## 4 Discussion
### Intensity Levels and Type of SW Administered  
Shockwaves are differently classified in studies. One study [31] separated SW as radial and focused. In this study, the authors found that FSW are effective on treating PF when compared with a placebo; despite promising results, no solid conclusions were drawn on RSW, due to the heterogeneity of results, probably related to the low quality of evidence included in the study. A double distinction by intensity levels and type of wave (radial or focused) administered was applied only in two studies [11; 20]. These studies do not clarify whether one type of SW is superior to the other: both authors concluded that RSW are effective ([PERSON], [PERSON] et al. [11] concluded that RSW is the most effective treatment for PF). The authors gave different conclusions on the FSW: [PERSON], [PERSON] et al. [20] stated that medium-intensity FSW is more effective, while [PERSON], [PERSON] et al. [11] concluded that only low-intensity FSW is effective (placebo was superior to medium- and high-intensity FSW). This result is the opposite of what [PERSON], [PERSON] et al. [35] demonstrated with their study, stating the effectiveness of high-intensity ESWT on PF. Additionally, [PERSON], [PERSON] et al. [38] compared the effects on the pain and success rate of medium-energy RSW/FSW with a placebo: both focused and radial SW had better results than the placebo. One limit of these studies is that they did not directly compare the different types of SWs but compared the results with a placebo. The authors believe that a difference in the type and the intensity of shockwave administered should be provided in future studies to better evaluate the effects of these treatments. Moreover, the studies often compared shockwaves without a rigorous protocol, with differences in the intensity levels, number of administrations, and pulses administered; this might have invalidated the results of some of them. Five studies [11; 21; 29; 34; 35; 38] analyzed the effects of SW by the intensity level. In particular, the intensity levels were differently classified: [PERSON], [PERSON] et al. [20] identified three intensity levels, low (\(<\)0.08 mJ/mm\({}^{2}\)), medium (0.08 to 0.28 mJ/mm\({}^{2}\)) and high (\(>\)0.28 mJ/mm\({}^{2}\)); [PERSON], [PERSON] et al. [11] cited [PERSON] following the same division; [PERSON], [PERSON] et al. and [PERSON], [PERSON] et al. [29; 38] also identified three levels, with different intensities (low \(<\)0.1 mJ/mm\({}^{2}\), medium 0.1-0.2 mm\({}^{2}\) and high \(>\) 0.2 mm\({}^{2}\)); and [PERSON] [34], [PERSON], [PERSON] et al. [35] and [PERSON], [PERSON] et al. [21] identified two levels, low (\(<\)0.2 mJ/mm\({}^{2}\)) and high (\(>\)0.2 mJ/mm\({}^{2}\)). As suggested by [PERSON], [PERSON] et al. [20], to obtain a therapeutic effect, it is important to provide a sufficient energy efflux density (EFD), which might be related to the reduction in the magnitude of pain, with a potential dose-dependent response. In the studies that compared different intensities of SW, three [20; 29; 34] assessed a better efficacy of medium- or high-intensity ESWT treatment rather than low-intensity in PF, though two studies [11; 21] reported better results with low-intensity treatment. Researchers might better explore this aspect in the near future.