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.
The virus can pass from person to person through contact with infected blood, semen, or vaginal fluids. Having unprotected sex with an infected partner increases your risk of infection. Other risk factors for HIV/AIDS include having a blood transfusion and sharing needles or syringes with an infected person.