Running with a Lumo Run sensor in your pocket will give you data but this data will not be correct measurements of the Lumo Run form metrics. The Lumo Run sensor needs to sit securely on your waistband on your hips in the provided Lumo Run clip such that it does not not move while you are in motion. (see “How to wear Lumo Run”)
Even the small amount of movement that can occur in a snug back pocket will compromise your data as it's not built to hold an item with the exact dimensions of the Lumo Run sensor.
The only garments you can use without the Lumo Run clip while preserving accuracy are Lumo garments. Lumo Run capris and shorts have specially designed back pockets that are configured to hold the Lumo Run sensor securely against your body, preserving data accuracy.