Weight plate

A weight plate is a flat, heavy object, usually made of cast iron,[1] that is used in combination with barbells or dumbbells to produce a bar with a desired total weight for the purpose of physical exercise.

A weightlifter holding an Olympic barbell loaded with plates ranging from 5 to 25 kilograms
A pair of adjustable dumbbells with "standard" plates
Grip plates arranged on a plate holder (or "plate tree")

Two general categories exist: "standard" plates, which have a center hole of approximately 25 mm (one inch), and "Olympic" plates, meant to fit on the 50 mm (two inches) sleeves of Olympic barbells.[2][3] Standard plates are usually paired with adjustable dumbbells and Olympic plates with full-size barbells, although standard barbells and Olympic dumbbells exist.[4][5]

Weight plates may incorporate holes for ease of carrying (called "grip plates") or be solid discs (especially those used for competition). Non-competition plates often have variable diameters and widths, such as on the adjustable dumbbells pictured right, with heavier plates generally being larger in diameter, thickness, or both. Weight plates are typically round, although 12-sided and other polygonal varieties exist.[6] Most plates are coated with enamel paint or hammertone[7] to resist corrosion; more expensive varieties may be coated with chrome, rubber, or plastic.[8][9]

Plate sizes

Plates are available in a range of weights. Common Olympic plate (50 mm center hole) denominations are in 1.25, 2.5, 5, 10, 15, 20, and 25 kg sizes,[10] or 2.5, 5, 10, 25, 35, and 45 lbs,[11] with 0.25, 0.5, and 50 kg,[12] or 1.25 and 100 lb discs less commonly seen.

Standard plates (25mm center hole) are commonly available in 1.25, 2.5, 5, 10, 15, and 20 kg,[13] or 2.5, 5, 10, 25, 35 and 50 lb[14] where pound denominated plates are used. Less commonly seen are plates of 0.5, 7.5, and 25 kg,[15][9] or 1.25, 7.5, 12.5, 20, and 100 lbs.[16]

Bumper plates are commonly available in 5, 10, 15, 20, and 25 kg,[17] or 10, 15, 25, 35, 45, and 55 lb in pound-denominated sets.[18]

Weight accuracy

Low-cost plates can vary widely from their marked weight. A 2% or 3% variation is not uncommon, with plates from some manufacturers frequently being 10% or more over or under (a 45-lb plate can weigh as little as 40 lbs, or as much as 50).[8][19] Tom Lincir, founder of the Ivanko Barbell Company, has encountered 45 pounds (20.4 kg) plates weighing as little as 38 pounds (17.2 kg), or as much as 59 pounds (26.8 kg) pounds.[20]

Plates can be weighed, and the equipment marked (using a paint pen or other permanent marker) with the true weight.[21]

Calibrated plates are available from high-end manufacturers; many advertise these plates as being accurate to within 10 grams (0.02 lb) of marked weight, which is the tolerance mandated by the International Weightlifting Federation for plates used in competition.[22][23][24]

Bumper plates
See also: Barbell § Bumper plates

Olympic plates may come in the form of bumper plates, which are made of resilient rubber. These are used for Olympic weightlifting, a category of movements that involve lifting a barbell high overhead, then letting it fall.[25] Their design permits a loaded barbell to be dropped (and to bounce) after a lift, with negligible damage to the floor, plates, and bar.[26] Unlike most iron plates, where heavier plates have larger diameters, bumper plates are all the same diameter, instead varying in thickness and construction. This helps to distribute the force of the dropped barbell across all the plates more evenly, reducing damage to the equipment.[27]

Lower-end bumper plates are generally made of solid rubber with a steel or brass hub. Competition-grade bumper plates are more compact, with a layer of rubber surrounding a steel core.[28][29]

Bumper plates used in competition have a diameter mandated by the International Weightlifting Federation of 450 millimetres (17.72 in) ±1 millimetre (0.04 in), with lighter plates being narrower than heavier plates.[30][24][31] The lightest bumper plates available are generally 5 kilograms (11 lb), or 10 pounds (4.5 kg) in pound-denominated sets. Plates lighter than this are generally smaller in diameter and are known as "change plates" when paired with bumper plates.[32]

As an alternative to rubber plates, "technique plates", made of plastic, are available. Technique plates are more expensive than rubber, but hold up better to repeated drops. Their primary purpose is to allow novice lifters to practice Olympic lifts at lighter weights that can put too much lateral stress on single pairs of rubber plates, damaging them.[33]

Vinyl plates

Standard (25 mm hole) "vinyl" plates are often sold paired with dumbbells or barbells as a low-cost option for casual strength training. These plates are made of cement or sand coated with a polyvinyl chloride sheath. The cement tends to break down over time and leak out of holes in the sheath, and the weights are less dense than iron so that fewer fit on a given bar.[34]

Weight stacks
The weight stack on a selectorized cable machine; in this example, each plate weighs 6 kg

Weight machines commonly use specialized sets of plates (called "weight stacks"), consisting of a set of rectangular plates mounted on rails. The load is transmitted to the user of the machine via a cable and pulley arrangement. The weight used is selected by inserting a pin in the stack that causes each plate above the pin to be pulled by the cable. This arrangement is known as a "selectorized" weight machine.[35]

