1 Isotonic -a muscle fiber contraction in which force production is unchanged when the muscle contracts causing movement of an external load.  Isokinetic -a muscle fiber contraction in which force production of the contraction is sufficient to overcome the external load.
HIV/AIDS. HIV Risk Behaviors. The risk of getting HIV varies widely depending on the type of exposure or behavior (such as sharing needles or having sex without a condom). Some exposures to HIV carry a much higher risk of transmission than other exposures.
Research suggests that HIV-negative individuals with an STI may be at increased risk of becoming infected with HIV through anal sex, vaginal sex, frontal sex (a term used by some trans people to refer to sex using genitals on the front of the body) and oral sex. 1 But how do STIs increase someoneâs risk of HIV infection?