I'll make a throwback and list the worst moments: match it with strength work out. If done before the training (walking is wanted because of the warming up and lifting the temperature) only discharge of glycogen depots and the loss of the pump at the work out.
Get a break in your training movement, if you've ever seen a tempo 3-0-2. So, flexion for 3 seconds – stopping 0 – extension for 2 seconds. You can have breathers at any time you want, even in the middle of movement. A second or two.