Announcing the strikes on Wednesday, Dr Ryan and Dr Nieuwoudt said doctors had been left with "no choice" without a "credible offer to keep us on the path to restore our pay".
Lord Robert Winston, a professor and TV doctor who was a pioneer of IVF treatment, resigned from the BMA on Friday over the planned strikes.
In an interview with The Times, he urged against strike action and said it could damage people's trust in the profession.
It comes as fresh polling from Ipsos, first reported by the Guardian, suggests public support for resident doctors' industrial action has fallen from 52% to 26% since June last year, when they last went on strike.
Resident doctors took part in 11 separate strikes during 2023 and 2024.
In order to end the previous strikes last year, the incoming Labour government awarded a backdated increase worth 22% over two years.
The action in England will not affect resident doctors in Scotland, Wales or Northern Ireland, who negotiate directly with their devolved governments on pay.
Resident doctors' basic salaries in England range from £37,000 to £70,000 a year for a 40-hour week, depending on experience, with extra payments for working nightshifts and weekends.
That does not include the latest 5.4% average pay award for this year which will start to be paid into wage packets from August.