Truth In Function: Joint Strength and Stability Center

04/26/2026

Chronic pain produces an inflammatory response within the region, igniting an inhibitory response to the muscles involved (Mukund & Subramaniam, 2019). The inhibitory response weakens the muscles’ capability to perform and create stability in the area while transforming type I muscle characteristics to those found in type IIb fibers (Mukund & Subramaniam, 2019; Pinto et al., 2020). The inhibitory effect from the inflammation will negatively impact the motor recruitment of the muscles, leading to a lack of stability of the joint while irritation from joint loading increases due to the nociceptor response that occurs when inflammation is present (Merkle et al., 2020; Russo et al., 2017).

Postural/joint control and stabilization stem from the overall response, and continued feedback of the muscle spindle and tonic activation of the type I muscle fibers (Gahmkhar & Kahlee, 2019; Sakai et al., 2022). The muscle availability and capability to respond and maintain a response to load or resistance through a constant communication occurring within the neuromuscular system due to afferent signaling from proprioceptors and efferent signaling from the central nervous system is known as tonus (Ganguly et al., 2021). Panjabi (1992) and Norris (1995) have both expressed the importance of muscle tone in the role of spinal stability, and decreasing or preventing chronic pain.

When pain and inflammation are present anywhere in the body, the inhibitory response on the muscles of the region may lead to compensation of different motor pathways when attempting to load or apply resistance to the region (Merkle et al., 2020). If this is occurring when attempting to treat the muscles of the region while performing resistance exercise, the targeted muscles may be non-respondent (Norris, 1995). A non-respondent muscle is a muscle that fails to respond to a light amount of resistance or force applied to the muscle testing position (Norris, 1995). Norris (1995) explains the importance of ensuring muscle response through testing the muscle’s response before applying isotonic resistance exercise. The muscle tone should be tested and strengthened prior to applying load to the muscle region in exercise as it is necessary for ensuring the preparedness of a muscle or muscles in the ex*****on of any movement or resisting of forces being applied for the purpose of creating adaptation in such muscles through exercise (Ganguly et al., 2021).

Learn more with Dr. Jeff Tardiff PhD, MS at Truth in Function

Call for your complimentary consultation/assessment 715-781-9741

03/27/2026

Stabilizing muscles vs. load or mobility muscles
- This is not a reality

“Stability muscles” are not separate of “force producing muscles”

ALL muscles have a duty in within the roles of stabilization
mobility
managing external load or force

In fact, the large the muscle, the more force it’s able to produce, and that means it is also responsible for stabilization of that force.

The difference is in muscle fiber characteristics. Stabilization is established through:
- Muscle responsiveness to the external force or activity demanded.
- Maintaining responsiveness through out the demanded duration and demanded range of motion within the activity or controlling of the external force.
- Appropriate capability to maintain the absorption and control of the external force.

If the capability to withstand the external forces involved is not met:
- The nervous system will then shut down the muscle responsiveness
- Stability will not be maintained
- The muscle will not be able to carry out the demanded activity

If the capability is met, but the capability is unable to sustain the forces for the duration of the required task:
- The nervous system will shut down responsiveness
- Muscle stability will not be present

Tonus Responsiveness, Availability, and Capability (TRAC) of each muscle working synergistically within a demanded task is required to ensure completion without:
pain
injury
long-term compensation

Dr. Jeff Tardiff PhD, MS

03/17/2026

TRAC — Tonus: Response • Availability • Capability™

Muscle tonus is the muscle’s capability to respond in contraction to an external force and the ability to maintain that response while controlling resistance throughout the demanded range of motion.

Muscle instability is the inability to do so.

There are three essential pillars of tonus: Response, Availability, and Capability.

All three pillars are required for the successful completion of any muscular activity—whether athletic performance, mobility, or simply maintaining posture against gravity.

If any of these three pillars within any muscle involved in a movement is absent, injury becomes likely, either immediately or through compensatory patterns that develop over time.

When a muscle cannot perform its role within any of these three pillars, other muscles must compensate in order to withstand the demands of the task. When compensation is no longer sufficient, passive structures—including ligaments, joint capsules, and connective tissues—begin to absorb the mechanical stress created by the external force.

Over time, this transfer of stress may contribute to chronic inflammatory conditions and structural breakdown.

