Nathan Swan, PT, DPT
In short, the answer to this question is yes, but maybe no. There is new evidence emerging that weak neck muscles are one of many risk factors for concussions. This would seem to at least partially explain why on average females and children have higher susceptibility to concussions. It is only natural to assume neck strengthening would reduce the risk for concussions; however research supporting this preventative intervention has yet to be published. It is also worth noting that the most important factor to reduce the force on the head during impact is the stiffness of the neck during impact. This means that it is not only the strength but the timing of your muscle activation (i.e. bracing for impact) that reduces impact forces. As an athlete in a contact sport, it is best to have a strong neck and have your head on a swivel so you can prepare for any impact you may encounter. You can find a few great neck stabilization exercises to strengthen your neck.
However, just to make things complicated, a new study looking at college football players found that players with the strongest and biggest necks had the largest impacts to their heads during concussions. While we do not yet know why this is the case, the authors speculated that bigger players had the tendency to involve themselves in bigger hits. This may explain why sometimes the biggest and strongest athlete on the football team can have the most trouble with concussions. I like to think of the neck muscles like seatbelts in a car. Nascar drivers have the best seatbelts, but they are more at risk for big crashes because they feel comfortable putting themselves at risk. In the same way, strong neck muscles can protect you like seatbelts, but if you place your head at risk your muscles can only do so much. Neck strengthening is only one of many modifiable risk factors for concussions. So yes, you should strengthen your neck to reduce high forces on your head from impacts you may encounter, but you should also be aware of your limitations and always take appropriate safety measures when playing a contact sport.