Body execution (i.e. a capias a.k.a. body attachment) is not a remedy that is available in any U.S. state, at least for mere nonpayment of a debt, and it hasn't been a remedy that has been available for that purpose for many decades. It has been held to be unconstitutional.
During the 20th century, on three separate occasions, the Supreme
Court affirmed the unconstitutionality of incarcerating those too poor
to repay debt. In 1970, in Williams v. Illinois, 399 U.S. 235,
the high court decided that a maximum prison term could not be
extended because the defendant failed to pay court costs or fines. A
year later, in Tate v. Short, 401 U.S. 395 (1971) the justices
ruled that a defendant may not be jailed solely because he or she is
too indigent to pay a fine. Most importantly, the 1983 decision in
Bearden v. Georgia, 461 U.S. 660, compelled local judges to distinguish between debtors who are too poor to pay and those who have
the financial ability but “willfully” refuse to do so.
(Source)
There are some circumstances in connection with debt collection where someone can be arrested and incarcerated, but this involves instances that amount to contempt of court, such as hiding an asset subject to a writ of execution and refusing to disclose where it is located.
These tools are employed predominantly in cases where a self-employed person fails to pay child support despite having a clear ability to pay, which is akin to traditional body execution but requiring a showing of willful non-payment. Inability to pay is a defense to remedy.
It is also used where someone has an asset protection trust or other hidden assets which are not disclosed, and where someone disregards court orders to provide information about their assets (just like any other failure to comply with a subpoena). Providing information and showing up to hearings is a defense in these cases, even if the debt is not paid.
The Massachusetts court website appears to indicate that the writ is used there to compel the debtor to show up for a hearing to provide statements to a magistrate about the debtor's ability to pay, much as a subpoena would be used in most jurisdictions, and not as a body execution in the traditional sense of that remedy where someone is incarcerated simply for inability to pay or non-payment that isn't shown to be willful.
The ACLU has been prominent in ending these practices, which debtors generally don't have the means to fight a constitutionality fight over. Inertia has often kept invalid practices in use long after they have been ruled unconstitutional. A 1976 law review note, written shortly after two of the key U.S. Supreme Court decision, discusses the impact that they had.
