Context: Neck size and strength may be associated with head kinematics and concussion risks. However, there is a paucity of research examining neck strengthening and head kinematics in youths. In addition, neck training is likely lacking in youth sport due to a perceived inadequacy of equipment or time.
Objective: Examine neck training effects with minimal equipment on neck strength and head kinematics following chest perturbations in youth athletes.
Design: Single-group, pretest-posttest case series.
Setting: Athlete training center.
Participants: Twenty-five (14 men and 11 women) youth soccer athletes (9.8 [1.5] y).
Intervention: Sixteen weeks of twice-weekly neck-focused resistance training utilizing bands, body weight, and manual resistance.
Main outcome measures: Head kinematics (angular range of motion, peak anterior-posterior linear acceleration, and peak resultant linear acceleration) were measured by an inertial motion unit fixed to the apex of the head during torso perturbations. Neck-flexion and extension strength were assessed using weights placed on the forehead and a plate-loaded neck harness, respectively. Neck length and circumference were measured via measuring tape.
Results: Neck extension (increase in median values for all: +4.5 kg, +100%, P < .001; females: +4.5 kg, +100%, P = .002; males: +2.2 kg, +36%, P = .003) and flexion (all: +3.6 kg, +114%, P < .001; females: +3.6 kg, +114%, P = .004; males: +3.6 kg, +114%, P = .001) strength increased following the intervention. Men and women both experienced reduced perturbation-induced head pitch (all: -84%, P < .001). However, peak resultant linear acceleration decreased in the female (-53%, P = .004), but not male (-31%, P = 1.0) subgroup. Preintervention peak resultant linear acceleration and extension strength (R2 = .21, P = .033) were the closest-to-significance associations between head kinematics and strength.
Conclusions: Young athletes can improve neck strength and reduce perturbation-induced head kinematics following a 16-week neck strengthening program. However, further research is needed to determine the effect of improved strength and head stabilization on concussion injury rates.
Keywords: concussion; quasi-isometric; resistance training; youth.