i don't know her training regimen but... 1) How quickly did she work up to the half? Adding distance too fast often causes problems 2) don't run everyday, take a day or two off in between especially after longer runs, do some elliptical or bike on off days if she wants to continue cardio 3) strength training on off days, split squats and lunges and resistance band stuff all good for strengthening those areas separately so power is balanced 4) shorter stride, faster cadence