(a) When conduct is charged to constitute an offense because it causes or threatens physical injury, consent to that conduct or to the infliction of the injury is a defense only if:

    (1)    The physical injury consented to or threatened by the conduct is not serious physical injury; or

    (2)    The conduct and the harm are reasonably foreseeable hazards of:

        a.    The victim's occupation or profession; or

        b.    Joint participation in a lawful athletic contest or competitive sport.

    (3)    The consent establishes a justification for the conduct under division 7 of this article.

    (b) The defendant shall have the burden of injecting the issue of consent.

(Code 1964, § 7.705)

     State law reference(s)--Similar provisions, RSMo. § 565.080.