Last night in Lausanne, she broke her pb for the mile by 3s and the British record. She has tried several times before at the mile record and failed. Her 800m a few weeks ago suggests her speed is still there so it seems that a little speed endurance is lacking. The 5000m would indicate that too. She's actually failed to break 4 minutes in a number of early season diamond League 1500m races in past years but still won due to lack of competition l. I think she is an athlete who thrives on hard racing and training and I'm more concerned about her scheduled break from racing before the worlds than her lack of speed/age.
Championship races are more unpredictable than league races and the women's competition has moved on. Never mind the Ethiopian talent, Ciara Mageean has gone from an also ran to an absolute unit in 9 months in a late twenties improvenent almost reminiscent of the Irish swimmer Michelle Smith, and Melissa Courtney Bryant is fulfilling her potential now injury free. Muir has less potential for improvement as she's already at her max, but I think she needs to race to be at her sharpest and retain her speed endurance.And she needs the big races to motivate her now.