Eccentric Strengthening Research Articles

Letter to the Editor and Response

We welcome the opportunity to respond to the informative letter regarding the terminology of concentric and eccentric. We certainly agree that it is exceedingly important to be as precise and accurate as possible when using these and any scientific terminology. The authors of the letter astutely point out the difference in terminology between movement of a single muscle compared with movement of a limb or body, with which we absolutely agree. However, we believe that we (as well as several other authors) have used the terms concentric and eccentric correctly as defined by the authors of the letter. In our article concerning eccentric strengthening for chronic lateral epicondylosis,1 the specific single muscle-tendon unit targeted by the eccentric exercise is the extensor carpi radialis brevis (ECRB). Perhaps we are guilty of not being precise enough in pointing out the difference between the eccentric contraction of the ECRB compared with the “extension” motion of the wrist along with the antagonist shortening of the wrist flexor muscle group. Instead, we expected the reader to assume that it should be understood without specifying that the term eccentric refers specifically to the ECRB, rather than the entire wrist or upper extremity. We suspect that many other authors have similarly been imprecise about specifying whether the terms concentric or eccentric refer to specific muscles or entire limb or body motions, even though their implicit meaning was for the terms to apply to single muscles. We agree that nonspecific use of these terms is perhaps more obvious when referring to landing from a jump or run unless a specific muscle is being studied in isolation, and hence, the terms are referring to that specific muscle. There seems to be a slight discordance between the precise theoretical scientific meanings of concentric and eccentric and the more practical clinical meanings. Perhaps, as the letter points out, the practical clinical use of the terms should more carefully specify a particular muscle if that is indeed the intent of the terms.

THE EFFECTIVENESS OF AN INTENSIVE EXERCISE PROGRAMME IN THE FUNCTIONAL RECOVERY OF A SEVERE DEGENERATIVE ACHILLES TENDINOPATHY. IS IT ENOUGH BY ITSELF? A CASE REPORT

IntroductionAchilles tendinopathy (AT) is classically known to be very resistant to treatment. Although other diagnoses such as bursitis and insertional problems have been described, the most common pathology is mid-portion...

Impact of autologous blood injections in treatment of mid-portion Achilles tendinopathy: double blind randomised controlled trial

Objective To assess the effectiveness of two peritendinous autologous blood injections in addition to a standardised eccentric calf strengthening programme in improving pain and function in patients with mid-portion Achilles...

Clinical and Morphological Changes Following 2 Rehabilitation Programs for Acute Hamstring Strain Injuries: A Randomized Clinical Trial

Randomized, double-blind, parallel-group clinical trial. To assess differences between a progressive agility and trunk stabilization rehabilitation program and a progressive running and eccentric strengthening rehabilitation program in recovery characteristics following an acute hamstring injury, as measured via physical examination and magnetic resonance imaging (MRI). Determining the type of rehabilitation program that most effectively promotes muscle and functional recovery is essential to minimize reinjury risk and to optimize athlete performance. Individuals who sustained a recent hamstring strain injury were randomly assigned to 1 of 2 rehabilitation programs: (1) progressive agility and trunk stabilization or (2) progressive running and eccentric strengthening. MRI and physical examinations were conducted before and after completion of rehabilitation. Thirty-one subjects were enrolled, 29 began rehabilitation, and 25 completed rehabilitation. There were few differences in clinical or morphological outcome measures between rehabilitation groups across time, and reinjury rates were low for both rehabilitation groups after return to sport (4 of 29 subjects had reinjuries). Greater craniocaudal length of injury, as measured on MRI before the start of rehabilitation, was positively correlated with longer return-to-sport time. At the time of return to sport, although all subjects showed a near-complete resolution of pain and return of muscle strength, no subject showed complete resolution of injury as assessed on MRI. The 2 rehabilitation programs employed in this study yielded similar results with respect to hamstring muscle recovery and function at the time of return to sport. Evidence of continuing muscular healing is present after completion of rehabilitation, despite the appearance of normal physical strength and function on clinical examination. Therapy, level 1b-.

Recurrent hamstring muscle injury: applying the limited evidence in the professional football setting with a seven-point programme

Recurrent hamstring injuries are a major problem in sports such as football. The aim of this paper was to use a clinical example to describe a treatment strategy for the...

