1. assistive devices
2. validity
3. reliability
4. SU physical therapy
5. hip strength
6. leg strength
7. grip strength
8. muscle strength
9. hand held dynamometer or hand held dynamometry
Use a combination of keywords with the "advanced search" feature to create an effective search string of keywords like this: validity and reliability AND (hand held dynamometer or hand held dynamometry) AND (hip strength OR grip strength OR leg strength)
OR
Even as simple as leg strength AND validity and reliability