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Sample 1SAMPLE REVIEWS

  1. Golf Swing & Low Back Pain
  2. Scapular Rehabilitation & Muscle EMG
  3. Alexander Technique, Massage & Exercise for Chronic Low Back Pain
  4. Neck Pain & Active Range of Motion After Manipulation
  5. ACL Rehabilitation - Open Vs. Closed Kinetic Chain Exercise
Sample 21: Golf Swing & Low Back Pain
Research Review by Dr. Shawn Thistle©
Date: Oct. 2008
Study Title: The lumbar spine and low back pain in golf: A literature review of swing mechanics and injury prevention
Authors: Gluck GS, Bendo JA, Spivak JM

Authors’ Affiliations: University of North Carolina, Department of Orthopedic Surgery; New York University School of Medicine; NYU Hospital for Joint Diseases, The Spine Center.
Publication Information: The Spine Journal 2008; 8: 778-788.
Summary: Golf is a unique sport which is growing tremendously around the world. It can be played regardless of age, gender, and skill level (through “handicapping"). Between 1970 and 1990, the reported number of golfers in the United States alone more than doubled to 23 million. By the year 2000, there were over 25 million golfers and 14 000 courses in the USA. The World Golf Federation expects 55 million golfers by the year 2020. Manual therapists should be aware that roughly 33% of golfers are over the age of 50, and this number will surely grow. These numbers all indicate the growing potential for a rising health-care burden related to the sport.

Golfers are prone to a number if injuries, with low back pain (LBP) being one of the most common. It is estimated that LBP accounts for 26-52% of golf-specific injuries. It is also estimated that up to 30% of touring professional golfers play injured at any one time. This study discusses the existing theories and literature surrounding the mechanics of a golf swing as they pertain to low-back injury, and the prevention and rehabilitation of potential golf-specific LBP.

Forces on the Spine During a Golf Swing:
  • it is well known that axial twisting is a risk factor for LBP – the golf swing combines this motion with compression, lateral bending, and anterior-posterior shear
  • this combination of motions (compression, torsion, and lateral bending) are also known risk factors for disc herniation
  • kinematic studies have revealed that during a golf swing the lumbar spine can sustain compressive loads of up to 8 times body weight (about 6100 ± 2400N in amateurs and 7584 ± 2400N in professional golfers) [NOTE: as a comparison, similar studies on NCAA football linemen revealed compressive forces of ~ 8600N while hitting a blocking sled, while cadaveric studies have revealed that disc prolapse can occur at loads of ~ 5800N]
  • facet joints resist ~ 50% of shear: a golf swing has been shown to produce anterior-posterior shear forces of 596 ± 514N [NOTE: loads of 570 ± 190N are able to produce pars interarticularis fractures in cadaver studies]
The Golf Swing: “Modern” versus “Classic”

Perfecting a golf swing is no simple task. In fact, it is one of the most complex athletic skills. The swing itself can be broken into four major components:
  1. back swing or takeaway
  2. forward swing
  3. acceleration with ball strike
  4. follow-through
Two general styles of golf swing are known – “Modern” and “Classic”:

