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.
What Increases Your Risk. Most people get HIV by having unprotected sex with someone who has HIV. Another common way of getting the virus is by sharing needles with someone who is infected with HIV when injecting drugs. You have an increased risk of becoming infected with HIV through sexual contact if you: 1  Have unprotected sex (do not use condoms). 2  Have multiple sex partners. 3  Are a man who has sex with other men.  Have high-risk partner(s) (partner has multiple sex partners, is a man who has sex with other men, or injects drugs).
Anyone can contract HIV, and while IDUs are at great risk because of practices related to their drug use, anyone who engages in unsafe sex (e.g., unprotected sex with an infected partner) could be exposed to HIV infection.frican-Americans account for a higher proportion of HIV infections than any other population at all stages of the disease from initial infection to death (see text box). Moreover, specific minority subgroups are at particular risk.