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.
Risk factors. When HIV/AIDS first surfaced in the United States, it mainly affected men who had sex with men. However, now it's clear that HIV is also spread through heterosexual sex. Anyone of any age, race, sex or sexual orientation can be infected, but you're at greatest risk of HIV/AIDS if you:1  Have unprotected sex.hen HIV/AIDS first surfaced in the United States, it mainly affected men who had sex with men. However, now it's clear that HIV is also spread through heterosexual sex. Anyone of any age, race, sex or sexual orientation can be infected, but you're at greatest risk of HIV/AIDS if you: