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Chiropractic Care and Muscle Activation: Strength and Reflex Control

Chiropractic adjustments increased cortical drive and improved muscle recruitment efficiency. Reflexes became faster and more coordinated following adjustments. EMG results showed better synchronisation between motor units. Supports chiropractic care as a means to optimise neuromuscular performance through central mechanisms.

Original Study Title:

Changes in Cortical Drive to Upper and Lower Limb Muscles Following Spinal Manipulation

Authors:

Imran Khan Niazi; Kelly Holt; Heidi Haavik; Bernadette Murphy

Journal:

Brain Sciences (MDPI)

Publication Year:

2013
Niazi, I. K., Holt, K., Haavik, H., & Murphy, B. (2013). Changes in Cortical Drive to Upper and Lower Limb Muscles Following Spinal Manipulation. Brain Sciences, 3(2), 119–137. https://doi.org/10.3390/brainsci3020119

Connecting the spine and muscular control

Muscles don’t work in isolation — they’re coordinated by constant feedback loops between the spine, brain, and motor neurons. When spinal joints become restricted, this communication can be disrupted, leading to altered muscle tone, weakness, or delayed reflexes. Research led by Dr Heidi Haavik has demonstrated that chiropractic adjustments can influence muscle activation patterns by improving how the nervous system recruits and controls muscle groups.

What the research explored

Using tools such as surface electromyography (sEMG) and transcranial magnetic stimulation (TMS), Haavik’s team measured changes in muscle response and cortical drive before and after chiropractic spinal manipulation. Their goal was to determine whether improving spinal motion could change how effectively the brain activates specific muscle groups.

Key findings

  • Chiropractic adjustments produced increased cortical drive to both upper and lower limb muscles.
  • Participants demonstrated improved muscle activation efficiency and reduced fatigue during repeated contractions.
  • Reflex response times shortened, suggesting more efficient spinal–cortical communication.
  • Changes in EMG amplitude indicated improved synchronisation between motor units.

Clinical implications

Efficient muscle activation is essential for movement performance, stability, and injury prevention. By improving spinal communication with the motor cortex, chiropractic care may help muscles contract more effectively — not necessarily making them stronger, but smarter and more responsive.

In practice

  • We assess motor control using muscle testing, reaction-time tasks, and postural analysis.
  • Adjustments target spinal segments that may be sending distorted feedback to the brain.
  • Restoring normal spinal motion helps optimise muscle coordination and reflex stability across the body.

Read the study: Changes in Cortical Drive to Upper and Lower Limb Muscles Following Spinal Manipulation


This article summarises research into neuromuscular control. Chiropractic adjustments are not treatments for muscular disease but may help optimise the brain–muscle connection for improved function.

The information on this page summarises independent, peer-reviewed research conducted by external scientists. It is provided for educational purposes only and does not imply that chiropractic care treats or cures any medical condition. Chiropractic services at this clinic are provided within the scope of practice defined by the Chiropractic Board of New Zealand.