Are you using these weights?
Stress 'u-SAN-do'. 'Pesi' = PEH-si — the 's' between vowels is voiced.
Ask this when you see dumbbells or plates on the floor near someone who may or may not still be using them. It's polite gym etiquette to ask before taking equipment.
'Stai usando' = you are using (present progressive: stare + gerundio). 'Questi pesi' = these weights (masculine plural). 'Stai' is the informal second person singular of 'stare'. In formal contexts, use 'sta usando' (sta + gerundio).
Stai ancora usando i manubri?
Are you still using the dumbbells?
With 'ancora' — still using.
Posso prendere questi pesi?
Can I take these weights?
Asking permission directly.
Hai finito con quei manubri?
Are you done with those dumbbells?
Another natural phrasing.
In Italian gyms, it is expected to return dumbbells and plates to their designated rack ('rastrelliera') after use. Leaving weights scattered on the floor is considered bad manners ('mancanza di rispetto'). Some gyms have signs reading 'Rimetti i pesi al loro posto' (Put weights back in their place).