Which phase of the OPT model introduces lifting near or at maximal intensity?

The phase of the OPT model that introduces lifting near or at maximal intensity is indeed Phase 4. This phase, known as "Maximal Strength Training," focuses specifically on increasing an individual's ability to exert maximal force. During this stage, the training protocol emphasizes lifting heavy weights for fewer repetitions, which is designed to develop strength and power.

In this phase, individuals typically engage in fewer sets with higher weights, which allows them to reach their potential strength levels. The adaptation during this phase is crucial for those looking to enhance athletic performance or gain significant muscle mass, as it pushes the body to adapt to higher loads.

The other phases of the OPT model focus on different training outcomes. Phase 1 is geared towards stabilization and endurance, Phase 2 emphasizes strength endurance, and Phase 3 focuses on hypertrophy or muscle growth. Each phase has a distinct training objective that builds upon the adaptations developed in the prior phases, culminating in the proficiency required to engage in maximal strength training in Phase 4.