Tonic and phasic muscle characteristics
Predominantly Tonic Muscles | Predominantly Phasic Muscles |
Anti-gravity; higher resting tonus (cons ... | Do not oppose gravity, but are available ... |
Slow-twitch (endurance-oriented) dominan ... | Fast-twitch (power/speed-oriented) domin ... |
Are responsible for “holding your postur ... | Are used for dynamic movement, and almos ... |
Tend to be short and tight. | Tend to be inhibited and weak. |
What is the difference between postural tonic and phasic muscles?
Postural - it means that muscle is used for keeping straight posture of human body Tonic - means that muscle contains mostly slow-contraction, long-duralibity fibers. These mucles have tendency to over-tension and to shorten (for example in spasticity). Phasic - means that muscle contains mostly quick-contraction, hi-power, short-duralibity fibers.
What are phasic muscles?
Phasic Muscles are composed of at least 51% fast-twitch muscle fibers. These are powerful muscles, but they fatigue more easily than do tonic muscles. Kind of a shame, too, as these muscles are primarily responsible for movement. The gluteals are good examples of phasic muscles.
What is the difference between tonic and phasic loading?
Faulty loading means any over-use, under-use, abuse (such as trauma) or disuse (such as not getting adequate exercise!). Tonic muscles tend to shorten in response to over-use, under-use or trauma, whereas phasic muscles tend to lengthen and weaken in response to these types of stimuli.
What are tonic muscles and what do they do?
Kind of a shame, too, as these muscles are primarily responsible for movement. The gluteals are good examples of phasic muscles. Tonic Muscles are slow-twitch dominant, composed of at least 51% slow-twitch muscle fibers. As such, they are highly resistant to fatigue and have a greater propensity for work.
What muscles are tonic phasic?
Choosing exercises wisely to improve functionPredominantly Tonic MusclesPredominantly Phasic MusclesPelvis – Thigh Hamstrings Iliopsoas Rectus Femoris Adductors Piriformis Tensor Fasciae LataeVastus Lateralis Vastus Medialis Gluteal MusclesLower Leg – Foot Gastrocnemius SoleusTibialis Anterior Peroneals Toe Extensors2 more rows•Nov 25, 2019
What is a tonic muscle contraction?
Term: tonic smooth muscle contraction. Definition: A process in which force is generated within tonic smooth muscle tissue, resulting in a change in muscle geometry.
What is phasic contraction?
Definition: A process in which force is generated within phasic smooth muscle tissue, resulting in a change in muscle geometry.
What is phasic control?
Beat-to-beat changes in myocardial contractility are affected by a "phasic control mechanism" that involves changes in at least five calcium fluxes in the myocardium.
What is the difference between phasic and tonic smooth muscles?
Tonic smooth muscles show continuous contraction as fluids move around them, while phasic smooth muscles show rhythmic motions that cease after a time , according to class notes from Florida State University College of Medicine. Phasic smooth muscles include those within the wall of the stomach, and tonic smooth muscles are found in arteries.
What are the tonic and phasic muscles?
Both tonic and phasic muscles are known as unitary smooth muscles, or visceral smooth muscles. ADVERTISEMENT.
How does phasic contraction work?
Phasic contractions work by using action potentials, a process during which the electrical impulses generated by muscle cells briefly reverse to cause a contraction, according to Encyclopaedia Britannica. Tonic muscles do not use electrical impulses or action potentials to work.
How often do phasic muscles contract?
For example, phasic muscles in the stomach contract only a few times per hour in between meals.
Where are phasic smooth muscles found?
Phasic smooth muscles include those within the wall of the stomach, and tonic smooth muscles are found in arteries. Scientists classify tonic muscles as continuously active muscles within the body that are usually filled with fluid.
Which muscle is used to contract when the body eliminates urine?
Muscles that line the bladder and ureter contract only a few times per day when the body eliminates urine. Tonic muscles are also found in sphincters. Phasic muscles rely on electrical impulses through calcium ions to contract, explains Florida State University. Phasic contractions work by using action potentials, ...
What are the characteristics of a tonic and phasic muscle?
“Hyperactive” and “lazy” are helpful generalizations, but to make use of tonic and phasic muscle theory you’ll want to be aware of the following characteristics as well: Anti-gravity; higher resting tonus (constant low-level activity) than phasic muscles.
Why is the tonic and phasic muscle theory important?
