# A Systematic Review of Insole Sensor Technology: Recent Studies and Future Directions
## 2 Materials and Methods  
The primary objective of this study was to examine relevant literature focusing on research articles, review articles, and systematic reviews published in English that are aligned with the research objectives. This investigation targeted publications from 2014 onwards, ensuring that the review reflected the most recent developments and contributions in the field. Three distinct databases were chosen for the literature search: PubMed, Scopus, and Web of Science (WoS). Each one of these databases offers unique strengths that are aligned with the research needs. PubMed, known for its extensive collection of biomedical and clinical studies, was chosen for its relevance and depth of clinical research. This database is renowned for its comprehensive coverage of topics related to healthcare, medicine, and related fields, making it an invaluable resource for the current study. Scopus and WoS were selected for their robust combination of quantitative and qualitative studies, along with their expansive coverage of scientific disciplines. Scopus is recognized for its extensive indexing of peer-reviewed literature, offering a wide range of scientific articles across diverse disciplines. Likewise, WoS also provides a comprehensive indexing of multidisciplinary research. Utilizing these three databases ensured a wide-ranging overview of the relevant literature, enhancing our analysis's quality and scope. Moreover, the databases chosen provided a balanced representation of clinical and broader scientific research, which was crucial for achieving the study's objectives. Nevertheless, to complete the information provided by the search in the three databases, searches were conducted without following guidelines, resulting in exploring articles suggested online or included in the works found previously. The proposed methodology allowed us to capture various perspectives and insights, contributing to a more nuanced understanding of the topics under investigation. In summary, the study's methodological approach facilitated a thorough and balanced literature review, leveraging each database's unique strengths to provide a robust and comprehensive analysis. A literature search was performed in the Web of Science (WoS) database using the query: ((\"wearable sensor\" OR \"wearable sensors\") AND (\"insole\" OR \"insole\") AND \"biomechanics\"), Table 1. The search produced a total of 3508 results. Afterwards, the data was evaluated using VOS viewer software, version 1.6.20, Netherlands, with a specific focus on titles, abstracts, and keywords as presented in Figure 1, wherein the clustering of specific phrases resulting from the search is illustrated. To enhance the accuracy of this search, the terms \"wearable sensor\", \"insole\", \"performance\", and \"rehabilitation\" were employed as keywords. These keywords were selected based on their alignment with the primary purpose and research topic. Preliminary searches allowed us to optimize the final query. Hence, this iterative procedure improved the search technique, ensuring the proper connection to our research. The analysis conducted with VOS viewer yielded insights into the thematic clustering of the chosen terms, hence strengthening the significance of the selected keywords in this study. The inclusion of \"performance\" and \"rehabilitation\" as supplementary keywords was of utmost importance, as they directly pertained to the proposed utilization of wearable sensor technology in biomechanical investigations. The intention was to encompass pertinent research that addresses both performance-enhancing and rehabilitation applications, ensuring a full overview of the literature in both areas. The methodological approach showcases a structured and focused search strategy, utilizing sophisticated bibliometric methods to extract pertinent literature.