Myofibrillar hypertrophy is an increase in the number and size of myofibrils in your muscle fibres. (fitnesscrest.com)
Myofibrillar hypertrophy is where the muscle's myofibrils increase in size and number which is responsible for the contraction of the muscle (strength.) (fitnesscrest.com)
Developmental regulation of MURF ubiquitin ligases and autophagy proteins nbr1, p62 / SQSTM1 and LC3 during cardiac myofibril assembly and turnover. (abcam.com)