Effect of Eccentric Strengthening on Pain, Muscle Strength, Endurance, and Functional Fitness Factors in Male Patients with Achilles Tendinopathy

The aim of this study was to investigate the effect of eccentric strengthening on pain, muscle strength, endurance, and functional fitness factors in Achilles tendinopathy patients. Thirty-two male patients with Achilles tendinopathy were assigned to either the experimental group that performed eccentric strengthening or the control group that performed concentric strengthening (n = 16, both groups) for 8 wks (50 mins per day, three times per week). A visual analog scale, an isokinetic muscle testing equipment, the side-step test, and the Sargent jump test were used to assess pain, muscle strength, endurance, and functional fitness factors before and after the intervention. In comparison with the control group, the experimental group showed significant improvement in pain, ankle dorsiflexion endurance, total balance index, and agility after the intervention (P < 0.05). However, there was no significant difference in dexterity between the two groups. Eccentric strengthening was more effective than concentric strengthening in reducing pain and improving function in patients with Achilles tendinopathy; therefore, regular eccentric strengthening is important for patients in a clinical setting.

Eccentric Peak Torque Analysis of Subjects Suffering from Chronic Ankle Instability

The purpose of this study was to examine the effect of chronic ankle instability (CAI) on eccentric peak torque of the ankle musculature. The study included fifty participants divided into two groups; the first group consisted of twenty five subjects suffering from CAI, the second group consisted of twenty five subjects with no prior history of ankle injury as control group. Eccentric peak torque of invertors, evertors, plantar-flexors and dorsiflexors was recorded for each participant at angular velocities 30 and 90o/sec by using (Biodex Medical Systems, Inc, Shirley, NY, USA). Analysis of variance (ANOVA) revealed that there was a significant deficit for eccentric inversion, eversion, and plantar flexion peak torques between CAI group and control group at both angular velocities (p 0.05). There was no significant increase in eccentric torque of invertors, evertors, plantar-flexors and dorsiflexors when the angular velocity increased from 30 to 90°/sec for normal and CAI group (p> 0.05). Eccentric strengthening of invertors, evertors, and plantar-flexors must be considered during rehabilitation of subjects suffering from chronic ankle instability.

Effect of Eccentric Strengthening After Anterior Cruciate Ligament Reconstruction on Quadriceps Strength

Interventions aimed at safely overloading the quadriceps muscle after anterior cruciate ligament (ACL) reconstruction are essential to reducing quadriceps muscle weakness that often persists long after the rehabilitation period. Despite the best efforts of clinicians and researchers to improve ACL rehabilitation techniques, a universally effective intervention to restore preinjury quadriceps strength has yet to be identified. A muscle's force-producing capacity is most optimal when an external force exceeds that of the muscle while the muscle lengthens. Hence, the potential to improve muscle strength by overloading the tissue is greater with eccentric strengthening than with concentric strengthening. Traditionally, the application of early postoperative high-intensity eccentric resistance training to the ACL-reconstructed limb has been contraindicated, as there is potential for injury to the ACL graft, articular cartilage, or surrounding soft-tissue structures. However, recent evidence suggests that the application of early, progressive, high-force eccentric resistance exercises to the involved limb can be used to safely increase muscle volume and strength in ACL-reconstructed individuals. As a result, eccentric strengthening may be another attractive alternative to traditional concentric strengthening to improve quadriceps strength after ACL reconstruction. In patients who have undergone ACL reconstruction, is there evidence to suggest that eccentric exercise positively affects postoperative quadriceps strength?

Efeito dos exercícios de fortalecimento e alongamento sobre a rigidez tecidual passiva

INTRODUÇÃO: Níveis excessivos ou reduzidos de rigidez passiva dos músculos, tendões, ligamentos e fáscias podem estar relacionados à ocorrência de disfunções de movimento e ao desenvolvimento de lesões musculoesqueléticas. O tratamento dessas condições comumente envolve a aplicação de técnicas voltadas para alterar a rigidez, tais como fortalecimento ou alongamento. OBJETIVO: Realizar uma revisão crítica da literatura para investigar os efeitos de exercícios de fortalecimento e alongamento sobre a rigidez tecidual passiva. MATERIAIS E MÉTODOS: Foi realizada consulta aos bancos de dados Medline, Scielo, Lilacs e PEDro. Foram incluídos estudos experimentais realizados em animais ou humanos, sem limite de data. RESULTADOS: Foram selecionados 20 estudos que investigaram o efeito do fortalecimento sobre a rigidez passiva e 13 que pesquisaram o efeito de programas de alongamento sobre a rigidez passiva. CONCLUSÃO: Os estudos sugerem que exercícios de fortalecimento de alta intensidade são capazes de aumentar os níveis de rigidez tecidual tanto em animais quanto em humanos. O aumento da área de secção transversa e modificações na composição dos tecidos são alguns dos mecanismos responsáveis por esse aumento. Em relação ao fortalecimento muscular em posição alongada e ao fortalecimento excêntrico em toda amplitude com carga moderada, os resultados são insuficientes para afirmar sobre o real efeito dessas técnicas em reduzir os níveis de rigidez. Por fim, programas de alongamento estático ou do tipo contrai-relaxa parecem reduzir a rigidez tecidual quando realizados por meio de protocolos de longa duração e/ou alta frequência.

