I use kettlebells extensively for supplemental training. The following are a few of the workouts I have done in the past couple of weeks that reflect typical supplemental training.
Sample 1 -- "100 of Everything"
Kettlebell (KB) warm up - rotations holding bell in front and behind, two-hand swings, deadlifts with various grips & single arm, "Around-the-World" both directions, single arm swings between legs & on sides, "Figure 8's" front and back
100+ reps in sets of 25, 24kg KB
20X one-arm swings (10 ea. arm), 16kg KB -- 5 rounds = 100 total swings
hold KB throughout, rest for count of 20 between rounds
> rest 3-5 minutes
10X one-arm presses (5 ea. arm), 16kg KB -- 10 rounds = 100 total presses
switch arms by swinging & cleaning KB, rest in rack position if needed
> rest 3-5 minutes
20X squats with 16kg KB in rack position (10 reps ea. side) = 100 total squats
switch side by swinging & cleaning KB
> rest 3-5 minutes
Cool Down - "waiter walks", 24kg KB, (25 steps ea. side) = 100 total steps
Some further thoughts related to KB's ...
Sample 2 -- "Push"
KB warm up - 24kg KB, various carries, deadlifts, swings, rolls holding KB, static holds (various positions)
Ice tool club swings (extra weight on tool head) - inside/outside circles & rotations
50 two-handed swings / 50 "Around-the-Worlds", 24kg KB, 2 rounds
Then extra single arm swings - between legs, sides, rotations
Skill Practice: KB Windmills, top & bottom, shoulder mobility, static position holds, squat mobility (bottom of squat holds, 24kg KB upright handle grip)
Circuit 1:
10X pull-over halo alternating directions, 24kg KB
10X push ups
50X box squats, unweighted, below parallel
5 rounds of full circuit
Circuit 2:
10X push ups
5X lying pull over - sit up - press, 24kg KB
20X cossacks (10 ea. direction), unweighted
5 round of full circuits
Cool Down - farmer walks with both 16kg & 24kg KB, switch hands and various holds
There are a number of athletic advantages to using kettlebells. The two I highlight in the video have a direct connection to climbing situations. Additionally kettlebells allow you to gain strength in many planes of motion and at extended ranges of motion. These two points help to prevent injuries. When using kettlebells you have to accelerate and decelerate the weight which is vital to developing power, controlling stability and counter acting force. The aspect of the weight "changing" force is due to the movement of the weight in space. The dynamic shifting of the load, and the ability to control it, is applicable to how we engage with the changing forces while climbing.
Some great resources for learning exercises and building up KB movements is the YouTube channel from Mark Wildman of Wildman Athletica: (https://www.youtube.com/channel/UCVYbUVLrZ6pEBfYV_UyvItA).
Other places to look would be anything from Dan John or Pavel Tsatsouline (Google either for books, videos, websites, etc.). There is also a dedicated kettlebell training program for climbers in an E-Book format through Power Company Climbing: