The Effect of the FIFA 11 + with Added Neck Exercises on Maximal Isometric Neck Strength and Peak Head Impact Magnitude During Heading: A Pilot Study

Abstract

Background Higher neck strength has been postulated to reduce head impact magnitude during purposeful heading in football. Objectives This pilot trial explored the effect of a neck exercise programme on (1) neck strength and (2) head impact magnitude during heading in male and female adolescent football players. Methods Boys and girls (aged 12–17 years) were randomised by team to the intervention (5 weeks of supervised neuromuscular neck exercises integrated into part 2 of the FIFA 11 + , completed three times per week) or the control group (usual part 2 of the FIFA 11 + , no neck exercises). Outcomes included isometric neck strength and head impact magnitude (peak linear acceleration and peak angular velocity) during standardised heading from a throw-in (at baseline and 6 weeks) plus completion of an evaluation survey by intervention players and coaches. Results In total, 52 players ( n = 31 intervention; n = 21 control) completed the study. Mixed-model analysis of variance (ANOVA) revealed significant differences in neck strength variables ( p < 0.001), peak linear acceleration ( p = 0.04) and peak angular velocity ( p = 0.04) between the intervention and control groups over time. Intervention players demonstrated increases in mean composite neck strength (53.8% intervention vs 15.6% control) as well as decreases in mean peak linear head acceleration during heading (− 11.8% vs − 5.0%) from baseline to follow-up. Reduction in peak angular velocity was more pronounced in girls (− 27.7%) than boys (− 11.5%) in the intervention group. The addition of neck exercises into part 2 of the FIFA 11 + was feasible and accepted by players and coaches. Conclusion On average, players who completed neck exercises demonstrated an increase in isometric neck strength and a decrease in head impact magnitude during heading. These exercises were easily incorporated into usual training. Australian New Zealand Clinical Trials Registry (no: ACTRN12619001375145). Supplementary Information The online version contains supplementary material available at 10.1007/s40279-021-01564-0.

Neck strength and concussion prevalence in football and rugby athletes

“…8 These findings may indicate that increasing the strength of the neck flexor muscles, thereby increasing the flexor/extensor strength ratio, is key in reducing head acceleration and stabilising the head-neck-torso during impacts to the head or body. 4,12 Earlier research reported that lower neck strength results in increased concussion incidence. 3,4 Intervention programmes that include neck strengthening exercises can decrease the number of head/neck injuries, including concussion.…”

“…27,28,29 In footballers, addition of neuromuscular neck exercises to the FIFA 11+ programme was also found to reduce head impact magnitude in adolescents. 12 However, such studies and interventions have focused on increasing neck strength as a whole, not the flexor/extensor strength ratio. Our findings are clinically important as they indicate a need for specific neck training programmes to focus on increasing the neck flexor/extensor strength ratio and subsequent stabilisation of the head on contact.…”

“…Neck strength measurements were assessed using a hand-held dynamometer (GSA Analyser™, Gatherer Systems, UK) and were completed for all athletes by the same experienced assessor (KP) following a standardised testing protocol with established reliability. [10][11][12] In sitting, a head harness with a load cell placed in series was secured to the athlete's head. Maximal isometric neck muscle contraction was tested using a 'break technique' where incremental manual loading of the head harness occurred until the athlete's head moved out of the neutral position.…”

“…Verbal informed consent was provided before testing and the athlete completed a warm-up and practice prior to assessment. [10][11][12] The highest value from two maximal isometric contractions of neck flexors, extensors and lateral flexors was recorded. [10][11][12] An a priori sample size calculation using g* power (version 3.1.9.7, Dusseldorf, Germany) estimated that a minimum total sample size of 214 athletes was required (n = 107 per sport for rugby and football) based on two independent Pearson's r tests with moderate correlation between variables (r = 0.50, α = 0.05 and β = 0.95).…”

“…[10][11][12] The highest value from two maximal isometric contractions of neck flexors, extensors and lateral flexors was recorded. [10][11][12] An a priori sample size calculation using g* power (version 3.1.9.7, Dusseldorf, Germany) estimated that a minimum total sample size of 214 athletes was required (n = 107 per sport for rugby and football) based on two independent Pearson's r tests with moderate correlation between variables (r = 0.50, α = 0.05 and β = 0.95). To account for a likely recruitment of more males than females it was estimated that a minimum of 161 males and 81 females (total n = 242) was needed based on two independent Pearson's r tests with moderate correlation between variables (r = 0.50, α = 0.05 and β = 0.95).…”