From sport-specific testing to competitive behavior in combat sports: matching designs to inferential questions

Sport-specific tests have improved the assessment of physical capacities in combat sports, but technical resemblance does not establish how a capacity is used against an opponent. This Perspective clarifies the evidence required to connect standardized measurement with predefined behavior under opposition. It distinguishes four related inferential questions concerning measurement, competitive association, contribution to competitive behavior, and transfer. The third question asks whether, and under which constraints, a measured capacity helps produce or regulate a predefined behavior during interaction with an opponent. These questions require different evidence without forming compulsory sequential stages or a uniform hierarchy of causal attribution. Drawing on measurement theory, representative design, and ecological dynamics, the argument follows kicking speed in taekwondo and grip strength in judo, supported by examples from other combat disciplines. It distinguishes integrated task performance from isolated capacities, capacity magnitude from individual use, and behavior from effectiveness and competitive success. Constrained opponent tasks can test whether capacity–behavior relationships vary with theoretically relevant constraints, but such interactions do not independently identify causal mechanisms. Longitudinal changes may be consistent with transfer while remaining compatible with familiarization, technical learning, or other intervention components. Standardized tests, opponent tasks, simulated bouts, and competition may therefore provide complementary evidence when the construct, behavioral criterion, opposition, and permissible inference are specified prospectively. Further progress may depend on both adequate measurement and studies linking capacities to behavior under clearly defined interactive conditions.