The effect of a neuromuscular neck exercise program on head impact magnitude during heading: A pilot randomised controlled trial

      Introduction: Football is the only sport where the head is deliberately used to strike a ball. While heading has always been an integral part of football, there is growing research and public concern that retired footballers have an increased risk for neurodegenerative disease due to changes to brain tissue from repeated ball-head impacts. Any impact to the head has the potential to cause a transmission of force to the brain. Whether this results in detrimental stress and strain to brain tissue is likely related to head impact magnitude. Head impact magnitude (including peak linear acceleration and angular velocity of the head) may be attenuated by player neck strength.
      Objectives: The primary objectives were to explore the effect of a neuromuscular neck exercise program on a) isometric neck flexor, extensor and side flexor strength, and b) head impact magnitude during purposeful heading in male and female adolescent football players. A secondary objective was to explore the acceptability of the exercise program.
      Design: Pilot randomised controlled trial.
      Methods: Male and female players (aged 12-17 years) were randomised by team to the intervention (five-week supervised neuromuscular neck exercises integrated into Part 2 of the FIFA 11+) or control (Part 2 of the FIFA 11+ but no neck exercises). Outcomes included isometric neck strength and head impact magnitude (linear head acceleration and angular velocity) during standardised heading (baseline and six-weeks) plus an anonymous evaluation survey.
      Results: From a total of 88 eligible players, 52 players (n=31 intervention; n=21 control) completed the study. Repeated MANOVAs revealed significant differences in neck strength variables (p<0.001) and peak linear acceleration (p<0.01) between the intervention and control groups over time. A trend towards significance was reported for peak angular velocity (p=0.05). Intervention players demonstrated significant increases in mean composite neck strength (53.8% intervention versus 15.6% control) as well as significant decreases in mean linear head acceleration during heading (-11.8% v -5.0%) from baseline to follow-up. Reduction in angular velocity was more pronounced in female (-27.7%) than male players (-11.5%) in the intervention arm. Players who completed neck exercises reported this as a positive experience which was beneficial to them and their team.
      Conclusion: Players who completed neuromuscular neck exercises demonstrated an increase in isometric neck strength and decrease in head impact magnitude during heading. The addition of neuromuscular neck exercises into Part 2 of the FIFA 11+ was feasible and accepted by players.
      Conflict of Interest: My co-authors and I acknowledge that we have no conflict of interest of relevance to the submission of this abstract.