Hello There,
I'm trying to find the name of a movie that I saw on PBS in the early
1990's. It was a claymation movie, I believe, in the fantasy genre.
All I can really remember is one of the characters in the movie was
able to run incredibly fast if he tied-up one of his legs and ran on
one foot.
Thank You For Your Help!  :)

I am confident that your movie is "The Fool of the World and the
Flying Ship," a delightful 1990 film which uses stop-motion animation.
The film was funded by WGBH (a public television station in Boston),
and was aired on PBS. The story (based upon a Russian folk tale) is
about a young man named Pyotr (known as "The Fool") and his adventures
on a flying ship with some unusual people, one of whom is a man who
can run extraordinarily fast. He keeps one leg tied to prevent himself
from traveling so rapidly as to step across the world in a single
stride.

"They flew on and on, and looked down, and there was a man on one leg,
with the other tied up to his head.

'Good-day, uncle,' says the Fool, bringing the ship to the ground.
'Why are you hopping along on one foot?'

'If I were to untie the other I should move too fast. I should be
stepping across the world in a single stride.'

'Sit down with us,' says the Fool." 

Old Peter's Russian Tales, by Arthur Ransome
http://www.mainlesson.com/display.php?author=ransome&book=russian&story=fool

"The six extraordinary friends who join Pyotr are: 

 Sharpshooter
 He's deadly accurate with a bow and arrow...

 The Farmer
 He carries Siberian straw so cold it can not be burnt...

 Lightning
 He keeps one leg tied up because he can run terribly fast, when released...

 Listener 
 A big-eared fellow with extraordinary hearing...
  
 The Forester 
 He carries magic twigs that become an army of saplings...

 The Forester's Wife 
 A woman with an extraordinary appetite!"

Toonhound: The Fool of the World and the Flying Ship
http://www.toonhound.com/fool.htm

This film has been released on VHS:

Amazon: The Fool of the World And The Flying Ship (1990)
http://www.amazon.com/gp/product/6304794487

My Google search strategy:

Google Web Search: "the fool of the world and the flying ship" "one leg"
://www.google.com/search?hl=en&q=%22the+fool+of+the+world+and+the+flying+ship%22+%22one+leg%22

I hope this is the correct film! If it is not, or if anything is
unclear or incomplete, please request clarification; I'll be glad to
offer further assistance before you rate my answer.

Best regards,
pinkfreud

Pink,

Let me guess, you remember seeing this on TV and somehow remebered it,
to answer this question.

Unbelievable!

Bowler-ga

Bowler,

My ancient mind is crammed full of memories of movies, TV shows,
songs, books, and other entertainments. Were it not for Google
Answers, this stuff would be totally useless, except to me. It is
marvelous to be able to put my mental trivia collection to good use. I
only wish the other parts of my mind worked as well as the media
library section.

~Pink