Leg day has always maintained a special place in my life. It's sacred to me, like a frequently occurring religious holiday. My best friend and I trained legs on his wedding day; years later, he reciprocated and we did the same on mine. One of my longstanding rituals is to squat on birthdays, Thanksgiving, and Christmas. Leg day is difficult, and that's why I love it.

Normally, I have specific training objectives and don't measure my success by pain, soreness, or puking. On occasions when I want a challenge, however, my "normal" workouts won't suffice. That's when I go for painful challenges and tests of fortitude. That's when I go for a special workout like the four sessions below. They're guaranteed to kick you in the quads.

Like any training program, a particular workout can be as hard or easy as you want. It comes down to intensity. Three sets of 10 reps can be absolutely terrifying or incredibly easy depending on your intensity. I add this disclaimer to remind you that the workouts on this page are meant to be performed with everything you've got.

Do not hold back. Do not shy away from heavy weight. Do not try to conserve energy. Use every last shred of willpower you have reserved. Whether training for strength, bodybuilding, or fat loss, you can break out one of these pants-ripping leg sessions whenever you need it.

1. The Kill

Two of my early mentors as a teenage bodybuilder were Craig Toth and Mitch Hodge, who introduced me to "the Kill." Don't scoff at the name; the Kill will destroy you. Nearly 10 years later, I still regret taking a couple of clients through this workout. It's a brutal 15-minute session that will sap your legs and leave you breathless.

Grab a training partner, push yourself hard, and make sure every repetition is difficult. This workout won't take very long to perform, but it may take you several days to recover.

2. Tabata Squats

New York City-based personal trainer Joseph Dowdell, CSCS, recently posted this gem on FaceBook: "New rule: If I see anyone post about their 45-60 minute Tabata Class or Tabata Boot Camp, it's an automatic delete. If you can perform the Tabata protocol for more than 4 minutes, period, you are not doing Tabatas. You are simply using a 20-seconds-on, 10-seconds-off protocol. End of story!"

Tabata Working Weight Calculator

Amen, brother! People all over the place are using the Tabata protocol incorrectly. They do circuits, multiple exercises, or some other thing that isn't really Tabata. The real protocol is simple: You train with max intensity for 20 seconds, rest for 10 seconds, and repeat until you hit 4 minutes. This version of high-intensity interval training (HIIT) will progress your endurance, VO2 max, and anaerobic capacity.

Load a light squat or front squat at about 25-30 percent of your one-rep max (1RM). Knock out as many reps as you can in 20 seconds and then rest for 10 seconds. After four minutes, you have my permission to die.

"After four minutes, you have my permission to die."Tabata Squat Workout

3. Breathing Squats

The brutality of breathing squats lies in their simplicity. You basically combine heavy weight and high volume to produce a squat workout that obliterates your strength and energy systems. This particular session works up to a brutal set of 20 squats. You don't rack the weight during that set. If you need to recover your strength, you just keep the weight on your back and breathe.

Heavy, high-rep squat sets have been used since this whole fitness thing began. You want muscle? Twenty-rep sets of squats will do it. Fat loss? You'll be wiping blubber off the floor when you're done. Many people consider high-rep squats useful for augmenting strength, as well.

I generally advise doing high-rep squats in a rack and with a spotter. If you lift heavy enough, you will get lightheaded, suck wind, and possibly puke.

Pick a weight that you would normally squat for 10 reps. Pace yourself, using brief pauses to rest and breathe between reps, to hit your total 20. If you can do this more than once, you weren't going hard enough. If you have anything left in the tank, wrap it up with a couple hard sets of accessory movements.

4. DTP Legs

Some high-volume training is always a fantastic counter to your heavy barbell work to spur additional growth and gains. In this particular jewel from Kris Gethin's DTP program, you will hit several hundred reps of leg presses and calf work.

Start on the lighter side, but make sure you reach failure on every set! Gethin's DTP utilizes a traditional pyramid format where the weights increase and the reps decrease each set. After you hit 10 reps for a couple sets, you reverse the pyramid by dropping weight and adding reps each set.

With DTP on the schedule, you'd better prepare yourself for several hundred reps.DTP Legs Workout