Certified Personal Trainer (NSCA) Practice Exam 2025 – Complete Prep Guide

Improved skill in performing the exercise is primarily responsible for strength gains after three weeks of resistance training due to the body's adaptation to the demands of the exercises. In the initial phase of resistance training, most strength gains are attributed to neural adaptations rather than changes in muscle size.

During the first few weeks of training, the nervous system becomes more efficient at activating muscle fibers, which enhances coordination and increases the recruitment of motor units. This means that the individual's ability to perform the exercises improves significantly, allowing them to lift heavier weights or perform more repetitions with the same weight.

As individuals practice the movements, they also develop better technique and learn to engage the right muscles more effectively, which contributes to increased strength. While muscle hypertrophy (the growth of muscle fibers) can contribute to strength gains over a longer period, it typically takes several weeks to months of consistent training to manifest.

Muscle hyperplasia, which refers to an increase in the number of muscle fibers, is a process that has not been conclusively shown to significantly contribute to strength gains in humans, especially in the early phases of training. Increased co-contraction is related to muscle timing and coordination but does not account for the substantial initial strength improvements seen in new trainees. Thus, for the