She has since quit and lodged a complaint with the labor inspection unit that oversees the company, which told her it would investigate, the South China Morning Post reported.

The woman, surnamed Yang, had recently moved to Hangzhou, in Zhejiang Province, and began her first job in June as a financial consultant on a monthly salary of CNY4,500 (US$670).

The role was in practice telesales, at a loan assistance company that Hong Kong's Sing Tao Daily identified as the Hangzhou branch of Suzhou Dongrong Information Technology.

Her team manager, surnamed Zhang, set each member a daily quota of 200 calls, one client visit and one client expressing an intention to work with the firm, according to the SCMP.

On July 28, after missing two of those targets, Yang was told she could do 100 squats or pay a CNY50 ($7) fine for each. She said she had no money and opted for the full 200.

Zhang named her in the company's WeChat group and required her to film the punishment as proof, Sing Tao Daily reported, citing the Zhejiang consumer affairs programme "1818 Golden Eye".

Footage running close to five minutes shows her moving between spots in the office building to get through the sets, her limbs shaking. By the end she is gripping a door frame to stay upright.

She told the programme her legs hurt so badly they felt as though they would burst, and that she could no longer walk.

Muscle breakdown

Short of money, Yang did not see a doctor for five days. She took a taxi to the nearest hospital on Aug. 2, after her urine turned dark.

Tests put her creatine kinase, an enzyme released into the blood when muscle tissue is destroyed, above 16,000 U/L, the SCMP reported, far beyond the roughly 1,000 U/L usually sufficient to diagnose rhabdomyolysis.

The condition floods the bloodstream with proteins that can block the kidney's filtering tubules and cause kidney failure.

Yang avoided that and was told to rest and stay off strenuous exercise. Her treatment cost CNY1,400 ($208).

She resigned on July 30, unable to work, and told the SCMP she believed the company had set targets it knew she could not meet in order to push her out.

She asked Zhang to reimburse her medical and transport costs and pay CNY15,000 ($2,230) for personal injury, enough to cover 75 days of living expenses until she was well enough to look for another job. He refused and told her to sue.

Speaking to "1818 Golden Eye", Zhang said he knew the punishment violated labor law but argued that a sales company has to apply a degree of pressure to hit its targets, Sing Tao reported.

He said the matter had nothing to do with the company and that the sum Yang wanted was unacceptable.

A court in an earlier case held a company 70% liable after an employee developed rhabdomyolysis from 100 squats ordered by managers in a work WeChat group, ruling that instructions posted there carried the company's authority and bound employees rather than merely encouraging them, The Paper reported.

Under China's Labor Law, an employer who humiliates or physically punishes a worker can leave the individual responsible facing administrative detention of up to 15 days.