A Comparison of the Effects of Two Therapeutic Exercises on the Muscle Action Potential of the Vastus Medialis

Electromyography was utilized to compare the effects of two therapeutic exercises at two work loads in knee extension on the muscle action potential in the vastus medialis. One exercise was extension to 180 degrees with a four second isometric hold and flexion to 90 degrees. The other exercise was extension to 180 degrees, 15 degrees flexion, 15 degrees extension and flexion to 90 degrees. Each exercise lasted for 10 seconds. The subjects in the study were 11 varsity female athletes from the fall and winter interscholastic athletic program at Eastern Illinois University. The subjects met for the first time to determine their work loads and to practice each exercise. The work loads were determined to be one-half and three-fourths of the maximum weight lifted to full knee extension. At a second meeting, data was collected from each subject for each exercise performed during two trials at two different work loads. The research design consisted of a single-group with two variables. The amplitude of the spikes was measured and the frequencies of the spikes on each interference pattern were counted. A quantitative figure was obtained by multiplying mean amplitude by frequency for each trial. This score was utilized with a multiple analysis of variance program by the Eastern Illinois University Data Processing Center. A null hypothesis was tested at the .05 level of significance. The null hypothesis stated: Exercising the quadriceps femoris through a full range of motion plus repetition of the last 15 degrees does not increase the muscle action potential of the vastus medialis when compared to a full extension and flexion exercise with the same time duration. Major findings of the study concluded that there was no difference in the muscle action potential in the two exercises. There was a significant difference in the muscle action potential due to the increase in weights between one-half maximum weight and three-fourths maximum weight

Knee extensor muscle function after arthroscopic partial meniscectomy

Erratum p. 5 and 20 written „2.3.2. Rehabilitation...“ right: „2.3.3. Rehabilitation...“ p. 65 last sentence written „…vigastatud jäseme külgmisel pakslihasel kulges aeglasemalt võrreldes reiesirglihase ja keskmise pakslihasega…” right: „…vigastatud jäseme keskmisel pakslihasel kulges aeglasemalt võrreldes reiesirglihase ja külgmise pakslihasega…”http://www.ester.ee/record=b4339573~S1*es

A Review of the Utilization of EMG Biofeedback

Electromyographic (EMG) biofeedback is gaining popularity as a treatment modality in physical therapy. It is used in the areas of neurological and orthopedic rehabilitation as well as injury prevention and performance improvement. The use of this modality can aid in the rehabilitation process by identifying weak muscles which need to be strengthened. Physical therapy also utilizes EMG biofeedback to identify and change movement patterns which may contribute to injury through the overuse or incorrect use of various muscles. EMG biofeedback is used to assist the patient in learning how to control muscular movement to correct the problems which are identified. Through the use of auditory or visual feedback, EMG biofeedback provides the patient and the therapist with immediate output on the level of activity in the targeted muscles or movement pattern. This is accomplished through the use of surface or needle electrodes appropriately placed on the desired area. Electrical impulses from the muscle are transmitted to the EMG unit which coverts the electrical signal into the visual or auditory feedback. The patient receives this feedback and is able to correctly learn voluntary control over specific muscles or movement patterns

Electromyographic Biofeedback Training for Patients with Patellofemoral Pain Syndrome: A Literature Review

The purpose of this literature review is to investigate the clinical effectiveness of electromyographic biofeedback training of the vastus medialis oblique and the vastus lateralis for the treatment of patellofemoral pain syndrome, and to evaluate the symptoms and etiology of patellofemoral pain syndrome. The literature review will also identify the advantages of closed chain knee exercise in comparison to open chan knee exercise specifically in relation to the patellofemoral joint. A treatment hierarchy of closed chain knee exercise used in combination with electromyographic biofeedback is presented within the research proposal. The research proposal compares open chain biofeedback assisted exercise to closed chain biofeedback assisted exercise for the treatment of patellofemoral pain syndrome. The purpose of the research proposal is to identify the most effective combination of treatment techniques for patellofemoral pain syndrome

