Open Kinetic Chain Exercises Research Articles

The Effectiveness of Traditional and Sling Exercise Strength Training in Women

Strength training often combines closed-kinetic-chain exercises (CKCEs) and open kinetic-chain exercises (OKCEs). The CKCE may be more effective for improving performance in lower-body training. Recently, we reported upper-body CKCE (using a commercially available system of ropes and slings, Redcord AS, Staubo, Norway) was as effective as OKCE training for strength gains and that CKCE was more effective than OKCE for improving throwing performance. To our knowledge the effectiveness of a strength training program that uses exclusively CKCE is unknown. In this study, we examined the effectiveness of CKCE vs. OKCE strength training programs in women enrolled in an introductory strength training program. Twenty-six participants were randomized to OKCE (traditional exercises) or CKCE (sling-based exercises). Participants completed 6 sets per week for 13 weeks. Pre and posttraining evaluations included the following: 1 repetition maximum (1RM) leg and bench press; sling exercise push-ups; isokinetic dynamometry; lateral step-down test; and the Star Excursion Balance Test. Both groups significantly improved bench press (by an average of 4-6 kg) and leg press (by an average of 23-35 kg) (p < 0.001). There was a significant group × time interaction (p < 0.001) for sling exercise push-ups (OKCE pre = 5.5 ± 8.6, OKCE post = 6.1 ± 8.2, CKCE pre = 6.8 ± 6.0, CKCE post = 16.9 ± 6.6). Isokinetic measures of knee extension, knee flexion, shoulder internal rotation, and shoulder external rotation increased (improvements ranged from 2.7 to 27.7%), with no group differences. Both OKCE and CKCE strength training elicited similar changes in balance. We conclude that CKCE training is equally as effective as OKCE training during the initial phases of a strength training program in women. The fact that only CKCE improved sling exercise push-ups supports previous findings suggesting functional superiority of CKCE.

COMPARATIVE ANALYSIS OF ELBOW JOINT LOADING IN PUSH-UP AND BENCH-PRESS

Upper extremity pain and dysfunction are common orthopedic problems in individuals who practice physical activities involving the upper limbs. Push-ups (PUs) and bench-presses (BPs), representing closed kinetic chain (CKC) and open kinetic chain (OKC) exercises, respectively, are among the most popular training exercises for the upper extremity in sports training and clinical rehabilitation applications. Utilizing a self-developed exercise testing model, the present study examines the difference in elbow joint loading between OKC and CKC exercises of the upper extremity. As many as 15 physically healthy male subjects with an average age of 19.8 years (S.D. 1.4), an average height of 176.8 cm (S.D. 4.2), and an average weight of 69.27 kg (S.D. 5.0) were studied. Each subject was asked to perform two different types of exercise, namely PUs and BPs. The kinematics, kinetics, and muscle activation of the elbow joint were calculated and analyzed using laboratory-developed motion analysis procedures. The PU exercises result in a greater loading on the elbow joint than the BP exercises, but produce a lower muscle activation. OKC exercises yield a greater muscle strengthening effect than CKC exercises. The increased shear stress on the elbow joint should be carefully noted when performing PU exercises. The results presented in this study provide valuable information for treatment and rehabilitation purposes in clinical applications.

Exercício físico no tratamento e prevenção de idosos com osteoporose: uma revisão sistemática

