Did the Sanhedrin always use strangulation for punishment of adultery?

Shalom, Thank you for your question. You are correct that the punishment mentioned in the Torah for adultery is strangulation (see Rambam, Sanhedrin veha`Onashin haMesurin lahem - Chapter 15, 13). Was this penalty always used? The answer is clearly no. This punishment firstly can only be carried out when the Sanhendrin (supreme Jewish court) sits in it's complete form – a situation that existed for only a relatively short time of Jewish history (so far – we believe it will ultimately be renewed). Even then, the conditions needed to carry out a death sentence are very exacting, and it is unlikely that this penalty was used very often (there are references in the Talmud to the fact that was almost never (if ever) used). Blessings.