Abstract:
This study aimed to explain the factors that increase exercise intention. we propose a model that incorporates the Self-Determination Theory (SDT) with perceived weight stigma. A middle-aged(30-64 years)sample of 636 adults in Bangkok completed online questionnaires regarding their SDT factors, weight stigma, and exercise intention.Path analysis with lavaan(R Package)was applied to examine the model fit.Participants were divided into three groups according to BMI:normal weight(BMI=18-22.9 kg/m2,N=253),overweight(BMI=23-29.9 kg/m2,N=206) and obese(BMI ≥30 kg/m2,N=177).The results from multiple-mediator analysis showed that1)all three causal models were consistent with the empirical data(normal weight ; Χ2=11.124,df=6,p=0.085,CFI=0.990,RMSEA=0.058,SRMR=0.029,overweight ; Χ2=11.065,df=6,p=0.086,CFI=0.990,RMSEA=0.064,SRMR=0.029,obese ; Χ2=8.351,df=6,p=0.214,CFI=0.992,RMSEA= 0.047,SRMR=0.032).2)perceived weight stigma had negative effects on autonomous motivation for all weight groups3)autonomous motivation had positive effects on exercise intention for all weight groups4)competence need mediated the relation between perceived autonomy support and exercise intention for all weight groups5)relatedness need and competence need had positive effects on autonomous motivation for overweight group6)autonomy need had positive effects on autonomous motivation for normal weight and obesity groups7)the causal model of normal weight ,overweight and obesity explained 47%,50% and 41%of the variance in exercise intention,respectively.The findings suggest that 1)autonomy support and reducing weight stigma are strategy tools to enhance exercise motivation, and 2)exercise motivation module was designed based on autonomy, relatedness and competence need assessment.