INTRODUÇÃO: A atividade física influencia a manutenção das atividades ósseas normais, e por este motivo vem sendo indicada no tratamento da osteoporose. OBJETIVO: Verificar na literatura científica a influência do exercício físico na prevenção e no tratamento da osteoporose em idosos. METODOLOGIA: A presente pesquisa foi sustentada através de revisão sistemática de literatura, com a utilização das bases de dado eletrônicas: LILACS, SciELO e PubMed. Foram utilizados os seguintes descritores na língua portuguesa: osteoporose, exercício físico, idosos, tratamento e prevenção, sendo estes utilizados para pesquisa nas bases LILACS e SciELO; e na língua inglesa, foram utilizados os seguintes: osteoporosis, physical exercise, elderly, prevention e treatment, sendo esta busca realizada na base de dados PubMed. Foram selecionados os resumos que apresentaram critérios iniciais de seleção. RESULTADOS: De um total de 203 artigos encontrados, 27 preencheram os critérios de inclusão e exclusão, sendo que 9 artigos se concentraram no tratamento, 16 na prevenção e 2 no tratamento e na prevenção. Os exercícios que mais se destacaram no tratamento da osteoporose foram os seguintes: exercícios de extensão isométrica de tronco, exercícios em cadeia cinética aberta, coordenação e equilíbrio. Já na prevenção, os mais evidenciados foram: exercícios físicos de alta intensidade, exercícios de alto impacto e exercícios aeróbios. CONCLUSÃO: Pode-se concluir que o exercício físico é dado como fator importante, tanto na prevenção quanto no tratamento do idoso acometido pela osteoporose, e que ele possui especificidades de acordo com o objetivo a ser alcançado.

The Effect of Closed-Kinetic Chain Exercises and Open-Kinetic Chain Exercise on the Muscle Activity of Vastus Medialis Oblique and Vastus Lateralis

Patellofemoral pain syndrome (PFPS) is one of the most prevalent musculoskeletal conditions of the lower limb. The muscle imbalance between the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles is one of the main factors leading to the development of PFPS. The disparity in research and the necessity to add to the existing literature base led to the development of this study. The aim of this study was to investigate the effect of 2 closed kinetic chain exercises and 1 open kinetic chain exercise on VMO and VL muscle activity. Twenty-two healthy asymptomatic individuals participated in this study. The surface electromyography (EMG) of VMO and VL was measured and used to calculate the VMO:VL ratio during 3 different quadriceps-strengthening exercises (a double leg squat with isometric hip adduction exercise, an open kinetic chain knee extension exercise, and a lunge exercise). The double leg squat with isometric hip adduction exercise was shown to produce a significantly greater VMO:VL ratio (1.14:1) than the other 2 exercises (p = 0.015 and p = 0.005). The open kinetic chain knee extension exercises produced significantly greater activation of VL than the lunge exercise (p = 0.001 and p = 0.036). The lunge exercise produced the VMO:VL ratio (1.18:1) closest to the idealized ratio of 1:1. Potential clinical recommendations can be made proposing the lunge exercise as a key tool in early rehabilitation when restoring preferential VMO:VL ratio is essential. The double leg squat with isometric hip adduction exercise would be useful in maintaining correct patella tracking and selectively strengthening VMO.

Effects of Vastus Medialis Oblique Retraining versus General Quadriceps Strengthening on Vasti Onset

To compare the effects of vastus medialis oblique (VMO) motor control retraining (MCR) and quadriceps strengthening (QS) exercises on the onset timing of the medial (VMO) and lateral (vastus lateralis, VL) quadriceps muscle. This single-blind randomized controlled trial involved 60 currently pain-free individuals with a history of anterior knee pain and delayed (>10 ms) onset of VMO relative to VL during stair stepping. A blinded assessor took measures at baseline, immediately after 6 wk of treatment, and after an 8-wk follow-up. Both exercise programs involved weekly individual physiotherapy sessions with home exercises. The MCR program comprised specific VMO exercises incorporating EMG biofeedback, mostly in functional weight-bearing positions. The QS program comprised progressive-resistance inner range open kinetic chain exercises. The primary outcome was the latency between the onset of VMO EMG activity relative to that of VL during stair stepping measured using surface electrodes. During stair ascent, there was a significant change immediately after the intervention in VMO-VL timing in the MCR group only (P = 0.04), but there was no significant difference in the change between groups. During stair descent, VMO-VL timing changed in both groups (P < 0.01), with the MCR group showing a greater change than the QS group (P = 0.02). At the completion of training, quadriceps strength was only improved in the QS group (all P < 0.001). At follow-up, VMO timing and quadriceps strength had improved in both groups compared with baseline (P < 0.01), but there was no difference between groups. Although greater changes in motor control during stair descent and strength are induced by interventions that target each of these parameters in the short term, both parameters are similarly improved after the cessation of training, regardless of the target of the intervention.

Biomechanics of Off-Center Monoarticular Exercises with Lever Selectorized Equipment

We have developed a 2-D analytical biomechanical model for monoarticular open kinetic-chain exercises with lever selectorized equipment, and different relative placement between the joint center of rotation (J) and the center of rotation (C) of the resistance input lever ("off-center" exercises). All the relevant geometrical aspects of such exercises have been characterized: the change with the joint angle of the distance between the resistance pad (P) and J, and of the angle between CP and JP (i.e., the angle between the resistance input lever and the exercising limb). These changes may strongly affect the joint load and the muscle torque in inverse dynamic problems, given the joint kinematics and the mass of the selected weight stack. Therefore, the muscle torque, the shear and axial components of the joint load have been calculated analytically as a function of the relative positioning of C and J, and the length CP, in addition to the parameters that define the joint kinematics, the equipment mechanics, and the external load. From these results we have derived the optimal cam profiles for "off-center" exercises, as well as the geometrical "off-center" setting that minimizes the shear component of the tibiofemoral joint load in leg extension equipment.

The Effects of 6-Week Training Programs on Throwing Accuracy, Proprioception, and Core Endurance in Baseball

With a limited number of outcomes-based studies, only recommendations for strength-training and rehabilitation programs can be made. To determine the extent to which throwing accuracy, core stability, and proprioception improved after completion of a 6-week training program that included open kinetic chain (OKC), closed kinetic chain (CKC), and/or core-stability exercises. A 2 x 3 factorial design. Division III college. 19 healthy baseball athletes with a control group of 15. Two 6-week programs including OKC, CKC, and core-stabilization exercises that were progressed each week. Functional throwing-performance index, closed kinetic chain upper extremity stability test, back-extensor test, 45 degrees abdominal-fatigue test, and right- and left-side bridging test. There was no significant difference between groups. An increase was evident in all pretest-to-posttest results, with improvement ranging from 1.36% to 140%. Both of the 6-week training programs could be used to increase throwing accuracy, core stability, and proprioception in baseball.

ELBOW LOAD DURING DIFFERENT TYPES OF BENCH-PRESS EXERCISE

The bench press is one of the most popular weight training open-kinetic chain exercise (OKCE) for the upper extremity. Reviewing the literature, there is a very little research regarding the biomechanical analysis of the OKCE of the upper extremity. The purpose of this study is to develop an OKCE testing model of the upper extremity by using the 3D Motion Analysis System. Furthermore, elbow joint loading of two different hand grip position during the bench-press exercise will be investigated. Thirteen male students volunteered for the study. Their average age was 26.1 years, with an average height of 170.6 cm, and an average weight of 70.3 kg. With both hands in neutral position, each subject was asked to perform bench-press type 1 (normal shoulder width), and bench-press type 2 (150% shoulder width). During the type 2 bench-press exercise, there is a significant increase in anterior–posterior and medial–lateral force on the elbow joint loading than the type 1 bench-press exercise. The valgus–varus, flexion–extension moment, and supination–pronation moment of the type 2 bench-press exercise are also greater than the type 1 bench-press exercise. As shown in this study, keeping the distance of both hand grips as shoulder width may reduce the elbow joint loading during bench-press exercise. These data will provide helpful information in clinical rehabilitation and treatment of the upper-extremity injures.

Fisioterapia em pacientes com síndrome fêmoro-patelar: comparação de exercícios em cadeia cinética aberta e fechada

Este estudo teve como objetivo comparar a eficácia do fortalecimento muscular na recuperação funcional da síndrome fêmoro-patelar (SFP). Foram selecionadas 20 mulheres com SFP divididas em dois grupos: o Grupo 1 (G1) realizou fortalecimento do músculo quadríceps femoral em cadeia cinética aberta (CCA) e o Grupo 2 (G2) em cadeia cinética fechada (CCF), durante oito semanas com freqüência de duas vezes semanais. Foi avaliada a dor, capacidade funcional, flexibilidade, encurtamento dos músculos isquiotibiais, ângulo Q e eletromiografia (EMG) dos músculos vasto medial (VM) e vasto lateral (VL) durante extensão isométrica da perna. Antes e após o tratamento, as variáveis foram analisadas pelo teste de Wilcoxon, e entre os grupos pelo teste t para amostras independentes ou Anova de Friedman ou Manova (a&lt;0,05). Após o tratamento, os resultados mostram que houve melhora da capacidade funcional, encurtamento dos músculos isquiotibiais e flexibilidade. Porém, somente o G1 apresentou diminuição da intensidade da dor e aumento da atividade EMG do músculo VL, enquanto ambos não modificaram o ângulo Q. Os dados sugerem que os tratamentos baseados no fortalecimento do músculo quadríceps femoral possibilitaram melhoras importantes nos principais sinais e sintomas apresentados pelas pacientes, não havendo diferenças evidentes entre os realizados em CCA e CCF.

