Procedure: How Do I Properly Adjust the Saddle on the Home Trainer?

The sequence of steps is the same as on a bicycle: saddle height, saddle tilt, setback, foot position, control. As a rough starting point for saddle height, you can stand next to the ergometer, feel the exposed point of the hip bone at the front upper edge of the pelvis, and set the saddle about a thumb's width higher than that. Alternatively, you could transfer your bicycle's saddle height and angle if you are sure it complies with the ergonomic rules. To do this, measure the distance from the top edge of the saddle along the seat post to the center of the bottom bracket with a ruler or tape measure. Apply the same procedure to the home trainer and set the same value here. The saddle angle can initially be adjusted visually. A third variant using inner leg length or stride length can be found in the video below. The basic rule for any method remains that the knee should never be fully extended throughout the crank rotation. Nevertheless, you should sit as high as possible without the pelvis tilting on the saddle. The angle in the knee joint should always be between 90 and 175 degrees, according to ergonomics experts.

Especially for strength-intensive training on the ergometer, a seat position that is too low is inefficient, more wear-intensive in the medium term, and often painful. Additionally, you don't use your muscles in their ideal working length. And since you don't have to stop at any traffic lights, you don't have to worry about not getting off the saddle in time to stand safely. Small exception: those participating in high-intensity spinning classes should reduce the determined saddle height by two millimeters again. In spin class programs, very high pedaling frequencies are often required, which can be implemented more conveniently if you don't sit at a limited height. After the saddle height, the setback adjustment follows. For indoor bikes, this is often possible on the saddle and along a horizontal extra rail; see video.

The setback determines how far you sit with the pelvis behind the bottom bracket. This, in turn, affects the knee angles and whether you pedal more from the gluteal muscle or the front thigh. Additionally, the setback shifts the pressure distribution between the bicycle saddle and the buttocks. If existing pressure pain cannot be eliminated through adjustments, the saddle should be changed. Most ergometers allow the installation of good ergonomic saddles like the Ergon ST Core or ST Gel for recreational riding, or the Ergon SR or SM for sporty riding. A significantly long or short setback can cause knee pain or premature partial muscle fatigue or lead to saddle discomforts. 
The sign of the ideal setback is a vertical line through the knee to the forefoot when the corresponding bike pedal is horizontal in the direction of travel. To check, you can tie a small weight to a thread and hold its upper end to the side of the knee where you suspect the contact between the kneecap and joint. The plumb line should now hang freely through the pedal axle. If it is in front of its center, adjust the saddle backward, analogously, and vice versa. Tools like the plumb line, a spirit level, measurement tables, and helpful templates can be found as a set in the specially developed Ergon Fitting Box.

You should also check the saddle angle. The saddle surface should be horizontal to start the alignment, which can be checked with a spirit level or mobile phone app. If you later want to set the handlebars lower with a correspondingly forward-leaning body posture, you can adjust the saddle tip a few millimeters lower than the rear edge to relieve the pubic bone and genital area; this is called a negative saddle tilt. As long as the saddle still provides sufficient support, the front nose of the saddle can also be lowered further. A positive, i.e., rearward-tilted saddle, should be set by people with a completely upright body posture.

Procedure: How to Properly Adjust the Handlebars on an Ergometer

Unlike the saddle, the adjustment of the handlebars defines the posture of the upper body and shoulder girdle. Aerodynamics naturally play no role without the wind, but the upper body is also the counterbalance to the legs. The more you lean over your legs, the more power you can push down into the pedals. Since steering physics and direction of view on the indoor bike also play no role, the inclination of the upper body and shoulders can be adjusted more according to the personal feeling of the user than on a classic bicycle or pedelec.

Handlebars and saddle at the same height are suitable for hard interval training and athletes with good mobility. The handlebars should be one to two hand widths above saddle level for health-oriented training and a more relaxed posture. You should generally choose your seating position to support yourself with at least light pressure on the handlebars. With full weight on the bike saddle, you tend to tilt the pelvis backward and thus get into an unfavorable hip angle for pedaling. Additionally, the angle of the pelvis no longer matches the horizontal saddle tilt, and the hips often fall into exaggerated lateral swinging, which both cost seating comfort after a few minutes. Speaking of which: To endure ergometer training as long as possible, you should fully utilize the handlebars of the home trainer, i.e., change the grip position often. If you can change the alignment of the handlebars, you should adjust their angle so that the posture in the upper body and shoulder girdle noticeably changes when gripping. For example, when the grips are significantly further away from the saddle. This way, you use different muscles in the torso during training and vary the pressure distribution on the buttocks. If you can't cope with this minimally forward-leaning posture and still want to train gently on the joints, you can try a recumbent ergometer, where all holding work is eliminated. This additionally relieves the heart for those with related pre-existing conditions, but you burn fewer calories in such a gentle posture.