Assumption of a risk by a person shall be considered by the trier of fact in apportioning negligence pursuant to section. For the purposes of this section, a person assumes the risk of injury or damage if he voluntarily or unreasonably exposes himself to injury or damage with knowledge or appreciation of the danger and risk involved. In any trial to a jury in which the defense of assumption of risk is an issue for determination by the jury, the court shall instruct the jury on the elements as described in this section.
C.R.S. § 13-21-111.7