Eccentric strengthening effect of hip-adductor training with elastic bands in soccer players: a randomised controlled trial

BackgroundSoccer players with weak hip-adductor muscles are at increased risk of sustaining groin injuries. Therefore, a simple hip-adductor strengthening programme for prevention of groin injuries is needed.ObjectiveWe aimed to investigate...

Eccentric hamstring muscle training can prevent hamstring injuries in soccer players

Does eccentric muscle training of hamstring muscles reduce the rate of hamstring injuries in male soccer players? Cluster randomised, controlled trial with concealed allocation. The 5 top men's soccer divisions in Denmark. First team squad soccer players from teams in the top 5 national soccer divisions were included. Players who joined a team after the start of the trial were excluded. Randomisation of 54 teams allocated 26 to the intervention group and 28 to a control group. Both groups followed their usual training program. In addition, the intervention group completed 27 sessions of the eccentric hamstring muscle training in a 10-week period during the midseason break, and once a week in the second half of the season. The hamstring exercise (the Nordic curl) involves the player using hamstrings to resist forward falling of the trunk from a kneeling position. Players completed 2-3 sets of 5-12 repetitions of the exercise for 1-3 sessions per week. The primary outcome was the number of overall, new, and recurrent acute hamstring injuries during one full soccer season. A hamstring injury was defined as any acute physical complaint in the region of the posterior thigh sustained during a soccer match or training. Recurrence of an injury already reported in the trial period was not included to avoid recording the same injury more than once. 50 teams with 942 players completed the study. At the end of the season, there had been 15 hamstring injuries (12 new, 3 recurrent) in the eccentric hamstring exercise group and 52 injuries (32 new, 20 recurrent) in the control group. The number needed to treat (NNT) to prevent 1 hamstring injury (new or recurrent) was 13 (95% CI 9 to 23). The NNT to prevent 1 new injury was 25 (95% CI 15 to 72) and the NNT for recurrent injury was 3 (95% CI 2 to 6). Apart from short term muscle soreness no adverse events were reported in the exercise group. An eccentric strengthening exercise program for the hamstring muscles that can be performed during training can help prevent hamstring injuries in soccer players.

Preventive Effect of Eccentric Training on Acute Hamstring Injuries in Men’s Soccer

Background: The incidence of acute hamstring injuries is high in several sports, including the different forms of football. Purpose: The authors investigated the preventive effect of eccentric strengthening of the hamstring muscles using the Nordic hamstring exercise compared with no additional hamstring exercise on the rate of acute hamstring injuries in male soccer players. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Fifty Danish male professional and amateur soccer teams (942 players) were allocated to an intervention group (461 players) or a control group (481 players). Players in the intervention group conducted a 10-week progressive eccentric training program followed by a weekly seasonal program, whereas players in the control group followed their usual training program. The main outcome measures were numbers of overall, new, and recurrent acute hamstring injuries during 1 full soccer season. Results: Fifty-two acute hamstring injuries in the control group compared with 15 injuries in the intervention group were registered. Comparing intervention versus the control group, overall acute hamstring injury rates per 100 player seasons were 3.8 versus 13.1 (adjusted rate ratio [RR], 0.293; 95% confidence interval [CI], 0.150-0.572; P < .001). New injury rates per 100 player seasons were 3.1 versus 8.1 (RR, 0.410; 95% CI, 0.180-0.933; P = .034), whereas recurrent injury rates per 100 player seasons were 7.1 versus 45.8 (RR, 0.137; 95% CI, 0.037-0.509; P = .003). Number needed to treat [NNT] to prevent 1 acute hamstring injury (new or recurrent) is 13 (95% CI, 9-23) players. The NNT to prevent 1 new injury is 25 (95% CI, 15-72) players, and NNT to prevent 1 recurrent injury is 3 (95% CI, 2-6) players. Conclusion: In male professional and amateur soccer players, additional eccentric hamstring exercise decreased the rate of overall, new, and recurrent acute hamstring injuries.

