Study Limitations
muscle contraction
The main limitation of this study is the lack of blinding of the study population and investigators. Unfortunately, the very nature of the NMES procedure is such that the study participant has a full understanding of whether he is being stimulated with muscle contraction or not. Additionally, the design of a single-centre study does not allow for the blinding of investigators. Therefore, the results of a prehabilitation program before cardiac surgery should be interpreted with caution. Although an identical approach was used in pre- and post-prehabilitation measurements of muscle status, we cannot exclude that the results of muscle strength assessment in the present study may overestimate the effect of NMES. To clarify this, a blinded, randomized controlled trial will be required to investigate the effectiveness of NMES in increasing muscle strength in patients before cardiac surgery. However, the results of this study indicate the advisability of NMES before cardiac surgery in this category of patients.In addition, the duration of the NMES course may have been too short, but the relatively short preparation time of the patient in the hospital did not allow for an increase in the rehabilitation period. A longer course of NMES can likely be utilised before the operation on an outpatient basis, but since our research was carried out in a hospital, its results cannot be extended to an outpatient course of NEMS.