We investigated the criterion validity and within- and between-day reliability of a novel method for human striking performance assessment. The Impulse Block Method allows the measurement and calculation of a range of striking variables using a load cell incorporating an impact absorption block and laser gate timer. To assess the criterion validity, we performed repeated drop tests and compared the relationship and agreement between predicted and measured velocity and initial momentum (calculated from impulse) with predicted values using linear regression and Bland-Altman plots (Experiment 1). In Experiment 2, 10 healthy adults performed palm strikes against the Impulse Block on two occasions, and within- and between-day reliability was calculated for impulse, initial momentum, velocity, effective mass, kinetic energy, and power. There was a strong linear relationship and high agreement between measured and predicted velocity and initial momentum (Experiment 1). In Experiment 2, the within- and between-day coefficients of variation were 4.95-10.2% and 6.15-12.1%, respectively, for all variables. Within- and between-day intraclass correlation coefficients were 0.72-0.99 and 0.92-0.99, respectively, for all variables, indicating moderate to excellent reliability. Our findings show that the Impulse Block Method is valid and reliable for analysing a range of striking performance variables in well-targeted and perpendicular linear strikes.