A Comprehensive Rehabilitation Program with Quadriceps Strengthening in Closed versus Open Kinetic Chain Exercise in Patients with Anterior Cruciate Ligament Deficiency

Background There is no consensus regarding the optimal rehabilitation regimen for increasing quadriceps strength after anterior cruciate ligament (ACL) injury. Hypothesis A comprehensive rehabilitation program supplemented with quadriceps strengthening in open kinetic chain (OKC) exercise will increase quadriceps strength and improve knee function without increasing static or dynamic sagittal tibial translation, compared with the same comprehensive rehabilitation program supplemented with quadriceps strengthening in closed kinetic chain (CKC) exercise, in patients with acute ACL deficiency. Study Design Randomized controlled trial; Level of evidence, 1. Methods Forty-two patients were tested a mean of 43 days (range, 20–96 days) after an ACL injury. Patients were randomized to rehabilitation with CKC quadriceps strengthening (11 men and 9 women) or OKC quadriceps strengthening (13 men and 9 women). Aside from these quadriceps exercises, the 2 rehabilitation programs were identical. Patients were assessed after 4 months of rehabilitation. Sagittal static translation and dynamic tibial translation were evaluated with a CA-4000 electrogoniometer. Muscle strength, jump performance, and muscle activation were also assessed. Functional outcome was evaluated by determining the Lysholm score and the Knee Injury and Osteoarthritis Outcome Score. Results There were no group differences in static or dynamic translation after rehabilitation. The OKC group had significantly greater isokinetic quadriceps strength after rehabilitation (P = .009). The hamstring strength, performance on the 1-repetition-maximum squat test, muscle activation, jump performance, and functional outcome did not differ between groups. Conclusions Rehabilitation with OKC quadriceps exercise led to significantly greater quadriceps strength compared with rehabilitation with CKC quadriceps exercise. Hamstring strength, static and dynamic translation, and functional outcome were similar between groups. Patients with ACL deficiency may need OKC quadriceps strengthening to regain good muscle torque.

Early versus late start of open kinetic chain quadriceps exercises after ACL reconstruction with patellar tendon or hamstring grafts: a prospective randomized outcome study

The purpose of the present investigation was to evaluate physical outcome after anterior cruciate ligament (ACL) reconstruction with early versus late initiation of open kinetic chain (OKC) exercises for the quadriceps in patients operated on either patellar tendon or hamstring grafts. Sixty-eight patients, 36 males and 32 females, with either patellar tendon graft (34 patients) or hamstring graft (34 patients) were enrolled in this study. All patients were randomly allocated to either early (the 4th postoperative week) or late (the 12th postoperative week) start of OKC exercises for the quadriceps, resulting in four subgroups: patellar tendon reconstruction, early start (P4) or late start (P12) of OKC quadriceps exercises, hamstring tendon reconstruction, early start (H4) or late start (H12) of quadriceps OKC exercises. Prior to surgery and 3, 5 and 7 months later, assessments of range of motion (goniometer), anterior knee laxity (KT-1000), postural sway (KAT 2000), thigh muscle torques (Kin-Com dynamometer) and anterior knee pain (anterior knee pain score) were evaluated. No significant group differences were found in terms of range of motion 3, 5 and 7 months postoperatively. The H4 group showed a significantly higher mean difference of laxity over time of 1.0 mm (CI: 0.18-1.86) than the P4 group (P=0.04). Within the same type of surgery, the H4 against the H12, the mean difference over time was 1.2 mm (0.37-2.1) higher in the H4 group than in the H12 group (P=0.01). There were no significant group differences in terms of postural sway or anterior knee pain at the different test occasions. Significant differences in trends (changes over time) were found when comparing the four groups, for both quadriceps muscle torques (P<0.001) and hamstring muscle torques (P<0.001). All groups, except the P4 group, reached preoperative values of quadriceps muscle torques at the 7 months follow-up. In the H4 and the H12 groups, significantly lower hamstring muscle torques at the 7 months follow-up compared with preoperative values were found. In conclusion, early start of OKC quadriceps exercises after hamstring ACL reconstruction resulted in significantly increased anterior knee laxity in comparison with both late start and with early and late start after bone-patellar tendon-bone ACL reconstruction. Furthermore, the early introduction of OKC exercises for quadriceps did not influence quadriceps muscle torques neither in patients operated on patellar tendon nor hamstring tendon grafts. On the contrary, it appears as if the choice of graft affected the strength of the specific muscle more than the type of exercises performed. Our results could not determine the appropriate time for starting OKC quadriceps exercises for patients who have undergone ACL reconstruction with hamstring tendon graft. Future studies of long-term results of anterior knee laxity and functional outcome are needed.

Evaluation of the Effect of Two Exercise Regimes in Producing Forces on Anterior Cruciate Ligaments: A Systematic Review

Background: Anterior cruciate ligament (ACL) injuries are common. A goal of rehabilitation is to restore functional capacity. Currently, there are contrary opinions regarding the effectiveness of using either closed or open kinetic chain exercises (CKC, OKC) only, or a combination of both, following ACL injury, to obtain the most effective outcome. The debate also reflects the approach which places the least force on the ACL itself. Objective: To identify the evidence of effectiveness of closed versus open kinetic chain exercises, or a combination of both, in anterior cruciate ligament rehabilitation. Methods: A systematic review was undertaken of experimental studies published since 1990. Included studies were on humans with ACL injury. The ACL ligament could be healthy, ruptured, deficient or reconstructed. Studies on animals and cadavers were excluded. The methodological quality of included studies was appraised with the PEDro tool. Studies were graded according to hierarchy level, methodological quality, statistical significance, effect size, and clinical relevance. Recommendations were made on the strength of the body of evidence. The outcome measure of interest was force on the ACL during exercise. Results: 23 eligible studies were included. The majority of studies reflected lower level experimental designs with moderate methodological quality. Three studies showed a significant difference in ACL force comparing CKC and OKC exercises, 11 demonstrated trends towards significant differences in outcome and nine showed no significant differences. Conclusion: There is moderate evidence to recommend CKC exercises or a combination of CKC and OKC exercises, rather than OKC exercises alone, for ACL rehabilitation when considering forces on the ACL.

The transition from a closed to an open kinetic chain exercise: A modeling perspective

The transition from a closed to an open kinetic chain exercise: A modeling perspective

Physiotherapy following elective orthopaedic procedures

As haemophilic arthropathy and chronic synovitis are still the most important clinical features in people with haemophilia, different kinds of invasive and orthopaedic procedures have become more common during the last decades. The availability of clotting factor has made arthroplasty of one, or even multiple joints possible. This article highlights the role of physiotherapy before and after such procedures. Synovectomies are sometimes advocated in people with haemophilia to stop repetitive cycles of intra-articular bleeds and/or chronic synovitis. The synovectomy itself, however, does not solve the muscle atrophy, loss of range of motion (ROM), instability and poor propriocepsis, often developed during many years. The key is in taking advantage of the subsequent, relatively safe, bleed-free period to address these important issues. Although the preoperative ROM is the most important variable influencing the postoperative ROM after total knee arthroplasty, there are a few key points that should be considered to improve the outcome. Early mobilization, either manual or by means of a continuous passive mobilization machine, can be an optimal solution during the very first postoperative days. Muscle isometric contractions and light open kinetic chain exercises should also be started in order to restore the quadriceps control. Partial weight bearing can be started shortly after, because of quadriceps inhibition and to avoid excessive swelling. The use of continuous clotting factor replacement permits earlier and intensive rehabilitation during the postoperative period. During the rehabilitation of shoulder arthroplasty restoring the function of the rotator cuff is of utmost importance. Often the rotator cuff muscles are inhibited in the presence of pain and loss of ROM. Physiotherapy also assists in improving pain and maintaining ROM and strength. Functional weight-bearing tasks, such as using the upper limbs to sit and stand, are often discouraged during the first 6 weeks postoperatively. This may be influenced by the condition of the joints of the lower limbs. Attention should be given to the total chain of motion, of which the shoulder itself is only a part. We conclude that physiotherapy management is of major importance in any invasive or orthopaedic procedure, regardless of which joints are involved. Both pre- and postoperative physiotherapy, as part of comprehensive care is needed to achieve optimal functional outcome and therefore optimal quality of life for people with haemophilia.

