ANSWER:

In fard prayers, standing up is one of the pillars of prayers that it is void if one is capable of standing and doesn’t stand. If you are able to stand up, you must do so as this is a pillar of prayer. When bowing, you should bow standing up when able. If you are unable to stand or there is too much of hardship if you do, you may sit down and lean a bit forward with your hands on your thigh or knee. When prostrating, you should lean a bit more than bowing with your hands on your thighs or knees. Allah is your judge as this is between you and Him.

have lot of pain in my knees. I have weak legs since many years. Daily overexertion & lack of sleep and stress is there as I take care of my 21m twins alone. Can I pray salah in sitting position on the floor? If I take chair my twins climb on it n play n fall n remove it when I go in sujood. I’m taking medicine for my weak legs but the day I get less rest n sleep it comes back again on n off.