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.
However, recent data indicate that sexual transmission of HCV can occur, especially among HIV-infected persons. CDC surveillance data demonstrate that 10% of persons with acute HCV infection report contact with a known HCV-infected sex partner as their only risk for infection (437).