The “Modern” Golf Swing:
  • emphasizes a large shoulder turn with minimal hip turn
  • the restricted hip turn is accomplished by keeping the front foot planted flat on the ground throughout the swing
  • this method maximizes shoulder-hip separation, and is thought to “quiet” the lower body and increase the chance of striking with a square club face
  • this separation angle is known as the “X-factor” – measured via lines drawn through the axial orientation of the hips and shoulders at the end of backswing
  • this swing can be problematic as it causes increased lateral bend – also called the “crunch factor” (see below), and exaggerated hyperextension on follow-through – also known as the “reverse C” position, which can lead to over-activation of the spinal extensor muscles
The “Classic” Golf Swing:
  • aims to reduce the “X-factor” by raising the front heel during the backswing to increase hip turn, shortening the backswing, or a combination of the two
  • a small set of data indicate that a reduced backswing does not have a detrimental effect on club head velocity or ball contact accuracy, although further study is needed to confirm this
  • this reduces the separation between the shoulders and hips, thereby decreasing torque on the lumbar spine
  • this swing emphasizes a balanced, upright form that also serves to reduce the “crunch factor”
  • the end of this swing is characterized by an erect “I” finish with balanced shoulders
  • case reports have indicated that this type of swing can reduce the incidence and recurrence of LBP, but more research is required
The “Crunch Factor” and Further Points of Interest:
  • the “crunch factor”, although lacking clinical evidence to support its relevance, is defined as the product of lumbar lateral bending angle and rotational velocity – further research is required to elucidate the utility and relevance of this measure
  • one epidemiologic and radiographic study of elite golfers(1) demonstrated that 55% of subjects had LBP, and those with LBP had significantly greater “trailing-side” vertebral body and facet arthritis when compared to age-matched controls
  • one study(2) showed that golfers with LBP consistently exceed their trunk rotation during swings compared to rotation in neutral posture at a controlled speed – this “supramaximal” rotation may cause excessive strain on viscoelastic structures surrounding the spine
  • in general, amateur and professional golfers utilize the “modern” swing in an attempt to maximize power and distance
  • Other common golf injuries: medial epichondylalgia (Golfer’s elbow), hook of hamate fractures, extensor pollicis brevis/abductor pollicis longus tenosynovitis, rotator cuff pathology, and knee injuries (which may not be as common, but can be severe - just ask Tiger Woods!)
Differences between amateurs and professionals:
  • professionals practice constantly with a consistent swing – leading to overuse injuries
  • amateurs do not play as frequently, and often demonstrate multiple inconsistencies in their swing, leading to injury resulting from poor mechanics
Lumbar Stabilization During the Golf Swing
  • EMG studies performed on golfers have indicated that similar muscles are involved in stabilization during a golf swing as in other athletic tasks – namely the internal/external obliques (IO/EO), quadratus lumborum (QL), erector group (spinae/multifidi), and rectus abdominus (RA)
  • specifically, during a golf swing the muscles most active are: contralateral EO, ipsiliateral IO and latissimus dorsi, QL, and RA
  • in general, the take away phase has the lowest overall muscle activation, while the forward swing/acceleration has the highest
  • studies have indicated that the gluteus maximus is a critical stabilizer of the hip during the golf swing, and contributes significantly to power generation during the swing
Treatment, Conditioning and Prevention Strategies:
  • there is a paucity of golf-specific literature in these areas
  • in a small collection of case studies on LBP in golfers, training with the “classic swing” method in combination with general trunk muscle stabilization exercise (McGill/Queensland) was recommended – however the contribution of swing modification to symptom resolution cannot be conclusively outlined yet
  • some evidence suggests that lack of lead hip flexibility is associated with LBP in a small group of professional golfers(3)
  • there is also some low-level evidence that golfers who stretch/warm-up for 10 minutes before playing have a lower risk of sustaining injury
Conclusions & Practical Application: The relation of golf to LBP will surely be the focus of a growing amount of research moving forward, assuming the sport continues to grow at its current pace. Manual therapists should stay abreast of this literature so we can assist golfers in conditioning and maintenance programs for the sport, and also to manage any injuries which may arise while considering the specific demands of the sport.

Additional References:
  1. Sugaya H et al. Low back injury in elite and professional golfers: an epidemiologic and radiographic study. In: FarrallyM, Cochran A, editors. Science and Golf III: Proceedings of the World Scientific Congress of Golf. Champaign IL: Human Kinetics, 1999: 83-91.
  2. Lindsay D, Horton J. Comparison of spine motion in elite golfers with and without low back pain. J Sport Sci 2002; 20(8): 599-605.
  3. Vad VB et al. Low back pain in professional golfers. Am J Sports Med 2004; 32: 494-497.

