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The Role of the SAID Principle in Joint Replacement Fitness

The SAID Principle, Specific Adaptation to Imposed Demand, is a fundamental law of human physiology. The classic definition of this principle is “the body adapts to what it does”.  A more precise, neuro-centric definition would be “the body ALWAYS adapts to EXACTLY what it does”. The takeaway is this: if you want a certain result, you must train with precision.

Joint replacements are an incredible medical innovation, but they are also incredibly traumatic events to the dermal, fascial, musculoskeletal, and nervous systems. Of specific concern for joint replacement clients are the mechanoreceptors that provide input to the brain about the joint and surrounding area through touch, pressure, stretch (skin and muscles/tendons), temperature, vibration, and movement.

Some studies have shown, depending on the type of replacement performed, joint capsule mechanoreceptors are no longer present and do not regenerate. The injuries to tissues or joints, whether acute or chronic, can result in dysfunctional proprioceptive feedback, and that is not automatically regained after joint replacement. So, we will need to train with precision to maximize and improve proprioceptive input and joint position sense.

Building variety into fitness training for joint replacement clients

Training with precision means taking our fitness training beyond “strengthening and stretching”. Our joint replacement clients likely got plenty of that during their physical therapy anyway. Another way to think about the SAID Principle is “use it or lose it”. If we want our joint replacement fitness clients to get the most out of their replacement, we need to program a variety of aspects:

  • Motor Control Drills for individual joints (the replaced joint as well as supporting joints) take the targeted joint through full, active, pain-free range of motion. It can be startling how many folks have poor motor control and joint position sense over some joints when asked to focus movement at only one joint.
  • Open & Closed Chain movements around the affected joint are both important and should be included. Barbells are great, but most human movement (walking, running, reaching, throwing, etc.) is open chain, so we need to train it!
  • Loading variations such as isometrics, free weights, and resistance bands require different firing patterns and levels of motor control. Isometrics specifically are a vastly underutilized form of strength training that is very “low threat” neurologically, allowing muscular force production in a very safe manner.
  • Speed of Movement variety can also improve motor control. Going through a movement in slow motion, or to the beat of a metronome, can be incredibly challenging but beneficial. 
  • Multi-Planar / Multi-Directional Movements are one of the most important variations to implement with joint replacement clients to build a large and detailed proprioceptive map of the new joint and surrounding musculature.

Programming for this type of variety is very important for joint replacement clients but also for general fitness, performance, and pain clients! Begin learning a neuro-centric approach to medical fitness and how to work with joint replacement clients with our Joint Replacement Fitness Specialist online course, available through the MedFit Classroom!


Pat Marques is a Z-Health Master Trainer and NSCA-CPT specializing in training the nervous system to improve performance and get out of pain.  After retiring from the Active Duty Army, Pat pursued his education and certifications in exercise science, initially working with wounded, ill, and injured soldiers. During this time that Pat discovered the power of using a neurological approach to training to get out of pain and improve fitness and performance. He currently provides exercise therapy, movement reeducation, and strength and conditioning for all levels of clients at NeuroAthlete, from chronic pain sufferers to Olympic-level and professional athletes.

 

References

  1. Cobb, E. (2020). R-Phase Certification Manual and Presentation. Z-Health Performance Solutions.
  2. Soulat, N., Alistair, P., and Gey, V. (2014). Assessing Regeneration of Mechanoreceptors in Human Hip Pseudocapsule After Primary Total Hip Arthroplasty. Journal of Orthopedics, Trauma and Rehabilitation (18)
  3.  Domoslavska, D. (2011). Restoring proprioception after sports injuries and pathological states of the shoulder complex. Journal of Combat Sports and Martial Arts (Vol. 2).
joint-replacement

Proprioception Training: An integral aspect of joint replacement fitness

Proprioception refers to the conscious and unconscious perception of postural balance, muscles sense, and joint position and stability. Basically, it is your sense of where you are in time and space for movement. We have found over the years that the best way to explain proprioception to clients comes from Dr. Eric Cobb at Z-Health Performance Solutions:

“Proprioception is the body’s 3D map of itself in time and space. AKA our movement and awareness map”.

The detail and definition of this “proprioceptive map” comes from several specialized mechanoreceptors (i.e. nerve endings) in the muscles, tendons, joint capsules, fascia, and skin. As fitness trainers as we are usually taught about muscle spindles and Golgi tendon organs when we learn about flexibility training, but there is a lot more to proprioceptive input. You are affecting the proprioceptive input to the brain when you use a neoprene knee sleeve (pressure), kinesiology tape (skin stretch), heat or ice packs (temperature), TENS units (electric), etc. 

Why understanding and training proprioception is important for joint replacement clients

Several conditions can alter proprioception, thus “clouding” the map and degrading movement sense and capability, including pain, trauma, effusion, and fatigue. A joint replacement client also likely had poor motor control of the joint in the first place that resulted in compensatory movement patterns and overuse injury over time. Complicating the matter further, although it may have been necessary, the surgery itself is an “insult” to the musculoskeletal and nervous systems.

To move a joint well, you must be able to feel the joint and surrounding tissue well. An extreme example of what can happen without the sense of touch or joint position is the story of Ian Waterman. A rare neurological illness resulted in his losing all touch and joint position sensation, effectively paralyzing him from the neck down even though the motor control area of his brain and the descending pathways to send movement information to his musculature were fine!

