THE ROLE OF MUSCLE STRENGTH AND MASS IN CHILDREN AND ADOLESCENTS
PROLOGUE: This is a lesson about your body (for children, parents, teachers)
We're not learning about records here.
We learn how to have a body that carries us through the day: in class, in the yard, at the computer, on the way home.
Strength and muscle mass are the alphabet of health.
Discover 10 chapters that explain WHY.
1. Energy for learning and concentration
What does it mean (in human terms)
Strong and active muscles help the brain work evenly, without "energy dips." This makes it easier to listen in class, remember patterns, and not let your mind wander.
How it works (simple biology)
Working muscles use glucose like a sponge, thanks to GLUT4 transporters, which reduce post-meal sugar spikes and even out blood sugar levels. This stabilizes the fuel supply to the brain.
In addition, short strength exercises increase the level of BDNF — a protein that supports the formation of neural connections (learning) — and improve sleep, which consolidates memory.
An example from real life
After lunch, Kacper used to doze off during history class. When he introduced 3 x 10 chair squats and 20 seconds of plank during his break, his "foggy" phase stopped. He says, "It's just easier for me to listen."
What can you do today (child/parent/teacher)
Child: Before a difficult lesson - 60 sec activation: 10 squats, 10 calf raises, 10 band curls.
Parent: After dinner, a quick “reset” with the child: 2 circuits (squat – wall push-up – bag row).
Teacher: at the beginning of the lesson - 30-45 seconds of "switch" (calves + breathing + 3 squats).
2. Pain-free back and better posture
What does it mean (in human terms)
Strong muscles in the core, hips, and shoulder blades hold your spine like good belts. They help you sit straighter and reduce neck pain.
How it works (simple biology)
The core creates intra-abdominal pressure, which relieves the spine.
Strong glutes and hamstrings stabilize the pelvis, and efficient muscles between the shoulder blades position the shoulders.
Regular training also strengthens the discs through better blood circulation and movement within safe ranges.
An example from real life
Zosia complained of neck pain after two lessons. After three weeks of planks, hip bridges, and band exercises, the pain disappeared, and she says, "I don't slump in my chair."
What can you do today (child/parent/teacher)
Child: daily 3×20–30 s planks, 3×12 hip bridges, 3×12 band pulldowns.
Parent: Place your child's screen at eye level; remind them to climb 10 times every 45 minutes.
Teacher: "a minute for the spine" between topics: shoulder blades down-back, 10 slow repetitions.
3. Better mood and sleep
What does it mean (in human terms)
When your muscles are working, your head feels clearer. You'll feel more calm, less tense, and it'll be easier to fall asleep.
How it works (simple biology)
Resistance exercise increases levels of myokines (e.g., irisin), endorphins, and BDNF. It also reduces low-level, chronic inflammation. This leads to a more peaceful mood and deeper NREM sleep, which "organizes" memory.
An example from real life
Michał was "always energized." After implementing three short strength sessions a week, he began falling asleep faster and stopped waking up during the night. He feels "lighter" in the mornings.
What can you do today (child/parent/teacher)
Child: 2–3 times a week, 25–30 minutes of full body circuit.
Parent: 60-90 min before bed – no screens, 5 min of breathing + 5 min of mobility.
Teacher: on test days — 45 seconds of activation before handing out papers (calves + breathing + "plank" 15 seconds).
4. Strong bones for life
What does it mean (in human terms)
During your school years, you're building a "bone bank." What you "deposit" now protects against fractures in the future.
How it works (simple biology)
Bones respond to stress (Wolff's law). Increased muscle strength increases compressive and tensile forces, which stimulates remodeling and mineral deposition. The pubertal window is the "golden period" for these stimuli.
An example from real life
Ania's results on the density test were poor. She added squats, lunges, and jumps in a controlled volume. After a year, her results and posture improved, and she was less likely to "limp" after PE.
What can you do today (child/parent/teacher)
Child: 3x a week leg exercises and jumping in small doses (e.g. 3x8 squats + 3x5 jumps).
Parent: a glass of milk/kefir or calcium equivalents every day + sun/exercise outside.
Teacher: Weave in safe landings (soft, knees over feet) and teach "quiet ground."
5. Fewer injuries, more courage
What does it mean (in human terms)
Strong legs and glutes, as well as good landing control, are a shield against injuries, especially to the knees.