Sample 32: Scapular Rehabilitation & Muscle EMG ... top
Research Review by Dr. Shawn Thistle©
Date: Oct. 2008
Study Title: Electromyographic analysis of specific exercises for scapular control in early phases of shoulder rehabilitation
Authors: Kibler WB, Sciascia AD, Uhl TL, Tambay N & Cunningham T

Authors’ Affiliations: Private sports medicine clinics, and Division of Athletic Training, University of Kentucky
Publication Information: American Journal of Sports Medicine 2008; 36(9): 1789-1798.
Summary: Recently there has been much attention in clinical and exercise rehabilitation research on scapular movement as it relates to shoulder girdle function and injuries. Specifically, it is now widely accepted that scapular dyskinesis (SD), encompassing alterations in static scapular position and loss of dynamic control, relates directly to the development and proliferation of many shoulder conditions.

In general, SD results in increased anterior tilt, decreased upward rotation, and increased internal rotation of the scapula. Together, these changes have been shown to alter the function of the joint by:
  • altering normal scapulohumeral rhythm
  • increasing tension in the anterior inferior glenohumeral ligament
  • decreasing subacromial space with arm abduction
  • inhibiting supraspinatus muscle activity
In a normal shoulder, specific patterns of muscle activation position the scapula to optimize the spatial relationship between the stable trunk and the mobile glenohumeral complex during movement. These muscle activation patterns have been shown to be altered in injured shoulders1. As such, rehabilitation of these deficits should be integral in any shoulder rehabilitation program.

Early rehabilitation of most shoulder conditions focuses on scapular control. The goal of these protocols should be to restore retraction of the scapula – a position of posterior tilt and external rotation. However, many exercises often employed in early rehabilitation are difficult to achieve for many injured shoulders as they require high degrees of arm elevation, glenohumeral rotation, or forward flexion/scapular protraction.

The goal of this study was to investigate the amplitude and sequence of muscle activation with specific exercises that can be used safely in early rehabilitation protocols. 39 subjects (average age ~ 30) were studied – 18 who were asymptomatic for shoulder pain, and 21 with shoulder pathology diagnosed by the first author (WBK) as impingement (n=9), labral injury (n=5), or rotator cuff tendinopathy (n=7), all of whom demonstrated scapular dyskinesis on clinical examination. Subjects were excluded from the study if they had any neurological condition or had previous shoulder surgery.

Four exercises were performed (described below) while EMG recordings (MVC normalized) were gathered from the following muscles: the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), anterior deltoid (AD), and posterior deltoid (PD). The UT, LT, and SA were selected because they are considered the most important muscles in the force couples that govern scapular motion.

The exercise protocol included the following exercises (with targeted muscles):
  1. Inferior Glide (SA/LT) – is an isometric exercise that emphasizes humeral head depression and scapular retraction. In a sitting position, the arm is placed in 90° of abduction on a supportive surface. The subject then applied force through their fist (which was resting on the surface) in an adduction direction while inferiorly depressing their scapula for 5 seconds.
  2. Low Row (SA/LT) – was performed as an isometric exercise emphasizing scapular external rotation and posterior tilt. With the arm at the side, subjects placed their hand on the anterior edge of a surface (ex. a table) with their palm facing posteriorly. They were then instructed to extend their trunk and push their hand into the surface in the direction of shoulder extension while maintaining retraction and depression of the scapula for 5 seconds.
  3. Lawnmower (SA/LT) – is a multi-joint exercise performed with the subject standing with the trunk flexed forward and rotated contralateral to the arm performing the motion (hand at opposite patella) – subject the rotates the trunk, extends the hip and trunk to vertical, and attempts to put their elbow in their back pocket (hence retracting and depressing the scapula) – this motion mimics starting a “pull lawnmower”.
  4. Robbery – is a multi-joint exercise that uses hip/trunk extension and bilateral arm motion to induce scapular retraction. The subject stands with the trunk forward flexed roughly 50° with arms forward (hands facing thighs). Then the trunk and hips are extended while pinching both scapulae toward the “back pockets” for a 5 second contraction.
Pertinent results of this study include:
  • there were no significant differences in muscle activation between symptomatic and asymptomatic subjects
  • the SA and LT were activated between 15-30% for all exercises – an amplitude known to provide strength gains
  • UT activity was higher (21-36%) in the lawnmower and robbery exercises
  • the inferior glide and low row, both safe to perform very early in rehabilitation, activated the SA/LT adequately to provide strength gains
  • when the scapula begins in a retracted position (as in the low row) – the SA is activated early – when retraction occurs later in the motion (as in the lawnmower and robbery), the SA is activated last
  • the trapezius showed task-specific patterns: when the shoulder begins in a closed-chain position (as in the inferior glide and low row), the trapezius (UT and LT) activate later; in the open chain exercises, the UT/LT become active sooner (see below for clinical application)
Conclusions & Practical Application: The exercises evaluated in this study are effective in sufficiently activating key scapular stabilizing muscles in task-specific patterns. This suggests that these exercises may be used in early and middle phases of a comprehensive shoulder rehabilitation program.

