Which behavior is characterized by a client expressing doubt in their ability to perform an exercise?

The behavior described indicates that the client is experiencing low self-efficacy. Self-efficacy refers to an individual's belief in their ability to perform a specific task or achieve a goal. When a client expresses doubt in their ability to perform an exercise, it signifies a lack of confidence in their capabilities, which is the essence of low self-efficacy.

When clients feel they are not capable of succeeding in a particular exercise or task, they may be less likely to engage in that behavior, which can hinder their progress towards fitness or health goals. Building self-efficacy is critical for behavior change, as those with high self-efficacy are more likely to take on challenges, remain motivated, and persist in the face of obstacles. Therefore, when assessing a client's attitude towards exercise, recognizing expressions of doubt as indicators of low self-efficacy can help trainers tailor their approach to nurturing the client's confidence and ability to succeed.