Technical side
When we look at stationary cycling, the main difference is that there are no downhills, thus no coasting time. When riding outside, you can spend 10-15% of the time not pedaling. However, when riding inside the time spent riding becomes 100% efficient, and that creates some extra fatigue, not only in the legs but also in the back.
On top of riding without any rest when riding indoors, the position on the bike makes it a bit harder due to it being completely static.
Generally, when riding seated, we see some sideways movement because of the ”non-perfect human pedaling technique. While riding the trainer, these sideways movements are amplified by the bike being fixed, which have to be absorbed by the body and creates extra strain on the back.
When riding standing, your body has more freedom of movement. The back will relax a bit, but the knees will feel the different movement patterns. Adding small standing intervals will help to keep a good balance with the position, start from 10-second intervals occasionally and increase progressively up to 1 minute.
When riding stationary, it is natural that we adopt a more relaxed body position as we don’t need to propel the bike. This can mean that we place more weight on the saddle, and the risk of developing saddle sores may increase even if we are accustomed to riding the bike outdoors.
In case you ride a lot indoors, a potential upgrade to your set-up is the MP1 Nfinity Trainer Platform from Saris. It is a platform that allows you to move the bike laterally, forward, and backward, and it’s compatible with every trainer.
Those who ride with a power meter may notice that there is a difference in the power-heart rate relationship when compared to riding outdoors. As we have noted, the body is less efficient riding indoors, so it is entirely reasonable to lose some watts at the same heart rate. There could be up to 30 watts difference, so don’t get demoralized because of the lower values!