Context: The Feeling Scale (FS) is a unique and underexplored scale in sport sciences that measures affective valence. The FS has the potential to be used in athletic environments as a monitoring and prescription tool. Purpose: To examine whether FS ratings, as measured on a repetition-by-repetition basis, can predict proximity to task failure and bar velocity across different exercises and loads. Methods: On the first day, 20 trained participants (10 females) completed 1-repetition-maximum (1-RM) tests in the barbell bench and squat exercises and were introduced to the FS. In the following 3 sessions, participants completed 3 sets to task failure with either (1) 70% 1-RM bench press, (2) 70% 1-RM squat (squat-70%), or (3) 80% 1-RM squat (squat-80%). Sessions were completed in a randomized, counterbalanced order. After every completed repetition, participants verbally reported their FS ratings. Bar velocity was measured via a linear position transducer. Results: FS ratings predicted failure proximity and bar velocity in all 3 conditions (P < .001, R2 .66–.85). Based on the analysis, which included over 2400 repetitions, a reduction of 1 unit in the FS corresponded to approaching task failure by 14%, 11%, and 11%, and to a reduction in bar velocity of 10%, 4%, and 3%, in the bench, squat-70%, and squat-80%, respectively. Conclusion: This is the first study to investigate whether the FS can be used in resistance-training environments among resistance-trained participants on a repetition-by-repetition basis. The results indicate that the FS can be used to monitor and prescribe resistance training and that its benefits should be further explored.