I'm always amazed to find young physical comedians who study and work hard at their craft and yet have only minimal familiarity with the silent films of Buster Keaton.
When I was in my early 20s —the pre VCR days— the only way to see his films was to go to Manhattan's Elgin Cinema (now the Joyce Theatre) for the annual Keaton festival and try to take in the enormous breadth of his work —without a rewind button. In the audience were half of the city's clowns, all muttering "how did he do that?" Nowadays, with DVD and the internet, there's no obstacle to appreciating and learning from the master.
So buy the DVD set and keep the remote handy. Meanwhile, here are several excellent video pieces analyzing his work. The first is from the noteworthy video series by Tony Zhou, Every Frame a Painting, which reminds us that Keaton was also a damn good film director, one who firmly believed that physical comedy should not be faked. (Thanks to Skye Leith and Mark Mitton for the link on this one!)
"One reason Sennet did not hire trained acrobats for his Keystone force was because a trained acrobat seldom can get laughs in pictures when taking a comedy fall. He looks what he is, a trained acrobat doing his stuff, instead of a character in the picture taking a stumble accidentally... Though I have been called an acrobat, I would say I am only a half-acrobat, at most. What I do know about is body control."
—Buster Keaton, My Wonderful World of Slapstick
Sometimes Keaton is known too much for his stunts and not enough for his talents as a comic actor. Here's a sweet two-and-a-half minute compilation of reaction shots by the great stoneface. (Thanks to Larry Pisoni for the link!)
Interesting fact: Did you know that Buster Keaton couldn't do a back handspring? He learned his acrobatics in vaudeville, not in a gymnasium.
Okay: "half-acrobat," comic actor, writer, stuntman, film director. But did you know that Keaton was also an early pioneer of film special effects? Here's a thorough documentary on the making of one of my favorite Keaton movies, Sherlock, Jr. This was put out by Kino in 2010 and the main credit reads: Written by David B. Pearson with Patricia Eliot Tobias.
If Keaton has a worthy successor in film, it's probably Jackie Chan. Here's Tony Zhou again with a spot-on analysis of how physical comedy works in Chan's films. Some really good insights.
In his notes to the YouTube video, Zhou summarized Chan's approach as follows:
The 9 Principles of Action Comedy
1. Start with a DISADVANTAGE
2. Use the ENVIRONMENT
3. Be CLEAR in your shots
4. Action & Reaction in the SAME frame
5. Do as many TAKES as necessary
6. Let the audience feel the RHYTHM
7. In editing, TWO good hits = ONE great hit
8. PAIN is humanizing
9. Earn your FINISH
If you haven't seen enough, here are two more related pieces from Zhou's Every Frame a Painting series:
• Edgar Wright: How to Do Visual Comedy
• You can support Every Frame a Painting here.