Where Barbells Come From. (PDF) Mitchell M. & Rippetoe M. 2007 (Aug.) Flashcards
most important piece of gym equipment and why
Barbell, critical exercise more difficult to do, spin will be poor, can’t train with bent barbell, or when under load
What are the varieties and variables of a barbell
Olympic weightlifting bars are produced in
training and competition grades and are designed to comply with International Weightlifting Federation specifications regarding markings and dimensions.
Why IWF recommended
springier and more lively—“whippy” is the term usually used—than other types of bars, because of the dynamic nature of the snatch and the clean and jerk.
Powerlifting bars, again in either training or competition grade, are stiffer than weightlifting bars,?
since bar oscillation is not desirable in the squat, bench, or deadlift
Specialized thicker bars for
squats
Bars used for deadlift
Longer in some federations
The surface of the bar can be finished in a variety of ways
chrome, zinc, black oxide, or unfinished, or stainless steel can be used.
Thicknesses vary from
25mm for women’s weightlifting bars to 1 3/8 inches for squat bars, on up to 3 inches for specialized fat bars designed for grip training
common length for general-purpose bars is?
84 inches (7 feet) but they are available in lengths of 72, 60, and 48 inches for specific needs.
variety of weights,
5kg to 60 pounds, with varied knurling depth and marking options;
type of retainers
bolt, snap ring, or roller pin retainers;
sleeves barbell
with bushing or needle-bearing
bar strength is measured in at least three ways
in at least three ways: tensile strength, yield strength, and test ratings of 2000, 1800, 1500, 1200, 1000, 700, and 500 pounds.
Powerlfitng bars
. Eight-foot squat bars with larger diameter shafts are now available that deform very little under the heavy loads modern powerlifting equipment permits lifters to handle
For deadlift bars
Longer-than-standard deadlift bars permit the wide stance used in Sumo-style deadlifting, are thinner for gripping purposes, and offer more flexibility in the bar to assist the pull from the floor.
How many bodies are there for olympic weightlifting
Olympic weightlifting, however, has one international governing body and one set of equipment specifications.
Diff between men and women
The major differences are the weight (20kg for men and 15kg for women) and diameter (28 mm for men and 25 mm for women).T
For novice and children
For training novice lifters and children, lighter bars are available in 10kg and 5kg sizes.
Weightlifting
are smaller in diameter than powerlifting bars.A smaller grip surface is necessary to allow the fast rotation of the bar, since the smaller diameter rotates at a higher angular velocity, and the smaller diameter makes it easier to assume the hook grip favored by weightlifters.
Why smaller diameter
A smaller diameter allows for greater bar flexibility, which facilitates the “whip” desirable in cleans, jerks, and snatches, but it also requires a more expensive higher grade of steel. Powerlifting bars need some, but not much, rotation. An all-purpose powerlifting bar will be thicker than a weightlifting bar.
When whip is not an issue
Whip is not an issue as the bar is carried in the palm, with closed fingers, or on the back during a lift.
Whip when not good
a squat and bench press bar must be “deader” than a weightlifting bar, because 800 pounds on a whippy bar causes bar oscillation during the lift that interferes with stability.
domestic and international high-quality bar manufacturers
ower Place Products, Ivanko, York, Chapman, Eleiko, Leoko, Uesaka, Werksan, Zhangkong,Texas Power Bar, and Solid Bar.
most important properties of bar stock
tensile strength and yield strength
How is tensile strength and yield strength measured?
Both of these characteristics are measured in psi, or pounds of force per square inch, and information about these two parameters is usually associated with weightlifting bars.
one psi
One psi is defined as a force of one pound applied to an area of one square inch
Tensile strength ?
Tensile strength is defined as the amount of stress (in psi) a material can take before breaking.
Yield strength
But equally important is yield strength, which refers to the amount of stress (again in psi) that a material can take without undergoing permanent distortion.
Kinds of distortion in barbells
This distortion is known in engineering as “plastic deformation,” as opposed to “elastic deformation,” which is a material’s ability to deform and return to its original configuration.::you can think of tensile strength as essentially resistance to breaking, and yield strength as resistance to bending.The higher these two measures of bar strength are—and the closer they are together—the better the bar.
example to buy for tensile strength and yield strength
Understanding this is critical. For example, a bar with a tensile strength rating of 195,000 psi and a yield strength rating of 120,000 psi will be next to impossible to break, but, in time, after some heavy squats, deadlifts and shrugs, you will notice a permanent bend or bow. On the other hand, a bar with a 195,000 psi tensile strength rating and a 175,000 psi yield strength rating will turn you into a lifetime customer for that wise, careful barbell manufacturer. As it turns out, information on yield strength is not as readily available as tensile strength info. The knowledgeable buyer will ask for both.
Pound test rating
Pound-
test ratings for bars are
established in a static
manner, with the bar
supported under the
specified load with no
bouncing or dropping. An
example of this test might
be a forklift with the forks
set under the bar in a grip
width position, holding the
bar loaded to 1500 pounds off the ground for a specified time. Upon unloading, if there is no permanent distortion or bend, the bar is rated as a 1500 pound test bar. A good 1500 pound test bar should be in the vicinity of 150,000 psi tensile and 130,000 psi yield strength.
Steps to make the bar
cut the bar stock to length.
During the primary machining process that a bar undergoes, raw bar stock is “turned” or machined down to size.
When it reaches the desired thickness, it is checked for straightness to very low tolerances, and some bars may need to be mechanically straightened in a press to meet tolerance levels.
bar is also checked for other defects such as cracks, pits, pots, and corrosion. Some manufacturers use X-ray technology to check for internal abnormalities.
knurling
finishing
Knurling
bar is also checked for other defects such as cracks, pits, pots, and corrosion. Some manufacturers use X-ray technology to check for internal abnormalities. feel the bar
Types pf finish
he performance markets—athletics and competition—hold a different view on the finish of a bar. Black oxide is accepted as a good “tacky” grip for powerlifters. Zinc or stainless may be preferred by weightlifters wanting a slightly smoother grip. Chrome doesn’t hold chalk as well, but it cleans more easily after use or when bloodied during a pull.
Sleeves
It is made out of a material known as Drawn Over Mandrel (DOM) tubing, a type of machine tubing that is made out of flat stock, rolled into a pipe configuration and then pulled through a die under pressure and rotation that ensures its straightness, strength, and internal integrity
Sleeve
Sleeve rotation in a high-quality bar is facilitated by either a bronze or steel bushing system or by precision needle bearings.
Sleeve assembly types
Finally, the sleeve assembly may be held in place in several ways.The most common three are snap rings, roller pins, and bolts. Snap rings are generally the preferred method, since they are not exposed to the platform and, at least in theory, cannot fail. Spring tension holds them in place in a groove cut into the internal diameter of the end of the sleeve. Roller pins were used to assemble York bars for decades, and they work well too since they cannot spontaneously loosen, but they can shear if the loaded bar is dropped hard on the end. Bolts of any kind are the mark of a cheap, inferior product. In time, continuous rotation of the sleeve, the impact of dropping the bar, and the inevitable lack of maintenance loosen the bolt. The wreck caused by a loaded sleeve sliding off the bar during a heavy attempt can be spectacular and very dangerous to both lifter and spotters.
