These 14th century illuminations depicting stilts are linked at http://www.larsdatter.com/stilts.htm. The images here have been cropped to focus on the stilts and their users.
Mother nursing on stilts in the Smithfield Decretals, Brit. Lib. Royal 10 E IV (c. 1300-1340) f29v
This image, depicting a mother nursing her child while simultaneously walking on tall stilts and balancing a pot on her head, offers a glimpse of how middle class mothers were viewed in the 14th century. Certainly, a fair amount of social commentary on the work of a mother was likely intended here, and it seems not much has changed these days. I would urge caution against adopting a literal interpretation of this image, but the form of the stilts themselves is likely technically correct. This shows a huge leap in design from the two 13th century images I posted earlier, as well as from other 14th century images shown below. I do not think this represents a revolutionary design development, however, but rather different stilts for different purposes. Some stilts, such as these, were professional equipment used by skilled workers, while other, simpler stilts were play things used by children and adolescents.
Boy and girl on stilts in the Smithfield Decretals, Brit. Lib. Royal 10 E IV (c.1300-1340) f77r
Like the woman above, these two youths are walking on stilts that strap to the calf, leaving the hands free to do work.
Ape on stilts, psalter, Douce 6 (c.1320-1330) f158v
This more crudely fashioned pair of stilts shows a design more commonly seen being used by children, here humorously being used by an ape.
Stilts in the Luttrell Psalter, Brit. Lib. Add. 42130 (c.1325-1340) f70v
Monkeys on stilts in Romance of Alexander, Bodley 264 (c.1338-44) f43v
Children on stilts in Romance of Alexander, Bodley 264 (c.1338-44) f65r
Cock on stilts in Romance of Alexander, Bodley 264 (c.1338-44) f91r
Boys wrestling on stilts in Romance of Alexander, Bodley 264 (c.1338-44) f123r
Boys fighting with stilts in Romance of Alexander, Bodley 264 (c.1338-44) f123r
These two youths have each abandoned one of their stilts and they appear to be using the other stilts like axes in a mock battle.
Man on stilts in Voeux du paon, PML G.24 (c.1350) f40r
Here we see a grown man standing on what I have come to think of as children’s stilts, but these are much taller. Note that like those used by the children and apes above, this man’s stilts are controlled by the hands, rather than strapped to the calves.
In summary, we see two general forms of stilts here: those which consist of a stripped and shaved branch with the crook of the remaining limb reinforced with a lashing and the pole extending upward to form a handle; and a more sophisticated design, milled from heavier lumber, carved to fit the foot, and strapped to the calf, leaving the hands free for work. What sort of workers used stilts professionally in the Middle Ages? I suppose someone working at ceiling height might have used stilts for jobs where more mobility was required than would have been afforded by scaffolding. These skilled workers were probably relatively well compensated, as the middle class dress of those depicted here suggests, and they may have encouraged their children to play with stilts. Note the height of the stilts used by adults, compared to the shorter stilts used by children. This may represent a progression in skill at using stilts, which can only come with years of experience.