A minimal decrease in the ‘spring effect’ after about a year is normal and cannot be prevented in the long term.
The soft elastic kybun shoe sole is subject to a high level of mechanical strain due to constant compression and decompression. A load of two to three times the body weight is placed on the kybun shoe sole with each heel strike. With increased wear and depending on use (for example, sport), the resilience is slightly reduced (for example, jogging shoes). It is often only possible to notice this decrease by comparing the old shoe with a new model. This also means that comfort while wearing remains the same and only the training effect declines with time.
Greater strain is placed on the soft, springy material due to different factors (for example, running or body weight above 120 kg), causing the material to wear at a higher rate. However, everyday activities such as walking, Nordic walking etc. do not pose any problems.