Identifying the Most Common CrossFit Injuries in a Variety of Athletes.

Background: CrossFit is an increasingly popular, rapidly growing exercise regimen. Few studies have evaluated CrossFit-associated musculoskeletal injuries on a large scale. This study explores such injuries and associated risk factors in detail.

The origins of sexually transmitted HIV among men who have sex with men.

Although it is known that most HIV-1 infections worldwide result from exposure to virus in semen, it has not yet been established whether transmitted strains originate as RNA virions in seminal plasma or as integrated proviral DNA in infected seminal leukocytes. We present phylogenetic evidence that among six transmitting pairs of men who have sex with men, blood plasma virus in the recipient is consistently more closely related to the seminal plasma virus in the source. All sequences were subtype B, and the env C2V3 of transmitted variants tended to have higher mean isoelectric points, contain potential N-linked glycosylation sites, and favor CCR5 co-receptor usage.