Note: The X Factor Interview is an excerpt from Iron Man Magazine.

What if you could pack on a solid five pounds of muscle almost every month? What would you look like one year from now? Are you kidding? Your physique would be outrageous! Radically different and unrecognizable because of so much extra muscle hanging off your joints. Well, in my estimation, Jonathan Lawson added at least five pounds of muscle to his already advanced physique in only one month—not one year, one month—and he’s been training for about 15 years. Add to that the fact that he did it while he was on a a low-calorie diet, and you can see the enormous muscle-building implications for you—especially if you’re not limiting calories, as he was. (Could you add even more, like 10 pounds of muscle, in one month if you followed his lead? Who knows?)

Lawson says the big key to his amazing transformation was X Reps, a power-partial technique he uses on specific exercises. This idea has a lot of science behind it. If you missed the first part of my interview with him, which discusses a lot of the research, go to Part 1 to get your muscle-building mojo moving. Now, to continue with the intense interrogation…

BL: So you do X-Rep power partials at the end of a set at a point where you think the muscle can fire with maximum-force generation—like near the bottom of an incline press. Why not just go right to the X Reps—you know, do heavy stand-alone X-Rep sets? Why not pack on the poundage, lower the weight to the X spot and blast out partials, and forget the regular full-range reps? Wouldn’t that be much more intense?

JL: Superheavy partials will hit the pure-strength muscle fibers, sure. And it could be a good addition to a full-range set or two. But bodybuilders need to train more than just one or two fiber types for full development. As I said earlier, scientists list more than five different types of fast-twitch fibers, which is the reason bodybuilders need to do sets with multiple reps—to build as many fiber types as possible. The size principle of fiber recruitment says that the low-threshold motor units fire first, followed by the mediums and then the high-threshold motor units. I think performing full-range reps makes that happen more efficiently—you get at more fiber types in one set. Then you move in for the kill with X Reps.

BL: Couldn’t you just do 10 to 12 X Reps and get the size-principle thing to happen?

JL: That’s an interesting idea and worth some experimentation. In fact, we’ve been doing that on some stretch-position exercises like stiff-legged deadlifts and flyes. Arnold used to do his flyes that way—just the bottom part of the stroke, which is like exaggerated X Reps. That seems to work best on stretch-position exercises where there’s no resistance at the top. Sissy squats would be another good one. Don’t come up more than halfway.

For most exercises, though, I think you should do full-range reps, or close to lockout, on at least a set or two to get more fibers involved. I think that’s especially true for contracted-position exercises like leg extensions, where you can flex the muscles against resistance. That will also help strengthen joints and ligaments through the full range to prevent injury. And you get more of a metabolic effect from full-range reps.

I think the bottom line as far as bodybuilding goes is that the more fibers and fiber types you can hit, the better your size increases will be. It’s the reason we do six to eight reps but mix in supersets and drop sets—and now X Reps, which seems to be the most effective of all. Trying to hit as many fibers as possible just makes sense from an overall muscle-density standpoint. You wouldn’t want to pump up only one section of an air mattress. All the sections need to be full to achieve maximum size. The same goes for the muscles. You won’t look your full, muscular best if muscle groups are partially deflated.

Since you brought it up, though, I will tell you that we’ve been experimenting with a version of what you’re describing. We do a straight set to failure and then immediately add weight for X Reps. We only rest long enough to get the weight on the bar—about 10 seconds. That gives us fatigue-product clearance. It’s kind of like Mike Mentzer’s rest/pause, only we’re using two different types of sets, a regular six-to-eight-rep set to failure followed almost immediately by a heavier X-Rep-only set. We up the weight enough that we can get about six ultraheavy X Reps.

BL: And what have you noticed? Any new gains?

JL: It’s still early, but I gotta say that four months after our photo shoot, using X Reps and those superheavy X Reps on a few exercises, with some drop sets and supersets thrown in for even more growth hormone production, has enabled [me and IM editor in chief Steve Holman] to stay very close to peak condition. And without a whole lot of volume. That’s pretty unbelievable considering that there’s no sense of urgency—no photo shoot looming—and we’re not eating nearly as strictly. We’ve both still got lots of veins crawling down our forearms and plenty of size and separation. That’s very exciting because in past years we were both flat and way off our best shapes two months after our photo shoot.

