Operationally ready: the association between motivation, psychological needs and health behaviours in Royal Naval...

Musculoskeletal injuries (MSKIs) are a leading cause of medical downgrades and reduced operational effectiveness in the UK military. Initial military training presents a high-risk period for sustaining MSKI but also provides an important opportunity for promoting positive health-related behaviours to mitigate future MSKI risk. Self-determination theory suggests that environments supporting basic psychological needs of autonomy, competence and relatedness can foster intrinsic motivation regulation and positive health-related behaviours. However, this link between environment and behaviour remains underexplored in military populations.

Weight-related health risk (determined from individual body weight, height and waist circumference) and health behaviours (relative to the Defence Health Behaviour Index) were assessed in 1591 Royal Navy participants (15.6% females; age range 16-61 years), comprising 941 recruits, 190 officer cadets and 460 trained personnel. Participants also completed the Work Behaviour Regulation Questionnaire and Basic Psychological Need Satisfaction and Frustration Scale. Linear regression and Multivariate Analysis of Covariance were used to explore relationships and group differences.

Supporting basic psychological needs in the workplace was positively associated with autonomous motivation (p<0.002), which was also associated with more favourable health behaviours (β=0.119, p<0.001). Frustrating psychological needs were associated with controlled motivation (p<0.001) and poorer health behaviours (β=0.082, p=0.006). Trained personnel reported higher weight-related ill-health risk, poorer health behaviours and greater psychological need frustration than trainees (p<0.001). Recruit trainees had the highest psychological need satisfaction but also the greatest introjected and external motivation regulations (driven by internal pressures or external rewards). Female and trained personnel exhibited greater weight-related ill-health risk (OR=0.51, p<0.001).

The data suggest that creating need-supportive military environments fosters autonomous motivation-promoting positive health-related behaviours. Establishing need-supportive environments during early-career phases could improve effectiveness in supporting positive health behaviours and mitigating MSKI risk.