Background: Therapeutic climbing exercises are employed for the treatment of shoulder-and knee-joint injuries. However, there is a void in the literature regarding muscle activation levels during the performance of these exercises. Thus, the purpose of this study was to investigate differences in muscle activation during therapeutic climbing exercises depending on the degree of task difficulty. Participants/Material and Methods: A sample of 10 healthy subjects (sex: 4 females, 6 males; age: 27 +/- 3 years; climbing experience: 5 +/- 3 years) performed three shoulder girdle (i.e., wide shoulder pull, narrow shoulder pull, shoulder row) and two leg extensor (i.e., ascending frontal, ascending sidewards) exercises. Electromyographic (EMG) data were recorded on the right side for eleven muscles and then normalised using the maximum voluntary contractions for each muscle. Results: With increasing task difficulty, muscle activity in all but one muscle (i.e., m. trapezius ascendens) increased significantly for the three shoulder girdle exercises. For the two leg extensor exercises, an increase in task difficulty produced a tendency towards yet not significantly higher muscle activity. Conclusion: Shoulder row was the most effective therapeutic climbing exercise in the ability to activate muscles while showing the highest EMG signals. The absence of significant differences in muscle activity between the two leg extensor exercises indicates their equivalent use for muscle activation during therapy.