The "need" to do dynamic work is very specific to why you need it. Squatting quickly is very different than speed squatting.
If you've just squatted, deadlifted, and OHPressed for the last week, then you DON'T need dynamic work. Get your squat up to 2xBW, your deadlift up to 2.5xBW, and then get back to me. At #120, the bar and a set of grey bands would crush you if you're new to lifting. Getting hurt is not a good way to get better.
Get the squat, deadlift, bench, and overhead (military) press on video. Make them as explosive as possible. If you want help on getting more explosive with them, I'll gladly help.