According to the official H!P site, after her checkup Mitsui Aika has been advised by doctors to rest for 8 weeks. Sayashi Riho was also told to rest 6 weeks due to ischium nerve pain on her right side.
They will both miss the rest of the Hello! Project 2011 Summer tour.
As always injuries are one of the main concerns for fans and while both Mitsui and Riho will miss the rest of the tour it’s good to see that they will follow the doctors orders and rest to heal their injuries since their health is the top priority.
Mitsui’s left ankle bone fracture seems to need a bit more rest before healing, and while she did appear at events and concerts and sat down during the performances it seems that it’s for the best for her to miss the the remainder of the H!P tour to make sure her injury heals well.
Riho’s ischium nerve pain, which according to Wikipedia is a fairly common lower hip bone injury caused by sudden movements during some sports although in this case it was due to the many hours of dancing that members need to due during performances.
Mitsui will need to rest 8 weeks and Riho will need to rest 6 weeks.
source from sayunii