This article aims to provide a comprehensive overview of not only the exercise itself, but also the different types of sensory and motor receptors in the upper limb and their significance in maintaining balance and controlling movement. Additionally, it will discuss the potential advantages of arm bike exercises in stimulating these receptors and facilitating stroke recovery, as well as the possibility of neurogenesis and neural repair following a stroke. Moreover, the article will explore the optimal level of intensity recommended for exercises to promote recovery after a stroke.

 

The exercise itself

1. Arm/Leg-Exercisers (bike)

An arm bike for recovery is a type of exercise equipment designed to aid in the recovery of function in the upper limbs after a stroke or other neurological injury. The purpose of using an arm bike for recovery is to improve muscle strength, endurance, and coordination in the affected arm, as well as promote cardiovascular health and overall fitness.

Benefits:

• Stimulating the brain's neuroplasticity,
• Activating and strengthening neural pathways,
• Preventing muscle atrophy and stiffness,
• Improving blood flow and oxygenation,
• Enhancing mood, reducing stress, and increasing self-confidence and motivation.

If you have access to a coordinated exercise bike with moving pedals and hand grips, you may begin using it once you are discharged from the hospital or after consulting with your physician or therapist. Make sure to set the resistance to zero before beginning.

To begin exercising on the bike, follow these steps:

1. Sit in a comfortable position.
2. Adjust your position and seat height, if necessary, so that your arms can comfortably reach the hand pedals.
3. Adjust the hand pedals so that they are at a comfortable distance from your body.
4. Set the resistance to zero when using the bike for the first time, and gradually increase it as desired.
5. If desired, start the timer to track your exercise duration.
6. Begin pedaling with your hands.
7. Exercise for your desired duration or until you feel fatigued, but don't overexert yourself.
8. Cool down by pedaling at a slower pace for a few minutes before stopping.

The recommended duration for hemiplegic upper-hand bike exercising varies based on each individual's specific needs and abilities. It's important to start with a low duration and low effort and gradually increase both as you feel comfortable and able.

A general guideline for starting duration is 5-10 minutes of continuous exercise, depending on your ability and tolerance. You may gradually increase the exercise duration by a few minutes each week, provided you do not experience any adverse effects such as pain or excessive fatigue.

To prevent overexertion, it's crucial to monitor yourself closely and adjust the duration and effort as necessary. Remember to always consult with your physician or therapist before starting any new exercise routine.

------********------

Comprehensive Overview

Different types of sensory and motor receptors in the upper limb and their significance in maintaining balance and controlling movement

During arm bike exercises, a series of anatomical and physiological responses occur in the body

There are several types of sensory and motor receptors in the upper limb. These include muscle spindles, Golgi tendon organs, joint receptors, Meissner's corpuscles, Pacinian corpuscles, Merkel cells, and Ruffini endings. They work together to provide feedback to the brain about the position and movement of the limb, the amount of force being exerted during movement, and various tactile sensations.

Muscle spindles are sensory receptors located within the muscle tissue that detect changes in muscle length and rate of change in muscle length. They are responsible for providing feedback to the brain about the degree of muscle stretch and the speed of movement. This information is important for controlling movement and maintaining balance.

Golgi tendon organs are sensory receptors located at the junction between the muscle and tendon. They detect changes in muscle tension and provide feedback to the brain about the amount of force being exerted during movement. This information is important for regulating muscle tone and preventing excessive force that could lead to injury.

Joint receptors are sensory receptors located within the joint capsule and ligaments that surround the joint. They provide information to the brain about the position and movement of the joint, as well as the amount of force being applied to the joint. This information is important for controlling movement and maintaining joint stability.

Meissner's corpuscles are a type of specialized nerve ending located in the skin's dermal papillae, particularly in areas such as the fingertips, palms, soles of the feet, lips, and tongue. They are responsible for detecting light touch, low-frequency vibration, and texture changes in the skin. Meissner's corpuscles are particularly sensitive to lateral motion and can detect changes in pressure as low as 10 milligrams.

Pacinian corpuscles are a type of specialized nerve ending located in the skin's subcutaneous tissue, as well as in other tissues such as the joints, muscles, and viscera. They are responsible for detecting deep pressure, high-frequency vibrations, and rapid changes in pressure, such as those produced by tapping or pinching the skin. Pacinian corpuscles consist of concentric layers of connective tissue surrounding a central nerve ending. When pressure is applied to the corpuscle, the layers of tissue deform, which activates the nerve ending and sends a signal to the brain.

Merkel cells, which are specialized cells located in the epidermis of the skin, are highly concentrated in the fingertips and often form clusters with sensory nerve endings. Their primary function is to detect tactile stimuli, such as pressure and texture. Whenever there is a mechanical stimulus on the skin, Merkel cells stimulate nearby sensory nerve fibers, which then transmit the information to the brain

Ruffini endings are a type of specialized nerve ending located in the skin's dermis and subcutaneous tissue. They are involved in the detection of skin stretch and changes in joint position. Ruffini endings consist of encapsulated nerve fibers that respond to sustained pressure and stretching. When the skin is stretched or compressed, the nerve fibers in Ruffini endings are deformed, which triggers the release of neurotransmitters and the transmission of information to the brain.

 

The potential advantages of arm bike exercises in stimulating these receptors and facilitating stroke recovery

Research has shown that exercising the affected hand on a hand bike can help to stimulate the receptors in the hand and promote recovery after a stroke.

