I find in order to get a workout you need to keep it in close to the highest mode and pedal fast and travel at 20 plus miles per hour. Lots of long hills as well. I wore my Garmin GPS fitness watch and my polar watch with HR monitor on a ride today of 16 miles and 1000 feet elevation gain. Polar said I burned 580 calories and my Garmin that thinks I am riding a regular bike said 1195 calories. Hills and speed are important. If you keep it in the lowest mode you will find it undesirable to pedal fast as there is little to no assist past 10 miles an hour and they are heavy bikes. I found that to be the case on the Bosch and rear drive systems.