BL: You mentioned more GH production. Do you think that’s one reason X Reps work so well—because they jack up growth hormone?

JL: Absolutely. Research has shown that muscle burn changes the pH of the blood, which can cause GH to surge. And, believe me, X Reps burn. If you think about it, it’s very difficult to get muscle burn on compound exercises just by going to failure. Add X Reps, though, and you set the target muscle on fire with one set, which helps pump up GH production. And if you do X Reps on those big exercises, which are also the best testosterone boosters, you get a double shot of anabolic hormones.

Still, I think the main reason X Reps work is that they enable you to get past nervous system failure and continue to stress the muscle at its point of maximum-force generation. More GH is a bonus—and I’m sure it’s what’s helping us stay lean. GH has been shown to be a potent fat burner. I gotta say, though, that it’s weird to see veins in my forearms when it’s cold outside. I’m used to being pretty smooth in the winter.

BL: So you use the partials at the end of a set to get past nervous system failure and keep the muscle firing, right?

JL: Yes. We have research on that posted in the X Q&A section at our Web site. The research on the growth hormone connection is there too. I’ve seen some studies that say that the reason you end a set isn’t nervous system failure, but in either case you should still move to the point of maximum force generation and extend the set with partials to stress as many fibers as possible.

BL: Well, if nervous system failure is what stops a set, how do the pros get so big? Wouldn’t every set they do be ineffective at building more muscle?

JL: Not ineffective, just inefficient. They do set after set in an attempt to get enough stimulation to grow. They may get a slightly different fiber recruitment pattern on each set by adding volume, so they may get at a little more of the muscle, a few different fibers perhaps. Growth does happen, but it’s slow, and in order to do all of that work, they have to take anabolic steroids to enhance their recovery abilities and speed things up.

Drug-free bodybuilders can also do multiple sets up to a point, but eventually they will overtrain and go nowhere fast. Using X Reps makes it unnecessary to do an excessive number of sets, so you have more energy left for recovery. It’s much more efficient.

Of course, you still have to work and sweat. I’m not saying that X Reps will let you get away with those B.S. once-a-month 10-minute workouts that are all over the Internet these days. If it’s muscle you’re after, those routines are flat-out ridiculous.

One other point about the pros: Many of them use loose form, blasting the weight out of the turnaround—at the bottom of a press or a barbell curl. Watch Ronnie Coleman’s training DVD and you’ll see what I mean. Creating an explosive movement near the max-force-generation point does produce critical overload right where the muscle needs it for more growth stimulation, but it’s very dangerous to train with explosive moves. Using X Reps accomplishes the same thing without the danger of joint injury or muscle tear. You stress that critical point in an exercise’s stroke, only you do it at the end of the set, no joint jarring necessary.

BL: Won’t forced reps do the same thing as X Reps—get you past nervous system failure?

JL: No. Once again it’s an efficiency thing. You waste a lot of nervous energy when your partner helps you through the full range. Plus, his help isn’t very precise, so it’s hard to tell how much work you’re doing and how much he’s doing. Oh, and your strength varies throughout the full stroke, so that adds to the difficulty. But the biggest problem is that you’re not taxing the muscle much at the X spot—the max-force point that’s so critical to growth stimulation.

BL: There you go again with the double Xes. You’ve got X spots, X Reps, full strokes. Dude, you gotta start training porn stars.

JL: You know, you may want to skip X Reps. Your testosterone is off the charts already. [Laughs] Anyway, instead of forced reps, it’s much more effective to do power pulses at the X spot at the end of a set. That way you increase the tension time on the most fibers at the precise maximum-force point. Remember, more force generation triggers more growth. With X Reps there’s no wasted effort; with forced reps most of the effort is wasted. There’s research on that at the site as well.

BL: Yeah, I read your reference materials there. You’ve also got stuff about a possible connection to hyperplasia, or fiber splitting, posted. Is that really solid info?