Therefore, all three pillars—Response, Availability, and Capability—are required for completing any physical tasks safely and efficiently at any level of demand, while they are equally required for the effective rehabilitation of injured muscle and connective tissues surrounding the targeted joint.

The tonus of muscles, and/or of specific muscle positions, can be clinically measured, making muscular instability under particular demands measurable, predictable, and avoidable.

TRAC — Tonus: Response • Availability • Capability™
Dr. Jeff Tardiff, PhD, MS

02/23/2026

Tired of winter? Come to Truth in Function and train. Working out is great for both the body and the mind. Our personal trainers can help you develop a workout routine specific to your goals.

Don’t wait for nice weather in order to work on yourself, stop in and see us at 1617 10th Ave. Menominee. 715-781-9741

02/16/2026

Muscle fiber types… did you know there’s more than one type of skeletal muscle in your body?

It’s important to understand how different muscle fiber characteristics function and how they adapt to training.

However, muscle fiber “types” are often oversimplified — sometimes to the point of being misunderstood due to charts and educational tools such as what tou see here.

Most human muscle fibers exist along a spectrum. Many are hybrids, expressing characteristics of multiple fiber classifications rather than being locked into a single rigid category.

When the body moves — especially during athletic performance — all fiber characteristics contribute. Strength, speed, endurance, and power are not produced by isolated fiber types, but by coordinated neuromuscular recruitment working together.

One of the most misunderstood characteristics in mainstream fitness is the slow-twitch fiber.

Slow-twitch fibers are not simply “for endurance running.” They play a critical role in maintaining muscle availability, structural integrity, and sustained neuromuscular control — including something as fundamental as resisting gravity.

When slow-twitch characteristics are underdeveloped, proprioceptive feedback diminishes, compensatory patterns increase, and structural integrity can decline. Over time, this may contribute to recurrent injury and mobility limitations.

Research suggests that individuals with chronic pain and movement dysfunction often demonstrate deficits in low-threshold motor unit availability — a key component of sustainable movement.

This isn’t just important for athletes.

It’s critical for long-term mobility, joint stability, and structural resilience in everyday life.

If you’d like to learn how your neuromuscular system is functioning —

Call us at 715-781-9741 to schedule your free assessment.

02/09/2026

Discipline is a skill. No one is born with a high degree of it. You have to train it, make it a habit.

When it comes to exercise, the first step of a disciplined routine is showing up for your workout. Be there. Be intentional.

At Truth in Function, we provide you with opportunity, knowledge, and equipment to help guide you on a path towards physical discipline .

Call us at 715-781-9741 or stop in to schedule an assessment. We are located at 1617 10th Ave. Menominee.

02/02/2026

Time under tension. The method of doing an exercise low weight for minutes at a time. Training endurance…

More importantly…training type 1 muscle fibers.

The fibers that hold us up and keep us steady all day long and we never think about them. These are the fibers we lose first as we age. Time under tension is an important training method when considering joint integrity and muscle function

At Truth in Function, we specialize in adapting training methods to meet your immediate needs. No preset plans. No popular routines. Personalized exercises to help you progress from where you are to a stronger, more mobile version of yourself. Contact us at 715-781-9741 or stop in at 1617 10th Ave. Menominee for a complimentary assessment.

01/15/2026

Many of you have been asking me about this. My dissertation has now been published.

Over the past few years, I’ve been working on a research project that grew out of a simple clinical question:

If muscle-targeting interventions improve chronic pain by correcting muscle instability, how do we validate the instability, confirm its correction, and measure it objectively?

I kept seeing the same pattern in the clinic: people weren’t weak in the traditional sense, and they didn’t necessarily have significant structural damage outside of the typical bulged discs and degeneration. What they did have was poor proprioceptive tonus — the ability for muscles to maintain low-level, position-specific tension that keeps the body stable. Tonus is the muscle’s capability to respond to an external load or stress on command and control it within the necessary range of motion. Surprisingly, this isn’t something that gets much attention in mainstream rehabilitation or performance literature, but there is a substantial amount of information in research literature.

