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.
Specific risk factors for chlamydial infection include the following: 1  Nonwhite race. 2  Multiple sexual partners or a new sexual partner. 3  Age 15-24 years (especially < 19 years) 4  Poor socioeconomic conditions (eg, homelessness) 5  Exchange of sex for drugs or money. 6  Single marital status. 7  Intercourse without a barrier contraceptive.