Exercise as it relates to Disease/Multiple Sclerosis and the Subsequent Effects of Resistance Training

This wiki factsheet is an analysis of the research article, “Effects of Resistance Training in Multiple Sclerosis” by F. de Souza-Teixeira, S. Costilla, C. Ayan, D. Garcia-Lopez, J. Gonzalez-Gallego, J.A. De Paz, taken from the journal of sports medicine. 2009 Apr;30(04):245-50

What is the background to this research?

Multiple Sclerosis (MS) is a demyelinating disease in which the insulating sheaths of nerves cells, of both the spinal cord and brain become damaged. This damage disrupts the nervous systems ability to communicate, which can result in double vision, sensational impairments, and decreased muscle function, leading to a reduction in walking ability, overall muscle weakness, and fatigue . New symptoms can develop through isolated attacks or build up progressively over time, making independence increasingly difficult. Symptoms and attacks can influence activities of daily living, and other aspects associated with quality of life, such as social interaction or leisurely activities .

As the cause of MS is unclear, and there is no current cure, researchers mainly focus on symptom management. Medication can be used to treat the symptoms of MS, however there are several side effects that stem from this method of treatment . Physical therapy was originally not advised as a treatment method, in a bid to preserve patient energy levels and to avoid increases in body temperature, however it is now known that limiting physical activity may be further detrimental, with non-sedentary behaviours being shown to improve the symptoms of MS, and the physical stresses associated with the disease

Due to the conventional recommendations applied to promote health in any individual, such as changes in body composition and cardiorespiratory fitness, and MS patients having higher instances of fatigue, most research is focused on aerobic exercise and its subsequent effects. These aerobic focused research studies have shown increases in bowel and bladder function, improved VO2 max, decreased levels of depression and fatigue, and developments in the capacity to perform activities of daily living .

Isometric, isokinetic, and isotonic force, are documented to by quite low in patients with MS, in comparison to a healthy population, especially in the lower extremities. It’s this detriment that contributes to less physical activity, decreased walking capacity, and in turn elevating the risk of cardiovascular disease. As strength decreases, so does an individual’s capacity to exercise, eventually becoming a cycle that results in further decreases in functional movement and overall health .

Resistance training has been documented improving several aspects of health for the general population and older adults, reducing the risk of injuries, reducing mortality, improving functional capacity, and aiding in walking velocity and independent living , however the effect of resistance training on patients with MS is much less documented. The critiqued paper, therefore sort, to examine the effect of different resistance exercise protocols on changes in strength, muscle mass, functionality, and health with the absence of injury in individuals with MS.

Where is the research from?

The research was conducted across several institutions in Spain:

• Biomedical Science Institute, University of Leon, Leon, Spain (F. de Souza-Telxeira, J. Gonzalez-Gallego; Ph.D. of Medicine , J. de Paz; Ph.D. of Medicine )
• Department of Radiology, Hospital de Leon, Leon, Spain (S. Costilla; Ph.D. of Medicine )
• Special Didactics, University, Pontevedra, Spain (C. Ayan)
• Laboratory of Physiology, European University Miguel de Cervantes, Vallodolid, Spain (D. Garcia-Lopez; Ph.D. in Sports Sciences and Education and reviewer for International Journal of Sports Medicine )

_{(Information regarding other researchers was difficult to maintain as much of their information is written in Spanish).}

The Research Ethics Committee of University of Leon approved this research study, on the condition that all participants with MS that were interested, may be offered to participate, so that no individual would be deprived of the possible benefits .

What kind of research was this?

The study used a ‘closed’ cohort design; due to the condition disclosed by the Research Ethics Committee in the paragraph above. ‘Closed’ cohort studies involve researching individuals of a specific population group, in this case individuals with MS, over a period of time. Due to the physical conditioning of the population involved, it was deemed unethical to deny the chance to possibly improve patient well-being, removing the option of implementing a randomized control trial. Once the research has started no new subjects are added to the observed population, keeping the participant numbers consistent, this is what dictates the ‘closed’ portion of the study. .

What did the research involve?

Following a patient inclusion criterion, to determine their ability to participant in the study, patients performed an initial evaluation 8-weeks prior to the commencement of the intervention, this was used as the control. Subjects were evaluated for their level of disability by a qualified neurologist, as well as their aptitude and the absence of any contraindication for physical activity. All subjects provided written and informed consent before participation . Following the control period, participants underwent an 8-week resistance training program, being tested on 6 different occasions throughout. Participants trained using the leg extension machine, twice a week, with at least 48 hours between each session. Each training session consisted of 10-15 repetitions for 3 sets, against loads of 40-70% of their maximal voluntary contraction, which was taken during the evaluation phase of the study. Rest periods between sets lasted for 3 minutes, with each session beginning with a 7-minute bike warm up (static), and an exercise specific warm up of 5 repetitions, with low load on the leg extension machine. All training sessions were fully supervised by qualified trainers .

