SET POINT THEORY

Set Point is the weight range in which your body is programmed to function optimally. Set Point theory holds that one’s body will fight to maintain that weight range.
Everyone has a set point and, just as you have no control over your height, eye color or hair color, you also have no control over what your set point will be. Your body is biologically and genetically determined to weigh within a certain weight range.

Set Points vary for each individual person. That is why it’s not a good idea to go by the weight charts that you see in medical books or hanging in your doctor’s office. For instance, a woman with a small frame may have a set point range between 120-130 lbs, but another woman with the same height may have a set point range between 130-140 lbs. Their set points may be different, but those are the weight ranges their bodies will fight to maintain. Scientists estimate that the average person has a set point range of about ten to twenty pounds, meaning at any given time, there is a ten-to-twenty-pound range at which your body will be comfortable and not resist attempts to change
Everyone who has ever tried dieting knows just how hard it is to lose weight and keep it off. In the first few weeks of dieting, weight is usually lost, but it is almost always gained back. Many people become frustrated because after a few weeks of dieting, they usually stop losing weight or start gaining it back, even though they are still restricting their food intake. That is a sign that the body is trying to fight to retain it’s natural weight.
When you go below your body’s natural set point, both appetite and metabolism adjust to try to return you to your set point. Your metabolism may slow down to try and conserve energy. Your body will start to sense it’s in a state of semi-starvation and will try to use the few calories it receives more effectively. You may start to sleep more, your body temperature will drop, which is why you hear so many people who suffer from anorexia nervosa complaining of being so cold, and after too much weight loss many women experience the loss of their menstrual cycle. Basically when a woman’s weight gets too low, her reproductive system shuts down because her body could not handle a pregnancy. When body fat is lost, appetite will likely increase. Many people who diet also experience uncontrollable urges to binge. That is because their bodies are asking for more food than is being provided in order to function properly.
Just as your metabolism will slow down when you go under your body’s set point, it will also increase if you go above it. The body will try to fight against the weight gain by increasing its metabolic rate and raising its temperature to try and burn off the unwanted calories.
The above description is an oversimplification as the processes that maintain hunger, digestion, and metabolism are incredibly complex and not entirely understood.
There is no test available to tell you what your body’s natural set point is. However, you can find your own set point. by listening to your body and eating normally and exercising moderately. If you have been dieting for years, it can take up to a year of normal eating for your body’s metabolism to function properly and return you to the weight range that is healthy for you.
Learning to accept the fact that your body needs to be at a certain weight is a good way to stop the vicious cycles of dieting. The more you try to go below your body’s set point range, the harder your body will fight to retain it’s natural weight. Engaging in a healthy eating and exercise routine, will allow your body to go to the weight it wants and needs to be at. Learning to love and accept who you are, will help you to accept your body’s natural set point. It is unfortunate that we live in a society that is obsessed with thinness, but we have to stop believing that thinness equals happiness. If we can all accept each other for who we are, no matter what size we are, people will be much happier, except, of course, for the diet industry, because they would be finally out of business!

3 Basic Energy Systems Provide Secrets; Allow Trainers' To Perfect Goal-Oriented Exercise!

During exercise, your body relies on three basic energy systems: the anaerobic a-lactic system, the anaerobic lactic system, and the aerobic system. Depending on the sports played, athletes rely on one system more than the others. 

An understanding of the involved energy systems in a particular sport gives valuable information about the strength qualities necessary in that sport. This information gives the personal trainer or strength coach clues on how to conduct the strength training. 

The Three Basic Systems

         1. Anaerobic A-Lactic (ATP-CP) Energy System

The anaerobic a-lactic (ALA) system, also known as the ATP-CP, or adenosine triphosphate - creatine phosphate system, provides high bursts of start-up energy for activities that last less than ten seconds in duration. Athletes who compete in sports that require high amounts of short duration acceleration - shot-putters, weight lifters, gymnasts, or sprint-distance speed skaters use the anaerobic a-lactic system. The ALA system does not create energy for sufficient duration to create a great deal of waste products.