Platelet-Rich Plasma Versus Autologous Whole Blood for the Treatment of Chronic Lateral Elbow Epicondylitis

Background: Chronic lateral elbow epicondylitis is a tendinosis with angiofibrolastic degeneration of the wrist extensors’ origin. Healing of this lesion is reported with the use of autologous blood as well as with platelet-rich plasma (PRP). Purpose: A comparative study of these 2 treatments was conducted in an effort to investigate the possible advantages of PRP. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Twenty-eight patients were divided equally into 2 groups, after blocked randomization. Group A was treated with a single injection of 3 mL of autologous blood and group B with 3 mL of PRP under ultrasound guidance. A standardized program of eccentric muscle strengthening was followed by all patients in both groups. Evaluation using a pain visual analog scale (VAS) and Liverpool elbow score was performed at 6 weeks, 3 months, and 6 months. Results: The VAS score improvement was larger in group B at every follow-up interval but the difference was statistically significant only at 6 weeks, when mean improvement was 3.8 points (95% confidence interval [CI], 3.1-4.5) in group B (61.47% improvement) and 2.5 points (95% CI, 1.9-3.1) in group A (41.6% improvement) (P < .05). No statistically significant difference was noted between groups regarding Liverpool elbow score. Conclusion: Regarding pain reduction, PRP treatment seems to be an effective treatment for chronic lateral elbow epicondylitis and superior to autologous blood in the short term. Defining details of indications, best PRP concentration, number and time of injections, as well as rehabilitation protocol might increase the method’s effectiveness. Additionally, the possibility of cost reduction of the method might justify the use of PRP over autologous whole blood for chronic or refractory tennis elbow.

Addition of Isolated Wrist Extensor Eccentric Exercise to Standard Treatment for Chronic Lateral Epicondylosis: A Prospective Randomized Trial

This prospective randomized trial found that an eccentric strengthening program produced significant improvements in pain, strength, and functional ability compared with a standard therapy approach in the treatment of lateral elbow tendinosis.

Eccentric Strengthening for Chronic Lateral Epicondylosis

Background:Effective treatments for chronic lateral epicondylosis have not been studied adequately. Eccentric overload exercises have been used with success for other chronic tendinopathy, mainly Achilles and patellar.Hypothesis/Purpose:To compare a wrist extensor eccentric strengthening exercise program with a wrist extensor stretching/modality program for the treatment of chronic lateral epicondylosis. The authors hypothesized that the eccentric strengthening program would produce more favorable results than a stretching/modality program.Study Design:Prospective randomized controlled trial.Methods:Twenty-eight adults with lateral epicondylosis of greater than 4 weeks’ duration were randomized to an eccentric strengthening group or a stretching group. Exercises were taught by a physical therapist, and participants performed most of the exercises on their own at home. Pain scores with visual analog scale from 0 to 100 were obtained at baseline and then at 4, 8, 12, 16, and 20 weeks after the start of the exercise program.Results:Both groups improved their pain scores from baseline to the 4-week time point, followed by nonsignificant further decreases in pain scores thereafter. No statistically significant differences were found between the eccentric strengthening group and stretching groups at any follow-up time point.Conclusions:Despite previous reports documenting favorable results with eccentric exercises for other tendinopathy, the authors were unable to show any statistical advantage to eccentric exercises for lateral epicondylosis during these periods compared with local modalities and stretching exercises.

A 17-Year-Old Ballet Dancer with Medial Ankle Pain

A 17-Year-Old Ballet Dancer with Medial Ankle Pain

Rééducation accélérée après ligamentoplastie par la technique DIDT par un protocole simple et adapté à chacun

With most procedures of rehabilitation following reconstruction of the anterior cruciate ligament that was treated though the technique of ligamentoplasty using gracilis and semi-tendinous, the hamstring can’t resume activity until four to six weeks after the operation. Comparing the engraftment of post-traumatic muscle damage, the described rehabilitation procedure is an accelerated procedure that uses early eccentric strengthening of the hamstring starting on day 8. This is achieved first by manual resistance until day 21 then on a hamstring chair from day 21 to day 45. The aim of such a treatment is not to resume sporting activity more quickly, but to ensure that the conditions for recovery are optimized. The described treatment also presents some limitations and should therefore be applied with caution so as not to jeopardize the ultimate recovery of the ligament.

