The children were clomping around the wooden floor in their heavy boots.

clomping 是动词 clomp 的现在分词形式。clomp 是一个拟声词，模仿重物撞击地面时发出的"咚咚"声，常用来描述穿着笨重鞋子走路时发出的沉重脚步声。