Clinicians and exercise specialists should focus on the LT/SA force couple, which is responsible for reducing a common finding in scapular dyskinesis – inferior/medial scapular border prominence. The astute clinician will recognize that de-emphasizing activation of the UT (the “shrug”) is a key in this type of rehabilitation. The results from this study suggest that the two closed-chain exercises (inferior glide and low row) create a muscle activation pattern that limits UT activation while stimulating the LT/SA in a manner that does not impinge the shoulder - making these exercises more useful very early in the program. The open-chain exercises may best be used a bit later in the program, as they incorporate dynamic patterns and larger motions that generate more joint shear.

NOTE: the authors acknowledge that the exercises chosen for this study are but a few of the possibilities for this type of rehabilitation. Future research will continue to elaborate on muscle activation patterns of other exercises to guide evidence-based implementation of this type of exercise.

Related Research Reviews:
  1. Disabled Throwing Shoulder: Part 1 – Pathology and Biomechanics
  2. Disabled Throwing Shoulder: Part 2 – SICK Scapula, Scapular Dyskinesis, Rehabilitation
Additional Reference:
  1. Cools AM et al. Isokinetic scapular muscle performance in overhead athletes with and without impingement symptoms. Journal of Athletic Training 2005; 40(2): 104-110.

Image3: Alexander Technique, Massage & Exercise for Chronic Low Back Pain ... top
Research Review By Dr. Shawn Thistle ©
Date Posted: Jan. 2009
Study Title: Randomised controlled trial of Alexander technique lessons, exercise, and massage (ATEAM) for chronic and recurrent back pain
Authors: Little P et al.
Author's Affiliations: Primary Care Group, Community Clinical Sciences Division, Southampton University, UK
Publication Information: British Medical Journal 2008;337:a884, doi: 10.1136/bmj.a884
Background Information: Few interventions have substantial evidence to support their use in the treatment of chronic low back pain (CLBP). Previous research demonstrates that moderate improvements in function can be achieved with combined spinal manipulation and physiotherapy-supervised exercise programs. It has also been demonstrated that individual or group classes consisting of spinal stabilization and strengthening exercises can be of some benefit. The Alexander technique offers an individualized approach to help patients develop skills to recognize, understand, and manage the poor habits that affect their posture and influence their back pain. A small body of literature has suggested that the Alexander method can positively affect postural tone and dynamic adaptability to changes in load and position (1,2,3). The goal of the Alexander technique is to reduce back pain by limiting muscle spasm, strengthening postural muscles, decompressing the spine, and improving coordination and flexibility (for more information on the Alexander technique, visit: www.alexandertechnique.com).

The purpose of this factorial randomized trial was to examine the effectiveness of the Alexander technique, massage therapy, and physician advice to undertake exercise in conjunction with behavioral counseling in a patient population (n=579) with chronic and recurrent LBP. This was the first randomized trial published on this technique, and had a companion published as a cost-analysis (4).
Pertinent Results: Of the 579 subjects who entered the study, 81% (469) completed the questionnaires at 3 months, while 80% completed them at 12 months. The responders at 12 months were more likely to have left full time education later, and be self-employed or homemakers (NOTE: including education and employment in the final analysis did not alter the results of this study).

Pertinent results of this study:
  • the patients had an average of 243 days of pain in the previous year, representing a chronic population (79% reported more than 90 days of pain)
  • overall, little change occurred in the Roland-Morris (RM) scores in the control group
  • at 3 months, significant improvements for all interventions (including massage) were noted compared to the control group for days in pain, and RM scores
  • in the group receiving 24 Alexander lessons – the effect at 12 months was greater than the effect at 3 months (42% reduction in RM score, and 86% reduction in days with pain at 12 months)
  • the effect of only 6 Alexander lessons was maintained at 12 months - demonstrating a 17% reduction in RM scores and 48% reduction in days with pain
  • 24 Alexander lessons had positive effects on all outcomes, while similar but only slightly smaller improvements were seen with 6 lessons followed by exercise
  • 6 lessons of Alexander technique and 6 massage treatments had similar outcomes at three months, but the results of the 6 Alexander lessons lasted through the 12 month point, while the massage benefits did not
  • adherence was good overall – 91% in the massage group, 94% in the group receiving 6 Alexander lessons and 81% in the group receiving 24
  • combining exercise with 24 Alexander lessons did not improve outcomes as much as the addition of exercise to 6 Alexander lessons – in fact, the combination of only 6 lessons with exercise was as effective (~72%) at one year as 24 lessons alone
  • only one adverse reaction was noted in a massage patient, while none were reported in any other intervention
Clinical Application & Conclusions: In this study, exercises and lessons in the Alexander technique improved pain and disability levels at one year in a very chronic LBP patient sample, while massage only demonstrated comparable short-term benefits. One on one lessons from registered Alexander teachers can have positive long-term benefits for chronic LBP patients. As this was a large, multi-center, multi-therapist trial, the results are not likely due to the superior skills of a few clinicians.
Study Methods: 64 general practices were recruited in England, from which 152 therapists agreed to participate. Each practice contacted a random selection of those who had attended their clinics with back pain in the previous five years, resulting in a study population of 579 patients.

Inclusion criteria:
  • presentation in primary care with low back pain more than three months previously (to exclude first episodes)
  • currently scoring 4 or more on the Roland disability scale
  • current pain for three or more weeks (to exclude recurrence of short duration)
Exclusion criteria:
  • previous experience of Alexander technique
  • patients under 18 and over 65 (serious spinal disease more likely)
  • clinical indicators of serious spinal disease
  • current nerve root pain (below knee in dermatomal distribution), previous spinal surgery, pending litigation (outcome may be different, groups too small to analyze)
  • history of psychosis or major alcohol misuse (difficulty completing outcomes)
  • perceived inability to walk 100m (exercise difficult)
Subjects were randomized to one of four treatment groups (each intervention was applied with or without general exercise prescription from a GP, resulting in 8 possible allocations): normal care (n=144), 6 massage therapy treatments (n=147), 6 lessons of Alexander technique (n=144) or 24 lessons of Alexander technique (n=144).

All outcomes were measured at baseline, 3 months and 12 months. The primary outcomes were the Roland-Morris Disability questionnaire and number of days in pain.
Study Strengths/Weaknesses: This study involved numerous treatment centers, teachers and therapists using a pragmatic treatment approach. The patient sample was also large for this type of study. The patients included were generally very chronic in nature, reporting a high number of pain days – these patients are traditionally difficult to treat so any quality studies with favorable outcomes should be viewed as influential and important. This study used simple and validated outcomes, achieved good adherence to treatments, and applied appropriate controls during the statistical analysis.
Additional References:
  1. Cacciatore T et al. Alteration of muscle tone through conscious intervention: increased adaptability of axial and proximal tone through the Alexander technique. Proceedings of the International Society for Posture and Gait Research, Vermont, USA, 14-18 July, 2007; 18.
  2. Cacciatore T, Horak F, Henry S. Improvement in automatic postural coordination following Alexander technique lessons in a person with low back pain. Physical Therapy 2005; 85: 565-578.
  3. Gurfinkel V et al. Postural muscle tone in the body axis of healthy humans. Journal of Neurophysiology 2006; 96: 2678-2687.
  4. Hollinghurst S et al. Randomised controlled trial of Alexander technique lessons, exercise, and massage (ATEAM) for chronic and recurrent back pain: economic evaluation BMJ 2008;337:a2656, doi: 10.1136/bmj.a2656.

