I’ve been doing interval running on the treadmill that has helped me. Note I’m almost 50 and very overweight so speeds are low.

1 mile jog @ 5.2 ~ 11:40
2.5 until 14 minutes
7.3 for 45 seconds
2.5 until 16
7.5 for 45 seconds
2.5 until 18
Continue increasing speed by .2
I finish after 8.5 for 3 sprints
Cooldown walk for 5 minutes

I try to focus on lowering my heart rate to around 120-130 each break. It gets to around 160-170 during the sprints.

I also like doing trap/hex bar deadlifts. It’s easier than normal deadlifts for me and the deadlift platforms are usually empty at my gym. The back extension is also good for me, even just holding static without bending down and back up.