The precedent, for the first time in the ACT, allowed an expert to tell a jury it is not uncommon for rape victims to ''freeze'' during an attack.

That evidence not only proved crucial in convicting a man of rape, but made history by changing the way consent will be interpreted in Canberra courtrooms.

The victim of the crime reported she froze during the assault, unable to move or respond.

The expert, Sarah Martin, director of Canberra's Sexual Health Centre, told jurors studies had shown partial or full paralysis was suffered by about 50 per cent of victims of sexual assault.

Dr Martin said the sensation could be attributed to the nervous system's automatic reaction when faced with danger.

''A trauma response or a fright response, a freeze fright response, combines both extreme fear and a sense of being unable to get away and a sense of being unable to move or respond.''

Canberra lawyer Katrina Marson, writing in an opinion piece on the issue, said that historically, rape victims were legally required to prove physical resistance in order to show they had not consented.

Ms Marson said while the law had changed there seemed to remain a misconception within the community, and therefore among jurors, that if a victim did not physically fight back or run away, particularly in sexual assaults, it meant in some way they had consented.

The precedent to lead expert evidence on the matter would hopefully help change community attitudes towards victims who had ''frozen'', she said.

But Canberra University legal academic Patricia Easteal said the legal shifts had not stopped defence counsel using a lack of fight or physical resistance as a ''dirty trick'' to discredit victims and suggest they had consented.

Professor Easteal said many in the community continued to unconsciously and consciously adhere to a lot of the mythology of a ''good rape'' versus a ''bad rape''.

''A good rape involves resistance: she fought back, so she got hurt and these injuries are evidence,'' Professor Easteal said.

''If she just shut down, she didn't get additional injuries, so it's not a good rape.''

Professor Easteal said crimes against women had undergone massive reforms in recent years, including in areas of sexual assault and family violence.

But the rape law expert said there was a ''huge gap'' between the black letter of the law of the reform and how it was actually implemented and practiced in the courtroom.

''The law is written in shades of grey … [it] is open to interpretation and it gives barristers plenty of leeway to argue because she didn't fight back then there must have been consent.''

Canberra Rape Crisis Centre chief executive Chrystina Stanford said the ACT precedent had been a positive step forward in clarifying the law for sexual assault.

She said part of the struggle with prosecutions had been juries were asked to be trauma experts.

''Which simply can't be the case - it takes expert evidence or prosecutors to raises awareness of juries so they are better informed to make decisions around sexual assault cases,'' Ms Stanford said.

''The better educated juries can be, better outcomes will be inevitable in sexual assault cases.''

The knowledge could also be used to re-empower the victim, Ms Stanford said.

Statistics estimate that only about 10 per cent of sexual assaults are ever reported to police.

The common reaction of victims of sexual assault was to blame themselves and feel an overwhelming sense of shame, Ms Stanford said.

Ms Stanford said the challenge for organisations like the CRCC was to help victims overcome those emotions and help them realise they were a victim of a crime.

Ms Stanford said she hoped future reforms would introduce a new legal test for the accused to prove they had gained consent, rather than the victim showing they had not agreed to sexual activity.

''It would be an amazing shift. Rather than the victim feel like they're on trial, instead have the accused on trial to prove that what they did was legal.''

Support is available for victims of sexual assault by calling Canberra Rape Crisis Centre on 6247 2525 or visit crcc.org.au.