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.
Factors which increase the risk of transmission include: 1  Smoking. 2  Substance abuse. 3  Vitamin A deficiency. 4  Malnutrition. Infections such as STDâ s. Clinical stage of HIV, including viral load (quantity of HIV virus in the 1  blood) Factors related to labor and childbirth.  Breastfeeding.