My dissertation explored research on this subject from 1992 to 2025. I set out to test whether restoring proprioceptive input and then reinforcing it with low-load, isolated (targeted muscle positions) isometric exercise can improve lumbopelvic muscle tonus in individuals with non-specific chronic low back pain, and whether or not this would have a significant impact on their pain. I have seen consistent positive outcomes in doing so over the past 15 years, but it has never been studied. The study ran for 12 sessions within 6 weeks across multiple time points and tracked changes in muscle tonus (responsiveness), function, and pain.

It is the first study to introduce an objective measure of muscle instability by measuring tonus with a handheld dynamometer within individual muscle-biased positions. It is also the first study to tie weak tonus to chronic pain, while demonstrating that increasing tonus decreases pain and increases function.

The study demonstrated substantial improvement in pain, with substantial improvement in function, while muscle tonus increased between 100–300%, even with herniated discs and severe degeneration present.

For those interested in the science behind neuromuscular stability, chronic low back pain, or direct muscle proprioceptive training, the full dissertation was officially published in the Liberty University library this week. I’m grateful to everyone who helped make this possible and to the participants who trusted the process.

If you’d like to read it or reference it, here’s the link:

https://digitalcommons.liberty.edu/doctoral/7844/

I’m looking forward to continuing this work and building on the clinical side of it as well.

For more information on the subject, call 715-781-9741

Dr. Jeff Tardiff PhD, MS

Nonspecific chronic low back pain affects most people through-out the world at some point within their lives, negatively impacting 80%-90% of the overall population, their families, and their communities. Thus far, the outcome of most studies indicate that the best form of treatment for this specifi...

01/05/2026

Turn of the year means a new opportunity to focus on joint mobility. Proper muscle function and strength are key elements in moving pain free. Stop by our facility and let us teach you how to maintain your body. Whether you are dedicated to fitness and looking for new ways to challenge yourself, or you just want the ability to do your day to day activities more effectively, we are here to help you keep moving strong! We are located at 1617 10th Ave. Menominee. 715-781-9741

01/01/2026

Happy 2026 from all of us at Truth In Function!🎊🎉
Thank you for trusting us with your physical health and mobility over the past years!

As you approach your New Year’s health resolutions, there are a few important principles we’d like to remind you of—principles that truly matter for long-term health, performance, and sustainability.

In long-term, sustainable weight loss, changes in body composition, and overall health, the type of calories you eat matters.

The training methods you choose, their long term impacts, your goals, your body, and the current state of your neuromuscular system matter.

The muscle fiber characteristics you develop matter.

Understanding the importance of resistance training—and selecting the most beneficial type of resistance training for long-term mobility and health (outside of your short term goals)—matters.

Understanding the role of cardiovascular challenge in driving physiological adaptation—and how cardiovascular demand can be achieved across multiple training modalities—matters.

Mobility matters.

Stability—muscle response capability within available ranges of motion—matters.

Tightness and pain during movement are often protective neurological responses. Identifying and addressing the cause of these symptoms is what truly matters.

Being able to engage in the things you love most in life—without pain or limiting restriction—matters.

Understanding the difference between active methods and passive methods matters.

Sugars are necessary—it’s the type of sugar and the timing of intake that matter.

BMI is not a judgment of your health. Body composition and internal health—or true “fitness”—far more matters.

Cholesterol plays a vital role in energy production, cellular function, and cellular regeneration for adaptation and healing.
Context and individual risk factors matter.

The footwear you choose—and its impact on both short-term and long-term muscular and structural health—matters.

Enjoying life matters!

Working toward physically identifying the causes of your mobility limitations, pain, and chronic issues, while educating you on how to prevent these issues in the future, so you can take part in all of the life activities you enjoy matters.

We are here for you—not only to address your current physical limitations, but to guide you toward what truly matters for your health and performance, based on your individual goals and current situation.

For a complimentary consultation or assessment, call 715-781-9741 or stop in at 1617 10th Ave Menominee

Every client that currently works with one of our specialist at least once per month receives 24/7 access to the facility and equipment!

Dr. Jeff Tardiff, PhD, MS
Health & Exercise / Performance Sciences
Neuromuscular, Mobility & Biomechanics Expert
Founder & Clinical Director
Truth In Function

12/22/2025

Merry Christmas to all of you, from all of us here at Truth in Function!! We are proud to serve our community in restoring and maintaining strength and mobility. Here’s to the close of another year. Keep moving and improving and we’ll see you in the next one!