stretching or
self-stretching. Although the efficacy of the neurophysiological
principles on which PNF was founded has come
into question, the results of numerous studies have demonstrated
that the various PNF stretching techniques effectively
increase flexibility and ROM.6,48,117,126,133,136,158,162
However, there is no consensus on whether one PNF technique
is consistently superior to another or whether PNF
stretching is more, less, or equally effective as static
stretching.
Types of PNF Stretching
There are several types of PNF stretching procedures. They include:
Hold–relax (HR) or contract–relax (CR)
Agonist contraction (AC)
Hold–relax with agonist contraction (HR-AC).
With classic PNF, these techniques are performed with combined muscle groups acting in diagonal patterns134,147 but have been modified in a number of studies and resources6,27,65,74,117,158 by stretching in anatomical planes or opposite the line of pull of a specific muscle group. (For a description of the PNF diagonal patterns, refer to Chapter 6.)
Hold–Relax and Contract–Relax
With the hold–relax (HR) procedure,27,74,119,134 the range limiting muscle is first lengthened to the point of limitation or to the extent that is comfortable for the patient. The patient then performs a prestretch, end-range, isometric contraction (for 5 to 10 seconds) followed by voluntary relaxation of the tight muscle. The limb is then passively moved into the new range as the range-limiting muscle is elongated. A sequence for using the HR technique to stretch shortened pectoralis major muscles bilaterally and increase horizontal abduction of the shoulders is illustrated in Figure 4.14.
NOTE: In the clinical setting and in a number of investigations
the terms contract–relax (CR) and hold–relax (HR) are
often used interchangably. However, it should be noted that
for classic PNF the techniques are not identical. Although
both techniques are performed in diagonal patterms, for the
CR technique the rotators of the limb are allowed to contract
concentrically whereas all other muscle groups contract
isometrically during the prestretch contraction of the
restricting muscles.134,147 For the HR technique, the prestretch
contraction is isometric in all muscles of the diagonal
pattern.
Practitioners in the clinical and athletic training settings
have reported that the HR and CR techniques appear
to make passive elongation of muscles more comfortable
for a patient than manual passive stretching.74 It has been
assumed that the sustained, prestretch contraction is followed
by reflexive relaxation accompanied by a decrease
in electromyographic (EMG) activity in the range-limiting
muscle, possibly as the result of autogenic inhibition.99,119
This assumption has been challenged in one study but supported
in a later study. In the earlier study,45 a postcontraction
sensory discharge (increased EMG activity) was
identified in the muscle to be stretched, suggesting that
there was lingering tension in the muscle after the prestretch
isometric contraction and that the muscle to be
stretched was not effectively relaxed. In the later study, no
postcontraction elevation in EMG activity was found with
the use of the HR or CR techniques.28 Consequently, clinicians
must evaluate the effectiveness of the HR and CR techniques and determine their effectiveness with individual patients.
P R E C A U T I O N : It is not necessary for the patient to
perform a maximal isometric contraction of the tight muscle
prior to stretch. Multiple repetitions of maximal prestretch
isometric contractions have been shown to result in an
acute increase in arterial blood pressure, most notably after
the third repetition.29 To minimize the adverse effects of the
Valsalva maneuver (elevation in blood pressure), have the
patient breathe regularly while performing submaximal
(low-intensity) isometric contractions held for 5 to 10 seconds
with each repetition of the stretchimg procedure. A
submaximal contraction is also easier for the therapist to
control if the patient is strong.
Agonist Contraction
Another PNF stretching technique is the agonist contraction (AC) procedure. This term has been used by several authors19,24,28,74 but can be misunderstood. The “agonist” refers to the muscle opposite the range-limiting muscle. “Antagonist,” therefore, refers to the range-limiting muscle.24 Think of it as the short muscle (the antagonist) preventing the full movement of the prime mover (the agonist). Dynamic range of motion (DROM)6 and active stretching158 are terms that have been used to describe the AC procedure.
To perform the AC procedure the patient concentrically
contracts (shortens) the muscle opposite the rangelimiting
muscle and then holds the end-range position for
at least several seconds.19,28,74 The movement of the limb
is independently controlled by the patient and is deliberate
and slow, not ballistic. In most instances the shortening
contraction is performed without the addition of resistance.
For example, if the hip flexors are tight, the patient can
perform end-rage, prone leg lifts by contracting the hip
extensors concentrically; the end-range contraction is held
for a number of seconds. After a brief rest period, the
patent repeats the procedure.
It has been suggested that when the agonist is activated
and contracts concentrically, the antagonist (the
range- limiting muscle) is reciprocally inhibited, allowing
it to relax and lengthen more easily.119,124,147 However, the
theoretical mechanism of receiprocal inhibition has been
substantiated only in animal studies, not in studies of
humans.120
Focus on Evidence
Several studies have evaluated the effectiveness of the agonist
contraction procedure for improving flexibility and
ROM. Two studies compared the effect of the AC procedure,
referred to as DROM, to static stretching of the hamstrings
of healthy subjects who participated in 6-week
stretching programs. In one study151 DROM was found to
be as effective as static stretching, but in the other study6
one daily repetition of a 30-second static stretch was
almost three times as effective in increasing hamstring
flexibility as six repetitions daily (with a 5-second, endrange
hold) of DROM.
