## 4 Discussion  
The main objective of the present study was to determine the effectiveness of an IFM training programme in patients with MS. By adding an IFM training programme to their regular rehabilitation, subjects experienced a clinical improvement in dynamic stability and self-perceived confidence, compared to patients who did not undergo the intervention. In the present study, it was observed that there were improvements in dynamic stability but not in static stability. The hypothesis proposed is that dynamic stability may depends to a greater extent on the IFMs, whereas static stability may depend more on other elements such as vision, the vestibular system, or the somatosensory system. However, no statistically significant differences between-groups were observed in terms of the amount of change when comparing pre- and post-intervention outcomes. [PERSON] et al. [9] suggested that the minimal detectable change value for the FSST was 43%, which means that a 43% reduction in the time taken to complete the test is needed to demonstrate a real change in the MS patient's performance. In the present study, subjects in the experimental group improved their performance on the FSST but did not reach the 43% difference between the pre- and post-intervention assessment. This statistical non-significance may be due to the small sample size. It is therefore proposed to increase the sample size in future studies. On the other hand, it should be taken into account that in order to improve stability it could be interesting to add training of the neural subsystem of the foot core. To the authors' knowledge this is the first study to evaluate the efficacy of an IFM training programme in subjects diagnosed with MS. However, several studies have shown the effectiveness of different modalities of stability training in MS patients. Most of these studies involved general stability or core-based exercises, in contrast to the present trial. [PERSON] et al. [13] showed that virtual reality stability training produced improvements in static (measured by posturography) and dynamic (assessed by functional reach test) balance in subjects with R-R MS; virtual reality training was superior to conventional treatment for dynamic stability. [PERSON] et al. [14] compared the efficacy of single-task stability training with the same dual-task training, assessing self-perceived confidence using the AsBC questionnaire. The authors observed an improvement of 6.79 points in the single-task group and 8.0 points in the dual-task group; both results are slightly better than those observed in the present study (6.06 points for the IFM training group). [PERSON] et al. [15] performed a sensory integration balance training that improved the AsBC questionnaire by almost 10 points. This result improved on that reported by [PERSON] et al. [14] and the present study. Although statistically significant improvements have not been reported in static and dynamic balance in patients with MS, several studies have shown that IFM training leads to improved stability in subjects without neurological disorders. [PERSON] et al. [18] showed a significant improvement (\(p<0.05\)) in dynamic stability, measured by the Y balance test, in healthy subjects who performed a 5-week training protocol based on the SFE. In a sample of subjects with chronic ankle instability, [PERSON] et al. [19] carried out an 8-week SFE training and reported an improvement in static stability of 49%, recording the medio-lateral, anteroposterior, and overall displacement of the centre of pressures on a force platform. The same authors also showed an increase in the Star Excursion Balance Test performance of 6.10% in subjects with CAI who had completed an IFM training protocol based on TSO, toe extension, and hallux extension exercises [20]. [PERSON] et al. [22] reported a significant improvement in static stability (\(p=0.01\)-\(0.04\)) in healthy older people who performed a 12-week IFM training. Finally, [PERSON] et al.