🦴 Use It or Lose It: How Skeletal Muscles Adapt Help students understand how skeletal muscles change with activity and inactivity in this engaging, science-based reading! This resource explains muscle hypertrophy, atrophy, aerobic vs. resistance exercise, muscle fiber types, and modern medical applications in a clear, student-friendly way. Students will explore how muscles grow stronger with use, shrink with disuse, and how different types of exercise lead to different physiological adaptatio