Exercise as it relates to Disease/Maximal strength training used to target strength, balance and walking, in individuals with Multiple Sclerosis

This is a critique of the research article: Karpatkin H, Choen E, et.al. The Effect of Maximal Strength Training on Strength, Walking, and Balance in People with Multiple Sclerosis: A Pilot Study" [internet]. Multiple Sclerosis International, Hindawi, vol. 2016, Article ID 5235971, 6 pages, 2016.

The critique was an assignment for the unit; Health, Disease and Exercise at University of Canberra, Semester 2, 2020.

Background to research
Multiple Sclerosis (MS) is a progressive, chronic disease, which affects the central nervous system. This leads to impaired mobility of an individual. People are diagnosed with MS between 20 and 40 years of age, however young children can also be diagnosed.

Previous studies have been conducted to investigate the effects of resistance training on mobility deficits, in individuals with MS. It was not examined as to whether or not maximal strength training (MST) had an impact on mobility measures, in those with MS.

The study focused on two topics:
 * 1) To examine the effects that low, MST had on endurance walking and balance, in those with MS.
 * 2) To examine the effects that MST had on fatigue.

This study is important as it was hypothesised that if individuals with MS showed signs of improvement in their mobility and did not have an increase in their level of fatigue, then clinicians could safely and effectively incorporate MST into their rehabilitation programs. The null hypothesis states that there is no relationship between MST and improved mobility, and that MST increases fatigue levels.

Research
The research was a noncontrolled, nonrandomized Pilot study, which was approved by the relevant institutional Review Board. A Pilot study is a small-scale test, used to evaluate the feasibility of a main, larger study. Pilot studies are undertaken to ensure that researchers do not launch a larger study, without having adequate knowledge of the methods proposed. This aims to reduce the occurrence of flaws in a larger, main study.

All 8 participants were recruited from a local, multidisciplinary MS clinic. Each participant had to have a definitive diagnosis of MS, be at least 18 years old and could walk freely for 6 minutes, either with or without the help of an assistive device. All the authors in this study are Physical Therapists, some with different certifications and specialities. For example, the first two authors are:
 * 1) Herb Karpatkin:, who has been specialising in MS since 1993.
 * 2) Evan T. Cohen, who is a Neurologic Certified Specialist.

It is important that the authors in this study are Physical Therapists, but it is even more effective to have people that specialise in Neurology and MS. The reason being, is that extra knowledge can be provided, to help one another better understand the results of the study.

The authors also declare that they had no competing interests. Therefore, there are no organisational/ sponsorship links are perceived as a conflict of interest/bias, from the findings in this study.

Methods of Study
The study was conducted over 8 weeks, with the MST intervention occurring twice a week. The method is as follows:

Balance:
 * Measured using the Berg Balance Scale (BBS), through the assessment of 14 tasks of varying difficulty.

Fatigue: Baseline Testings:
 * Measured using the Fatigue Severity Scale (FFS). This is an effective tool, as it is a widely used, valid and reliable measurement tool.
 * 1RM
 * BBS
 * 6-minute walking test (6MWT)

Warm-up: Main assessment: Cool-down:
 * 5 min, no resistance cycle ergometer, at a comfortable pace
 * Then 5 minutes of seated resting
 * 5 repetition, horizontal leg press warm-up, at 50% of their 1RM.
 * Then 90 second rest
 * 4 sets, 4 reps per set at 85-95% of their 1RM, for each leg.
 * 90 second break between each set.
 * A timing model which has been used in previous MST studies was incorporated into this current study, where participants had to perform a concentric contraction, then followed by a more controlled, slow eccentric contraction.
 * 5-minute cycle ergometer cooldown, same as the warm-up.

Strengths

 * All participants came from the same, multidisciplinary MS clinic
 * All participants had a definitive diagnosis of MS
 * All authors are Physical Therapists, with some specialising in MS and Neurology
 * Uses the FFS test, which is a widely used, effective measurement tool
 * Looks at other studies which investigates Neural drive and how this correlates with the findings
 * A timing model was incorporated, which has been used in previous MST studies

Limitations

 * Non-controlled and Non-randomized study, which can limit the generalisations that can be made
 * Other studies and literature around resistance training programs for those with MS, mainly target intensities which rarely exceed 70% of 1RM. This may be that heavier loads could lead to complications around neurogenic fatigue.
 * Only 8 participants in this study. The recommended number of participants in a Pilot study is a minimum of 12. Therefore, data results may not be as accurate, due to a smaller sample population.

As with all Pilot studies, a follow-up study with a larger sample size must be undertaken, to support and confirm the results.

Results
Results showed:
 * MST had quite a significant impact on strength, on both the right and left leg, between pre-tests and post-tests, demonstrating a greater increase in leg press strength
 * The FFS scores showed minimal effect of MST on fatigue levels throughout the protocol
 * There was an average of a 46m improvement in the 6MWT. Averages were taken and analysed from the results, for each variable.
 * The was an improvement in the BBS results
 * From the results, a P value of <0.05 was determined. This means that the null hypothesis was rejected, so therefore MST did not increase fatigue levels, and there is a relationship between MST and improvement in mobility.

Conclusions
Individuals with MS have an increased risk of falls, as their balance is impaired. Their walking endurance is also reduced. The results in this study provide evidence that MST may be a feasible means of improving mobility issues, however implications are not over emphasised. An improvement in the 6MWT, strongly suggests that there are improvements in walking endurance, which is quite an important finding. The BBS improved by 5.3 points in this assessment, which therefore demonstrates a significant improvement in balance and mobility. FFS scores were not high, which is another important finding, as this demonstrates how MST was handled well by all the participants, without instigating high fatigue levels. Another study was conducted in 2016, which assessed the effects that MST had on wheelchair propulsion, work economy. The results from that study also supported the findings in this study, as both showed improvements in mobility, as a result of MST.

The authors also investigated how MST impacts Neural Drive. MST works by increasing muscle motor recruitment and neural drive. This increases muscle activation, which therefore improves motor recruitment, coordination, strength and mobility.

Future Studies Suggestions

 * Participants could undergo a follow-up assessment, every 3 months to see whether MST improvements were sustained or not.
 * A greater range of lower extremity resistance training could be incorporated. Greater improvements may be identified in functional measures, as a result of this
 * Mobility assessments could incorporate characteristics of power, which could measure more direct effects of lower extremity resistance training in MS
 * Investigate sex differences, in response to resistance training

Practical Advice
If you or someone you know has MS, it might be beneficial to consult with a health professional or a rehabilitation clinician, to determine if it is safe to incorporate MST into rehabilitation programs. There are a variety of assessments, such as those discussed in this article, which could be incorporated, such as: Results from this study support MST for individuals with MS, to improve mobility without an increase in fatigue levels.
 * Leg Press
 * 6MWT
 * Mini-BESTest
 * FSS
 * 1RM
 * Plantar flexion

Further Readings/Insights
If you are interested in further information and readings, please refer to the links below:
 * Maximal Bench Press Strength Training
 * Strength Training to improve Gait in MS
 * MS: Effects of Strength Training on Mobility
 * Sex differences in response to resistance training
 * MST and Enhanced Neural Drive