Table 5.

Ball properties and their relationship with head impact magnitude

Study	Participants	Ball characteristics				Results for peak linear head acceleration (g)	Study conclusions
		Ball size	Ball mass (g)	Ball pressure (psi)	Ball velocity (m/s)
Peek et al. (2021) [44]	n = 61 youth players (n = 35 boys), mean age: 14.52 ± 1.37 years	5 4 5 5	192 432 255 430	5 5 5 10.5	6.3	6.3 11.4 8.1 15.4	The lightest size 5 ball and the size 4 ball demonstrated linear head accelerations up to 59% lower (p ≤ 0.01) when compared with the size 5 higher-pressure match ball
Dorminy et al. (2015) [105]	n = 16 division I adult men	5	430	8	13.4 17.9 22.4	34.7 49.2 50.7	Higher ball speeds are associated with higher head acceleration
Lukášek and Kalichová (2015) [106]	n = 16 boys, aged 10 years	4	–	–	3.1 4.4 5.5	6.0 7.7 10.1	Results showed head accelerations increase as ball velocity increases
Funk et al. (2011) [107]	n = 20 healthy adults	5	430	8	5.0 8.5 10.0 11.5	6.8 15.0 18.0 21.0	Higher ball speeds are associated with higher head accelerations
Shewchenko et al. (2005) [89]	n = 3 healthy adult men	3 4 5 5	299 351 444 444	11.6 11.6 11.6 Various 8.7–16.0	6.0	11.9 14.3 14.5 Range 14.4–17.8	Linear acceleration decreased by 10% with a 20–32% decrease in ball mass and size. Linear acceleration decreased by 10% for a size 5 ball with a 50% reduction in ball pressure

psi = pounds per square inch, m/s = metres per second