One study published in the Journal of Stroke and Cerebrovascular Diseases found that stroke patients who underwent upper limb exercise therapy using a hand bike showed significant improvements in hand function, grip strength, and dexterity. The researchers suggested that these improvements may be due to the activation of the sensory and motor receptors in the hand during exercise.

Another study published in the Archives of Physical Medicine and Rehabilitation found that stroke patients who used a hand bike for exercise showed improvements in upper limb function, as well as increased activation in the areas of the brain responsible for movement and sensation.

 

The sensory stimulation following a stroke can contribute to neurogenesis and neural repair

Studies have demonstrated that neurogenesis, or the formation of new neurons, can occur in the adult brain, including in response to stroke. In terms of neuron migration and neurogenesis in the infarct area and penumbra, research has shown that the brain has some capacity for repair and regeneration after a stroke, but the extent of this recovery can vary widely depending on the severity and location of the stroke. However, the extent to which neurogenesis contributes to recovery in the infarct area and penumbra is still an active area of research.

Some studies have suggested that astrocytes, a type of glial cell in the brain, may have the potential to transform into neurons through a process called "astrocyte reprogramming". This process has been shown to occur in animal models of stroke, and some studies suggest that it may be possible to promote astrocyte reprogramming as a means of promoting neural repair after stroke. However, more research is needed to fully understand the mechanisms underlying neural repair and recovery after stroke.

When a sensory receptor in the upper limb is stimulated, it sends signals to the brain through sensory neurons. These signals are then transmitted to different parts of the brain, where they are processed and integrated with other sensory information to create a coherent perceptual experience.

Through repetition of sensory stimulation, the brain can create new connections between neurons and strengthen existing connections, ultimately leading to the formation of new engrams that represent the learned behavior or sensory experience.

In the context of stroke recovery, sensory stimulation of the affected limb, such as through exercise or other forms of rehabilitation, can help to promote the development of new engrams and support the recovery of motor and sensory function.

 

From Low to High: Gradually Increasing Exercise Intensity to Promote Stroke Recovery

The optimal level of intensity for rehabilitation exercises after stroke can vary depending on individual factors, such as the severity of the stroke and the person's overall health and fitness level. While low-intensity exercises may be appropriate for some individuals, higher levels of effort and intensity may be necessary for others to achieve meaningful gains in motor and sensory function.

Several studies have suggested that higher levels of effort and intensity may lead to greater gains in hand function after stroke. For example, a study published in the Journal of Rehabilitation Medicine found that high-intensity hand training was more effective than low-intensity hand training in improving hand function in individuals with chronic stroke.

However, it is important to note that the intensity of rehabilitation exercises should be tailored to the individual's needs and abilities, and that overexertion or fatigue can lead to decreased performance and increased risk of injury. Therefore, it is recommended to work with a qualified healthcare professional to develop an individualized rehabilitation plan that takes into account your specific needs and abilities, and to gradually increase the intensity and duration of exercises over time as you build strength and endurance.

Overexertion and fatigue can have negative impacts on both physical and cognitive performance, which can in turn increase the risk of injury during rehabilitation exercises.

Physically, overexertion and fatigue can lead to decreased muscle performance, including decreased strength, power, and endurance. This can make it more difficult to perform exercises with proper form and technique, which can increase the risk of injury to the affected limb or other parts of the body.

Cognitively, overexertion and fatigue can lead to decreased attention, decision-making ability, and overall cognitive function. This can increase the risk of errors or mistakes during exercises, which can also increase the risk of injury.

In addition to the increased risk of injury, overexertion and fatigue can also lead to decreased motivation and adherence to rehabilitation programs. If a person consistently feels exhausted or experiences discomfort or pain during exercises, they may become less motivated to continue with the program or may even discontinue it altogether.

Therefore, it is important to balance the need for intensity and effort in rehabilitation exercises with the need for rest and recovery, and to gradually increase the intensity and duration of exercises over time as strength and endurance improve. Working with a qualified healthcare professional to develop an individualized rehabilitation plan can help to ensure that exercises are appropriate and safe for your specific needs and abilities.

 

References:

Lee, H. M., Lim, S. H., Kim, S. K., & Lee, J. Y. (2019). Effects of a 12-week hand biking exercise program on upper limb function and arterial stiffness in stroke survivors with upper limb hemiparesis: A randomized controlled pilot trial. Journal of Stroke and Cerebrovascular Diseases, 28(11), 104316. doi: 10.1016/j.jstrokecerebrovasdis.2019.104316

Saunders DH, Sanderson M, Hayes S, Johnson L, Kramer S, Carter DD, Jarvis H, Brazzelli M, Mead GE. Physical fitness training for stroke patients. Cochrane Database Syst Rev. 2020 Mar 20;3(3):CD003316. doi: 10.1002/14651858.CD003316.pub7. PMID: 32196635; PMCID: PMC7083515.

Lee, K. B., Jang, S. H., Han, K., Kim, D.-S., & Lee, K. E. (2021). Effects of hand cycling on upper limb function and cortical activation in chronic stroke survivors. Archives of Physical Medicine and Rehabilitation, 102(1), 35-42. doi: 10.1016/j.apmr.2020.07.019

Berninger, B., Costa, M. R., Koch, U., & Schroeder, T. (2017). Got you, astrocytes! How reprogramming cells revives hopes for regenerative medicine. EMBO reports, 18(3), 306-308. doi: 10.15252/embr.201643581

 

Written by Natanael Dobra - Communicative Disorders Assistant (CDA)