Trainer-exerciser relationship: The congruency effect on exerciser psychological needs using response surface analysis.

Perceptions of fitness trainers' need-supportive and need-thwarting behaviors have been shown to impact exercisers' psychological need satisfaction and frustration. Currently, it is unknown whether an agreement or disagreement between exercisers' and fitness trainers' reported perceptions of these behaviors leads to the satisfaction and/or frustration of psychological needs. Based on self-determination theory, the present study examined the effect of congruency between fitness trainers' and exercisers' perceptions of need-supportive and need-thwarting interpersonal behaviors on basic psychological need satisfaction and frustration. A sample of 130 fitness trainers (43 females; Mage  = 31.58 ± 7.65) and a total of 640 gym exercisers (350 females; Mage  = 34.23 ± 11.59) participated in this study. Findings suggested that the majority of fitness trainers tended to over-report their use of need-supportive behavior and under-report their need-thwarting behaviors. Results showed that when there was congruency between fitness trainers' reported use and exercisers' perception of interpersonal behaviors, basic need satisfaction tended to increase. This effect was greater for exercisers that rated their respective fitness trainer high on relatedness support. Fitness trainers should be self-aware of their interpersonal behaviors when engaging with exercisers and interventions based on self-determination theory could serve as a promising avenue to improve the quality of exercisers' experience.