Mixed

Using external momentum (cheat repetitions) during single-joint upper body resistance training produces muscle hypertrophy equivalent to strict technique, despite generating significantly higher volume load.

If you are doing single-joint exercises like bicep curls or tricep pushdowns, you don't need to be rigid about 'strict' form to maximize muscle growth. Using 'cheat' reps (adding momentum) allows you to lift more total volume, which resulted in the same muscle growth as strict reps in this study. However, be cautious of joint stress, especially in your back and hips, as momentum can increase injury risk. Use this technique strategically, perhaps at the end of a set, rather than for every rep, to balance gains with safety.