Constructs	Statements
Perceived Autonomy (PA)	PA1: My fitness apps usage is consistent with my preferences and interests.
	PA2: I have several options when deciding how to use my fitness app.
	PA3: I feel free to decide what activities to do in my fitness app.
	PA4: I have the opportunity to make choices and set goals on my fitness app.
Perceived Competence (PC)	PC1: I feel I have made a lot of progress in relation to the goal I want to achieve using my fitness app.
	PC2: I think that I am good enough when I use my fitness app.
	PC3: I am satisfied with my performance when using my fitness app.
	PC4: I often feel that I am competent when using my fitness app.
Perceived Relatedness (PR)	PR1: When I use my fitness app, I feel like other people care what I do.
	PR2: I really like the people in my fitness app social network.
	PR3: The people in my fitness app social network are friendly towards me.
Fitness App Quality (FAQ)	FAQ1: The functionality of my fitness app allows me to complete my activities.
	FAQ2: Overall, my fitness app is highly reliable.
	FAQ3: My fitness app is efficient in allowing me to complete my exercise.
Perceived Benefits (PB)	PB1: My fitness app helps improves the quality of my life.
	PB2: My fitness app helps me enhance my physical fitness.
	PB3: My fitness app increases my productivity in doing exercises.
Perceived Hedonic Gratification (PHG)	PHG1: I find using my fitness app to be enjoyable.
	PHG2: I have fun interacting with my fitness app.
	PHG3: I find the experience of the exercise and the related fitness app use pleasant.
	PHG4: I find the experience of the exercise and the related fitness app use exciting.
Perceived Competitive Climate (PCC)	PCC1: The amount of recognition I get within my social network in this fitness app depends on how my rank on leaderboard compares to others.
	PCC2: My friends within this fitness app frequently compare their results of physical activity performance with mine.
	PCC3: Others within this fitness app frequently compare their results of physical activity performance with mine.
Social Comparison (SC)	SC1: I often compare my performance with others.
	SC2: The amount of recognition I get within my social network in my fitness app depends on how my rank on leaderboard compared to others.
	SC3: My friends within my fitness app network frequently compare their results of physical activity performance with mine.
	SC4: Other fitness app users frequently compare their results of physical activity performance with mine.
Facilitating Conditions (FC)	FC1: My social network (e.g., family, friends, colleagues) encourages me to exercise more and keep fit.
	FC2: My fitness apps are well-matched with other technologies that I use.
	FC3: My fitness apps promote physical activities.
Intrinsic Motivation (IM)	IM1: I use my fitness app because it is fun.
	IM2: I use my fitness app because it is interesting.
	IM3: I use my fitness app because I like it.
Extrinsic Motivation (EM)	EM1: I use my fitness app because I will feel bad about myself when I do not carry out physical activities.
	EM2: I feel under pressure from my friends/family to be physically active.
	EM3: I use my fitness app because other people say I should.
	EM4: I use my fitness app because I feel guilty when I do not exercise.
Continued Use (CU)	CU1: I intend to continue using my fitness apps rather than discontinue their use
	CU2: In my opinion, it is desirable to continue using fitness apps.
	CU3: I plan to continue using my fitness app.
	CU4: I think that continuously using my fitness app for exercise is a good idea.