I squatted HUGE today as you can probably tell by the pic! I'm kidding, but I did squat today. I kept the bar at 225 and went for reps and form. the quest for some big legs continues and I am making such slow process I feel. Disappointed at this, I attempted to blow my legs up so bad that I would not be able to walk. Needless to say, I did not succeed. Here's what I did:

Squats
185# x 10
225# x 6 x 3 sets

Straight Leg Deadlift
225 x 8 x 3 sets

Circuit 1
Knee Ext. Techno Gym Pyramid Dropsets to fail. (every time I failed, I dropped one plate for a total of 3 drops)
60#
70#
80#
90#
100#
Techno Leg Press (I died here! Everything was until fail)
180#
140#
140#
120#
100#

Circuit 2 (I do not remember all my weight here, sorry. I will just list what I did.) 5 Sets
Single Leg Press
SB Single Leg Bridge
Single Leg Hamstring Curl Machine (Near Strive circuit)
Seated Calf Raises

Spin!

So I thought more about the antagonist question you asked me involving a chest press and I think I have my definitive answer.

Agonist: Pec Major
Synergist: Tricep, Antreior Delts, Serratus Anterior
Antagonist: Biceps, Lats, Rhomboids, Traps (?)

Muscle of the Day
Rectus Femoris (Quad Complex)

Origin: Spine of Illiac Crest
Insertion: Patella Tendon
Functions: Knee Extension and Hip Flexion

Other Facts: This is 1 of 2 muscles in the quad that actually help with Hip Flexion! This one originates from the hip and therefore can assist with hip flexion. This next part is little confusing so bear with me! When the knee is already extended, it is not a strong hip flexor. When the Hip is already flexed, it is not a great knee extender. Here is why, in both scenarios, the Rectus Femoris is already in a shortened state. Based on your NASM knowledge ( :) ), what happens when a muscle is tight? It cannot contract fully and produce as much force right? Same concept here, the muscle in each of the positions mentioned is already in a shortened state (similar to being contracted) and so it cannot produce as much force.

Let's talk about agonists and antagonists some more. I am going to do a little more digging and see if I can find a definitive answer for you. In the meantime, hope this helped!