Image4: Neck Pain & Active Range of Motion After Manipulation ... top
Research Review by Dr. Shawn Thistle©
Date: Oct. 2006
Study Title: Immediate effects on neck pain and active range of motion after a single cervical high-velocity low-amplitude manipulation in subjects presenting with mechanical neck pain: A randomized controlled trial
Authors: Martinez-Segura R et al.
Publication Information: Journal of Manipulative and Physiological Therapeutics 2006; 29: 511-517.
Summary: Neck pain is a common affliction, with a lifetime incidence between 45-55%. Similar to the lumbar spine, there are many potential pain-generating structures in the cervical spine. Mechanical dysfunction is common in the neck, and can be related to many types of headache complaints, thoracic pain, and functional shoulder problems.

Spinal manipulation is a common method used to treat mechanical neck dysfunction. Clinically, we have all seen immediate effects of manipulation reducing pain (or pressure-pain threshold) and ROM. The literature to date is relatively sparse, but seems to support the idea that manipulation can (at least transiently) increase ROM and reduce pain in the cervical spine. Debate is continuous however, on whether manipulation is superior to mobilization, and whether any advantage justifies the proposed increase in risk.

It has been a number of years since a study was performed investigating immediate results of high-velocity low -amplitude (HVLA) SMT for the cervical spine (I believe Pikula 1999 was the last one). This study from Spain is simple in its design, has a relatively large sample size for this type of study, and is well controlled. As with most studies in this area, patient and therapist blinding is next to impossible.

The aim of this study is evident in the title. Seventy patients (25 males, 45 females aged 25-55 [average 37]) with mechanical neck pain were randomized to the experimental group - which received one HVLA thrust to a dysfunctional segment between C3-C5, or a control group - which received a single manual mobilization procedure.

Patients were included if they satisfied the following criteria…
  1. complaint of mechanical neck pain for at least one month
  2. clinical presentation of C3-C5 joint dysfunction diagnoses with a lateral glide test (essentially a supine joint challenge)
…and excluded if:
  1. SMT was contraindicated
  2. previous diagnosis of fibromyalgia
  3. previous history of whiplash injury or cervical surgery
  4. radiculopathy or myelopathy
  5. underwent SMT treatment within a month of the study
  6. exhibit a positive extension-rotation test (Houle's/George's)
All patients over the age of thirty had plain film radiographs taken of their neck to rule out the presence of excessive degenerative change.

Dysfunctional segments were identified in both groups utilizing a "lateral glide" test - described as a patient-supine joint challenge using the index finger of the examiner's hand. The HVLA manipulation described would be familiar to chiropractors as a routine cervical manipulation utilizing lateral flexion and contralateral rotation. An audible cavitation was noted with all manipulations in this study. The mobilization procedure used in the control group was a standard supine lateral flexion mobilization - held for 30 seconds with no additional thrust. It is important to note that in BOTH GROUPS, the side of treatment was randomized with no regard for palpatory findings.

Active ROM was measured with a cervical goniometer, a reliable measurement tool which has been shown to correlate well with radiographic measurements of cervical flexion and extension. Pain was measured pre/post intervention with a visual analogue scale.

