Reciprocal inhibition is part of the mechanism behind how movement takes place. When one muscle contracts, its antagonist relaxes. For example, when the biceps flex, the triceps extend and the reverse is true as well.
However, when one muscle is too tight to move, this creates altered reciprocal inhibition, which then leads to movement dysfunction.
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Reciprocal inhibition is a vital concept for anyone aiming to optimize their fitness training and ensure balanced muscle function. In this article, I delve into the intricacies of reciprocal inhibition, explain its role in the fitness coach framework, and provide practical applications to incorporate into your training routines. By the end of this guide, you will have a thorough grasp of how reciprocal inhibition works and how to apply it effectively to improve your clientsโ performance and prevent injuries.
As a NASM-certified personal trainer for more than 12 years, Iโve used the concept of reciprocal inhibition with many clients.
In this article I discuss how NASM, NSCA, ISSA, and ACE depicts reciprocal inhibition, and review how to use this concept to fix poor movement patterns.
The Concept of Reciprocal Inhibition
Reciprocal inhibition, as defined by the National Academy of Sports Medicine (NASM) in the NASM personal training certification, is a neuromuscular phenomenon that occurs when the muscles on one side of a joint are activated, resulting in the simultaneous relaxation of the opposing muscles on the opposite side of the joint. This process is mediated by the central nervous system and serves to maintain balance and stability during movement.
By inhibiting the contraction of antagonistic muscles, reciprocal muscle inhibition allows for smooth and efficient muscle activation patterns, reducing the risk of injury and optimizing performance. NASM emphasizes the importance of understanding reciprocal inhibition in designing effective exercise programs and corrective strategies to address muscular imbalances and movement dysfunctions.
ISSA, ACE, and NSCA both cover the same topic, however ISSA calls it “Sherringtonโs law of reciprocal inhibition.” in the ISSA CPT.
In order to fully understand reciprocal inhibition, you have to understand how muscles work.
The Role of Muscles in Movement
The muscles and skeletal systems play vital roles in human movement. Tendons connect the muscles to the bones, then the bones form intersections where the muscles and connective tissues join. These are called joints. Joints are the place where movement happens when muscles contract during activity.
Muscles are either agonists, synergists, stabilizers or antagonists in regard to movement.
Agonists are muscles that are the primary muscles responsible for a movement. Synergist muscles are secondary helpers in that movement. Stabilizers support the prime mover during the movement but donโt directly assist in the movement. Finally, antagonists perform the opposite action of that movement.
Muscles need to have 4 characteristics: extensibility, elasticity, contractility, and excitability. Tissue extensibility refers to the muscle’s ability to lengthen. Elasticity means that the muscle can return to its initial shape after stretching. Contractility is the muscles’ ability to contract and create force. Finally, the term excitability details the muscle’s capability to respond to stimulation via electrical impulses.
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Inside muscles are spindles running parallel to the muscle fibers which respond to changes in muscle length. When the muscle stretches, the muscle spindles stretch and help to regulate the contraction using sensory neurons, sending muscle spindle information to the central nervous system. Muscle spindle activity allows for coordinated movement and prevents unwanted muscle contractions.
During muscle contractions, the filaments deep inside the muscles slide across each other. This process is called sliding filament theory.
One of the other main features of muscle is the golgi tendon organs. These are sensory receptors which sit next to the connection of skeletal muscle tissue and tendon. Golgi tendon organ activation protects the muscle from overstretching via the inverse stretch reflex.
Reciprocal inhibition, a fundamental concept in exercise science, is closely tied to the functioning of muscle spindles, specialized sensory organs within muscles that play a crucial role in maintaining proper muscle balance and coordination.
Understanding Muscle Imbalance
Synergistic dominance happens when synergists function for weak or inhibited prime movers.
This can lead to issues and injury over time when compensation occurs.
For example, I often find that clients with poor upper back strength tend to overuse their biceps when pulling instead of the rhomboids and lats. This creates two problems.
- You canโt pull as much weight, because the biceps are a smaller muscle group than the lats.
- Itโs much easier to injure your biceps when you overuse it instead of utilizing your larger muscle groups.
Over time, muscle imbalances can also lead to arthrokinetic dysfunction.
Arthrokinetic dysfunction occurs when the joint motion is altered. This can be caused by a change in the length-tension and force-couple relationships which changes what happens to the joint and decreases the efficiency of movement, lowering total force production.
Letโs take the first example again. A client overuses their biceps in a pulling movement instead of engaging the back. As this person continually incorrectly performs the movement, over time the movement itself changes and changes the way the joints move with the elbow being over utilized over the shoulder joint.
Common Causes of Muscle Imbalances
Muscle imbalances are often caused by a variety of factors that disrupt the normal functioning of the musculoskeletal system. These causes include postural stress, emotional duress, repetitive movements, cumulative trauma, poor training techniques, lack of core strength, and insufficient neuromuscular efficiency.