JL: Well, hyperplasia is still a controversial topic, but animal-based research has shown that it occurred as a result of stretch overload. What’s interesting is that a lot of the biggest bodybuilders use what we call X Reps to get stretch overload. For example, Tom Platz, who had some of the freakiest legs ever, did a lot of partials in the stretch position of specific quad exercises. One of his favorite spots was near the bottom of a hack squat, pulsing at the end of a set of full-range reps till he couldn’t stand the burn. Could that stretch overload have caused fiber splitting in his quads, and could it explain why he got such mind-numbing development? It could be partly responsible. The same goes for Arnold Schwarzenegger and those heavy partial flyes he used to do for his chest. By only moving through the bottom of the stroke, he created stretch overload—slightly exaggerated X Reps on a stretch-position exercise.

BL: Yeah, and Larry Scott used to do burns near the stretch point on preacher curls, kind of like X Reps. Maybe he was increasing his biceps’ size potential with fiber splitting every time he bottomed out with those partials. This is interesting stuff. I’m totally amped! Hey, are you still using Positions of Flexion training?

JL: Yes, that’s a given. POF full-range training is a must for full-muscle development, although we recently started splitting the positions over two workouts. For example, on quads we do midrange work, like hack squats, and stretch work, like sissy squats, at one workout. Then, the next time we work quads, we do hacks again for the midrange movement but this time combined with contracted-position work, like leg extensions.

That’s something else we’re experimenting with over the winter. During our summer ripping phase, however, we did all the positions in one workout, and we did X Reps on one set of almost every exercise. We’re still using X Reps on most exercises—and those superheavy X Reps I mentioned earlier. Those can be a bit scary, like on incline presses. Your upper chest feels shot, but you jump off the bench, add weight and then lower the bar to the X spot for partials anyway. I have to admit, though, they really hammer the muscle.

BL: Now that I’m part of the X-Men militia, do you have any specific diet recommendations?

JL: You don’t want to restrict your carbs too much. Even when Steve and I were in the last week before our photo shoot, our carbs never went below 140 grams per day. You need glycogen-and-creatine-loaded muscle to get them to fire as effectively as possible at the X spot. Otherwise, they’ll crap out early, limiting your gains.

BL: So the key X-Rep supplement is pancake syrup?

JL: [Laughs] Only if you use it immediately after you train—poured over whey-and-creatine flapjacks.

Seriously, right after the workout is prime nutrition time, the anabolic window, so you want to get plenty of fast carbs and fast protein to feed your depleted muscles. There are postworkout powders designed specifically for that time. Throw some creatine into the mix, and you’ve got the perfect meal for your most important feeding of the day. Loading your muscles with glycogen and creatine will give your X Reps maximum firepower.

BL: Can you outline the diet you used during the month when you made the transformation with X Reps?

JL: Sure. Keep in mind that this is my lowest calorie level—around 2,400. I also did lots of cardio as the shoot got closer.

Meal 1 (after cardio)
1 cup egg whites, scrambled
1 serving Cream of Rice
1 tablespoon peanut butter
1 scoop Pro-Fusion in water

Meal 2 (before training)
2 scoops Pro-Fusion in water
Meal 3: (after training)
X Stack shake (in water)
3 scoops RecoverX
1 scoop CreaSol

Meal 4
Chicken breast
1 cup broccoli
1 scoop Pro-Fusion in water

Meal 5
Protein shake (in water)
1 packet Muscle Meals
1/2 scoop Pro-Fusion

Meal 6 (two hours before cardio)
2 scoops Pro-Fusion in water

Meal 7 (after cardio)
1 cup egg whites
scrambled with 1 whole egg
1 handful cashews and almonds
1 scoop Pro-Fusion in water

BL: So that’s your rock-bottom lowest calorie level?

JL: Yes. When I start dieting, usually around late March, my calories are more than 3,000. I make a couple of calorie reductions, working in higher-carb days along the way to keep leptin levels stable and to stay sane. I also gradually increase my activities to create a calorie deficit so I burn more bodyfat. Our new diet e-book, X-treme Lean, outlines all the specifics about leptin, cheat days, macronutrient ratios and so on. We’ve been experimenting with ripping diets for five years running, so we’ve learned quite a few important things along the way. Getting in ripped condition isn’t nearly as difficult as it used to be.

BL: My abs have been in hibernation for a while, so I’ll be checking your site for that—and may I suggest a gallery of X starlets using X Reps? That would certainly add to your Internet presence.

JL: Because there’s a severe shortage of pornography on the Web, right?

BL: Just trying to help.