Exercise as it relates to Disease/The Effect of High Intensity Exercise on Persons with Multiple Sclerosis

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This Wikibooks page is an analysis of the research article "High Intensity Exercise in Multiple Sclerosis: Effects on Muscle Contractile Characteristics and Exercise Capacity, a Randomised Controlled Trial" by Wens et al. (2015)[1]

What is the background to this research?[edit | edit source]

Overview[edit | edit source]

Multiple Sclerosis (MS) is a chronic neurological autoimmune disease of the central nervous system (CNS) that impairs the function of neurons. It attacks and damages the myelin sheath covering the axon of a neuron (demyelination), negatively affecting the conductivity of an impulse. Physically, MS is characterised by a number of different gait abnormalities, loss of coordination, visual impairment, difficulty balancing, and an overall decline in cognitive function [2]. A survey conducted by the Australian Bureau of Statistics in 2009 estimated that approximately 23,700 Australians were suffering from MS[3].

Multiple Sclerosis and Exercise[edit | edit source]

As the symptoms of MS have an impact on mobility, the lifestyle of a sufferer generally becomes sedentary. There is often a decline in muscle strength, loss in exercise capacity, and overall reduction in the contractile properties of the muscle[1]. Several studies have shown that endurance and resistance training can improve the physical aspects of multiple sclerosis, and provide a better quality of life. Endurance training in particular can improve dysfunctions associated with gait, with beneficial effects on sitting-to-standing and standing-to-sitting transitions, stair climbing, and walking speed. Regular resistance training has shown to increase muscle strength that can have superior effects on balance, reduce muscular fatigue, and reduce the risk of falling[4]. Whilst a number of studies have presented the benefits of endurance and resistance training, Wens et al (2015) has suggested that there has been a lack of studies that have evaluated the effects of high intensity exercise on persons with MS [1].

Where is the research from?[edit | edit source]

The research was conducted and approved at the Jessa Hospital in Hasselt, and the University of Hasselt in Hasselt, Belgium. All authors are professors within the Hasselt University, and are associated with the rehabilitation departments. The main acknowledgement of the study is to Dr. Niel Hens, who provided statistical and discussion advice to the authors[1].

What kind of research was this?[edit | edit source]

The research conducted by Wens et al (2015) is a randomised controlled trial (RCT) study. The study included a control group, and two variable groups. All the MS patients were randomised when placed into these groups[1].

RCTs are generally appropriate and effective when testing a before and after effect. However, there are some limitations to RCTs, and particularly, the use of the design in this study. Firstly, the effects of the treatment, or in this study, the high-intensity exercise training will only account for a small number of subjects, meaning that the results may misrepresent how effective high-intensity training can be on all individuals with MS. Secondly, RCTs tend to not include a long term follow up examination due to the time constraints and costs, which can make it difficult to determine whether the testing protocol is an effective intervention to be applied over a long period of time[1][5]

What did the research involve?[edit | edit source]

34 patients were diagnosed with MS before commencing the study. All the patients had to be over the age of 18, physically inactive, and not have any other disorders[1].

The patients were randomly selected into either a control group, or two exercise groups. The control group remained physically inactive during the study and were instructed to continue their daily activities without altering their routines. One of the exercise groups exercised for 12 weeks with high intensity endurance training and resistance training, and the other exercise group exercised for 12 weeks with high intensity interval training and resistance training. Both the exercise groups increased their intensities, and training frequency over the 12 week period. Before and after the testing protocol, all the MS patients had to undergo specific testing to measure the effects of the training program. The primary outcome measure was the measurement of muscle fibre CSA and proportion. This was measured from a muscle biopsy. The secondary outcome measures were: isometric strength (measured using an isokinetic dynamometer), endurance capacity (measured using an electronic cycle ergometer), body composition (measured from a DEXA scan), and a self report of physical activity level (this was measured using a physical activity scale for persons with physical disabilities[1].

The study mentions that due to ethical precautions, only one muscle biopsy was conducted on each individual before and after the 12 week program. Initially, the authors were guided to collect a total of three biopsies, with each collection at different depths of the muscle, with an overall sample of 150 fibres per test. The reasoning for three different biopsy measurements was to reduce sampling errors. Additionally, the inclusion of the patients to self report their physical activity level increases the room for bias and error. Whilst it is important for some subjective collection of data, there is a tendency for some patients to over-report their physical activity level, and under-report their time spent participating in sedentary behaviours[6][1].

What were the basic results?[edit | edit source]

The tables below represents the significant findings of the study.