Some weight machines, such as the sled-type leg press, or the Smith machine, are designed to be loaded with Olympic plates instead of using a cable-driven stack.[35]

References
  1. "Cast Iron Weight Plates". Dick's Sporting Goods. Archived from the original on 3 December 2017. Retrieved 20 November 2016.
  2. "IWF technical and competition rules and regulations" (PDF). International Weightlifting Federation. p. 48.
  3. Doyle, Kip. "Olympic Weights Vs. Standard Weights". Livestrong. Archived from the original on 29 July 2017. Retrieved 20 November 2016.
  4. "Bodymax 6 ft Standard Spinlock Barbell with collars". Powerhouse Fitness. Archived from the original on 8 July 2017. Retrieved 20 November 2016.
  5. "Olympic Dumbbell Handle". Troy Barbell. Archived from the original on 28 February 2018. Retrieved 26 February 2018.
  6. "CAP 12-Sided Olympic Cast Iron Grip Plate". CAP Barbell. Archived from the original on 21 June 2017. Retrieved 20 November 2016.
  7. "York Olympic Hammertone Cast Iron Weight Plate 1 x 20kg". Workout For Less. Retrieved 2022-12-01.
  8. "Barbell Weight Plates – A Comparison of Iron and Rubber Models". Adamant Barbell. Archived from the original on 23 December 2016. Retrieved 20 November 2016.
  9. "Bodymax 1" Hammertone Weight Discs". McSport, Ireland. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  10. "Bodymax Olympic Trigrip Grip Discs". McSport, Ireland. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  11. Stoppani, Jim (1 October 2014). Jim Stoppani's Encyclopedia of Muscle & Strength, 2E. Human Kinetics. pp. 27–. ISBN 978-1-4504-5974-7. Archived from the original on 28 February 2018.
  12. "Products – CBPP – Ivanko". Ivanko Barbell Company. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  13. "Elite Ezi-Grip Standard Weight Plate". Elite Fitness NZ. Archived from the original on 2 July 2017. Retrieved 26 February 2018.
  14. "1" Standard Contour Cast Iron Plate". York Barbell. Retrieved 2020-02-04.
  15. "Viavito Cast Iron Standard Weight Plates". Viavito. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  16. "CAP Barbell Catalog". Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  17. "KG Rogue Bumpers". Rogue Fitness. Archived from the original on 2017-06-26. Retrieved 7 March 2018.
  18. "Black Training Bumper Plates". Vulcan Strength. Archived from the original on 5 September 2017. Retrieved 7 March 2018.
  19. "A Guide to Buying Steel Powerlifting Plates & Discs". Garage Gyms. 16 November 2017. Retrieved 2020-07-30.
  20. Lincir, Tom (Summer 2001). "The Making of a Perfect Olympic Plate" (PDF). National Fitness Trade Journal. Archived (PDF) from the original on 2016-04-17. Retrieved 2016-11-18. The worst examples – a plate that weighed 37.5 pounds, and one that weighed 59 pounds.
  21. Starting Strength (19 December 2012). "The Dumbbell Rack with Mark Rippetoe". Archived from the original on 28 February 2018. Retrieved 20 November 2016 – via YouTube.
  22. "Rogue Calibrated KG Steel Plates". Rogue Fitness. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  23. "Products – OCB – Ivanko". Ivanko Barbell Company. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  24. "The Levels of Bumper Plates". Box Pro Magazine. 3 November 2014. Archived from the original on 21 November 2016. Retrieved 20 November 2016.
  25. Schmitz, Jim. "Dropping Weights". IronMind. Archived from the original on 21 November 2016. Retrieved 20 November 2016.
  26. "About Bumper Plates". Vulcan Strength Training Systems. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  27. "Are Bumper Plates a Good Choice For a Home Gym in 2021?". gymcrafter.com.
  28. "Bumper Plates Sets For Crossfit & Weightlifting – Pricing Guide". Garage Gyms. 11 February 2014. Archived from the original on 25 November 2016. Retrieved 20 November 2016.
  29. "Bumper Plates FAQ". Bumper Plates for Weightlifters, by Weightlifters. Archived from the original on 16 July 2017. Retrieved 20 November 2016.
  30. "Equipment". International Weightlifting Federation.
  31. "Bumper Plate Guide for CrossFit and Strength Training". Beyond the Home Gym. 19 May 2016. Archived from the original on 21 November 2016. Retrieved 20 November 2016.
  32. "Olympic Change Plates Review and Shopping Guide". Garage Gyms. 6 July 2015. Archived from the original on 27 December 2016. Retrieved 20 November 2016.
  33. "10-Pound Bumper Plates vs Technique Plates". Garage Gyms. 18 February 2015. Archived from the original on 6 November 2016. Retrieved 20 November 2016.
  34. "Vinyl Weights or Cast Iron Weights?". Stay-Fit Bug. Archived from the original on 19 November 2016. Retrieved 20 November 2016.
  35. "Plate Loaded vs. Selectorized Weight Machines". Empire Fitness Services. Archived from the original on 30 October 2016. Retrieved 20 November 2016.
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