This women's gym vest by Skins ticks so many boxes. The shape is really flattering with a cutaway shoulder to enhance all your hard work. The wide racer back is great if you like to keep your high support sports bra under wraps. The fit is reasonable high around the armpit which again gives a little more coverage but maintains the comfort, especially as the fabric is so soft - the don't call it "Silken" for nothing!
Feedback we've had in the past about dropped armholes is that when you wear high support bras for your run or HIIT session there's often a little squeeze around the under arm area which you don't want to show - feel confident in this great women's training tank.
There are reflective logo's too for low light and outdoor activities, the fabric is breathable and light weight with a loose fit at the bottom for days where you want a little more coverage. We love the length and the colour - go smash that 10k in comfort and style.