Can't do much leg training?

Today I did the following:

1. Leg extensions (30 kg x 20 reps x 3 sets)
2. Smith machine squats (30 kg x 9 reps x 1 set, 30 kg x 10 reps x 3 sets)

This is my second day doing Smith machine squats. The great thing about the Smith machine is that the path of movement doesn’t change, so I can notice when my form starts to deteriorate due to fatigue toward the end of the set and correct it.

I could only manage 9 reps in the first set of Smith machine squats, and my heart rate was 145, but in the second set, I was able to do 10 reps smoothly, and my heart rate rose to 160. According to the AI, this is apparently due to the effects of PAP (Post-Activation Potentiation).

Leg training makes my heart pound so intensely that I can’t push myself to the limit, and I need plenty of rest, so I ended up leaving after just these two exercises.