Researchers tested several variables during the study, these included maximal voluntary contraction (leg extension load cell), maximal power (position transponder), muscular endurance (max repetitions using same protocol as maximal power), and functionality (up and go test). Researchers also used Magnetic Resonance Imaging (MRI) to observe any possible increases in lean muscle mass for the thigh region.

Despite the numerous amount of testing researchers performed, to determine if the implementation of a resistance training protocol could exhibit significant benefits for individuals with MS, there were limitations. The population group consisted of only 13 patients, due to the patient inclusion criteria, and researchers only offering intervention participation to individuals belonging to the Multiple Sclerosis Association of Leon. Likely depriving some members of the local region with MS, of the possible benefits associated with such an intervention, and affecting the overall validity of the results. Expanding the population pool to members of the public with MS that still met the inclusion criteria may have assisted in increasing the population group and improving research validity.

The length of the training phase is another limitation. To truly reap the benefits of a resistance training program, individuals must continue to exercise consistently across the length of their life. Due to the higher levels of fatigue and weakness seen in MS patients, a longer training phase would have allowed researchers to assess whether this program would be suitable over the life of the patient. Performing subsequent MRI’s and having access to machines, including those used for measuring maximal voluntary contraction can also be costly, increasing the difficulty for other researchers to repeat the study. Researchers may also have considered the possibility of dividing testing subjects between gym based exercises and home-based exercises. The ability to obtain access to training equipment and gyms can be a financial limitation for even healthy individuals. Being able to train from the comfort of home would be much more meaningful and beneficial in the long run for those with MS.

What were the basic results?

During the control phase of the study, there were no substantial changes noted in any of the observed variables. However, when comparing the pre-and post-tests, following 8 weeks of resistance training, researchers noted significant differences (P<0.05) in maximal voluntary contraction (P<0.01), maximal power (P<0.001), muscular endurance (P<0.001), and the up and go test (P<0.001). Researchers also noted a mean gain of 3.6% in 6 of the thigh MRI slices. While this is an improvement it was not as noteworthy as the increases observed in the other variables. Researchers also discovered a relationship between cross sectional area (CSA) from the MRI and strength manifestations. While there was no significant correlation between muscle mass and muscular endurance, values pertaining to muscle mass and maximal voluntary contraction (r=0.687-0.887), and maximal power (r=0.583-0.817) showed a positive relationship. Equal emphasis was made on each measured variable, with researchers never sitting on a result for longer than deemed necessary.

What conclusions can we take from this research?

Since this study was one of the few to assess the possible benefits of a resistance training program on individuals with MS, its finding still holds weight despite the small number of research participants. Muscular endurance improved by 84% after the training program, which is a particularly interesting finding given MS patient susceptibility to increased levels of fatigue. If the researchers could look further into the longevity of such a program, it could have meaningful applications towards improving quality of life for these individuals by allowing greater access to social interactions or outdoor activities. The same can be said for muscular power values, which improved by 51% and is often used as an indicator of physical and functional conditioning in the elderly, another population group often associated with impaired independence following decreased musculature .

Despite the fact there were increases in all variables tested by researchers, increases in mean muscle mass of the thigh did not increase substantially. The absence of any notable lean muscle gains could indicate that the other variables were affected by neural adaptations rather than hypertrophy, such as increased motor neuron recruitment or neuron firing rates, an important possible finding for a neural disease such as MS. Further research would have to include measures for testing improved neural activation.

Overall, researchers observed increases in muscular strength, muscular endurance, and functional movement in patients with MS following 8 weeks of resistance training, which was similar to the findings made by L J White et. al. who found improved ambulation and decreased fatigue following 8 weeks of knee flexion, knee extension and plantarflexion exercises , and U. Dalgas et. al. who also observed increased muscular strength and functionality in the lower extremities of patients with MS following 12 weeks of intense progressive resistance training .

Practical advice

Currently MS effects over 23,00 Australians and more than 2 million people globally . As global levels of inactivity increase, it’s become more important for people to find ways to become more active, this includes individuals with MS. Regular exercise is important in improving cardiovascular health, increasing muscle strength and endurance, as well as helping maintain spasticity and managing MS related fatigue . With the use of appropriate guidelines, exercise programs may be used to develop the maximal physical potential of MS patients. However, individuals shouldn’t have the need to regularly attend gym sessions with trainers to meet their physical activity needs, instead being able to perform catered programs developed for use in the comfort of their own home. Resources for developing programs such as these would be highly beneficial for the MS community, provided they were more readily made available and researched. As for any individual looking to improve their physical well-being, initial consultations with GP’s and health professionals should be made to ensure participant safety.

Further information

• Multiple Sclerosis Australia: Wellbeing & MS: https://www.msaustralia.org.au/living-ms
• National Multiple Sclerosis Society: https://www.nationalmssociety.org/
• Active MSers: http://www.activemsers.org/exercisesstretches/tipsexercisingwithms.html