Findings in this study include:
  • there were no significant differences between the experimental and control groups in terms of age, pain level, and ROM
  • in the HVLA SMT group - significant improvements in both pain and ROM were noted post-treatment
  • the control group also improved in pain and ROM, but to a lesser degree, and interestingly not in cervical rotation (the SMT group did increase rotation)
  • remember, both groups received the intervention on a randomized side, which didn't necessarily correlate with their symptomatic side
  • males and females improved equally in both groups
  • a negative correlated was noted between ROM and neck pain - that is, with increased ROM, pain decreased
Conclusions & Practical Application: This study demonstrated that a single manipulation was more effective for reducing pain and increasing active ROM in mechanical neck pain patients. It is important to remember that the mobilization group also improved, but only small to moderate effect sizes were seen compared to the large effects in the SMT group. I think a very interesting finding in this study is the improvement in both groups despite randomizing the side of treatment.

This has a couple of implications. First, SMT may have a non-specific effect that can affect the biomechanics or neurology of the neck regardless of side of application. Also, it may indicate that the therapists in this study were unable to be side-specific with the intervention - that is, the effect of the manipulation may not occur directly at the level it is applied to (as we all know, published literature already suggests that manipulation is relatively non-accurate in the lumbar and thoracic spines).

These results are in agreement with previous studies, and strengthen the existing evidence supporting the immediate effects of cervical SMT on pain and ROM. Although this study does not clarify long-term effects of SMT, most patients with neck pain will appreciate the immediate effects. As always, proper rehabilitation and active care should be employed to facilitate longer-term effects. More studies in this area are certainly required.

The mechanism by which SMT exerts its effect is still being investigated. Popular theories include stimulation of mechanoreceptors in the facet capsules, reflex inhibition of overactive cervical musculature, and "resetting" of muscle spindle activity. A difficult topic to study to say the least, the answer likely lies in a combination of many factors.

Image5: ACL Rehabilitation - Open Vs. Closed Kinetic Chain Exercise ... top
Research Review by Dr. Shawn Thistle©
Date: Feb. 2008
Study Title: A comprehensive rehabilitation program with quadriceps strengthening in closed versus open kinetic chain exercise in patients with anterior cruciate ligament deficiency: A randomized clinical trial evaluating dynamic tibial translation and muscle function
Authors: Tagesson S, Öberg B, Good L, Kvist J
Authors’ Affiliations: Divisions of Physiotherapy, Orthopedics/Sports Medicine, and Clinical and Experimental Medicine, Linköpings Universitet, Linköpings Sweden.
Publication Information: American Journal of Sports Medicine 2008; 36(2): 298-307.
Summary: After an injury to the anterior cruciate ligament (ACL) of the knee, the primary goal of rehabilitation is to restore normal knee function and neuromuscular control. The major components of this objective include rehabilitating muscle strength, proprioception, coordination, and tissue health. One challenge of particular importance in ACL injury rehabilitation is to adequately strengthen the quadriceps. Existing literature suggests that many ACL patients experience continued quadriceps weakness, which has been shown to correlate with poor function after injury.

From a training and rehabilitation perspective, quadriceps strengthening can be achieved in two different ways:
  1. Open Kinetic Chain (OKC): isolate one joint of the kinetic chain with the distal segment free to move (ex. seated leg extension)
  2. Closed Kinetic Chain (CKC): modeled as single linkages, movement in one joint causes simultaneous movement in other joints of the limb (normally with the distal part of the limb planted – ex. squat)
It is generally accepted that CKC exercises are safer than OKC exercises, as they produce lower amounts of anterior shear forces (particularly in the final 30° of extension), and hence they normally form the majority of exercises in an ACL rehabilitation program. Clinical studies have suggested that OCK exercises result in higher anterior tibial translation when compared to CKC exercises, although this tenet is somewhat controversial. Despite this, some clinicians argue that OKC exercises have a role to play, as they do activate and stress the quadriceps considerably.

Patients with ACL deficiency have diminished capacity to withstand anterior shear at the knee joint, with potential for further injury due to increased tension on secondary stabilizers. Thus the question of OCK vs. CKC exercises becomes important, particularly in terms of anterior translation and functional clinical outcomes. Therefore, the aim of this study was to compare the efficacy of a comprehensive rehabilitation program for patients with ACL insufficiency supplemented with either OCK or CKC exercises, on static and dynamic sagittal tibial translation, subjective knee function, and muscle function.