Evaluation of an exercise concept focusing on eccentric strength training of the rotator cuff for patients with subacromial impingement syndrome

Objective: To evaluate the effect on pain intensity and function of an exercise concept focusing on specific eccentric strength training of the rotator cuff in patients with subacromial impingement syndrome. Design: Single-subject research design with baseline and treatment phases (AB design). Setting: Home-based training programme supervised and supported by visits to physiotherapy clinic. Subjects: Ten patients, mean (SD) age 54 (8.6) years, symptom duration 12 (9.1) months. Intervention: Daily eccentric strengthening exercises of the rotator cuff during 12 weeks. Main measures: Primary outcome measures: Pain intensity, assessed with a visual analogue scale, and function, using the Patient-Specific Functional Scale. Secondary outcome measures: Shoulder function evaluated with the Constant score, and shoulder-related quality of life evaluated with the Western Ontario Rotator Cuff Index. Results: Pain intensity decreased significantly in eight of the ten subjects. Function improved significantly in all ten subjects. Constant score increased in nine subjects and Western Ontario Rotator Cuff Index increased in seven subjects. Mean Constant score for the whole group increased significantly from 44 to 69 points (P = 0.008). Mean Western Ontario Rotator Cuff Index increased from 51 to 71% (P = 0.021). Conclusion: A 12-week eccentric strengthening programme targeting the rotator cuff and incorporating scapular control and correct movement pattern can be effective in decreasing pain and increasing function in patients with subacromial impingement syndrome. A randomized controlled trial is necessary to provide stronger evidence of the method.

Lower Extremity Weakness and Paresthesia in a Recreational Runner

HISTORY: A 20 year female student/runner reported one month history of lateral leg, foot, and toe numbness. The symptoms began as she increased her running mileage for marathon training. She noted difficulty with walking, tripping with occasional falls, intermittent pain at her fibular head, and "pins and needles" in her lateral calf. PHYSICAL EXAMINATION: The patient's Lower Quarter Screen showed diminished sensation to the R lateral leg and great toe, decreased strength of R foot and ankle, an inability to heel walk, and difficulty toe walking. Sensation was absent to 10-mg monofilament testing in the peroneal nerve distribution. MMT grades were as follows: Ant Tib 3/5, Post Tib 3+/5, Peroneals 3+/5, EHL 2+/5, FHL 4/5, FD 3/5. Gait showed increased knee flexion, limited dorsiflexion, and increased extensor digitorum activity on the R in swing phase. Joint play was hypomobile at the proximal and distal anterior tibio-fibular joint. Supine SLR test was + for pain near the fibular head and lateral calf tingling. DIFFERENTIAL DIAGNOSIS: mass lesion; acute compartment syndrome; lumbar radiculopathy; peroneal neuropathy TEST AND RESULTS: EMG findings showed a complete conduction block of the peroneal nerve at the fibular head. FINAL WORKING DIAGNOSIS: Idiopathic peroneal neuropathy TREATMENT AND OUTCOMES: The pt. began PT 3x/wk for proximal and distal anterior tibio-fibular joint mobilizations, anterior taping of the fibular head, peroneal nerve glides, NMES of the dorsiflexors/evertors, a dorsiflexion assist taping, and a HEP for ankle and toe strengthening. After 2 months, tibio-fibular joint mobility was normalized and neural gliding was discontinued. Strength was improving but sensation remained absent. Treatment was decreased to 1x/wk for selective muscle strengthening including: active-assisted ROM, multi-angle isometrics, and eccentric strengthening. One month later pt. was released to a HEP and FAAM scores were recorded: ADLs 64%, Sport 0%. Monthly follow-ups continued until pt. discharged from PT 9 months after eval. Complete resolution of symptoms occurred 10 months after symptom onset. At discharge sensation was intact to 10-mg monofilament testing, strength was 5/5 in the foot and ankle, gait was normalized, and FAAM scores were 100% in ADLs and Sports. The pt. was running 6-10 mi/day, 6 days/week.

Minimal Additional Weight of Combat Equipment Alters Air Assault Soldiers’ Landing Biomechanics

The additional weight of combat and protective equipment carried by soldiers on the battlefield and insufficient adaptations to this weight may increase the risk of musculoskeletal injury. The objective of this study was to determine the effects of the additional weight of equipment on knee kinematics and vertical ground reaction forces (VGRF) during two-legged drop landings. We tested kinematics and VGRF of 70 air assault soldiers performing drop landings with and without wearing the equipment. Maximum knee flexion angles, maximum vertical ground reaction forces, and the time from initial contact to these maximum values all increased with the additional weight of equipment. Proper landing technique, additional weight (perhaps in the form of combat and protective equipment), and eccentric strengthening of the hips and knees should be integrated into soldiers' training to induce musculoskeletal and biomechanical adaptations to reduce the risk of musculoskeletal injury during two-legged drop landing maneuvers.