Try lifting the lead leg
Those step ups are a great tool for gaining strength in the hills. WHY? Glute power. (AKA Butt power)
QUICK TIP: Next time, try lifting the lead leg (leg on the bench) about 1 inch up then drop back down as you lift the drop leg up off the ground. This will further engage the glute, right where it meets the hamstrings. Also, try bringing the drop leg up all the way to 90 degrees in the hips so you also engage the hip flexor and the core with stabilization. This will train bi-lateral control and help you get even more power. You want those glutes and hip flexors balanced.
Let me know how they go.
Best,