Hypertrophy

Merriam-Webster Medical Dictionary defines ‘hypertrophy’ as: excessive development of an organ or part
specifically : increase in bulk (as by thickening of muscle fibers) without multiplication of parts.

In case of skeletal muscles this (hypertrophy) is what happens in those who undertake strength training. Multiple cycles of repetitions – muscle contractions/ relaxations daily compounded over weeks and months leads to hypertrophied muscle.
In the initial phase there is a lot of wear and tears (micro trauma) to the muscle causing soreness to un-accustomed muscle group but eventually this persistence leads to bulking up of the particular muscle group.

Y’hoshua (Joshua) 1:8 CJB
[8] Yes, keep this book of the Torah on your lips, and meditate on it day and night, so that you will take care to act according to everything written in it. Then your undertakings will prosper, and you will succeed.
https://bible.com/bible/1275/jos.1.8.CJB

The Hebrew word for meditate is hagah (הגה) which literally means to mutter/ to utter or speak. This day and night meditation by means of constant utterance and repetition is commonly found in the book of Psalms.
Psalm 1:2 AMPC
[2]  But his delight and desire are in the law of the Lord, and on His law (the precepts,
the instructions, the teachings of God) he habitually meditates (ponders and studies) by day and by night.
https://bible.com/bible/8/psa.1.2.AMPC

The human brain is not a muscle to be hypertrophied but the constant repetition day after day brings about a change from the inside out. Saturation with God’s truth kills the weeds of doubts and fear. Verbal repetition strengths the neural pathways in the brain responsible for memory, especially long-term memory.

Just as repetition cause muscles to hypertrophy and bulk up, become more resistant to injury & stress, repetition of God’s word causes our brains to form strong neural pathways to remind us constantly of His truth.
I believe this form of meditation is what caused David the little boy to bulk up (not physically but spiritually) to the giant Goliath. He could operate from a place of Faith when all his countrymen cowered in fear.

May God’s word be the object of our meditations as our minds bathe in the knowledge of His truth.

God bless!