Profuse Problems When Power Muscles Perform Posture Positions
Profuse Problems When Power Muscles Perform Posture Positions: Understanding the Difference Between Power and Posture Muscles
As a chiropractor, I often see patients whose muscular imbalances lead to a wide range of complaints, from chronic pain to fatigue. A key factor in these issues is the role that power muscles play in maintaining posture—something they’re not designed to do. In this blog, I’ll explore how power muscles and posture muscles differ, why the misuse of power muscles in postural tasks leads to problems, and how adopting good posture can help alleviate these issues.
Power Muscles: The Movers of Your Body
Power muscles are the larger, more superficial muscles that are responsible for producing significant force during movement. These muscles, like the trapezius in your shoulders or the iliopsoas in your hip flexors, contract to move joints and control your body in space. They are primarily made up of fast-twitch (Type II) muscle fibres, which are designed for short bursts of strength and power. However, these fibres fatigue relatively quickly when overworked.
Examples of power muscles include:
Trapezius: Responsible for shoulder shrugging and neck movement.
Sternocleidomastoid (SCM): A strong neck mover that helps rotate and flex the head.
Iliopsoas: The powerful hip flexor that helps lift the leg during walking or running.
These muscles excel when they’re used for dynamic movements like lifting, walking, or sprinting. However, when they’re forced to maintain prolonged contractions—such as holding the neck and upper back in position during prolonged sitting or slouching—things start to go wrong.
Posture Muscles: The Subtle Stabilizers
In contrast to power muscles, posture muscles are smaller, deeper muscles, often located along the spine. Their primary job is to stabilise joints and maintain posture throughout the day. These muscles, such as the multifidus and erector spinae along the spine, are rich in slow-twitch (Type I) muscle fibres, which are designed for endurance and can sustain low-level contractions for long periods.
Unlike power muscles, posture muscles are built to hold your spine and other joints in a stable position, keeping everything aligned while you go about your daily activities. They don’t produce large amounts of force, but they’re essential for keeping your body upright and balanced.
The Problem: When Power Muscles Take Over Postural Roles
When power muscles are forced to maintain postural positions, especially during activities like repetitive sitting or slouching, they become fatigued. This happens because these muscles are not designed for endurance. Over time, fatigue in these muscles can lead to the development of trigger points—tight, painful areas of muscle that feel like knots.
Let’s take a look at two common scenarios:
Trapezius & SCM Overload: If you spend a lot of time sitting at a desk or slouched over a computer, your trapezius and sternocleidomastoid muscles are likely working overtime to hold your head and shoulders in position. Over time, these power muscles become fatigued, resulting in neck pain, headaches, and shoulder discomfort.
Iliopsoas Fatigue: Prolonged sitting also forces your iliopsoas, a major hip flexor, to stay contracted for extended periods. This can lead to tightness in the lower back and hips, contributing to discomfort and even lower back pain.
When these power muscles are overworked, they not only fatigue but also stop functioning optimally, leaving you with muscle tension, pain, and reduced mobility.
The Remedy: Restore Balance with Good Posture
The solution to this issue lies in allowing the muscles that were designed for posture—the small, deep spinal stabilisers—to do their job. Good posture is defined as the position that places your spine in a healing environment. For each individual, this posture will be slightly different, depending on body composition, flexibility, and movement patterns.
How to Encourage Posture Muscles to Work
Adopt Your Unique Good Posture: While there’s no “one-size-fits-all” posture, your optimal posture is the one where your spine and joints are in a neutral, aligned position. This helps distribute stress across your entire body and minimises the workload on your power muscles.
Break the Slouching Habit: Frequent slouching shifts the responsibility of maintaining posture from your slow-twitch posture muscles to your fast-twitch power muscles. By being mindful of your posture throughout the day, particularly when sitting, you can help engage your posture muscles instead of overworking your power muscles.
Strengthen Your Posture Muscles: Incorporating exercises that target your core and spinal stabilisers can help improve their endurance and ability to maintain good posture for long periods. Pilates, yoga, and specific spinal stabilisation exercises are great options for this.
Give Your Power Muscles a Break: If you find yourself relying on your trapezius, SCM, or iliopsoas too often, it’s time to give them a break. Stretching and releasing these muscles can help alleviate tension, while strength training for your posture muscles will help take the load off your power muscles in the long term.
Conclusion: Let Your Posture Muscles Do Their Job
When power muscles are left to perform postural tasks, the result is often pain, tension, and trigger points. To avoid this, focus on maintaining good posture by allowing your body’s natural stabilisers—the posture muscles—to do their job. Strengthening these muscles, alongside being mindful of your daily posture, will lead to better balance, reduced fatigue, and improved overall wellbeing.
Remember, good posture is not just about standing tall; it’s about creating a sustainable environment for your muscles and joints to thrive in. Let your posture muscles take charge, and you’ll experience fewer aches and better movement throughout your daily life.
______________________________
References:
Tantanatip A, Chang KV. Myofascial Pain Syndrome. [Updated 2023 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499882/
Talbot J, Maves L. Skeletal muscle fiber type: using insights from muscle developmental biology to dissect targets for susceptibility and resistance to muscle disease. Wiley Interdiscip Rev Dev Biol. 2016 Jul;5(4):518-34. doi: 10.1002/wdev.230. Epub 2016 May 19. PMID: 27199166; PMCID: PMC5180455. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5180455/
Plotkin DL, Roberts MD, Haun CT, Schoenfeld BJ. Muscle Fiber Type Transitions with Exercise Training: Shifting Perspectives. Sports (Basel). 2021 Sep 10;9(9):127. doi: 10.3390/sports9090127. PMID: 34564332; PMCID: PMC8473039. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8473039/
Paillard T. Relationship between Muscle Function, Muscle Typology and Postural Performance According to Different Postural Conditions in Young and Older Adults. Front Physiol. 2017 Aug 15;8:585. doi: 10.3389/fphys.2017.00585. PMID: 28861000; PMCID: PMC5559497. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5559497/
Waongenngarm P, Rajaratnam BS, Janwantanakul P. Perceived body discomfort and trunk muscle activity in three prolonged sitting postures. J Phys Ther Sci. 2015 Jul;27(7):2183-7. doi: 10.1589/jpts.27.2183. Epub 2015 Jul 22. PMID: 26311951; PMCID: PMC4540846. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4540846/
