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).
In 2010, African Americans represented 17% of teenagers and 16% of people aged 20â24 in the overall population, but accounted for 57% of new HIV infections among those aged 13â24. Young men who have sex with men (MSM), especially those of color, have the highest risk of HIV infection among young people. Among youth aged 13-24 diagnosed with HIV in 2014, 80% were gay and other MSM. Of those, 55% were black, 23% were Hispanic/Latino, and 16% were white. Adolescent females are also at risk.