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).
Sex and Intimacy With HIV. If you or your partner has HIV, know this: With treatment and protection, you can have a long, healthy life together -- and have good sex together, too. Make Sex Safer. You have to use protection, whether you're HIV-positive or you're in a mixed-status couple, in which one person has HIV and the other doesn't. Use condoms every time you have sex. Unprotected sex is the most common way of spreading the virus. Male and female condoms dramatically lower the chances of transmitting HIV.