Final answer:
The Maximal Strength Phase of the OPT model is designed to improve the maximum amount of force a muscle can exert in a single contraction, through heavy weight lifting and lower repetitions, targeting muscular strength rather than endurance or size.
Step-by-step explanation:
The Maximal Strength Phase of the Optimum Performance Training (OPT) model primarily focuses on improving maximal strength. This phase emphasizes lifting heavy weights with lower repetitions to increase a muscle's ability to exert the maximum amount of force during contraction. Unlike muscular endurance, which is the muscle's ability to contract repeatedly over time, or hypertrophy, which involves increasing muscle size, the goal of the maximal strength phase is singular: to maximize the amount of weight you can lift in a single effort. Resistance exercise during this phase leads to adaptations in muscle and connective tissue strength, enabling the body to handle heavier loads. This training often results in increased muscle fiber recruitment as well as enhancements in nervous system efficiency in activating muscles.