The terms explanatory and pragmatic trials were first articulated by Schwartz and Lellouch in 1967,1 clarifying their focus on efficacy (causal hypothesis) versus effectiveness (choice of care), respectively.2 Then, in 1986, Flay warned against uncritical adoption of ‘programme causes outcome’ logic that bypasses theory-driven causal testing.3 Subsequently, the PRECIS framework in 20092 operationalised a continuum of explanatory to pragmatic trials. Explanatory trials test effects under ideal conditions, while pragmatic trials assess whether an intervention works in real-world contexts, tolerating variability and lower fidelity with intention-to-treat designs, acknowledging that few trials are purely explanatory or pragmatic.4 Early-stage research should prioritise explanatory trials to establish mechanistic causal inference. By maximising control first, these trials provide the plausible range of effects that may be observed in later implementation-focused studies.4 Yet anterior cruciate ligament (ACL) injury prevention research often bypasses explanatory trials,…