Q. Can a man rest on a hammock since he is laying parkedon or on his back which is assur?
A. On question 1665 regarding laying on ones back by the chiropractor instructions, we wrote:
“Mishna Berura (239: 6) rules that it is a severe prohibition to lie flat on ones back or front (parkedan). Shalmas Chaim (226) permits awakening someone sleeping in that position.
Although from the Talmud (Brochos 13b), Rashi, Rishonim and Poskim it would appear that the prohibition applies only when someone is sleeping, some Poskim maintain that one should always avoid lying flat on ones back (Divrei Yisroel 3: 137, Piskei Teshuvos 239: 8, et. al.). However, even the above permit, when there are medical issues involved (ibid.).
Medical doctors we consulted were unaware of a natural biological sex arousal reaction in our days when lying in that position.
Horav Shlomo Miller’s Shlit’a opinion is to be lenient in medical need.”
In regard to resting on a hammock. the Rov’s opinion is that since one lays in an oblong or semi-oval position as opposed to flat, one can be lenient,
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a