Exercise as Medicine Post-Stroke (Part 3)

People who are left with neurological injuries following a stroke often experience changes in their brain, body, mentality, and lifestyle. A combination of these changes can cause loss of gross motor control and increased fat storage within insulin-resistant muscle fibres. In short, this means that the body is now less efficient in transporting and using its major energy stores. Without intervention, this can lead to the development of glucose intolerance and type 2 diabetes. These conditions are seen in >75% of stroke survivors. In addition, reduced levels of physical activity are associated with endocrine problems such as reduced growth hormone. This can lead to reduced bone density, predisposing the individual to pathologic bone fractures. Numerous adapted exercise modes for stroke survivors have been shown to produce biological adaptations and a conditioning response whereby patients experience improvements in functional independence, cardiovascular disease risk factors, aerobic capacity and bone structural integrity. Below, I explain how these adaptations are possible through exercise:

Benefits of Complimentary Strength Training:

Strength training that is individualised and progressed slowly with time spent on proper instruction of technique; and taking hemiparesis and/or spasticity into consideration is recommended. A lack of lower limb strength has been associated with an increased risk of falls. It has been shown that walking has improved when exercise programs have incorporated strengthening of: knee extensors, ankle plantarflexors and hip flexors and hip extensors. The treating exercise physiologist will ensure their client elicits correct muscle activation sequencing, leading to improved neural firing sequences, neural plasticity, and enabling the client to regain muscle memory. Over time, this can aid in the recovery of motor control and sensation. Numerous studies have also shown that strength training with biofeedback that further stimulates neural activity can significantly improve gait retraining in stroke survivors. Resistance training will also accelerate protein synthesis and thickening of myofibrils within the muscle to aid in muscle mass weight gain. Increased muscle mass will promote a shift away from adipose tissues towards lean mass by increasing insulin sensitivity and improving glucose uptake. In addition, a large amount of shear stress at the bone caused by contraction of major muscle groups can cause increased osteoblastic activity. This is needed to prompt increases in bone calcification, and thus results in improved bone mineral density; reducing the risk of pathologic fractures.

Aerobic Adaptations:

Following stroke, peak aerobic performance can drop below 50% that of matched sedentary control groups. On top of this, there is much larger energy cost (1.5 to 2 times more) attributed to abnormal walking biomechanics as seen with the hemiparetic gait.  The combination of someone having reduced aerobic ability from fatigue and reduced walking economy can only be sustained for short periods. This is because walking will now use approximately 70 percent of the person’s total aerobic ability; making it difficult to independently complete many ADL’s. Training aerobic capacity and gait biomechanics is important to improve fatigue resistance, minimise weight gain, and improve endothelial function to reduce the risk of developing further cardiovascular-related co-morbidities such as heart disease, obesity, etc. It has also been shown that the mild stress provoked by aerobic exercise can improve spatial memory; making it easier for the person to independently function within their environment.

Benefits of Flexibility / ROM Exercises:

Both passive and active range of motion exercises (ROM) have been found to benefit this population. As the spine and shoulders are often affected by hemiparesis, it is important to establish and maintain flexibility in these areas. In addition, light to moderate ROM exercises that are performed daily have been shown to prevent learned non-use by aiding the electrical signalling between the brain and muscles, which helps to keep these connections alive. This can also help to reduce spasticity, muscle stiffness and prevent painful contractures.

It’s important to note that the benefits of exercise therapy are rapidly lost with cessation of exercise training. Thus, to maintain these gains upon cessation of acute rehabilitative services, it’s important to implement home-based and community-based physical activity. For long-term improvements in physiological, neurological and psychosocial function, Absolute Balance’s team of Accredited Exercise Physiologists specialise in providing individualised, evidence-based exercise rehabilitation services to further enable people to regain function and independence upon cessation of acute rehabilitative care.

Nicole Barber (B.Sc. – Exercise & Sport Science)
Accredited Exercise Scientist (AES) (ESSAM)

References:

Abdul-Ghani, M. and DeFronzo, R. (2010). Pathogenesis of Insulin Resistance in Skeletal Muscle. Journal of Biomedicine and Biotechnology, pp.1-19.

Billinger, S., Arena, R., Bernhardt, J., Eng, J., Franklin, B., Johnson, C., MacKay-Lyons, M., Macko, R., Mead, G., Roth, E., Shaughnessy, M. and Tang, A. (2014). Physical Activity and Exercise Recommendations for Stroke Survivors: A Statement for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke, 45(8), pp.2532-2553.

Dobkin, B. (2008). Training and exercise to drive poststroke recovery. Nature Clinical Practice Neurology, 4(2), pp. 76-85.

Duncan, P., Studenski, S., Richards, L., Gollub, S., Lai, S., Reker, D., Perera, S., Yates, J., Koch, V., Rigler, S. and Johnson, D. (2003). Randomized Clinical Trial of Therapeutic Exercise in Subacute Stroke. Stroke, 34(9), pp.2173-2180.

Flint Rehab. (2018). 15 Useful Stroke Exercises to Improve Mobility at Home (with Pictures) – Flint Rehab. [online] Available at: https://www.flintrehab.com/2018/stroke-exercises/ [Accessed 08 Oct. 2018].

Moore, G., Durstine, J. and Painter, P. (2016). ACSM’s exercise management for persons with chronic diseases and disabilities. Champaign, ILL: Human Kinetics, pp.235 – 247.

National Institute of Neurological Disorders and Stroke. (2018). Post-Stroke Rehabilitation Fact Sheet National Institute of Neurological Disorders and Stroke. [online] Available at: https://www.ninds.nih.gov/Disorders/Patient-Caregiver Education/Fact-Sheets/Post-Stroke-Rehabilitation-Fact-Sheet [Accessed 7 Aug. 2018].