Former US Olympic gymnastics coach John Geddert, who had ties to disgraced team doctor Larry Nassar, has been charged with multiple felonies including human trafficking and sexual assault. 

The criminal charges filed in a Michigan court against the 63-year-old Geddert, who was coach of the women's team that won gold at the 2012 Olympics, consist of 20 counts of human trafficking and one count each of first-degree sexual assault, second-degree sexual assault, criminal enterprise and lying to a police officer. 

"These allegations focus around multiple acts of verbal, physical and sexual abuse perpetrated by the defendant against multiple young women," said Michigan Attorney General Dana Nessel. 

"I am grateful for these survivors coming forward to cooperate with our investigation and for bravely sharing their stories." 

Geddert's attorney Chris Bergstrom did not immediately respond when asked to comment. 

According to the Attorney General's office, Geddert used his reputation as an Olympic-level coach and promised parents that he could turn his students into world-class athletes. 

The Attorney General's office said that under the guise of coaching, Geddert reportedly subjected multiple young women to an environment of continued abuse, in which he also neglected advice of medical doctors, except that provided by Nassar, who served for around 20 years as Geddert's team physician. 

Geddert, who ran a Lansing-area gymnastics centre called Twistars, was suspended by USA Gymnastics in January 2018. 

Former USA Gymnastics doctor Nassar has been given two prison sentences in Michigan of 40 to 125 years and 40 to 175 years for molesting young female gymnasts. He is also serving a 60-year federal term for child pornography convictions.