As someone who trains in both Muay Thai and kettlebells I will tell you flat out that this combination is exceptional for your health and fitness. These two ingredients go together like cereal and milk or french fries and ketchup! If you practice one or the other then I will tell you that you need to strongly consider both! You see the beauty of both kettlebells and Muay Thai is that both consist of mastering the art of movement which sets them both up to be the perfect marriage.
As you may or may not know Muay Thai is a tremendously effective martial art that has mastered the act of striking. In order to strike in Muay Thai a fighter must master punching, kicking, using elbows, using knees, and even clinching. These physical acts require your body to be fit and powerful. To be effective in Muay Thai you must have discipline and heart and be willing to endure some intense physical training. At the same time kettlebell training can be just as challenging. Like Muay Thai, kettlebell training is a movement based form of strength training. A kettlebell basically resembles a cannonball with a handle attached it and this awkward design causes you to have to utilize your body as a whole in order to lift and move it effectively.
Being that kettlebell training is movement based your body is conditioned by having to move up against the resistance of the bell. The lifts and exercises that you perform with kettlebell training such as swings, snatches, get ups, and jerks are all consistent with the movements and actions you need to be an effective Muay Thai fighter, or any fighter for that matter. Not only do you stand to gain the benefits of strength, but you will improve in your cardiovascular conditioning, mobility, balance, and over all resiliency at the same time. As a strength and conditioning specialist I also work and train with Muay Thai fighters on a regular basis and they will tell you that the art form of kettlebell training will add to your fighting fitness unlike anything else.
Ideally if you want to achieve a superior level of fitness and performance you should train in both of these art forms. Take your martial arts training and fitness to the next level by incorporating the use of the kettlebell. Remember that most any fighter can train hard, but only the champions train smart my friend.