These databases are a Physical Therapist's best place to start researching. They contain research topics such as sports medicine modalities, kinesiology, injury care and prevention, health education, physical activities, sport science, psychology, and biomedicine.
Besides BioMed Central and the PLoS journals, here are several smaller journals related to physical therapy.
Use these additional databases, after searching the specific databases, if more resources are needed or preforming a review of all the literature on a given topic.
Open Access databases contain peer-reviewed materials that are freely available online.