Table 4. Mean and standard deviations for heading biomechanics dependent variables.

	Strengthening Group		Control Group		Interaction
	Pre	Post	Pre	Post
PLA at 11.18 m/s	22.70±2.11	20.01±1.59	22.10±2.72	25.21±5.44	p=0.43, ηp2=0.06
PRA at 11.18 m/s	4456.20±916.54	3547.10±835.10	5027.84±793.66	4046.62±508.83	p=0.96, ηp2<0.01
Duration at 11.18 m/s	10.35±0.99	8.78±1.28	11.50±3.22	15.13±5.95	p=0.53, ηp2=0.04
GSI at 11.18 m/s	24.78±5.08	16.88±3.23	26.30±8.59	43.72±23.59	p=0.33, ηp2=0.09
PLA at 17.88 m/s	30.84±4.45	22.83±3.29	25.24±1.45	20.89±3.56	p=0.34, ηp2=0.08
PRA at 17.88 m/s	4279.75±1126.39	3383.56±946.99	4838.79±219.14	3843.23±614.17	p=0.97, ηp2<0.001
Duration at 17.88 m/s	11.34±1.38	8.91±2.05	12.02±2.56	8.59±1.51	p=0.79, ηp2=0.01
GSI at 17.88 m/s	41.98±12.13	22.30±7.04	31.70±4.11	19.51±5.39	p=0.48, ηp2=0.05

PLA=peak linear acceleration, PRA=peak rotational acceleration, GSI=Gadd Severity Index