Teixeria approved because the results of his study showed that intrinsic motives were positively associated with exercise behavior in all samples. He stated that exercisers are more likely to adhere to a program or plan if they are participating in activities they enjoy rather than those that are forced or pressured (Teixeira). .
A study by Christina Frederick also supports intrinsic motives over extrinsic. She states it is important for individuals to understand the negative influences extrinsic motivation has on participation, regardless of the value of adherence; and these negative influences include feelings of pressure and anxiety, and a lack of enjoyment of the exercise regiment, which could lead to abandoning exercise entirely (Frederick). Secondly, this theory supports that people have three innate psychological needs that, if satisfied, can increase vitality, optimal function and growth, and well-being. The three needs are autonomy, competence, and relatedness. The need for autonomy reflects the desire of individuals to be the origin of their own behavior, and when satisfied, individuals perceive their behavior as self-endorsed (Vlachopoulos). Autonomy is expressed as the freedom of choice, and individuals prefer to be involved in exercising because they chose to do so and not because external factors have pressured them. Competence is explained by individuals' experiences with success or failure, or the extent to which they are good or bad at something. People want to perform well on an activity; therefore, they are more likely to participate in something they are good at, in contrast to participating in something they are weak or bad at because they are more likely to quit and dropout. .
Lastly, relatedness reflects the need for one to have close relationships and personal connections with others. It is the universal want to interact, be connected to, and experience caring for and from others.
