Force on a fixed object-- help settle a debate please!

I was hoping to settle a debate with a friend. He is planning to install a rope climb from the ceiling of his home. The engineers told him that the load rating of the beam that the rope would be affixed to was 300 pounds. He happens to weigh 230 pounds. His concern was that varying pulling strength of individuals would affect the force exerted on the mounting location. In other words, two people of the same weight could exert a different amount of force on the beam that the rope is mounted to while climbing, depending on their strength and how explosively they climb the rope. My thought was that no matter what the strength of the person, they would still not be able to generate more force while hanging, than what their body weight is.

Could anyone set both of us straight? Neither of us have a physics or engineering background.

Thanks in advance.