Abbreviations[edit | edit source]

SED = Control Group (Sedentary)

HCTR = High Intensity Continuous Endurance + Resistance Training

HITR = High Intensity Interval + Resistance Training

Fibre Type Proportion and CSA[1][edit | edit source]

Fibre Type Proportion (%) SED HCTR HITR
Type 1 +7.9 +26.8 +21.7
Type IIa +5.1 +6.6 +6.9
Type IIx -19.2 -46.0 -20.1
Fibre CSA (um^2)
Mean +3.5 +23.3 +21.1

Isometric Strength[edit | edit source]

Muscle strength of the SED group remained relatively unchanged after the 12 week period. Knee flexion and knee extension of the weakest leg of the HITR group improved significantly (24 to 44%), and the group's strongest leg also had increases in strength (13 to 20%). The HCTR's group had a stable value in strength in their strongest leg after the 12 week program, but had a notable increase in strength in their weakest leg (19 to 33%)[1].

Endurance Capacity, Body Composition, Physical Activity Level[1][edit | edit source]

Endurance Capacity SED HCTR HITR
Test Duration (min) -3.1% +5.2% +24.7%
VO2 max (ml/min/kg) +2.5% +7.5% +17.8%
Tidal Volume (ml) -11.2% -1.2% -0.5%
Body Composition
Lean Tissue Mass +0.6% +0.9% +1.4%
Fat Percentage -2.8% -2.5% -3.9%
Physical Activity Level (METs: h/week) -2.9% +73% +86%

The authors concluded that high intensity, combined with resistance training was the most effective method in improving muscle contractile properties, and endurance capacities in those with MS. Whilst their findings support this argument, there is no conclusive recognition by the authors that the data may not be of significant importance to real world situations due to the lack of studies that exist measuring high intensity on MS, the sampling size, and other factors that may have caused errors[1].

What conclusions can we take from this research?[edit | edit source]

The study conducted by Wens et al provided important information regarding the effects of high intensity exercise combined with resistance training on persons with MS. As there have been a lack of studies that have measured this specific variable, there is a level of significance that this data provides to future studies on MS. However, the data presented in the study, and the lack of recognition by the authors to apply their findings in real world situations, makes it hard to establish the findings significant when regarding everyday individuals suffering from MS. Whilst it is evident that high intensity exercise does have noteworthy benefits, those suffering from MS may not be able to replicate the exercises performed in the study due to insufficient resources, and a lack of professional supervision and guidance. Ultimately, the training program conducted in the study is not beneficial to those with MS unless they have adequate resources, and professional supervision.

Practical advice[edit | edit source]

As mentioned previously, the study presents numerous benefits of high intensity exercise on those with MS, but can only be performed with ample resources, and professional supervision. If individuals with MS are looking to implement high intensity exercise in their routine, then the appropriate resources, and adequate professional supervision should be present. Whilst high intensity training may not be possible, any physical activity that incorporates a form of cardiovascular or resistance training is highly recommended to maintain the symptoms of MS. Any individuals suffering from MS should seek a medical professional before any type of exercise is prescribed.

Further information/resources[edit | edit source]

For further information regarding MS, please visit these sites:

References[edit | edit source]

  1. a b c d e f g h i j k l m Wens, I., Dalgas, U., Vandenabeele, F., Grevendonk, L., Verboven, K., Hansen, D. and Eijnde, B. (2015). High Intensity Exercise in Multiple Sclerosis: Effects on Muscle Contractile Characteristics and Exercise Capacity, a Randomised Controlled Trial. PLOS ONE, [online] 10(9), p.e0133697. Available at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0133697 [Accessed 24 Aug. 2017].
  2. Goldenberg, M. (2012). Multiple Sclerosis Review. PMC, [online] 37(3), pp.175-184. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3351877/ [Accessed 25 Aug. 2017].
  3. Abs.gov.au. (2012). Multiple Sclerosis - Profiles of Disability, Australia, 2009. [online] Available at: http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4429.0Main+Features100182009 [Accessed 28 Aug. 2017].
  4. Döring, A., Pfueller, C., Paul, F. and Dörr, J. (2011). Exercise in multiple sclerosis -- an integral component of disease management. EPMA Journal, [online] 3(1). Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3375103/ [Accessed 5 Sep. 2017].
  5. Shean, G. (2014). Limitations of Randomized Control Designs in Psychotherapy Research. Advances in Psychiatry, [online] 2014, pp.1-5. Available at: https://www.hindawi.com/archive/2014/561452/ [Accessed 21 Sep. 2017].
  6. Krüger, T., Behrens, J., Grobelny, A., Otte, K., Mansow-Model, S., Kayser, B., Bellmann-Strobl, J., Brandt, A., Paul, F. and Schmitz-Hübsch, T. (2017). Subjective and objective assessment of physical activity in multiple sclerosis and their relation to health-related quality of life. BMC Neurology, [online] 17(1). Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5237144/ [Accessed 24 Sep. 2017].