Kettlebells are versatile training tools that offer a completely unique training effect. You can maximize the benefits of your kettlebell work with a proper warm up to ready your body for their unique stimulus.
Anyone who trains with kettlebells on a regular basis can attest that they often feel lighter when putting them away after a workout than when you carry them out at the beginning. It stands to reason that we should perceive them heavier while fatigued, but we often experience the contrary. Your kettlebell feels lighter after a workout because your body has adapted to moving the weight. Despite fatigue, you nervous system has grown accustomed and better-suited for the engagement required to move and control external weight. Your warm up should create this effect before you even get to your working sets.