Another opposite worked for me. I was doing bodyweight and low resistance (25 lbs) and high rep workouts for a while. Wasn't watching motivating videos like P90X and couldn't generate enough intensity. Also strength was not improving, couldn't feel it in daily life, couldn't break through high rep plateus. Stayed at ~50 pushups, 20 25 lb curls, 40 25lb tricep extensions. Barely any muscle growth.

And most of all I hated those workouts.

Then I got a weight set and started doing squats, deadlifts, rows etc. Starting Strength like routine. Was increasing weight constantly. I was in horrible shape so the workouts felt very intense at 50-90 lbs. There was noticeable muscle growth and I felt a lot more strength in daily activities.

I liked those workouts and had zero motivational problems. No mental tricks necessary, except maybe having the weights at home staring at me. The results were more obvious. Tried my old high rep routines and could do 35 25lb curls etc. Maybe I am cut out to be like Arnold, it feels like smooth sailing.

It is well known that low weight, high reps lead to an increase in endurance, while heavy weights and low reps (as in 4~6 repetitions leading to exhaustion) lead to hypertrophy i.e. muscle growth.

Yes but I was talking about liking endurance vs short intense workouts. The article mentions that heavy squats and cleans will wear you down so you'll stop coming to a gym. Perhaps that's the case for the author.

For me the case is the opposite. I get sick of feeling "burn" from high rep routines and would rather do squats then cleans that leave me panting on the floor, without burn.

It may be a genetic difference. People have different proportions of fast and slow twitch muscle and excel at different sports.

And the P90X style workouts with bodyweight do cause some muscle growth. That's how people post ripped pics of themselves after programs like P90X. A bit of muscle growth usually combined with fat loss.

I was surprised that a mere 100 lb weight set would feel so heavy even though I could do 50 pushups, 12 pullups, etc. I expected I'd need 2-300 lbs to really feel the weight, really overestimating the shape I was in after doing bodyweight drills.

I've got a couple friends doing p90x as well, and i'm concerned that it'll simply make them look like endurance runners, eg skinny as rakes, unless you're on steroids. What's your thoughts on that?

I'm personally trying the reg park system (pre steroids style powerlifting, through stronglifts.com) because i'm aiming for a bit of bulk (i have no illusions of becoming mahoosive).

I've always been quite skinny and my metabolism drives it very well, I sweat fast, etc. And I'm tall too, which means more muscle mass to get the same size. I also did the P90X doubles version, which starts at month 2 and adds 3 more endurance workouts weekly. All that taken into account, I still managed to get good functional muscle growth.

It is very easy to modify the program to suit your needs. If your friends do not care that much about endurance, I would suggest not doing the doubles version, keeping rep counts low (eight or less) and trying to increase the weight from week to week. They should also take in enough protein, perhaps through whey protein supplements, but definitely no steroids.

What's more important than anything of the above is how much effort you put into every workout. If they push themselves hard enough during the resistance training parts, there will be nothing to worry about and there's plenty of massive after-pictures from P90X online to prove this.

P90X will give you massive performance improvements for almost every physical activity. If you just want to bulk up, look up hypertrophy training. That will be much easier mentally if you don't necessarily care about fitness.

I've seen a few hundred P90X before/after shots from real people and didn't see much size growth. Skinny people got cut, which makes them look bigger and fitter. Doesn't mean they are heavier when they weigh in. Maybe added 5-10 lbs of muscle in a year. Full people got cut, also looks bigger and fitter in most cases. When you work out the whole body your bodyshape changes, shoulders get bigger so the perception is that you are bigger

A lot of hollywood actor training uses these principles. Actors need to get in shape quickly for various roles and trainers focus on getting the ripped P90X look instead of forcing real growth in such short timeframes. Ripped will look better naked than adding 10 lbs of non-ripped muscle. For example Bradd Pitt was maybe 160 lbs in Fight Club but looked much bigger because of muscle definition and upper body shape.

But if you really want to go from skinny to big/normal, not just ripped, heavy weights are the long term solution. 30 lbs of new muscle will look better than ripped. I don't know the details of P90X but recommended equipment is 50-90lb dumbells and a pullup bar. Most people use 50 lbs max and that's not going to cut it.

That's probably true. As a rower, I didn't need to be much heavier, just stronger. I put on about 4kg (almost 10 lbs) during those 3 months not even counting the fat I burned. And I didn't have the option to increase weights much, didn't eat that much either.

Depends on their calorie intake mostly. If there's a calorie deficit (they burn more calories than they eat) they'll lose weight and look like rakes. If they eat more than they burn, they'll get bigger and usually stronger.

I agree it's definitely not one size fits all. But I'm curious to know, had you been exercising at all before you started out on P90X? Or was it just one day to the next you were working out full time?

I did karate in grades 2-8, but I was never very keen on the fitness stuff and didn't push myself very hard. I enjoyed doing sports recreationally, e.g., soccer, volleyball, basketball. But then all through high school I would only have a PE class once a week and maybe do some cross country or cycling occasionally. So very little exercise. When I started P90X last summer, it was very much the discrete switch you describe. I was about to start working at a startup that summer, so I aligned the two to start the same day and committed to both.