Test show that cardiovascular training is more efficient for weight loss when coupled with resistance training.
Spinning gets the heart rate wat up there. the metabolism says something like "Holy Moley" and climbs uo to the range of a highly tuned V-Tec motor in full throttle in an effort to combat the intensity. The metabolism has such a kick that is stays high for hours, and the end result is a 45 minute workout that burns fat all day.
Then we climb a hill and make the leg muscles work under load.
Spinnining couples cardiovascular training with resistance training.
Spinning burns fat.
So the thigh muscle loses the comfy little flab that hides it from admiring eyes. But here comes the curve ball. Because spinning focuses on the legs, the legs are carrying the load for the entire workout. They adapt to the load, define themselves ans start looking "HOT!". And that's not even the good news. In a Spinning workout we climb hills. To effectively climb a hill out of the saddle the body uses the bum muscle above all else forcing the bum to adapt, define and start looking better than "HOT!"
Common question that women ask is "Will it give me big legs?" Absolutely not. The big legs we see in professional cyclist come from climbing mountains for hours on end. In Spinning workout we climb for minutes.
Spinning will tone and shape the leg muscle better than anything ever devised by mankind, but will not build them into those of a weightlifter.