They may not lift barbells but they still lift “weights”. This particular Shaolin Monk is shown building shoulder and upper-body strength with a wooden log. ~ Any kind of object can build strength, so long as it is trained with in a progressive manner.
Kettlebells go back a long way but Chinese Stone Locks predate them by several thousand years. Martial artists in China have been using stone weights like these to develop their bodies for centuries. There are, of course, many ‘kettlebell’ exercises that can be done with stone locks, but they carry with them their own specific kind of training — and a specific set of results. Stone locks training is particularly good for grip and forearm work.
An interesting comparison of bent-press techniques. On the left, Real Lacombe of Toranto, Canada bent-presses a heavy dumbbell. On the right, grandmaster martial artist Wang Zi Ping does something similar with a Chinese stone lock. The bent-press is not, to our knowledge, named so in ancient Chinese training literature, but it is clear that it — or a version of it — was certainly practiced.
Another interesting martial art training method is to build up hand strength and conditioning by driving them into sand… then rice… then gravel… then iron shot. As the size and density of the striking material increases, the hands follow suit. Keep in mind that this is simply another form of progression, the principle behind all successful physical training.