Neuropathy "The Painful Enigma"

For individuals starting to lift weights, motor units are important for muscle movement. Can building more motor units help build strength and maintain muscle mass?

Motor Units

Motor units control the skeletal muscles and are the force behind every body movement. (C J. Heckman, Roger M. Enoka 2012)
This includes voluntary movements like lifting weights and involuntary movements like breathing. When lifting objects and weights, the body adapts to motor unit needs, meaning that individuals must consistently increase the weight to progress. 

• Lifting weights regularly trains the body to generate more motor units and force.
• General guidelines recommend lifting weights for all muscle groups two to three non-consecutive days a week.
• Consistency helps maintain muscle mass.
• Regular progression increases the risk of plateauing.

What They Are

Exercise increases the body's muscle strength, while sedentariness and inactivity weaken them. A motor unit is a single nerve cell/neuron that supplies the nerves to innervate a group of skeletal muscles. The neuron receives signals from the brain that stimulate all the muscle fibers in that particular motor unit to generate movement.

• Muscles comprise different fiber types.
• They are attached to the bones with connective tissue, which is stronger than the muscle.
• Multiple motor units are dispersed throughout the muscle.
• The motor units help ensure muscle contraction force is evenly spread throughout the muscle.
• Motor units are different sizes and operate differently depending on where and what they do.
• Small motor units might only innervate five or ten fibers. For example, to blink or sniff.
• Large motor units can comprise hundreds of muscle fibers for swinging or jumping movements.

How They Work

The number of units activated depends on the task. Stronger muscle contractions require more. However, fewer units are needed to accomplish the movement for individuals expending less effort.

Contraction

• Once a unit receives a signal from the brain, the muscle fibers contract simultaneously.
• The force generated depends on how many units are required to accomplish the task. (Purves D. et al., 2001)
• For example, picking up small objects like a pen and paper requires only a few units to generate the force needed.
• If picking up a heavy barbell, the body needs more units because more force is needed to lift the heavier load.
• The body can generate more force with stronger muscles.
• This happens when lifting weights on a regular basis and overloading the muscles with more weight than they can handle.
• This process is known as adaptation.

Adaptation

The purpose of lifting weights is to challenge the muscles so they adapt to the new challenge and grow in strength and mass. Motor units are a major part of the adaptation process. (Dr. Erin Nitschke. American Council on Exercise. 2017)

• When first starting weight training, the brain recruits more units every time a muscle is contracted. (Pete McCall. American Council on Exercise. 2015)
• As individuals continue working out, their ability to generate more force increases and units activate more rapidly.
• This makes movements more efficient.
• Individuals can increase motor unit recruitment by consistently increasing the weight challenge to their muscles.
• The development creates movement memory.
• A relationship between the brain, muscles, and motor units is established even if the individual stops working out. The pathways are still there no matter how long the individual takes off.
• When returning to training, the body will remember how to ride a bike, do a bicep curl, or squat.
• However, the muscles will not have the same strength as the strength needs to be built back along with endurance that may have been lost.
• It is the movement memory that remains.

Military Training and Chiropractic Care: Maximizing Performance

General Disclaimer *

The information herein is not intended to replace a one-on-one relationship with a qualified healthcare professional or licensed physician and is not medical advice. We encourage you to make healthcare decisions based on your research and partnership with a qualified healthcare professional. Our information scope is limited to chiropractic, musculoskeletal, physical medicines, wellness, sensitive health issues, functional medicine articles, topics, and discussions. We provide and present clinical collaboration with specialists from various disciplines. Each specialist is governed by their professional scope of practice and their jurisdiction of licensure. We use functional health & wellness protocols to treat and support care for the injuries or disorders of the musculoskeletal system. Our videos, posts, topics, subjects, and insights cover clinical matters, issues, and topics that relate to and directly or indirectly support our clinical scope of practice.* Our office has reasonably attempted to provide supportive citations and identified the relevant research studies or studies supporting our posts. We provide copies of supporting research studies available to regulatory boards and the public upon request.

We understand that we cover matters that require an additional explanation of how it may assist in a particular care plan or treatment protocol; therefore, to further discuss the subject matter above, please contact Dr. Alex Jimenez or contact us at 915-850-0900.

Dr. Alex Jimenez DC, MSACP, CCST, IFMCP*, CIFM*, ATN*

email: coach@elpasofunctionalmedicine.com

Licensed in: Texas & New Mexico*

References

Heckman, C. J., & Enoka, R. M. (2012). Motor unit. Comprehensive Physiology, 2(4), 2629–2682. https://doi.org/10.1002/cphy.c100087

Purves D, Augustine GJ, Fitzpatrick D, et al., editors. (2001). Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001. The Motor Unit. Available from: https://www.ncbi.nlm.nih.gov/books/NBK10874/

Dr. Erin Nitschke. American Council on Exercise. (2017). How Muscle Grows (Exercise Science, Issue. https://www.acefitness.org/resources/everyone/blog/6538/how-muscle-grows/

Pete McCall. American Council on Exercise. (2015). 10 Things to Know About Muscle Fibers (Exercise Science, Issue. https://www.acefitness.org/resources/pros/expert-articles/5411/10-things-to-know-about-muscle-fibers/

Neuroregeneration could become an option for spinal cord injury treatments in the future. A spinal cord injury or SCI is when there is damage to the bundle of nerves and cells that send and receive signals from the brain and body. A spinal cord injury can be caused by direct trauma/injury to the cord or damage to the tissue and vertebrae. The damage can result in temporary or permanent changes in:

• Sensation
• Movement
• Strength
• Body function/s below the injury site.