Each of these factors can alter the length-tension relationships of muscles surrounding a joint, leading to some muscles becoming overactive (tight) and others underactive (weak). For instance, repetitive movements can lead to overuse of certain muscle groups while neglecting others, resulting in imbalances.
Similarly, poor posture, such as sitting for extended periods, can cause certain muscles to tighten and shorten while others weaken, contributing to muscle imbalances.
The modern sedentary lifestyle results in many people spending their days in seated positions in front of a screen or in the car during their daily commute rather than moving about. When your hips are stuck in a semi-flexed position, this is going to lead to overactive hip flexors, underactive glutes, and tightness in the upper back and thoracic spine as well.
Imbalances can also arise from inflammation caused by past injuries or improper lifting technique. Often a muscle becomes injured, and the soft tissue never recovers fully before becoming re-injured. This injury cycle only leads to more problems and movement compensations, leading to alterations in movement.
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Finally, muscle imbalances can be caused by a poor workout routine.
For instance, often people choose to exercise the muscles they can see in the mirror, like chest, shoulders and arms, and neglect working out their back and legs. Over time, these types of exercises lead to imbalances in the body and the potential for improper mechanics and injury if you don’t work the other muscles of the body.
Addressing these imbalances through targeted exercises and stretches is crucial for maintaining overall musculoskeletal health and preventing injuries.
Benefits of Reciprocal Inhibition
By incorporating exercises that target the weaker or underactive muscles in a reciprocal manner, we can promote balance and symmetry within the body. This can be achieved through various techniques such as performing exercises that involve both concentric and eccentric contractions, utilizing resistance bands or cables, and incorporating unilateral movements to address specific imbalances. By consistently applying reciprocal inhibition principles in our training programs, we can effectively correct muscle imbalances and improve overall muscular strength and function.
Correcting reciprocal inhibition with exercise training offers numerous benefits. By engaging reciprocal inhibition, individuals can enhance their overall muscular balance and coordination. When you can activate the antagonist muscles while simultaneously inhibiting the agonist muscles, this leads to improved joint stability and reduced risk of injury. Additionally, reciprocal inhibition helps optimize muscle activation patterns, allowing for more efficient movement and greater power output during exercise.
Furthermore, healthy reciprocal inhibition promotes better neuromuscular control and proprioception, enhancing overall athletic performance. Incorporating reciprocal inhibition into exercise training programs can therefore result in increased strength gains, improved flexibility, and enhanced functional movement patterns.
Techniques to Facilitate Reciprocal Inhibition
Both the NASM CPT and the NSCA personal training certification recommend using a combination of corrective flexibility and active flexibility training to correct improper reciprocal inhibition.
Corrective flexibility involves foam rolling and static stretching.
Foam rolling, a self-myofascial release technique, involves applying gentle pressure to muscle adhesions or knots to release muscle tension and improve flexibility. By using a foam roller to target tender spots, you can stimulate the Golgi tendon organ, which reduces muscle spindle activity, leading to decreased muscle tension and improved muscle alignment. Foam rolling before stretching can enhance tissue lengthening and flexibility, while using it post-exercise aids in muscle recovery and reduces soreness. Foam rolling is a versatile tool that can enhance muscle function, flexibility, and overall physical performance.
Active flexibility techniques use stretching both agonists and synergists to dynamically increase range of motion. This improves motor neuron excitability.
Active-isolated stretching, a key component of active flexibility, employs agonist and synergist muscles to dynamically move a joint through its range of motion while the functional antagonist muscles are stretched. This process uses reciprocal inhibition and increases motor neuron excitability, allowing for a more effective stretch. An example of active-isolated stretching is the supine straight-leg raise, where the hip flexors and quadriceps lift the leg, thereby stretching the hamstring complex. These techniques are recommended for pre-activity warm-ups, particularly for activities involving high intensity or sports competition. By incorporating active flexibility exercises, individuals can achieve better muscle function and reduced risk of injury during physical activities.
Active stretching employs a 2 second static stretch and incorporates the antagonist contraction as you move through the stretch utilizing repetitions.
This is different from static stretches where you hold a position for 30-60 seconds. Active stretching includes movement.
For example, in a static pec stretch, you press the elbow against a flat surface and hold the stretched position. In the active variation of the pec stretch, you squeeze the antagonist muscles in rear delt, and rhomboids and lean forward and backwards for reps.
Dynamic stretching can also be used in some cases to facilitate reciprocal inhibition through using momentum to move joints through range of motion.
Another style of stretching using reciprocal inhibition is PNF stretching. This is similar to active stretching but uses external force. Often, in a personal training session, a trainer will use manual resistance to help a client during PNF.
Proprioceptive Neuromuscular Facilitation (PNF) stretching is a technique used to enhance both active and passive range of motion with the goal of improving motor performance and aid in rehabilitation. This method involves both stretching and contracting the targeted muscle group.
A typical PNF stretch consists of a muscle group being passively stretched, followed by an isometric contraction against resistance, and then another passive stretch which ideally should go further into the range of motion. PNF stretching utilizes the concept of reciprocal inhibition, where contracting the muscle opposite to the one being stretched can help in lengthening the target muscle. This stretching method is particularly effective in increasing flexibility, improving muscular strength, and enhancing neuromuscular efficiency. PNF stretches are often used in clinical settings and athletic training due to their ability to maximize flexibility gains in a short period.
