Objective: This randomised repeated measures study explored the effect of ball pressure and maximal isometric neck strength on head acceleration during purposeful heading in adult football players during heading drills within a laboratory environment. Methods: Recreational football players (n = 17) attended one familiarisation session to determine baseline maximal isometric neck strength, followed by two experimental sessions where they randomly trialled two conditions (>72-h apart). The first condition included 20 rotational headers with a match-ball at low-pressure (58.6 kPa; 8.5 psi) and the second included 20 rotational headers with a match-ball at high-pressure (103.4 kPa; 15.0 psi) whilst instrumented with an inertial measurement unit. Results: A statistically significant difference between conditions for both peak linear head acceleration (F = 15.2; p=