There are incomplete and complete injuries. Injuries that cause limited or no cell death can achieve a full recovery. Injuries that are more serious and/or are higher on the spinal cord can cause permanent damage and/or paralysis. Automobile crashes, accidents, and serious falls are the most common causes of spinal cord injuries.

• An incomplete injury means the cord can still transmit messages, but there is interference/disturbance.
• A complete injury means communication and motor function/voluntary body movement is not transmitting.

Symptoms

Symptoms of a spinal cord injury include:

• Unnatural or awkward positioning of the spine or head.
• Pain or pressure in the head, neck, or back.
• Numbness
• Tingling
• Loss of or changes in sensation in the hands and feet.
• Problems with walking.
• Weakness or inability to move parts of the body.
• Loss of movement.
• Paralysis can occur immediately or develop over time as swelling and bleeding affect the cord.
• Loss of bladder and bowel control.
• Changes in sexual function.
• Difficulty breathing.

SCI Damage Control

A spinal cord injury affects the central nervous system, the body's central headquarters. Damage can cause complications through what's called the secondary injury cascade, which is a series of chemical reactions the body activates to help the situation. However, if the chemical response does not stop and stays active, it can worsen the injury. The body recognizes that an emergency has occurred and tries to go into a shut-down mode that kills off some of the cells in the central nervous system.

When a spinal injury happens, treatment focuses on stopping the damage as quickly as possible to stop the injury cascade and prevent as much cell death as possible. This act is called neuropreservation, meaning that the team is trying to preserve and save as many nerve cells as possible.

Injury Neuroregeneration Treatment Studies

While current treatment primarily focuses on stopping as much damage as possible then going through physical therapies to maintain spinal alignment and rehabilitate the body, the future of injury treatment is looking towards regrowing and repairing the damaged nerve cells through a process known as neuroregeneration. Repairing nerves that have been damaged could change life for many. Neuroregeneration Treatments being studied include:

Surgery

• A study in The Lancet Neurology presents how getting surgery as soon as possible after an injury can provide significant benefits.
• The findings could change all of the guidelines for spinal cord injury.

Medication

• A study on Riluzole, a medication that has shown promise to slow down nerve cell damage.
• A team completed a randomized controlled trial for the medication; soon, the final results will be available.

Antibody treatment

Antibodies are being studied in two ways.

• To stop nerve cells from being damaged.
• To help damaged nerve cells regenerate.

Stem cells

• Scientists are studying ways to grow new nerve cells from an individual's stem cells without the need for embryonic stem cells.
• Specialized stem cells could also be used to help other nerve cells regenerate.

Electrical stimulation

• Another approach is using electrical stimulation to restore function in the spinal cord.
• Therapy that could help a paralyzed individual walk again.

The Future of Neuroregeneration

Aside from early surgery intervention, most neuroregenerative treatments are not ready or accessible yet. There's still much more research before it can become a mainstream treatment option. Treatment that involves regenerating nerve cells will take longer than a treatment designed to protect nerve cells. However, more clinical trials are expected to be done in the next few years, with stem cell therapies taking the longest. Some of these therapies could be ready to be used on actual patients in 5-10 years.

Body Composition

The Importance of Measuring Body Composition

Most diet and fitness programs focus on weight loss or gain. However, they tend to overlook that individuals have completely different body compositions. Body composition describes the amount of:

• Fat
• Bone
• Water
• Muscle
• In the body.

Measuring body composition can tell a body's unique makeup and help identify areas to work on to improve overall health and wellness. Body composition analysis provides a snapshot of an individual's health/fitness levels to help achieve health goals from the inside out.

General Disclaimer *

The information herein is not intended to replace a one-on-one relationship with a qualified health care professional, licensed physician, and is not medical advice. We encourage you to make your own health care decisions based on your research and partnership with a qualified health care professional. Our information scope is limited to chiropractic, musculoskeletal, physical medicines, wellness, sensitive health issues, functional medicine articles, topics, and discussions. We provide and present clinical collaboration with specialists from a wide array of disciplines. Each specialist is governed by their professional scope of practice and their jurisdiction of licensure. We use functional health & wellness protocols to treat and support care for the injuries or disorders of the musculoskeletal system. Our videos, posts, topics, subjects, and insights cover clinical matters, issues, and topics that relate to and support, directly or indirectly, our clinical scope of practice.* Our office has made a reasonable attempt to provide supportive citations and has identified the relevant research study or studies supporting our posts. We provide copies of supporting research studies available to regulatory boards and the public upon request.

We understand that we cover matters that require an additional explanation of how it may assist in a particular care plan or treatment protocol; therefore, to further discuss the subject matter above, please feel free to ask Dr. Alex Jimenez or contact us at 915-850-0900.

Dr. Alex Jimenez DC, MSACP, CCST, IFMCP*, CIFM*, ATN*

email: coach@elpasofunctionalmedicine.com

Licensed in: Texas & New Mexico*

References

Aguilar, Juan et al. "Spinal cord injury immediately changes the state of the brain." The Journal of neuroscience: the Official Journal of the Society for Neuroscience vol. 30,22 (2010): 7528-37. doi:10.1523/JNEUROSCI.0379-10.2010

Badhiwala, Jetan H; Wilson, Jefferson R; Witiw, Christopher D; et al. (February 2021). The Lancet Neurology Vol. 20, No. 2, P. 117. The Influence of Timing of Surgical Decompression for Acute Spinal Cord Injury: A Pooled Analysis of Individual Patient Data. DOI: 10.1016/S1474-4422(20)30406-3

Chari, Aswin et al. "Surgical Neurostimulation for Spinal Cord Injury." Brain sciences vol. 7,2 18. 10 Feb. 2017, doi:10.3390/brainsci7020018