You’re crazy if you think the average human can produce 0.1 HP sustained.
But the following is an explanation of the original definition of horsepower:
The term "horsepower" was invented by James Watt to help market his improved steam engine. He had previously agreed to take royalties of one third of the savings in coal from the older Newcomen steam engines[4]. This royalty scheme did not work with customers who did not have existing steam engines but used horses instead. Watt determined that a horse could turn a mill wheel 144 times in an hour (or 2.4 times a minute). The wheel was 12 feet in radius, thus in a minute the horse travelled 2.4 × 2p × 12 feet. Watt judged that the horse could pull with a force of 180 pounds (just assuming that the measurements of mass were equivalent to measurements of force in pounds-force, which were not well-defined units at the time). So:power = \frac{work}{time} = \frac{force \times distance}{time} = \frac{(180 \mbox{ lbf})(2.4 \times 2 \pi \times 12 \mbox{ ft})}{1\ \mbox{min}}=32,572 \frac{\mbox{ft} \cdot \mbox{lbf}}{\mbox{min}} This was rounded to an even 33,000 ft·lbf/min[5].
So a horsepower is 33,000 foot-pounds per minute.
The guy on the website must be crazy because he claims to be able to produce 300+ watts (25 year) and 200+ watts for a 50 year old. Maybe he is saying that it is not sustained.
One horsepower is equal to about 746 watts. One tenth of a horsepower would be 74.6 watts. I think someone might be able to do that sustained (such as the leader of the Tour de France -- a person such as Lance Armstrong -- in his prime. Could I or you? Probably not.