There's actually a very simple explanation as to how this could happen, and it involves physics. "If the downward intra-abdominal pressure forces during a lift are greater than the ability of the rest of the abdominal canister to counteract them, then the outcome is more pressure down on the tampon," Dr. Pagliano says. "Thus pushing it out." In other words, if you exhale or brace too hard before a lift, and your pelvic floor , abdominals, and deep back muscles aren't strong enough to withstand that pressure, a tampon could come out.