A hand-rod puppet, a style developed by Jim Henson, is a puppet which is controlled by both hands. The puppeteer's dominant hand goes into the head of the puppet, operating the mouth, and at times, facial features. The puppeteer's less dominant hand controls the "arm rods", thin rods connected to the puppet's hand or arms.
Arm rods tend to be painted black, and have wooden dowels connected at the bottom for easier grip.
Popular examples of this type of puppet are Kermit the Frog, Miss Piggy, Gonzo, Bert, Elmo and Grover. Hand-rod puppets tend to have smaller arms and hands than live-hand puppets, in order to be proportionate to their body.
The Muppets Make Puppets! included a section on hand-rod puppets.
By moving the rod, the puppeteer can move the arm of the Muppet. In most cases, the dominant hand of the Muppet character is the character's left hand -- the inverse of the right-handed puppeteer. The Muppet's other arm (usually the right) is posed in a neutral position at their side, or just left limp.
In specific cases when a character has to move both arms, a dual-rod method is employed -- in such instances as clapping, waving arms, dancing, etc. The single puppeteer usually controls both arm rods. The arm movement is slightly limited –- usually resulting in the arms moving somewhat together. Moving the two rods believably is similar to learning how to use chopsticks. In rare cases, a second puppeteer may assist with a second rod.
Rods are occasionally used to move other body parts or joints as well. For example, there are some scenes in The Muppet Show with Kermit sitting on a wall, and occasionally tapping his foot or moving his leg. The extra rods are performed by a second puppeteer.
Removing the Rods
In the more recent Muppet movies and productions, the rods are digitally removed to hide the effect. Brian Henson said in the Muppet Treasure Island DVD commentary that "in the movies we remove them in the computer, because techniques have moved along so quickly that all the rods will be gone in Muppets from Space, for instance... Nowadays, when we make a Muppet movie, we pretty much do whatever we want with the arm rods and remove them later."