Upright bikes usually do not have a backrest like supine bikes. The seat is adjusted in a similar way to a supine bike. The best way to know if the bike you want to buy will fit your leg length is to measure your inseam and make sure that the bike you are looking at will meet your inseam measurement. You can learn more about measuring your inseam here. Once you know that your inseam fits the bike you want, simply adjust the bike seat to a height that matches the length of your inseam. Another method is to stand directly next to the bike seat and move the seat to about the same height as your hip bone (iliac crest). When you are on the down stroke while pedaling, your knee bend should be between 25 and 35 degrees. Since upright bikes are designed for use by riders in a more upright riding position, you shouldn’t feel the need to lean forward too much to grab the handlebars. If you find yourself needing to wrap your back or fully extend your arms to reach the handlebars, then you may need to move your seat forward. If you can’t move the seat forward on your upright bike, you may need to bend your hips as you reach forward to grab the handlebars while keeping your back flat. These simple changes in position will have a major impact on the way you use your exercise bike.