Body Composition - DEXA Scan (Mason Sim)

DEXA Scan 

It is the most accurate and efficient method to measure body composition . There is very little chance for human error , increasing the reliability of the machine . Also , it is able to detect other things as well (Bones Density)

Disadvantages : It is extremely costly and the scanner is only of a certain width , making it unsuitable for people of certain sizes to use the machine .

Mason Sim 

Measuring Body Composition: Underwater Weighing (Farrell Nah)

                                                                  Underwater Weighing

Underwater (hydrostatic) weighing is done based on Archimedes' Principle. Because body fat is less dense than water, it increases one's buoyancy while the fat-free mass, which has a density greater than water, makes one sink. This is once considered the gold standard, as it is more accurate than other methods such as skinfold measurement but the emergence of newer and more sophisticated methods are now more accurate than this method

Limitations

The largest source of error in underwater weighing is thought to be the determination of residual volume (RV; the amount of air remaining in the lungs following maximal expiration). When RV is estimated rather than measured, the precision of underwater weighing is little better than anthropometric (skinfold) determination.

Testing Procedures

1. Weigh the subject to the nearest 0.1 kg.
2. Measure or estimate the subject's RV. If possible, directly measure RV using the diluted helium or oxygen techniques. Otherwise, RV can be estimated by measuring vital capacity (VC) and multiplying it by 0.24 or 0.28 for males and females, respectively.

• VC is the amount of air that can be maximally exhaled. To measure VC, place a noseclip on the subject. Have the subject maximally inhale, place the mouthpiece from the spirometer in his/her mouth, and then maximally exhale. Perform 2-3 trials and use the highest volume. Also, correct the volume to BTPS by multiplying the volume by the correction factor (see an instructor for this value).

1. Tare (zero) the scale in the underwater weighing tank. While seated in the tank, instruct the subject to blow out all the air that he/she can exhale, bend slowly forward until the top of his/her head is underwater, and to remain motionless until the scale has settled and the computer indicates that it has a reading. Have the subject perform 6-10 trials and average the heaviest 2-3 readings.

Equations 

Determination of Body Density 

Body Density = dry weight / [((dry weight - wet weight) / water density)- RV - 0.1]  

Note: Units for all weights are in kg and RV is in L. The 0.1 represents an estimated volume (L) of gas in the GI tract.

Estimation of Percent Fat

The two most commonly used equations for estimating percent fat from body density are the Siri (1961) and Brozek (1963) formulae. A limitation to these formulae is that they assume the density of fat-free mass to remain a constant across the population when in fact is varies. Thus, the actual percent fat tend to be slightly higher than the measured percent fat in the lean, muscular individual and the opposite effect in obese individuals.

Siri	Percent Fat = [(495 / Body Density) -450] * 100
Brozek	Percent Fat = [(4.570 / Body Density) - 4.142] * 100

http://www-rohan.sdsu.edu/~ens304l/uww.htm

http://sportsmedicine.about.com/od/fitnessevalandassessment/g/UnderwaterWeigh.htm

Bioelectrical Impedance (Jemima)

I like the bioelectrical impedance because it is easy to use, portable and it is relatively cheaper. However, it might not be very accurate as the machine might not be working well and the results obtained will be inaccurate. Research studies have shown that it is quite variable and it was not regarded by many as providing an accurate measure of body composition. They tend to under-read fat percentage.

My preference

I choose the skinfold measurement because it is the most easily available  and can other results like X-rays even though it is measuring body composition. It is better than the rest as underwater weighing, bioelectrical impedence and Bod Pod are all not accurate.How Therefore, I chose this method.

Body Composition - Skinfold (Kaelan)

Skin fold method involves the measurement of fat under the skin.

It is advantageous as the equipment is cheap and easy to maintain and is faster than the other methods. This makes it much cheaper than other methods and allows the measurement to be taken conveniently in places such as schools and clinics

ME CHOICE VERY GOOD

I choose the DEXA because it is the most accurate and can other results like X-rays even though it is measuring body composition. It is better than the rest as underwater weighing, skinfold measurements, bioelectrical impedence and Bod Pod are all not accurate. Therefore, I chose this method.

Softball Modified Rules

Softball Modified Rules

§  Any ball going outside the 1st or 3rd base line is a foul ball ( runners can not advance and batter gets another try unless the ball was caught in the air, which translates to an out)

§  An official game is 7 innings (a inning is when both teams have had their turn to bat)

PITCHING

§  Pitcher must have both feet on the pitcher’s rubber and can only take one step forward while pitching

§  Ball must be thrown underhand

BATTING

§ Batters must follow the same order throughout the whole game The batter is out if and when:

o   three strikes have been called

o   a fly ball is caught

        

BASE RUNNING

§ Runners must touch each base in order

§ One base runner can not pass another base runner that is ahead of them.

§ Stealing a base is not permitted A runner is out if:

o   they are tagged with the ball before reaching a base

o   the ball gets to 1st base before the runner

o   they run more than 3 feet out of the base line to avoid being tagged

TERMS:

§ Ball- a legally pitched ball that does not enter the strike zone (four balls equals a walk) Grounder

§  Fly ball- ball hit up in the air to the infield

§  On deck- the next batter

§  Pop up- ball hit up in the air to the infield

§  Strike- term used when a ball is swung at and missed or is called when the ball enters the strike zone and is not swung at all

§  Strike zone- the ball passes the batter over the plate between their chest and knees