I found it completely fascinating, so I did a bit of reading up to find out that the clubs these men are holding are called Meels in the Pahlavani wrestling tradition of Iran. Practicioners of Pahlavani attend a particular gymnasium called Zurkhaneh where music is played live and athletes execute group exercises.
A quick youtube search for Zurkhaneh or Pahlavani yields a good collection of videos. Most of the manoeuvres with the Meels consist in swinging the clubs in different manners but there are some spectacular high throws as well. Although strict juggling is not part of the traditional repertoire, one can find pictures and footage of people juggling three or two in one hand.
Some people suggest that the Iranian clubs were introduced in India for the practice of the closely related martial art Malla-yuddha. A streamlined version of these clubs, known as Indian clubs, were exported and became popular in the 19th century in Europe and the US and subsequently ended up being one of the precursors of our present juggling club.