system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When picking someone up (literally), why do people who are tensed up feel "heavier" than relaxed people?

I understand the the whole mass vs weight thing but what is the actual cause? Center of mass?
gpt
Grappler here. It's all about the other person's center of gravity. When you are under a person's center of gravity, even people who weigh quite a bit can feel light. When a person tenses, a lot of the time their muscles will expand or they will frame away from you. These actions push their center away from your's and they will feel relatively heavier.