Maximal horizontal deceleration and change-of-direction performance in female rugby union players across age categories and playing positions

This study determined the intra-session reliability of the maximal horizontal deceleration test, compared deceleration and change-of-direction (COD) performance across age categories (U14, U16, U18 and Senior) and playing positions (backs and forwards), and explored associations while controlling for age, body mass and position. One-hundred-and-eight female rugby union players (U14: n = 28; 13.11 ± 0.96 years; U16: n = 24; 15.13 ± 0.74 years; U18: n = 26; 16.69 ± 0.79 years; Senior: n = 30; 23.93 ± 5.48 years) completed two trials each of a 20-m sprint, maximal horizontal deceleration test and 505 COD test in a single session. Moderate to excellent reliability was found (ICC = 0.66–1.00; CV = 0.25–8.10%). U18 and Senior players showed higher maximum velocity (Vmax), better average deceleration (DECave) and faster COD times than U14 and U16 players. Compared with forwards, backs showed higher Vmax, better DECave, and faster COD acceleration and total times; they were also faster in COD deceleration in U16, U18 and Senior. DECave was associated with COD acceleration, deceleration and total times; Vmax with COD acceleration, reacceleration and total times; and horizontal braking power with all COD metrics. These findings support assessing maximal horizontal deceleration, as deceleration metrics provide complementary information to sprint velocity when characterising phase-specific COD performance.