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.
New research has found that practising oral sex can dramatically increase the risk of developing throat cancer by as much as 22 times. A study found that people carrying the virus HPV (human papillomavirus)-16 were twenty two times more likely to suffer from a potentially lethal tumour.