# Mechanical Focal Vibration Therapy for Muscle Injury Recovery in a Runner
## 4 Discussion  
The aim of the study was to evaluate the administration of mechanical Focal Vibration in an adult male amateur runner with a grade II lesion of the rectus femoris muscle. In the last years, VT has been gaining popularity as a possible post-exercise recovery modality to reduce pain and muscle soreness [33, 34]. The increase in blood flow from WBV could accelerate the recovery process by increasing oxygen delivery, raising muscle temperature, and enhancing the removal of waste products that inhibit tissue repair [35, 36, 37]. However, the efficacy of WBV for post-exercise recovery remains equivocal; acute WBV showed no benefit on running performance recovery or metabolism following high intensity intermittent running, whereas a repeated bout of WBV following downhill running reduced muscle soreness and muscle inflammation [33, 38].  
\begin{table}
\begin{tabular}{l c c c} \hline \hline  & **T0** & **T1** & **T2** \\ \hline NRS (0–10) & 8 & 4 & 2 \\ EQ5D3L Index (0–1) & 0.431 & 0.663 & 0.873 \\ CoP speed (mm/s) & 70.2 \(\pm\) 13 & 59.5 \(\pm\) 9 & 46.7 \(\pm\) 8 \\ Elliptic area (mm\({}^{2}\)) & 258 \(\pm\) 31 & 245 \(\pm\) 24 & 203 \(\pm\) 25 \\ \hline \hline \end{tabular} Abbreviations: CoP—Centre of Pressure; EQ5D3L—European Quality of Life 5 Dimensions 3 Level Version; NRS—Numeric Rating Scale.  
\end{table}
Table 1: Outcome measure results for each timepoint.  
Figure 2: Ultrasound evaluation. T0: baseline; T1: at the end of the treatment; T2: four weeks after the end of the treatment.  
The recovery time for mild to moderate muscle injuries usually ranges from 1 to 4 weeks. Severe injuries, however, can require up to 9-12 months to heal completely; furthermore, some factors have a negative impact on recovery: involvement of the tendon tissue, proximity of the injury to the bone, length and sectional area of the lesion [39, 40].  
In this scenario, four weeks after the therapy, the lesion was healed, in line with the healing times demonstrated in the literature; however, we believe it is very interesting to underline the early good recovery in balance (as demonstrated by the reduction in CoP speed (mm/s) from 70.2 \(\pm\) 13 to 46.7 \(\pm\) 8 when asking the patient to stand on one leg for 20 s with eyes closed and the knee flexed at 15\({}^{\circ}\), the hip joint fully extended, and with arms crossed over the chest) and the relief of pain (VAS reduced from 8 to 2) which occurred from T0 to T2, allowing the patient a return to sport in a short time.  
Regarding muscle recovery and proprioception, the adjunct of mFV to conventional physical therapy highlighted that mFV effectively enhances muscle recovery and balance awareness of the participant. Major findings might suggest that mFV could be considered as safe an approach as other physical agent modalities, such as shortwave diathermy or neuromuscular electrostimulation [41]. In this scenario, mFV might influence motor coordination and performance [42]. Finally, mFV may produce short-term recovery effects as early as 60 min after the end of treatment, perhaps suggesting its potential for rapid recovery and rehabilitation from muscle injury [43].  
This case report has some strengths. To the best of our knowledge, no previous study has evaluated the administration of mechanical focal vibration on a grade II muscle injury. The safety of the approach could suggest a relative expansion of the sample; furthermore, the method could reduce the use of pharmacological or minimally invasive therapies, especially in professional sports contexts.  
Nonetheless, this study has some limitations. First, it was presented as a case report, which does not provide substantial evidence. Second, it was not possible to investigate the organic and structural improvements in muscle recovery, but only the functional outcomes. Third, the subject included in the study was a senior amateur athlete, so the results might not be generalizable to younger professional subjects.