Background: Aggression is a fundamental, yet complex, component in pugilism (boxing). While often perceived as a singularly aggressive sport, the expression of aggression is hypothesized to be strategically modulated by a boxer's competitive level. The distinction between instrumental aggression, which is goal-oriented and controlled, and hostile aggression, which is reactive and emotional, is critical in this context.

Objective: This study aimed to quantitatively compare the levels and types of aggression between amateur and professional boxers, testing the hypothesis that professionals exhibit higher levels of instrumental aggression, while amateurs show higher levels of hostile aggression.

Methods: A cross-sectional research design was employed. A sample of 150 active male boxers (75 amateurs, 75 professionals) completed the Buss-Perry Aggression Questionnaire (BPAQ), a validated instrument measuring four facets of aggression: physical aggression, verbal aggression, anger, and hostility. Independent samples t-tests were used to compare mean scores between the two groups.

Results: Professional boxers scored significantly higher on the physical aggression subscale (M=28.4, SD=5.2 vs. M=25.1, SD=6.1; t(148)=3.78, p<.001), which is linked to instrumental aggression. Conversely, amateur boxers scored significantly higher on the hostility subscale (M=23.8, SD=4.9 vs. M=20.1, SD=5.3; t(148)=4.52, p<.001), which is indicative of hostile, reactive aggression. No significant differences were found in verbal aggression or anger.