42 patients were randomly assigned to one of two treatment groups (see below) if they met the following inclusion criteria: age between 15-45, with a diagnosis of a unilateral ACL rupture that was no more than 14 weeks old (NOTE: all ACL injuries were verified by MRI imaging and/or arthroscopy). Exclusion criteria included:
  • additional injury to the lower extremity
  • previous surgery to the lower extremity
  • Exceptions: partial injury to the medial meniscus or minor medial collateral ligament injury in the ipsi- or contralateral knee
Treatment Groups:
  1. OCK Group (n = 22): the unique exercises utilized were seated knee extension, as well as standing hip extension
  2. CKC Group (n = 20): the exercise unique to this group was the 1-legged squat (which also served to load the hip extensors)
Each treatment group underwent an identical rehabilitation program aside from the above mentioned exercises, in the following phases:
  1. PHASE 1: protection (weeks 1-4)
  2. PHASE 2: early strength training (weeks 5-8)
  3. PHASE 3: intensive strength training (weeks 9-12)
  4. PHASE 4: intensive strength training and return to sports
Activities included in the program:
  • bicycle, running and cross trainer – progressed as tolerated
  • straight leg raise
  • 2-leg Swissball wall squats
  • 20 cm step-ups
  • variety of balance exercises
  • hip ab/adduction
  • heel raise
  • 1-leg curl
  • lunges
  • slide board
  • 2-leg lateral jumps
  • agility drills and sport-specific activities
Strength exercises were started at 50-60% of 1 repetition maximum (1RM = as determined with the healthy leg) and progressed 70-80% 1RM throughout the phases.

Outcomes were measured at baseline and after 4 months of rehabilitation, and included:
  • passive and active knee ROM
  • joint swelling measured as mid-patella knee joint circumference
  • instrumented Lachman test (CA-4000, OSI Inc., Haywood, California) with the knee in 20° flexion – average of three values using both 90N and 134N of force
  • gait testing with a Kistler Force Plate to measure dynamic anterior translation
  • surface EMG recording (normalized by MVC of non-injured leg) of activity in the vastus medialis, vastus lateralis, hamstrings, lateral gastrocnemius, and gluteus maximus
  • subjective knee function was measured with The Lysham Score and the Knee Osteoarthritis Outcome Score (KOOS)
Pertinent results of this study include:
  • there were no significant between-group differences in joint swelling and passive ROM in the injured knees after rehabilitation, despite both groups having significant swelling and passive ROM limitations before rehab (p < 0.05)
  • Lachman test results were not significantly different for maximal tibial translation between groups for the uninjured leg, injured leg, and the ratio of injured:uninjured before and after rehab
  • there were no significant differences in tibial translation during gait between groups, before or after rehab
  • muscle activation was similar in both groups before and after rehab (p < 0.001)
  • isokinetic strength of the quadriceps in the injured leg (presented as a % of the uninjured leg maximum) was significantly greater in the OKC group compared to the CKC group (p < 0.009) after rehab (note: no hamstring differences were noted)
  • in optimally compliant subjects, the above difference in strength was even greater
Conclusions & Practical Application: This study demonstrated that a comprehensive rehabilitation program supplemented with OKC quadriceps exercise can lead to greater improvements in quadriceps strength compared to a similar program with CKC exercises. It should be emphasized here that both protocols were effective, with no differences noted in anterior tibial translation (statically or dynamically), hamstring strength, and functional outcomes.

This study was limited by a relatively small sample size, poorly defined initial level of injury, low compliance in some subjects, and potential for confounding among the exercises included in the standard program. To elaborate, each group performed Swissball squats and lunges, two CKC exercises. It could therefore be argues that the OKC group did do some CKC exercises, which may cloud the results somewhat. That being said, the significant increase in quadriceps strength in the OKC group in the absence of any untoward effects suggests that OKC exercises may have a role to play in ACL rehab…this should be the take home message from this study. Further research is required.
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