The Effect of a Toe-Heel Pedal Exercise Machine

Muscle strengthening exercise in Open Kinetic Chain (OKC) and muscle strengthening exercise in Closed Kinetic Chain (CKC) with a Toe-Heel Pedal Exercise Machine were performed, and were compared the results of knee proprioception tests (threshold test / position sense test). The subjects were 17 patients who had received total knee arthroplasty. They were assigned to either group A (OKC exercise group, n = 9) or group B (CKC exercise group, n = 8). The effect of 3-week exercise therapy was evaluated as the outcome of the knee proprioception tests. In group A, improvement rates were 3.8 ± 6.9% in the threshold test and 7.6 ± 10.7% in the position sense test. In group B, improvement rates were 25.2 ± 4.9% in the threshold test and 27.6 ± 8.2% in the position sense test. Thus, the group of muscle strengthening exercises in CKC with the Toe-Heel Pedal Exercise Machine showed higher improvement rates both in the threshold test and the position sense test.

Open- or Closed-Kinetic Chain Exercises After Anterior Cruciate Ligament Reconstruction?

Open-kinetic chain (OKC) and closed-kinetic chain (CKC) exercises may not differ in their effects on the healing response of the anterior cruciate ligament (ACL)-reconstructed knee. Recent biomechanical studies have shown that the peak strains produced on a graft are similar. Clinical studies suggest that both play a beneficial role in the early rehabilitation of the reconstructed knee.

Basic principles of aggressive rehabilitation after anterior cruciate ligament reconstruction

Rehabilitation after ACL (anterior cruciate ligament) reconstruction has drastically changed over the last decade, with the adoption of a more aggressive approach, right from the first day after surgery. Progress in the effectiveness of rehabilitation is based on improvements in operative techniques, as well as on the encouraging results of histological studies regarding graft healing. Despite a huge amount of research papers on this topic, a rehabilitation golden standard still has not been established, due to the complexity of this problem. In this review, we point out the basic principles of rehabilitation after arthroscopically assisted ACL reconstruction based on actual practices, as well as the importance of specific procedures for the prevention of complications during the postoperative period. The importance of range-of-motion exercises, early weight bearing, an appropriate gait scheme, patella mobilisation, pain and oedema control, as well as stretching and balance exercises is explained. The functional advantages of closed kinetic chain exercises, as well as their influence on the graft are also described, in comparison to open kinetic chain exercises. The fundamentals of returning to sports are revealed and the specific aspects of rehabilitation regarding graft choice are pointed out. While waiting for new clinical investigations, which are expected to enable the establishment of a rehabilitation golden standard, the outlined principles should be followed. The complexity of this injury requires treatment in highly specialised institutions.

Open versus Closed Kinetic Chain Exercises in Patellofemoral Pain

Background Today, no clinical studies have been undertaken to examine the long-term effects of an open kinetic chain or closed kinetic chain program. Hypothesis The long-term follow-up results after a conservative exercise protocol are significantly worse than the short-term results. The long-term effect of closed kinetic chain training is significantly better compared to the effect of open kinetic chain training. Study Design Prospective randomized clinical trial. Methods Sixty patients were randomized into a 5-week conservative program, consisting of only closed kinetic chain exercises or only open kinetic chain exercises. Assessment of muscular characteristics, subjective symptoms, and functional performance was evaluated in this study at the time of initial physical examination, at the end of the treatment period, and 5 years later. Results At the 5-year follow-up, both groups demonstrated maintenance of good subjective and functional outcomes achieved immediately after the conservative treatment. No significant difference between both groups was observed at the 5-year follow-up for the majority of the examined parameters. However, on 3 of the 18 visual analog scales, the open kinetic chain group showed significantly less complaints compared to the closed kinetic chain group. Conclusions On the basis of these results, the authors conclude that both open kinetic chain and closed kinetic chain programs lead to an equal long-term good functional outcome.

