A hybrid functional electrical stimulation training program for persons with advanced multiple sclerosis

This pilot study will investigate the possible improvements to aerobic fitness that can be elicited in persons with advanced multiple sclerosis from 12 weeks of hybrid Functional Electrical Stimulation (FES) exercise training. This involves a combination of FES cycling and arm cranking. Prior to the 12 weeks of training, participants will undertake pre-testing, separated by between two days to a week. These will be repeated at the conclusion of the trial and at the midpoint (6 weeks) the incremental arm crank test will be conducted. Participants will be carefully monitored during all tests; the tests will be concluded immediately if the participants appear over fatigued, distressed, or ill. The tests will be conducted by exercise physiology honours students. An experienced exercise scientist will supervise the trials and will have the skills, training, and experience to recognize the expected response elicited during the exercise tests. The testing will include: Test A - maximum arm cranking - Maximal arm crank exercise test trial: Participants will perform an incremental maximum arm crank test on the Monark 881E Arm Ergometer where they will be required to maintain the cranking at 50 rpm. The power output required to turn the cranks will be increased by 5 watts every 2 minutes until the participant cannot maintain the cadence. This data will be used to determine their arm cranking capacity and prescribe the workloads for the proceeding tests and training. Test B - Arm cranking - Participants will warm up at 20% of their assessed maximal arm crank power, then arm crank for four minutes at 40%, 60%, 80%, and 100% of the maximal power achieved in the maximal arm crank trial. There will be 6 minutes rest between each arm cranking workload. Excluding warmup, this test will comprise a total of 16 min arm cranking exercise. Test C - Hybrid FES exercise (arm crank & FES cycling). The final trial will involve the superimposed arm cranking trial (B) on 40min of FES leg cycling. In total this trial will comprised of 40min FES cycling and 16min of hybrid exercise where arm cranking and FES cycling will be performed simultaneously. Initially the stimulation amplitude will be set at 30 mA, frequency will be 35 Hz and pulse width 300 microseconds. The stimulation will be slowly increased over the session until the peak muscle stimulation intensity that can be comfortably tolerated by the participant is reached. Throughout test B and C, the aerobic exercise response will be monitored through routine non- invasive measures of cardiorespiratory metabolism, e.g. oxygen consumption and heart rate. Oxygen consumption and other cardiorespiratory metabolism will be measured by a metabolic cart. Heart rate will be monitored with a standard chest strap heart rate monitor. At the end of each exercise trial participants will be asked how hard the exercise felt and how fatigued they feel on a visual analogue scale. Intervention - Hybrid exercise involves simultaneous voluntary arm cranking (Monark881E Arm Ergometer) and FES cycling (iFESLCE), which has been modified to suit persons with multiple sclerosis. The duration of exercise for each session will be 40 minutes and 2 sessions will take place per week for a total of 12 weeks. The hybrid exercise training program will take place at the University of Sydney, at the FitAbility rehabilitation Gym. As part of the FES cycling, participants will be set up to ensure maximum extension is 15 degrees knee flexion, to ensure hyperextension does not occur. FES will be progressively increased over the first 20 minutes until at their maximum tolerable intensity, as previously determined during the pre-testing, then sustained for the remaining 20 minutes. Participants will be instructed not to voluntarily cycle with their legs during this time. The arm crank cadence will be set at 50rpm. Intensity will be determined by power output, at a target of 60% of maxPO. After a short warm up, intermittent arm cranking exercise will begin when the muscle stimulation reaches its maximum (e.g. at 20min). As a supplementary measure of work intensity, rate of perceived exertion (RPE) will be taken every 5 minutes with an aim to maintain a rating of 14 (“somewhat hard”) on the 15-point BORG scale. Due to arm paresis and fatigue associated with MS, continuous arm cranking would not be plausible. Thus, while the lower limb exercise performs continuous involuntary exercise, the upper limb with engage in interval training. Participants will alternate between 30 seconds of arm cranking and a 30 second rest period, while continuing to cycle. The on/off periods will be modified in future sessions depending on the arm cranking ability and tolerance of the individuals. Intervention adherence will be assessed for this training program and is defined as performing 75% or more of the intervention as it was prescribed by frequency of days/week exercise and total duration of exercise in minutes/week. Where possible participants will be rescheduled if they are unable to attend a training session. Participants are able to withdraw from the trials or training program at any time. FES cycling equipment - Functional electrical stimulation will be performed on the iFES-LCE developed at the University of Sydney which has been specically modified to suit persons with multiple sclerosis. The iFES-LCE comprised a motorized cycle ergometer (MOTOmed Viva 1), a chair with passive leg restraints, a portable computer and a muscle stimulator. Stimulation is delivered by gel backed surface electrodes (Empi) which will be placed on the quadriceps, hamstrings, and gluteal muscles of each leg. Using instantaneous pedal crank position data, the computer program directs the muscle stimulator to provide stimulation to six muscle groups (left and right gluteals, hamstrings, and quadriceps muscles) at the appropriate times to elicit a smooth cycling pattern. The cycling will be at cadence of 10rpm.