Varied stimulus drives improved mapping

We can improve proprioception in several ways:

  • Reduce causes of proprioceptive “inhibition” (i.e., pain, fatigue, and effusion) – Therefore we need to only move in pain-free ranges of motion, and build muscular endurance.
  • Augment sensory information – We can do this by providing novel sensory stimulus to the affected area such as vibration, kinesiology taping, skin stimulation, pressure, or temperature. 
  • Weight Bearing Exercise Therapy – Loading, appropriately and progressively, compound movements.
  • Motor Skills Training – Exercises to target accurate movement such as multi-directional movements based on visual stimulus.

The important take away is that building a “library” of prior movement patterns is especially important for the post-medical joint replacement client. We want to get their new joint moving in multiple directions, at multiple speeds, under multiple loads.

The concept of proprioception and how to harness it is not only for joint replacement, but also for general fitness, performance, and pain clients! Begin learning a neuro-centric approach to medical fitness and how to work with joint replacement clients with our Joint Replacement Fitness Specialist online course, available through the MedFit Classroom!


Pat Marques is a Z-Health Master Trainer and NSCA-CPT specializing in training the nervous system to improve performance and get out of pain.  After retiring from the Active Duty Army, Pat pursued his education and certifications in exercise science, initially working with wounded, ill, and injured soldiers. During this time that Pat discovered the power of using a neurological approach to training to get out of pain and improve fitness and performance. He currently provides exercise therapy, movement reeducation, and strength and conditioning for all levels of clients at NeuroAthlete, from chronic pain sufferers to Olympic-level and professional athletes.

 

References:

  1. Lephart, SM and Fu, FH. (2000). Proprioception and Neuromuscular Control in Joint Stability. Champaign, IL: Human Kinetics.
  2. Roijezon, U., Clark, N., and Treleaven, J. (2015). Proprioception in musculoskeletal rehabilitation. Part 1: Basic science and principles of assessment and clinical interventions. Massage Therapy (20).
  3. Cole, J. and Waterman, I. (1995). Pride and the Daily Marathon. MIT Press.
  4. Roijezon, U., Clark, N., and Treleaven, J. (2015). Proprioception in musculoskeletal rehabilitation. Part 1: Basic science and principles of assessment and clinical interventions. Massage Therapy (20).
Stroke-Neuroplasticity

Sensory Input Drives Motor Output – “You gotta feel it to move it!”

In our previous article, we showed you this picture to help understand neuroplasticity and how neurons that wire together, fire together. In this blog we’ll use the same picture to understand how sensory input to the brain affects motor output.

The sensory area (purple) is on the front “slice” of the parietal lobe. The neurons here will be activated by sensory input such as touch, vibration, threat, pressure, temperature and joint position. Lying just in front of the sensory area is the motor area (blue), which is the back “slice” of the frontal lobe. The neurons here are activated through volitional movement.

In both the sensory and motor areas of the brain, you can see in the illustration that specific areas are dedicated to specific body parts. And those areas are represented in the same areas for sensory and motor (e.g., where the hand is located in the sensory area is in the same place in motor area along the “slice”).

Why sensory input matters for stroke survivors

The bottom line is that for you to move an area well, your brain must be able feel, or “sense”, the area well. This is why issues like peripheral neuropathy in the feet so greatly affect the ability to balance and walk. Having good sensory input from an area of the body is a prerequisite for good motor control when we try to move an area.

One of the most prominent dysfunctions after stroke is a reduced ability to move one side of the body. This can occur at many different levels, from total paralysis to reduced coordination of fine motor skills. Common examples include limb spasticity, usually in flexion (e.g., a clenched fist held close into the chest), or what is termed “drop foot”, an inability to dorsiflex (lift) the foot, which severely interferes with a safe, functional gait pattern. This happens because the stroke damaged areas in the motor cortex associated with the affected body part.

The good news is that by increased sensory input to the affected area, we can begin to improve motor output. You have likely seen this already if you have ever used things like percussion guns or kinesiology tape. The many new “toys” we see in the fitness industry these days are simply sensory input devices, providing the sensory area with more and novel input, which then allows the motor area to “fire” better and provide better movement (i.e., improved range of motion, more strength, etc.).

A 2017 study found that “kinesio tape application to the tibialis anterior has significant effects on motor recovery of the lower extremity, spasticity, ambulation capacity, HRQoL (health-related quality of life) and gait compared to the control group and baseline.” (1)

The concept of sensory input affecting motor output and how to harness it is not only for stroke recovery, but also for general fitness, performance, and pain clients!

Begin learning a neuro-centric approach to medical fitness and how to work with stroke survivors with our Stroke Recovery Fitness Specialist online course, available through the MedFit Classroom.


Pat Marques is a Z-Health Master Trainer and NSCA-CPT specializing in training the nervous system to improve performance and get out of pain.  After retiring from the Active Duty Army, Pat pursued his education and certifications in exercise science, initially working with wounded, ill, and injured soldiers. During this time that Pat discovered the power of using a neurological approach to training to get out of pain and improve fitness and performance. He currently provides exercise therapy, movement reeducation, and strength and conditioning for all levels of clients at NeuroAthlete, from chronic pain sufferers to Olympic-level and professional athletes.

References

  1. Belma Fusun Koseoglu, Asuman Dogan, Hilmi Umut Tatli, Didem Sezgin Ozcan,Cemile Sevgi Polat (2017). Can kinesio tape be used as an ankle training method in the rehabilitation of the stroke patients? Complimentary Strategies in Clinical Practice, Vol. 27.