Dynamics, Electromyography and Vibroarthrography as Non-Invasive Diagnostic Tools: Investigation of the Patellofemoral Joint

The knee joint plays an essential role in the human musculoskeletal system. It has evolved to withstand extreme loading conditions, while providing almost frictionless joint movement. However, its performance may be disrupted by disease, anatomical deformities, soft tissue imbalance or injury. Knee disorders are often puzzling, and accurate diagnosis may be challenging. Current evaluation approach is usually limited to a detailed interview with the patient, careful physical examination and radiographic imaging. The X-ray screening may reveal bone degeneration, but does not carry sufficient information of the soft tissue conditions. More advanced imaging tools such as MRI or CT are available, but expensive, time consuming and can be used only under static conditions. Moreover, due to limited resolution the radiographic techniques cannot reveal early stage arthritis. The arthroscopy is often the only reliable option, however due to its semi-invasive nature, it cannot be considered as a practical diagnostic tool. Therefore, the motivation for this work was to combine three scientific methods to provide a comprehensive, non-invasive evaluation tool bringing insight into the in vivo, dynamic conditions of the knee joint and articular cartilage degeneration. Electromyography and inverse dynamics were employed to independently determine the forces present in several muscles spanning the knee joint. Though both methods have certain limitations, the current work demonstrates how the use of these two methods concurrently enhances the biomechanical analysis of the knee joint conditions, especially the performance of the extensor mechanism. The kinetic analysis was performed for 12 TKA, 4 healthy individuals in advanced age and 4 young subjects. Several differences in the knee biomechanics were found between the three groups, identifying age-related and post-operative decrease in the extensor mechanism efficiency, explaining the increased effort of performing everyday activities experienced by the elderly and TKA subjects. The concept of using accelerometers to assess the cartilage degeneration has been proven based on a group of 23 subjects with non-symptomatic knees and 52 patients suffering from knee arthritis. Very high success (96.2%) of pattern classification obtained in this work clearly demonstrates that vibroarthrography is a promising, non-invasive and low-cost technique offering screening capabilities

Knee joint contact stresses : the influence of deformity and muscle activity

Studies have shown that the alignment of the knee in the coronal plane has a significant effect on the joint contact stress. However, gait analysis demonstrated that factors other than alignment contributed significantly to the outcome of corrective surgery. It was therefore hypothesized that muscle contraction can alter the stress distribution within the knee joint and that overloading can occur in the absence of a deformity. Six normal knees were harvested from different donors. The exact orientation of all muscle groups was recorded and their tendinous insertions carefully preserved. Custom built pressure transducers (6 per compartment, 0.5 mm thick, 10 mm diameter) were inserted through 2 small, posterior, capsular incisions and placed on the tibial surface and the menisci. The knees were mounted in a loading system which allowed free self-alignment of the joint under load. All muscles were replaced by wire cables instrumented with force transducer, tensioner and grip. Several alignment models (5, 10 degree varus, neutral, 5 degree valgus and 15 degree of flexion) as well as the effect of contraction of all major muscles crossing the knee joint were tested. An even pressure distribution was seen in neutral alignment. In a varus deformity the peak pressure shifted medially and laterally in valgus. Unloading of the opposite compartment was seen for deformities as small as 5 degrees. A flexion deformity produced a postero-lateral shift of the peak pressure area. Muscle contraction increased the pressure significantly in a region next to the muscle. Generally, unloading - though less significant - was seen in a region diagonally across the joint. These results suggest that muscular hyperactivity may considerable increase the contact stresses. However, muscle weakness or lack of muscular contraction may indirectly play a significant role in affecting the contact pressure distribution. If the muscle force is insufficient to counterbalance the external moment condylar lift-off occurs. This increases the angulation between femur and tibia thereby overloading the compartment where contact takes place; One can therefore conclude that abnormal gait patterns or neuromuscular control mechanisms may result in unphysiologically high contact stresses which may cause the development of unicompartmental osteoarthritis and subsequently, a deformity