A systematic review of evidence for anterior cruciate ligament rehabilitation: how much and what type?

This paper provides an evidence-based review of the effectiveness of various rehabilitation programs that have been used for surgically or non-surgically treated anterior cruciate ligament (ACL) injuries in adult patients. The methodological quality of the studies was assessed using specific criteria. The databases disclosed 33 randomized clinical trials (RCTs). Several of the RCTs in this systematic review have significant flaws, and limited evidence could be derived from them. The review of the literature revealed the following evidence for ACL rehabilitation: Immediate weight-bearing after ACL reconstruction is useful, rehabilitation programs must be monitored by a physical therapist, but continuously monitoring may not be necessary. The literature supports the use of closed kinetic chain exercises at knee joint motions of less than 60° and open kinetic chain exercises with knee flexion angles greater than 40° for quadriceps muscle strength training without increasing the strain on the ACL, and without increased stresses on the patellofemoral joint. There is evidence that high intensity neuromuscular electrical stimulation in addition to volitional exercises significantly improves isometric quadriceps muscle strength compared to volitional exercises alone. There is some evidence for neuromuscular training. Future studies should focus on high quality RCTs, reporting randomization procedures, power calculations, compliance to intervention programs, and long term follow-up results.

Exercise therapy for patellofemoral pain syndrome.

Patellofemoral pain syndrome (PFPS) is a common problem among adolescents and young adults, characterised by retropatellar pain (behind the kneecap) or peripatellar pain (around the kneecap) when ascending or descending stairs, squatting or sitting with flexed knees. Etiology, structures causing the pain and treatment methods are all debated in literature, but consensus has not been reached so far. Exercise therapy to strengthen the quadriceps is often prescribed, though its efficacy is still debated. This review aims to summarise the evidence of effectiveness of exercise therapy in reducing anterior knee pain and improving knee function in patients with PFPS. We searched the Cochrane Musculoskeletal Injuries Group and Cochrane Rehabilitation and Related Therapies Field specialised registers, the Cochrane Controlled Trials Register, PEDro - The Physiotherapy Evidence Database, MEDLINE, EMBASE, CINAHL, up till December 2001 for controlled trials (randomised or not) comparing exercise therapy with control groups, or comparing different types of exercise therapy. Only trials focusing on exercise therapy in patients with PFPS were considered. Trials in patients with other diagnoses such as tendinitis, Osgood Schlatter syndrome, bursitis, traumatic injuries, osteoarthritis, plica syndrome, Sinding-Larssen-Johansson syndrome and patellar luxations were excluded. From 750 publications 12 trials were selected. All included trials studied quadriceps strengthening exercises. Outcome assessments for knee pain and knee function in daily life were used in a best evidence synthesis to summarise evidence for effectiveness. One high and two low quality studies used a control group not receiving exercise therapy. Significantly greater pain reduction in the exercise groups was found in one high and one low quality study, though at different time points. Only one low quality study reported significantly greater functional improvement with exercise. Five studies compared exercise therapies that could be designated closed kinetic chain exercise (foot in contact with a surface) versus open kinetic chain exercise (foot not in contact with a surface). Two of these studies were of high quality, but no significant differences in improvement of function or reduction of pain were apparent between the types of exercise in any of the studies. The remaining four studies, all of which were of low quality, focused on other treatment comparisons. The evidence that exercise therapy is more effective in treating PFPS than no exercise was limited with respect to pain reduction, and conflicting with respect to functional improvement. There is strong evidence that open and closed kinetic chain exercise are equally effective. Further research to substantiate the efficacy of exercise treatment compared to a non-exercising control group is needed, and thorough consideration should be given to methodological aspects of study design and reporting.