Paradigms of Lower Extremity Electrical Stimulation Training After Spinal Cord Injury

Spinal cord injury is a traumatic medical condition that may result in elevated risks of chronic secondary metabolic disorders. Here, we presented a protocol using surface neuromuscular electrical stimulation-resistance training in conjunction with functional electrical stimulation-lower extremities cycling as a strategy to ameliorate several of these medical problems.

The overall goal of this rehabilitation intervention is to highlight different uses of surface neuromuscular electrical stimulation resistance training, and functional electrical stimulation lower extremity cycling, as strategies to ameliorate several of the health-related consequences of spinal cord injury. So this method can help to answer key questions in the area of rehabilitation, on how to effectively design an electrical stimulation protocols for persons who has spinal cord injury. The benefit of these techniques is to maximize cardio-metabolic benefits, and to increase muscle mass after a spinal cord injury.

We would like to investigate this research question to improve rehabilitation protocols available for persons with spinal cord injury. Should an individual with the spinal cord injury who are new to this method may struggle because of pain, that may experience at the beginning of the training. However, these patients may likely to have intact sensation, and as they develop training and move on in their training, they are likely to develop used to the program, and they become more tolerant to electrical stimulation protocol.

Demonstrating the neuro-muscular electric stimulation protocol is Refka Khalil. She is a research coordinator in our lab. Demonstrating the FAS cycling for lower extremity training is Robert Lester and Sally Abilmona.

Both of them are research assistants in our lab. To begin, measure the participant's resting blood pressure and heart rate. With the participant seated in a wheelchair, instruct them to remove their shoes.

Position a pillow behind the participant's calf, to support the legs during knee flexion. Then, secure ankle weights to the participant's ankles. Position the distal electrode approximately 1/3 the distance between the patella and inguinal fold.

Next, position the proximal electrode over the vastus lateralis muscle, laterally and adjacent to the inguinal fold. Position the proximal electrode longitudinally, and parallel to the midline access of the hip and knee joints. Set the frequency of a portable stimulator to 30 hertz, with a biphasic rectangular pulse width of 450 microseconds, and an inter-pulse interval of 50 microseconds.

Then, connect the stimulator cables to each electrode. Start with the right leg, and gradually increase the current until visible tension is observed in the knee extensor muscle group. Slowly ramp the current until the knee is fully extended.

Keep the knee in this position for three to five seconds to achieve maximum tension in the motor units. Then, progressively decrease the current until it is below 50%of the current required to extend the leg, and return the leg to the starting position. Record the current amplitude needed to achieve full leg extension.

Complete a training protocol consisting of four sets of 10 repetitions per leg, alternating between the right and left legs. If the participant cannot achieve full knee extension, record the percent range of motion, and allow the participant to take more time between repetitions. First, measure the participant's resting blood pressure and heart rate.

Then, position the participant, seated in their personal wheelchair, in front of an FES ergometer bike. Add here the distal electrode of the knee extensors to the skin over the vastus medialis, approximately 1/3 the distance between the patella and inguinal fold. Next, position the proximal electrode over the vastus lateralis muscle laterally, and adjacent to the inguinal fold.

Adhere the distal electrode for the knee flexors to the skin two to three centimeters above the popliteal fossa, and apply an elastic wrap to secure its positioning. Then, position the proximal electrode 20 centimeters above the popliteal fossa. Next, instruct the participant to lean forward in the direction of the ergometer.

Adhere two electrodes parallel and on the bulk of the muscle belly of the gluteus maximus. Inspect the front and back of the ergometer to ensure that the participant is appropriately positioned, and connect the electrodes to the stimulator. Then ensure the participant's wheelchair is locked, and secure the participant's feet to the ergometer pedals.

Next, passively move the participant's legs to observe their movement in the ergometer. Adjust the height of the bike if the participant's legs are compressed or hyper-extended. Use two hooks located at the base of the ergometer to secure the wheelchair to the ergometer.

Then, place two wooden blocks under the wheels of the wheelchair to prevent movement during cycling. On the stimulator, set the appropriate stimulation frequency for each muscle group. Then, select the appropriate cycle and interval training parameters.

While the participant is completing the training session, measure their blood pressure every two to five minutes. Finally, record the participant's heart rate, speed, power, distance, resistance, and percent stimulation every 30 seconds, until the training session is complete. As shown in this table, the results indicate that with FES-LEC, there is an increase in the percentage of current stimulation to offset for the increase flywheel resistance over the 12 weeks of training.

Resistance progressed from 1.0 to 4.5 newton meters during the first stage, 1.6 to 5.5 newton meters during the second stage, and 2.1 to 5.5 newton meters during the third stage. Finally, power output increased by two to four times in each of the three stages between week one and week 12. Power progressed from four to 12 watts during the first stage, 5.4 to 11.24 watts during the second stage, and 2.6 to 11 watts during the third stage.

The implication of this techniques extend towards therapy and rehab of person who has spinal cord injury because of the dramatic muscle atrophy he has experienced that lead to significant health-related consequences after spinal cord injury. This method is essential, and can provide insights in how to apply electrical stimulation to other clinical population, not only spinal cord injury with neurological disorders. It can also be applied to other systems, such as upper extremity, abdominal, and trunk muscles.