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Exercise as it relates to Disease/Effects of high resistance training for patients with myotonic dystrophy

What is the background to this research?Edit

Myotonic Dystrophy which is commonly known as DM is a muscle condition that comes under the term Muscular Dystrophy. Being the most common form of muscular dystrophy worldwide it is said to affect around 1 in 8000 people.[2] All forms of Muscular Dystrophy have three things in common

  • They are progressive
  • They are hereditary
  • And; each cause a characteristic, selective pattern of muscle weakness and wasting

Myotonic Dystrophy differs from other forms of muscular dystrophy as along with these three things mentioned above, it is associated with some other disorders including.[3]

  • Myotonia (delayed relaxation of muscles after contraction)
  • Clouding of the cataracts
  • Cardiac conduction defects
  • Infertility in Males

There are two forms of myotonic dystrophy which affect different genes. They are DM1 which is generally associated with the muscle weakness of the hands, neck, face and lower legs. Whilst DM2 the rarer of the two is associated with the neck, shoulders, elbow and hips.[2][3]

The purpose of this study was to assess effects of a high resistance training program on muscle strength, muscle area and muscle fibres in patients with DM and how it affects the muscles and benefits of the program.

Where is the research from?Edit

The research for this study comes from the Department of Neurology and Radiation Physics, Karolinska Hospital, Stockholm, Sweden. It was conducted by 7 main authors: Anna Tolback, PhD, Stefan Eriksson, RPT, Anna Wredenberg, RPT, Goran Jenner, MD, Roberto Vargas, RT, Kristian Borg, MD, PhD and Tor Ansved MD, PhD.[1]

What kind of research was this?Edit

This research was a small scale qualitative study which was based in Stockholm, Sweden. The study was based on 9 patients who have been diagnosed with DM

What did the research involve?Edit

This research involved 9 patients (2 Males, 7 Females) who have been diagnosed with myotonic dystrophy from the outpatient clinic within the department of neurology at the Karolinska hospital. To participate the patients were required to have knee extensor strength than enabled full knee extension against a 3KG load. If any signs of cardiac issues that could potentially affect the study were also excluded.

The patients were first tested to get baseline scores using a isokinetic dynamometer and testing their 1 Rep max (RM) of a randomly chosen leg which subsequently meant the opposite leg acted as the control. They were then required to undertake a 12 week progressive high resistance training program which consisted of free weight training 3 times a week aiming to complete 3x10 repetitions at 80% of the patients 1RM.

The patients began at 60% 1RM and moved up by 10% each week. Each repetition required to run for 9 seconds with concentric, isometric and eccentric movements lasting 3 seconds each and a 10 second rest in between reps.[1]

ResultsEdit

Of the 9 patients who started the program, 3 withdrew (2 males, 1 female). Leaving 6 female subjects to obtain results from, they completed 76% of all training sessions. Following the program the patients were tested on 1RM strength, had an MRI to assess the Cross Sectional Area (CSA)of the quadriceps and a muscle biopsy taken from the Vastus Lateralis muscle.

1RM results

Pre-Training Post Training
16.4 ± 3.4 kg 21.8 ± 2.6 kg

The MRI results revealed that there were no major significant differences in the CSA of the three portions of quadriceps muscle

Pre-Training Post training
4090 ± 591mm2 4154 ± 585mm2

The muscle biopsy results were inconclusive as the number of test subjects was too small, however, after training there was a tendency towards an increase in the CSA of the Type I muscle fibres. Other than that there were no real signs of difference before and after training.[1]

Interpretation of resultsEdit

Tollback et al.[1] found that following the 12 week program patients with myotonic dystrophy improved their overall leg strength without any negative side effects. The results may have varied a little if the male patients had completed the program

ConclusionsEdit

Although there is a lack of research out there for myotonic dystrophy, this article provided evidence to suggest that people living with DM can benefit from the resistance training program in the short term with no side effects. It is recommended that resistance programs be used in the early stages due to the fact that there is a larger amount of trainable muscles. With the increase in the strength and size of the muscles this may have a flow on effect and improvement in pain within the muscles, myotonia and issues with balance, which allows patients a greater quality of life and the potential to move more freely.[4]

However, depending on the severity of the disease this form of training may not be possible as they have no potential for the training as shown with the number of participants who dropped out or did not meet the requirements for the study.

Implications of the researchEdit

The implications of the research was that based on the results a high resistance training for people suffering from myotonic dystrophy can be very beneficial as it increases the strength of the muscle and also an increase in the size of certain muscle fibre types. The results are only indicative of a small population as per the amount of people tested and there only being one gender fully participating. However it is highly recommended that these programs are commenced in the early stages of the disease as this is when it is most effective due to the higher number of trainable muscles.[1][5][6]

More research in this area is vital as it will improve the sufferers quality of life.

ReferencesEdit

  1. a b c d e f Tolback, A., Erikkson, S., Wredenberg, A., Jenner, G., Vargas, R., Borg, K., Ansved, T. (1999). Effects of high resistance training for patients with myotonic dystrophy. Scandinavian Journal of Rehabilitation Medicine. DOI: 10.1080/003655099444678.
  2. a b Muscular Dystrophy Australia. 2015. MYOTONIC DYSTROPHY . [ONLINE] Available at: http://www.mda.org.au/disorders/dystrophies/myt.asp.
  3. a b Genetic Home Reference. 2010. What is myotonic dystrophy?. [ONLINE] Available at: http://ghr.nlm.nih.gov/condition/myotonic-dystrophy.
  4. Wiles, C.M., Busse, M.E., Sampson, C.M., Rogers, M.T., Fenton-May, J., Van Duersen, R. (2006) Falls and stumbles in myotonic dystrophy. J Neurol Neuroserg Psychiatry. 77(3) 393-396. DOI: 10.1136/jnnp.2005.066258
  5. Muscle training in muscular dystrophies. Ansved, T. (2001). Acta Physiologica Scandanavia, 171(3):359-66
  6. The effect of exercise in muscular dystrophy. Vignos, P.J., MD, Watkins, M.P. (1966). The Journal of American Medical Association. 197(11) 843-848 DOI: 10.1001/JAMA.1966.03110110067015.