02/10/2019 at 2:41 pm #47264Amelia DisspainParticipant
These discussion subjects are just recommended for your self study- however if youd like feedback from me, your course administrator, or if youd like to share your thoughts with your fellow studenst then post your answers here
1 Explain the concepts of joint complexes and muscle groups.
2 Discuss how the practical study of the body can be made simpler by using the concepts of joint complexes and muscle groups rather than trying to work with individual muscles and individual joints.
3 Discuss the four states you can create with muscle activation and relaxation around each of the 9 main joint complexes.
17/11/2019 at 4:47 pm #48207Daniel ThyerParticipant
A joint complex is multiple joints that work together as one and muscle groups are multiple muscles that together perform the same task.
Instead of trying to learn the roles of all the individual joints and muscles in the body, it’s much simpler to break them down into nine main joint complexes and the opposing muscle groups (agonists and antagonists) around those joint complexes.
For example instead of thinking of all the joints through the toes, feet and ankles we can refer to them as the Ankle joint complexes and even more simply the ankles. Taking this through the entire body we have six pairs of joint complexes, Ankles, Knees, Hips, Wrists, Elbows and Shoulders and well as the three joint complexes of the pelvis and spine. The lumbosacrococcygeal joint complex which for ease can be simplified to the Lumbar spine joint complex (Lower back), the Thoracic spine joint complex (middle back) and the Cervical spine joint complex (upper back i.e. neck). Giving us 15 main joint complexes.
Then instead of referring to the individual purpose of each muscle throughout the entire body we can simplify to the groups of muscles around the joint complexes and the actions they perform as a group. For example the muscle group that flexes the knee joint are referred to as the knee flexor group and the muscles that oppose these that bring the knee into extension as the knee extensor group.
There are four states you can create with muscle activation around each joint complex in the body. Before we go further a little more explanation of agonists and antagonists is required. Agonists are the group of muscles that activate to create a joint action, i.e. when you raise your leg in front of you, the hip flexor group active to create hip flexion and are referred to as the agonists. The antagonists are the opposing muscle group that are required to relax and lengthen to allow the joint action to occur. In the case of hip flexion this would be the hip extensors. This is known as the reciprocal stretch reflex, which states when a muscle group activates/tenses (agonists) the opposing muscle group (antagonists) must relax/lengthen.
However, there are four states that can be created around a joint complex.
1. The agonists and antagonists can be relaxed. This would be referred to as a passive stretch. Which may have some usefulness however during a passive stretch there is no protection around the joint complex and it may become compressed. There is also a chance if you move too quickly into a passive stretch you may initiate a myotatic (stretch) reflex. This occurs when the antagonist (the muscle you’re probably trying to lengthen) feels sudden tension (due to lengthening too quickly) and due to a nerve reflex suddenly tightens to stop it lengthening. This is quite useful if you’re walking along and you unexpectedly role your ankle, the reflex will tighten the suddenly stretched muscle and stand you back up before you fall over. However, if it occurs in a passive stretch you will either shorten the muscle you were attempting to stretch or worse potentially tear the muscle.
2. The agonists can be tensed and the antagonists relaxed. This is the reciprocal stretch reflex that I referred to above.
3. The agonists can be relaxed and the antagonists can be tensed. Once you’ve moved actively into a position you can then reverse the action of the muscles by actively trying to come out of the position without actually moving. For example when moving into a lunge as you step your back leg back, the hip extensors are the agonist (active) and the hip flexors are the antagonists (lengthen/relax). Once in position if you attempt to pull your back leg forwards without actually moving, the hip flexors will become active and the extensors can relax. This can be quite useful as once you then relax your hip flexors they will lengthen more, essentially speeding up the effect of the inverse myotatic reflex which states if you hold a stretch long enough the muscles will lengthen.
4. The agonists and antagonists can both be tensed. This is known as bandha. In the case of the back leg in a lunge if you keep the hip extensors active in the lunge while simultaneously activating the flexors by attempting to pull the leg forwards you have active agonists and antagonists. This is the most stable way to be around a joint and is useful in aiding to simultaneously strengthen and lengthen muscles. In the case of the lunge the hip flexors in the back leg would be getting lengthened and strengthened at the same time.
14/03/2020 at 11:33 am #50329Zoe CooperParticipant
1. Explain the concepts of joint complexes and muscle groups.
Joint complexes are a series of individual joints that work together. There are 9 important joint complexes in the body (15 in total including 6 pairs) compared with 650 individual joints.
They are: the ankle, knee, hip (includes the sacral and pubis), waist or lower back (lumbar spine), chest or upper back (thoracic spine), neck and head, shoulder, elbow, wrist (includes the hand) joint complex.
Various movements take place at the different joint complexes, involving the different muscle groups. Muscle groups are a set of muscles that cross a particular joint, that have the same function around that joint.
There are 6 primary and 3 opposing pairs of movement, that is; flexion (to bend closer to the head or face) and extension (to straighten away from head/face); abduction (to take away) and adduction (adding two parts together); internal rotation (to move in) and external rotation (to move out).
2. The practical study of the body can be made simpler by using the concepts of joint complexes and muscle groups. This saves one from trying to work with individual muscles and individual joints with which there are hundreds of names!
For example, the knee has 16 individual muscles with the purpose of bending (flexing) or straightening (extending). Referring to the different muscles involved in this particular action as the two opposing muscle groups, that is the knee flexors and knee extensors, then the purpose of the knee can be more easily described.
The hip flexors are another example of all the muscles that cross over the hip joint when activated that create hip flexion. Similarly for the group of muscles that cause hip extension when activated over the hip joint are called hip extensors.
3. Muscle activation and relaxation can occur in 4 different states around a joint complex. When one muscle group is activated, or performing the specific action, it is known as the agonist. This triggers what is known as the reciprocal stretch reflex, where the opposing muscle group known as the antagonist, must relax or stretch and lengthen, in order to perform the desired movement.
The four main states that can be created with muscle activation and relaxation around each of the 9 main joint complexes are:
*agonist and antagonist are both relaxed, that is essentially a passive stretch, and not ideal in practising hatha yoga as it can cause the stretch (myotatic) reflex to happen
*agonist is tensed or activated and the antagonist is relaxed known as the reciprocal stretch reflex
*agonist is relaxed and antagonist is actively tensed, great for when already in a yoga pose to safely lengthen the opposing muscle group further, as created with the inverse myotatic reflex
*agonists and antagonists are simultaneously tensed ie a bandha or co-activation of both opposing muscle groups around a joint complex, that is very helpful to lengthen and strengthen the muscles around the joint complex as well as develop stability in the asana and vinyasa.
24/11/2019 at 3:29 am #48258Francesca ManiglioParticipant
each muscle has a defined action. muscles have particular roles: stabilizer, neutralizer, agonist, antagoinist) that can vary from one situation to the next. we have single joint muscles, two joint muscleds and multijoint muscles.
it is important to work with muscle groups rather tahn with individual muscles. therefore yoga practice should be varied with a variety of asanas for each muscle or muscle group.
we need to be aware of nerve reflexes when lenghtening a muscle and avoid the fight or fright response that occurs when stretching or tensioning a muscle
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