## 3 Results
\begin{table}
\begin{tabular}{c c} \hline \hline
**Loop** & **Definition** \\ \hline B1 & HS re-injury loop \\ B2 & Effect of psychological factors loop \\ B3 & Effect of neuromuscular coordination on fatigue and the total injury risk \\ B4 & Negative workload effect on neuromuscular coordination due to fatigue loop \\ R1 & Positive workload effect on neuromuscular coordination loop \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Definition of the main feedback loops presented in the HI-CLD. with decreased HS flexibility, eccentric strength, or endurance the risk for injury during HSR increases [5, 5, 77, 5]. Similarly, an athlete with low HS strength endurance may be at an increased injury risk, specifically when HSR exposure is elevated, as this athlete is more prone to hamstring fatigue [57]. As shown in the B3 feedback loop, the quality of the neuromuscular coordination has a considerable influence on accumulative fatigue and the quality of HSR biomechanics affecting the risk for HI. Finally, neuromuscular coordination affects the quality of HSR biomechanics through dynamic core stability and HS EMG activation patterns (Figures 1 and 2). Interaction of Previous Injury Characteristics, Age, and Psychological Mood with the Athlete's Neuromuscular Coordination That Affect Risk for HI  
The likelihood of HI escalates with a history of earlier hamstring strain, particularly if the injury occurs during the same season [5]. Factors such as chronicity [33, 36], injury type [5], number of previous injuries [43], and injury severity [5, 36] are pivotal factors that influence the risk of HI. Previous injuries alter the athlete's internal neuromuscular coordination [5] and psychological mood [21, 22, 62] having a considerable impact on the whole HI-CLD [5, 12]. For example, the size of scar tissue and the duration of time lost due to an earlier HI critically degrade soft tissue quality [44, 45, 48, 86]. Stakeholders emphasize the significance of soft tissue quality post-injury, which affects the muscle's capacity to generate adequate strength  
Figure 2: Causes tree of factors affecting the quality of high-speed biomechanics that affect risk for HI. and functionality under sport-specific demands [44; 45; 48; 86]. Shortened biceps femoris long head length [48; 66; 87; 86] and increased HS fascial stiffness post-injury [64; 65; 66; 72; 88] modify the structural and flexibility attributes. These interconnected factors culminate in the B1 feedback loop within the HI-CLD, delineating the etiology of HI recurrence (Figures 1 and 3). Furthermore, extended absence from sports due to ACL injury can detrimentally affect overall neuromuscular coordination [5], whereas given the anatomical and functional connectivity between the calf muscles and hamstrings, an injured calf muscle diminishes force absorption during dynamic actions, thereby imposing increased loads on the hamstrings [5]. The B2 feedback loop of the HI-CLD revealed that an athlete's psychological mood is influenced by injury history, fatigue, and factors such as team financial stability (Figures 1 and 3). Various psychological aspects (e.g., daily hassles, anxiety, negative life events, and common mental disorders (CMD)) associated with football injuries or observed post-recovery [62; 63; 67; 89] can degrade athlete concentration and reaction times [21]. These factors elevate the injury risk, and psychological interventions have been shown to mitigate this risk [62]. Despite stakeholder discussions and consensus on incorporating these psychological mood aspects into the HI-CLD, supporting literature specifically regarding HS injuries remains limited. Age is also a decisive risk factor for HIs [5; 12]. Older athletes (>25 years old) with extensive injury histories significantly affect the entire etiology system [5; 90]. Aging is associated with a decline in neuromuscular coordination and soft tissue integrity [5; 12]; however, older athletes often face greater exposure to sports and higher workloads [5].