Exercises for Balancing Muscle Activation
Make sure to include exercises together that activate both sides of a joint. This could mean including exercises such as lunges, where the quadriceps are activated while the hamstrings are stretched along with leg curls, where the hamstrings contract while the quads stretch.
For the upper body, combine push-ups, where the chest muscles are activated while the back muscles are stretched along with TRX rows. By incorporating these exercises into your workout routine, you can improve muscle balance and prevent muscle imbalances, ultimately reducing the risk of injury and enhancing overall athletic performance.
Whether you are an athlete, fitness enthusiast, or someone looking to improve their posture, understanding and implementing reciprocal inhibition exercises can be a game-changer for your overall body alignment and muscle balance.
By engaging the antagonist muscles to the ones being stretched or relaxed, reciprocal inhibition helps activate and strengthen the weaker muscle groups, leading to improved posture and reduced risk of injury. By activating the antagonist muscles, reciprocal inhibition also contributes to better movement efficiency and power output during exercise. Understanding and incorporating this principle into training programs can greatly enhance overall performance and functional mobility.
Integrating Reciprocal Inhibition into Training Programs
When incorporating exercises that promote reciprocal inhibition, such as dynamic stretches and specific resistance training protocols, trainers should assess what overactive or underactive muscles clients exhibit.
Assessing underactive and overactive muscles is crucial for identifying and correcting movement impairments. Overactive muscles are those that are excessively tight and tend to dominate movements, leading to compensatory patterns. Common overactive muscles include the hip flexors, adductors, and the tensor fascia latae, which can cause issues like excessive internal rotation and adduction of the femur during squats. Conversely, underactive muscles are often weak or inhibited, failing to perform their stabilizing roles effectively. Examples include the gluteus medius and gluteus maximus, which, when underactive, can lead to poor hip stabilization and movement dysfunctions. Proper assessment involves identifying these imbalances and incorporating corrective strategies such as stretching the overactive muscles and strengthening the underactive ones to restore proper movement patterns and reduce injury risk.
Here is a sample program to help promote proper reciprocal inhibition in a client with overactive quads.
Remember, if a muscle is overactive, you want to stretch it and lengthen the muscles on the opposite side to promote ideal reciprocal inhibition.
So, in this case, the quadriceps are overactive, so we want to stretch them and strengthen the gluteus maximus and hamstrings:
- Active isolated quad stretch 2 sets of 15 reps
- Foam roll the quads 2 minutes per side
- Weighted Hip extension 2 sets of 10-15 reps
- Hamstring curls 2 sets of 10-15 reps
Conclusion
Reciprocal inhibition is a concept that highlights the interplay between agonists, synergists, and antagonists during movement. By understanding this concept, fitness professionals and athletes can optimize their training and performance. Reciprocal inhibition, a key principle in certifications such as the NASM CPT, plays a significant role in this process. It refers to the simultaneous activation of one muscle group while the opposing muscle group is inhibited to allow for smooth and coordinated movement. This principle is often used in corrective exercise strategies to address muscular imbalances and improve overall movement patterns in clients.
Reciprocal inhibition can be integrated into training programs to promote balanced muscle activation and prevent compensatory movements that can lead to injuries. By assessing and correcting muscular imbalances through exercises that target specific muscle groups, individuals can improve their overall strength and movement efficiency.
Reciprocal Inhibition FAQs (Frequently Asked Questions)
What is the definition of altered reciprocal inhibition?
What are the two primary actions of the Golgi tendon organ?
What are the two primary actions of the muscle spindle?
What are two contraindications for self-myofascial techniques?
What are two signs of a muscle being overstretched?
What is meant by reciprocal inhibition?
What is an example of a reciprocal inhibition exercise?ย
How do you use reciprocal inhibition?
What are the benefits of reciprocal inhibition?
Does reciprocal inhibition improve flexibility?
How to perform reciprocal inhibition?
References
- Clark, M. A., Lucett, S. C., Mcgill, E., Montel, I., & Sutton, B. (2018). NASM essentials of personal fitness training. Burlington Jones & Bartlett Learning.
- National Academy of Sports Medicine. โThe Integrated Flexibility Continuum (NASM CPT Podcast).โ NASM, blog.nasm.org/fitness/the-nasm-cpt-podcast-ep-6#:~:text=Reciprocal%20just%20means%20the%20thing,is%20going%20to%20now%20relax.
- Fahmy, R. (2022). NASM Essentials of Corrective Exercise Training. Jones & Bartlett Learning.
- Scott, Vanessa, et al. Foundations and Applications for a Certified Personal Trainer. 10th ed., ISSA, LLC, 2021.
- Coburn, Jared W, and Moh H Malek. NSCAโs Essentials of Personal Training, 2nd ed., Human Kinetics.
Tyler Read
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