How six months of exercise affected self-concept and well-being in middle-aged adults
Two randomized field experiments published in 2000 tested six-month exercise programs in middle-aged adults, tracking physical self-concept, self-esteem and subjective well-being and comparing exercise with wait-list or active attention-control conditions.
What the study did and found
Alfermann and Stoll published Effects of physical exercise on self-concept and well-being in 2000 in the International Journal of Sport Psychology. The paper reported two field experiments in middle-aged adults, with participants randomly assigned to exercise or control conditions. In Experiment 1, 24 women and men completed a six-month exercise program and were compared with 13 people on a wait-list. Physical self-concept, self-esteem and subjective well-being were measured before and after the intervention. The exercise group showed greater improvement in physical self-concept and fewer psychosomatic complaints than the wait-list group.
Experiment 2 used an active attention-control comparison. Fifty-seven adults participated in six-month running or mixed-sports programs, while 36 control participants took part in relaxation or back-training. Outcomes were measured before and after the program and again six months later. The Exercise and Self-Esteem Model (EXSEM) was only partially replicated. The authors also observed improvement over time in dependent variables and motor performance outside the exercise groups, leading them to conclude that exercise can support mental health but is not the only intervention capable of producing change.
Why it is cited
The paper has been cited in later work on physical activity, self-esteem, self-concept and psychological well-being. Its two field experiments remain relevant because participants were randomly assigned, and Experiment 2 used active attention controls - relaxation or back-training - rather than a no-treatment comparison. That design supports a cautious reading: psychological change was not exclusive to exercise, a limitation already reflected in the original authors' interpretation.
Later evidence supports an association between physical activity and well-being, while also showing that effects vary by outcome, population and study design. A meta-analytic review by Buecker and colleagues, published in 2021, found a small positive overall relationship between physical activity and subjective well-being across experimental and non-experimental studies, with substantial heterogeneity. A 2026 individual-participant-data meta-analysis by Rehder and colleagues likewise found small, variable associations between physical activity and affective well-being in daily life.
The topic today
Research on this topic now separates physical self-concept, global self-esteem, affective well-being, quality of life and clinical mental-health outcomes more carefully than earlier work often did. Contemporary studies also use methods such as accelerometers, smartphones and repeated daily assessments to examine short-term, within-person links between activity and well-being. The 2000 study remains useful as an early intervention example because its own results cautioned against attributing every improvement exclusively to exercise.