Final answer:
Progression is the key method for challenging the body in workouts.
Explanation:
Progression would be the most appropriate method for Yanni to incorporate in his scenario. Progression involves gradually increasing the intensity, duration, or frequency of exercise to continue challenging the body and pushing it beyond its limits.
For example, Yanni can increase the weight he lifts, the number of repetitions he performs, or the duration of his workouts to keep pushing his body and stimulating further growth and adaptation.
By utilizing progression, Yanni can ensure that his workouts remain challenging and continue to drive improvements in his physical fitness.
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