###### Abstract  
Blockchain technology is increasingly recognized as a promising solution for managing health-related data, particularly in promoting well-being through physical activity. This is becoming more significant as the Internet of Things (IoT) and sport monitoring sensors continue to expand and become more available, leading to a growing number of users in sports and prolonged usage of these devices, which continuously capture large volumes of physical activity data. The substantial volume of data generated in sports and physical activities, combined with distinct concerns compared to medical and health-related information, makes this domain a unique case for blockchain applications. This paper presents a systematic review of blockchain applications in physical activity, exercise-based rehabilitation, fitness, sport, and exercise-based therapeutics (PARFSET). It specifically focuses on examining their quality attributes, including privacy, security, accountability, personalization, adherence, and extensibility. Our objective is to establish a foundational understanding of the benefits of a blockchain in PARFSET domains, particularly following the decline in initial hype for blockchain technology. We aim to provide a clearer perspective on potential applications, future advancements, and research directions. To this end, we assess the maturity levels of blockchain adoption in these areas and highlight specific examples where a blockchain contributes to enhanced data protection, user-centered customization, trust through accountability, and system scalability. Additionally, we present a hypothetical illustrative case to demonstrate how blockchain applications and their quality outcomes can be effectively integrated. Finally, the paper explores the challenges associated with blockchain implementation and outlines potential directions for future research. blockchain; data management; sport; physical activity; fitness; quality attributes; exercise-based therapeutics; exercise-based rehabilitation +
Footnote †: journal:IoMT platforms enable the extensive and continuous collection of PARFSET data from users through various sensors, especially wearable devices. In this context, each individual becomes a source of a continuous stream of extensive data, requiring the application of big data science techniques. Blockchain technology offers a solution for the secure, decentralized, immutable, and continuous logging, recoding in ledger the transaction and metadata on these data streams generated by sensors and collected through IoT or IoMT systems. The features of blockchain technology are a result of how it functions. In the blockchain-based data storage model, data records (also known as transactions) from various sources are continuously grouped into blocks with a specific structure. The general structure of these blocks is illustrated in Figure 1. Each block contains a certain number of data records or transactions in its body, and each record is associated with a hash value. A hash value is a fixed-size string of characters or numbers generated based on the content of the data. Any change in the content will alter the corresponding hash value. In a blockchain, pairs of hash values are recursively hashed to create a new hash value. This process of hashing pairs of records and hash values forms a binary tree, where any change in a leaf node affects the hash value at the root. This tree is known as a Merkle tree, named after its inventor. By maintaining the root hash value, it is possible to validate the integrity and immutability of the original data. In blockchain technology, this concept is extended by linking blocks together through the inclusion of the root hash value from each block in the subsequent block. This creates a chain where the last block contains a hash value that represents all previous contents in the chain. As a result, any attempt to tamper with the contents of any block will invalidate the final hash value, ensuring the security and integrity of the blockchain.