2. Anaerobic Lactic (Glycolytic) Energy System

The anaerobic lactic (AL) system (also known as fast glycolysis) provides energy for medium to high intensity bursts of activity that lasts from ten seconds to two minutes. Some American football skill positions, baseball players, soccer players, judokas, middle distance runners (400m-800m) and sprinters rely on this system. The anaerobic lactic system, as well as the ATP-CP system, are capable of high intensity levels, and do not rely on oxygen for fuel. The primary difference between the two systems is in the capacity of the system. You can think of capacity as the amount of time that the system can work at peak output before dropping off.
Whereas the ATP-CP system will only produce energy for 10 seconds, fast glycolysis works at capacity for as long as two minutes. As a result, waste products such as lactic acid accumulate in the blood and in muscle cells. A burning sensation in the muscle, shortness of breath and fatigue are all symptoms of lactic acid build up.

         
3. Aerobic Energy System

The aerobic system is the most utilized of the three. It provides energy for low intensity activities that last anywhere from two minutes to a few hours. Unlike the other two systems, the aerobic system requires oxygen and takes much longer to overload. Sports and activities that use continuous sustained efforts such as long distance swimming, crew (rowing) and sea kayaking rely on the aerobic system.

In reality, most sports use a variety of energy systems, or at least the power (time to reach peak output) and the capacity (duration that peak output can be sustained) of the system. The only real exceptions are Olympic weight lifting and certain field events, such as hammer or shot put. Which is energy system is most prevalent in a given sport dictates the training intent. 

Reference: Bindu Nambiar (bodybuilding.com)

SPASTICITY VS RIGIDITY

1.Spasticity is an increased resistance to the passive movement of a joint due to abnormally high muscle tone (hypertonia) which varies with the amplitude and speed of displacement of a joint.

1.Rigidity is an increased resistance to the passive movement of a joint which is constant throughout the range of joint displacement and not related to the speed of joint movement; resistance is present in both agonist and antagonist muscles.

 

2.Spasticity is usually uni-directional, and is velocity and amplitude dependent.

2.Rigidity is bi-directional, and is non velocity or amplitude dependent.

When it Happens: The important of such differentiation is that spasticity is typically caused by damaged to the corticospinal tract, while rigidity is usually extra-pyramidal in origin.

How to Assess and Differentiate: 

A simple way to assess spasticity is by fast flexion or extension of selected joint, typically the elbow or knee, to elicit a sudden increase in tone. This demonstrate the velocity dependent nature of spasticity. Another phenomenon known as clasp-knife phenomenon, describe a sudden release of tone after an initial hypertonia of selected joint movement when the examiner passively move the joint to the extreme, this demonstrate the amplitude nature.

To test for rigidity, passively move the joint in both direction, a relatively uniform rigidity in both agonist and antagonist muscle group is known as lead-pipe rigidity; if there is tremor superimposed with background increase of tone – cogwheel rigidity. These rigidity is commonly seen in Parkinson’s disease.

Importance of Closed vs Open Kinematic Chain in Clinical Practice

I often hear the terminology open-packed and close-packed joint positions used in the clinic. In general, clinicians know to mobilize in the open-packed position and avoid manipulation in a close-packed position, but what else should we know about these terms? Is there any other clinical significance to the open vs close-packed positions?

Open-packed Position •Position with the least amount joint surface congruency •Capsule and support ligaments are lax •Accessory motion or joint play is maximized

Close-packed Position •Position with the most amount of joint congruency •Capsule and supporting ligaments maximally tight •Accessory motion is minimized​​

How Should PT's Interpret Open vs Close-Packed Clinically?

As I mentioned above, it is important to start your joint assessment and treatment in the open-packed position. Since the joint has the most available room for movement, mobilizations are best tolerated in this position. For example, the open-packed position of the knee is 25 degrees of flexion. The close-packed position is full extension. At 25 degrees of flexion the knee is loose- one can assess varus and valgus ligament stress testing or check tibial IR/ER mobility in this position. Biomechanically, the knee is 'unlocked.' Following an injury, the body favours this position because there is space for swelling and other fluid to accumulate within the joint. As the patient's ROM improves, pain decreases, and the swelling subsides, the clinician can start to mobilize the joint in other positions of flexion and extension as needed.

