Sounds absolutely ridiculous to me

Sounds like your friend is either trying to f*** with you or doesn't know what the hell he/she is talking about. That is absurd.

That doesn't even make sense.

Actually, telling you from direct experience because I lift weights, this can cause some effect to building muscle. Your testosterone level drops severely after sex, and this is primary in the building of muscle during weight lifting. It won't necessarily effect it that much, but you won't be able to perform as well and over time this coupled with a slightly reduced ability could possibly lead to less gains. Sex after, now that's pretty incredible and I strongly recommend you wait. Also, abstaining from sex for a period of time can increase your gains, in fact it used to be used by Chinese kung fu adepts a long time ago to develop red sand palm, a powerful techinque where a strike can stop someone's heart. So anyway, if you have sex before working out, it will effect your workout.

I really can't see it making a big enough difference to change your habits for especially considering the health benefits of sex. Also, wouldn't that mean masturbation would have the same effect? I can't any find any research on the subject and am not at all convinced that there will be a noticeable difference.

Then it's clear you haven't lifted before to any significant extent. Masturbation would have the same effect, yes. I don't see why you don't see the connection. Testosterone levels need to be high for maximum gains. After sex they drop significantly and don't really recover for about 24 hours. That's it.

I am not saying that testosterone levels do not drop. I am just saying that I can't imagine it having noticeable effects unless I see some research on the subject. I just cannot imagine anyone feeling the need to have muscles to the extent that they change their habits and give up something that is actually good for them, but that's just me.

I finally was able to find an article on the subject. It's not a research article, but it is better than nothing. According to this article, an athlete would need to abstain from sex and masturbation for seven days in order for his testosterone levels to spike. After working out on day seven, he would need to ejaculate. I still say it's not a good enough reason for reason for me to go without sex/masturbation and its benefits, but like I said, that's just me.

Also, keep in mind, they are not saying this is proven. They are saying this is what some research suggests. It might seem like a subtle difference between "suggests" and "proven", but it is definitely there. Also, that this does not mean you can't build muscle if you have sex or masturbate. This article was about testosterone levels and ejaculation, but it does not really get into noticeable differences in muscle gain between men who ejaculate within the seven days before working out and those who did not.

"Researchers found that abstaining from ejaculation for six days had no impact on serum testosterone levels. On the seventh day, serum testosterone levels peaked to 145.7% of baseline, and then declined rapidly on the eighth day..... By postponing ejaculation for seven days, testosterone levels spike. This testosterone spike is thought efficacious for muscle building and recovery.... Research demonstrates that testosterone levels rise as a response to sexual stimuli. Therefore, an athlete could benefit pre-workout by being exposed pre-workout to sexual stimuli. The athlete could then exercise with increased testosterone levels and aggression.... One hour post-exercise, the athlete should achieve ejaculation. This will increase the natural level of killer cells, thus increasing immune-system function and enhancing recovery abilities. The increase in killer cells will prevent over-training....You may also choose to postpone the achievement of ejaculation for seven days so as to maximize testosterone on a day of the athletes choosing - i.e. on the hardest training or competition day. If the athlete chooses this protocol, ejaculation should be achieved on the seventh day, post workout and according to the above protocol, so as to avoid the negative feedback suppression of LH demonstrated on day eight of abstinence."
[link removed]

Some people have in order for maximum results. You don't give up sex, that's not what I said, you give up doing it right before you work out, which is just like not eating right before. You can look around if you want, but I know from my own experiences that it has an effect so I don't need to read anything but I'm sure there are articles you can find, and if you want just ask a professional body builder, they'll tell you the same thing. You don't have to believe, but you should work out!

thx stan i realy think this is true so i guess i will have to lower sex or have sex after my work out lol...

You don't have to decrease how much you have sex, just don't do it before you work out, that's it. You can do it after, or the day after if you're resting, but if you do it before, wait at least one hour before working out and preferably more like 8 if you can.