with a grand a trader would be silly to open a standard account, or even a mini, the leverage is simply to high in your example, a good place to start would be a micro.
Anyone that says they can double their money in such a short amount of time is usually to high geared, and normally they are the first lot of traders who have to top their accounts up because they have blown it.
Low gearing and good money management will lead to steady growth, if you looked at good growth on a line chart it would be a nice smooth curve up. Not jagged up and down.
They are clearly massively leveraged and taking way more risk than is prudent for most traders. Either that, or they were extremely lucky during that 6 day period. Where are the long-term results? That little sample means absolutely nothing.
It can definately be done but you might as well go to the casino’s and bet on Red/Black because that is what they are doing. Eventually they will lose and lose it all.