In a study of young adults with hypomobile hip flexors
and periodic lumbar or lower-quarter pain, investigators
compared “active stretching” using the AC procedure
to static passive stretching.158 Both techniques resulted
in increased hip extension with no significant difference
between the active and passive stretching groups.
In addition to the results of studies on the the AC
stretching procedure, clinicians have observed the
following.
The AC technique seems to be especially effective when
significant muscle guarding restricts muscle lengthening
and joint movement and is less effective in reducing
chronic contractures.
This technique is also useful when a patient cannot generate
a strong, pain-free contraction of the range-limiting
muscle, which must be done during the HR procedure.
This technique is also useful for initiating neuromuscular
control in the newly gained range to re-establish
dynamic flexibility.
The AC technique is least effective if a patient has close to normal flexibility.
P R E C A U T I O N S : Avoid full-range, balllistic movements when performing concentric contractions of the agonist muscle group. Rest after each repetition to avoid muscle cramping when the agonist is contracting in the very shortened portion of its range.
Hold–Relax with Agonist Contraction
The HR-AC stretching technique combines the HR and AC procedures. The HR-AC technique is also referred to as the slow reversal hold–relax technique.134,147 To perform the HR-AC procedure, move the limb to the point that tissue resistance is felt in the tight (range-limiting) muscle; then have the patient perform a resisted, pre stretch isometric contraction of the range-limiting muscle followed by relaxation of that muscle and an immediate concentric contraction of the muscle opposite the tight muscle.28,50,119,134,147
For example, to stretch knee flexors, extend the
patient’s knee to a comfortable position and then have the
patient perform an isometric contraction of the knee flexors
against resistance for 5 to 10 seconds. Tell the patient
to relax the knee flexors and then actively extend the knee
as far as possible, holding the newly gained range for several
seconds.
Focus on Evidence
Studies comparing two PNF stretching procedures produced
differing results. In one study,48 the HR-AC technique
produced a greater increase in ankle dorsiflexion
range than did the HR technique. Both PNF techniques
produced a greater increase in range of ankle dorsiflexion
than did manual passive stretching. However, in another
study, there was no significant difference between the use
of the HR and HR-AC techniques.74
P R E C A U T I O N S : Follow the same precautions as described for both the HR and AC procedures.
Integration of Function into Stretching
Importance of Strength and Muscle Endurance
As previously discussed, the strength of soft tissue is
altered when it is immoblized for a period of time.23,60,111
The magnitude of peak tension produced by muscle
decreases, and the tensile strength of noncontractile
tissues decreases. A muscle group that has been overstretched
because its opposing muscle group has been
in a shortened state for an extended period of time also
becomes weak.85 Therefore, it is critical to begin lowload
resistance exercises to improve muscle performance
(strength and endurance) as early as possible in a stretching
program.
Initially, it is important to place emphasis on developing
neuromuscular control and strength of the agonist, the
muscle group opposite the muscle that is being stretched.
For example, if the elbow flexors are the range-limiting
muscle group, emphasize contraction of the elbow extensors
in the gained range. Complement stretching the hamstrings
to reduce a knee flexion contracture by using the
quadriceps in the new range. Early use of the agonist
enables the patient to elongate the hypomobile structures
actively and use the recently gained ROM.
As ROM approaches a “normal,” or functional,
level, the muscles that were shortened and then stretched
must also be strengthened to maintain an appropriate
balance of strength between agonists and antagonists
throughout the ROM. Manual and mechanical resistance
exercises are effective ways to load and strengthen muscles,
but functional weight-bearing activities, such as
those mentioned below also strengthen antigravity
muscle groups.
Use of Increased Mobility for Functional Activities
As mentioned previously, gains in flexibility and ROM
achieved as the result of a stretching program are transient,
lasting only about 4 weeks after cessation of stretching.156
The most effective means of achieving permanent
increases in ROM and reducing functional limitations
is to integrate functional activities into a stretching program
to use the gained range on a regular basis. Use of
functional activities to maintain mobility lends diversity
and interest to a stretching program.
Active movements should be within the pain-free
ROM. Examples of movements of the upper or lower
extremities or spine that are components of daily activities
include reaching, grasping, turning, twisting,
bending, pushing, pulling, and squatting to name just
a few. As soon as even small increases in tissue extensibility
and ROM have been achieved, have the patient
use the gained range by performing motions that simulate
functional activities. Later have the patient use all of the
available ROM while actually doing specific functional
tasks.
Functional movements that are practiced should complement
the stretching program. For example, if a patient has been performing stretching exercises to increase
shoulder mobility, have the patient fully use the available
ROM by reaching as far as possible behind the back and
overhead when grooming or dressing or by reaching for
or placing objects on a high shelf (Fig. 4.15). Gradually
increase the weight of objects placed on or removed
from a shelf to strengthen shoulder musculature simultaneously.
If the focus of a stretching program has been to
increase knee flexion after removal of a long-leg cast,
emphasize flexing both knees before standing up from
a chair or when stooping to pick up an object from the
floor. These weight-bearing activities also strengthen
the quadriceps that became weak while the leg was
immobilized and the quadricepts was held in a shortened
position.
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