The significance of tonic and phasic muscle theory lies in the influence these muscle groups have on each other, and the way that imbalances in the body can occur because of the simple fact that muscles do not all function in the same way. While phasic muscles activate when we insist that they do, tonic muscles can be thought ...
What happens when tonic and phasic muscles are on opposing sides of the agonist-antagonist relationship
The differing responses of tonic and phasic muscles to improper stimuli can lead to musculoskeletal imbalance and joint instability when these muscles are located on opposing sides of the agonist-antagonist relationship (and, as you’ll see in the chart below, they often are).
What happens when a jockey's tonic muscles shorten?
This means that as our desk jockey’s tonic muscles shorten and tighten and his corresponding phasic muscles lengthen and weaken, the resulting imbalance and joint instability will create (or exacerbate) faulty movement patterns and create pain that may become chronic.
Why is the hyperactive group of muscles called the tonic group?
Janda called the hyperactive group of muscles “postural” (today called “tonic”) because of the important role they play in opposing gravity and keeping us upright. He called the more languid group of muscles “phasic” because of the way they fire up only when strictly necessary, then quickly return to a relaxed state.
Which muscles are agonists?
Soleus. Tibialis Anterior. Peroneals. Toe Extensors. You’ll notice that most tonic muscles are flexors, most phasic muscles are extensors, and many tonic and phasic muscles have agonist-antagonist relationships (that is, they oppose one another).
Who discovered the tonic and phasic muscles?
Understanding tonic and phasic muscles. Tonic and phasic muscle theory originated in the late 1960s with Dr. Vladimir Janda, a Czech neurologist and physiotherapist. Using electromyography (EMG), Dr. Janda found that some muscles are practically always active and seemingly resistant to fatigue, while others fatigue easily ...
What is the difference between phasic and tonic muscles?
One of the major differences between phasic and tonic muscles that is of particular interest to triathletes is how these muscles respond to faulty loading. Loading is the resistance which the muscles of the body must overcome. In the gym, it may be a dumbbell.
What are phasic muscles?
Phasic Muscles are composed of at least 51% fast-twitch muscle fibers. These are powerful muscles, but they fatigue more easily than do tonic muscles. Kind of a shame, too, as these muscles are primarily responsible for movement. The gluteals are good examples of phasic muscles. Tonic Muscles are slow-twitch dominant, ...
Is gluteal muscle phasic?
The gluteals are good examples of phasic muscles. Tonic Muscles are slow-twitch dominant, composed of at least 51% slow-twitch muscle fibers. As such, they are highly resistant to fatigue and have a greater propensity for work. The iliopsoas is an example of a tonic muscle group. One of the major differences between phasic and tonic muscles ...
Does phasic musculature weaken?
Phasic musculature does the exact opposite. It tends to lengthen and weaken in relation to its relative antagonist (s) or opposing muscle (group). The problem is then magnified by the fact that muscles which are short and tight will hold their antagonists in a lengthened position.
Can tonic muscles turn on?
With a lower threshold for stimulation, tonic muscles need very little encouragement to turn on. This can, and often does, result in hyperactivity of a tonic muscle, limiting the motion at the joint (s) over which that muscle crosses. As mentioned in Chapter One of Holistic Strength Training for Triathlon ...
What is phasic muscle?
Phasic muscles are those that have the propensity to belong and weak. Tonic and phasic muscles can create postural compensation. Imbalances between muscles can be caused by posture, sedentary or faulty loading. As fitpros we can help fix imbalances. Posture is one of 8 modules inside your Level 3 anatomy exam.
What level of anatomy exam do you need to know about tonic and phasic muscles?
As a Personal Trainer, you need to know the difference between Tonic and Phasic Muscles for your Level 3 anatomy exam. In your exam, you will be tested on your knowledge of 50 muscles, and that includes the relationship of those muscles to postural compensations, which is basically talking about Tonic and Phasic Muscles.
What is the propensity of a muscle to be tonic?
Every muscle in our body has a propensity (tendency) to be either Short and Tightened or Long and relaxed. This means that every muscle in the body has a propensity to be tonic or phasic. So you can learn a list of tonic muscles and a list of phasic muscles in the body to predict which postural compensations are likely to occur naturally.
Why do phasic muscles contract so quickly?