Additionally, understanding the open and closed packed positions is essential when performing manipulations. We want to manipulate a joint in the open-packed position, but often times we cannot target a specific joint unless we lock out or close-pack the surrounding joints. For example, when performing a prone SIJ distraction manipulation, the hip needs to be placed in extension, abduction, and internal rotation. These three movements are the close-packed position of the hip joint. You must lock out the hip so you do not manipulate it when you are targeting the SIJ.

Each joint has a different open and close packed position and being able to quickly recall that position will make you a more efficient clinician. If you do not understand the open and close-packed positions of regional joints, the specificity of your techniques will decrease. 

Thanks to Jim

Source: https://www.thestudentphysicaltherapist.com/featured-articles/importance-of-open-closed-packed-positions

Which is better for shoulder diagonals: Thera-Band or Dumbbells?

Shoulder rehabilitation often includes Thera-Band® exercises. One popular exercise is the “PNF” diagonal shoulder exercise from the Proprioceptive Neuromuscular Facilitation concept. The PNF diagonal exercise includes tri-planar motion of the shoulder against resistance; the resistance provided can be manual, dumbbell, or elastic band resistance. Few researchers have investigated the EMG activation levels of shoulder muscles during PNF diagonal exercises.

Researchers at the University of Cincinnati in Ohio assessed the activation of scapular muscles in 21 healthy subjects. The subjects performed 4 diagonal patterns (D1 Flexion, D1 Extension, D2 Flexion, and D2 Extension) with both a 3 pound dumbbell and a blue Thera-Band resistance band. For the band exercises, the subjects were seated using a length of band equal to the distance between the floor and their greater trochanter as measured when the subject was standing.
The results showed that both Thera-Band and dumbbell exercises provide similar levels of EMG activity, which is consistent with findings of other researchers who compared EMG levels during isotonic and elastic resistance (Andersen et al. 2010). The serratus anterior, an important scapular stabilizer, remained moderately active in each exercise with no significant difference between exercises (42.5 to 50% of maximal).

When evaluating an exercise for suitability in rehabilitation, it’s important to consider not only the absolute activation but the activation relative to other muscles including agonists and antagonists.  The trapezius is prone to muscle imbalance. The upper portion is prone to tightness and the lower portion is prone to weakness according to Janda. Shoulder patients, particularly those with impingement, often exhibit scapular muscle imbalance.

The D2 Flexion pattern had the highest activation levels for the middle and lower trapezius compared to the other patterns; the D1 and D2 flexion patterns also had more upper trapezius activation than their extension movement counterparts. While the Thera-Band resisted D2 Flexion exercise produced higher levels of middle and lower trapezius activation compared to dumbbell resistance, the Thera-Band resistance also produced higher levels of upper trapezius activation compared to the dumbbell. 

In contrast to D2 Flexion, the D2 Extension exercise with Thera-Band had the lowest levels of upper trapezius activation. It also had the most desirable ratio of upper to lower trapezius activation (0.9), meaning the lower trapezius was activated at a higher level than the upper trapezius.
As with other surface EMG studies on healthy subjects, these results should be used with caution in patient populations. The authors chose blue Thera-Band resistance, which may not be appropriate in early stages of rehabilitation. It would have been valuable for the authors to report on the eccentric phase of the exercise, or during different phases of the exercise due to the large arc of motion.
The authors concluded that the D2 Flexion pattern with either dumbbell or Thera-Band resistance provides the greatest activation of scapular muscles, and the D2 Extension pattern with Thera-Band provided the best ratio of upper and lower trapezius activation.

REFERENCE: Witt D, Talbott N, Kotowski S. Electromyographic activity of scapular muscles during diagonal patterns using elastic resistance and free weights. Int J Sports Phys Ther. 2011 Dec;6(4):322-32.