Phasic muscles contract quickly (yes this is due to fibre distribution ) and have poor endurance. They’re prone to lengthening when they’re weak, and this coupled with the tightening of an overactive antagonistic tonic muscle about a joint can cause a misalignment in the joint.
What does it mean when your body is dynamic?
The body is a dynamic system (that just means it can change how it works), and it adapts to the things it is asked to do. If you’re constantly asking it to sit at a desk all day and only squat when you need to go to the toilet, it’s going to begin to default towards using tonic muscles.
Can you talk and listen at the same time?
Now replace the idea of talking, with the idea of contractions in a muscle – it is much the same. They can’t talk and listen at the same time, so when the muscle is contracted the other Must listen, which really means it relaxes and lengthens.
Do phasic and tonic muscles contract?
They’re also prone to overactivity and finally, tend to tighten when they’re overactive. Phasic muscles contract quickly (yes this is due to fibre distribution) and have poor endurance.
Why is the postural muscle called the phasic muscle?
He named certain of these muscles “postural” because of their tonic or anti-gravity behavior. Other muscles he called “phasic.”. Phasic muscles are available on demand but are not responsive to the pull of gravity.
What is postural phasic muscle theory?
It’s about function, how the body is designed to perform and how to improve that function by working within the body’s design. If we understand function, we can problem solve and plan better programs for our clients’ individual needs. Learning and working with postural and phasic muscle applications is a good place to start.
What happens if your postural erector spinae are tight?
If the postural erector spinae are tight, the phasic abdominals, flexors of the trunk, will not be able to override the back extensors in the exercise. The client’s abdominal curl will be incomplete or forced and will not change despite diligent practice. The client may give up in frustration.
What muscles tend toward weakness?
Consider the current emphasis on “core” strength and stability. The phasic abdominal muscles tend toward weakness. Conventional training frequently tries to strengthen the abdominals in isolation, forgetting they are paired with shortened postural muscles (ie.., the erector spinae). I will return to this topic later.
What is the dominant pull of a postural muscle against an opposite phasic muscle?
The dominant pull of a postural muscle against an opposite phasic muscle may show itself as a postural deviation or a movement dysfunction. The chart below shows an array of such opposing muscle groups: POSTURAL MUSCLES. PHASIC MUSCLES.
What is the postural pathway of a muscle?
In the above example, the rectus femoris is the only postural muscle of the quadriceps group. As a biarticular muscle, the stretch for it must take into account both the hip and the knee joints.
What is postural phasic relationship?
The postural/phasic relationship is “a natural, physiologically balanced imbalance between two systems.”. Thus, muscles are not created equal. Variations in structure, function and physiology are well known. The chart below outlines the characteristics and “balanced imbalance” of postural and phasic muscles. POSTURAL MUSCLE CHARACTERISTICS.
What is phasic muscle?
Phasic - means that muscle contains mostly quick-contraction, hi-power, short-duralibity fibers. These muscles have tendency to under-tension (getting weak), and loose. They also lose their mass very quickly while hypokinesia.
What does it mean to be a tonic?
Tonic - means that muscle contains mostly slow-contraction, long-duralibity fibers. These mucles have tendency to over-tension and to shorten (for example in spasticity).
What does "postural" mean in a muscle?
According to this, it's impractical to distinguish Postural and Phasic muscles, becouse term "postural" doesn't refer to conception of different fibers content in muscle, it only means that exemplary muscle is used to keep human posture straight.

Tonic and Phasic Muscle Characteristics
A Real World Example
- Think of a typical office worker who spends long hours sitting at a desk. He tries to sit up straight while he works, but finds himself constantly slouching—though he doesn’t realize that this is, in part, because his over-used tonic muscles (e.g., pectoralis minor and upper trapezius) are pulling his under-used phasic muscles (e.g., rhomboids and mid/lower trapezius) into an excessively len…
Choosing Exercises Wisely to Improve Function
- When we understand the differences between tonic and phasic muscles and the influence they have on each other, we can improve the body’s function by working with rather than against its design. Rather than choosing exercises at random, we can strategically address issues that arise due to less-than-ideal relationships between opposing muscle groups and types. Interestingly en…
Sources
- 1 Joseph H. Pilates and William J. Miller: Return to Life through Contrology 9(Pilates Method Alliance, 2012) Phillip Page, Clare C. Clark, and Robert Lardner, Assessment and Treatment of Muscle Imbalance: The Janda Approach (Human Kinetics, 2010)