How it works (simple biology)
Relative strength improves braking, knee alignment (reducing valgus), and hip stability. Neuromotor training improves responsiveness and shock absorption. The result: fewer sprains and ACL injuries, especially in girls.
An example from real life
During basketball practice, Maja landed with her knees straight. After six weeks of working on her glutes and landing technique, she began landing softly, knees over feet—injuries stopped lurking.
What can you do today (child/parent/teacher)
Child: 3x a week glute exercises (bridges, rubber abduction), squat and knee-in-axis landing.
Parent: Ask your trainer for a 5-minute preventative block (glutes + landings) at each workout.
Teacher: Landing quality scale (1-3) instead of a jump count race.
6. Faster and Higher – Strength Builds Power
What does it mean (in human terms)
Even if you're not chasing records, you run faster, jump higher, and brake more easily when you have a foundation of strength.
How it works (simple biology)
Power = strength × speed. Strength training shifts the force-velocity curve. In young people, "control quality" first improves, which provides immediate benefits in sports and physical activities.
An example from real life
Bartek "had no jump." After eight weeks of squats, band deadlifts, and low jumps, jumping up to the board was no longer "mission impossible."
What can you do today (child/parent/teacher)
Child: 2 days of strength (whole body) + 1 day of power games (jumps, short sprints, braking).
Parent: support regeneration: sleep 8–10 hours, regular meals.
Teacher: Simple power tests (standing long jump) tracked every 4 weeks.
7. Metabolism in balance (sugar under control)
What does it mean (in human terms)
Muscles are the largest storehouse of glucose. When they are active and slightly larger, it's easier to keep energy in check.
How it works (simple biology)
Muscle contraction activates GLUT4 transporters independently of insulin - glucose enters cells and turns into glycogen.
More quality muscle means more storage and fewer sharp sugar swings. This protects the pancreas and brain.
An example from real life
After a sweet snack, Ola experienced a "comedown" after 30 minutes. When she added a short walk and two sets of leg exercises after the meal, the comedown disappeared—"I can still think."
What can you do today (child/parent/teacher)
Child: after lunch 5–10 minutes of exercise (stairs, climbs, squats).
Parent: Dinner with protein and vegetables; sweet snacks "with the meal", not "in between".
Teacher: After a long sitting period - 45 seconds of calf activation ("blood pump").
8. More courage and self-confidence
What does it mean (in human terms)
Strength teaches, "I can." This translates to school, relationships, and choices.
How it works (simple biology)
Each micro-progress (one rep, 10 seconds in plank) increases self-efficacy. The brain records: effort → progress → reward. This strengthens the habit and the courage to try new things.
An example from real life
Kamil avoided PE. He was given "an assignment: +1 repetition each week." After a month, he wanted to show the class what he could do. He also started speaking up more often in math class.
What can you do today (child/parent/teacher)
Child: Keep a "journal of small victories" (3 lines: what I did, how I felt, what I will add next time).
Parent: Praise the effort and technique, not just the result (“I see you watching your knees”).
Teacher: Movement quality rubric (technique, control, focus) instead of ranking.
9. For Every Body (Inclusivity in Practice)
What does it mean (in human terms)
Strength can be scaled. It's a system where everyone has their own victory, regardless of starting position.
How it works (simple biology)
Scaling involves changing the levers, range, and supports: wall push-ups instead of floor push-ups, chair squats instead of full squats, bands instead of barbells. These are the same movement patterns, at a safe level of difficulty.
An example from real life
Basia was terrified of returning from a knee injury. She began with squatting on a high chair and doing band abductions. Five weeks later, she was running after a ball again—without pain.
What can you do today (child/parent/teacher)
Child: choose the variant that feels “clean” to you and increase the difficulty in small steps.
Parent: Don't compare your children with each other - ask: "What was 1 better today than yesterday?"
Teacher: three levels of difficulty at each station, clear criteria for passing (when the technique is "green" - advancement).
10. Habit for the Future (Your 30 Minutes a Week)
What does it mean (in human terms)
Strength and muscle are insurance for adult life: less pain, better metabolism, more agency.
How it works (simple biology)
Habits are formed from small, repetitive stimuli. In young people, immediate neural benefits predominate; hypertrophy is moderate but functional—strengthening bones and stability. This pays dividends for decades.
An example from real life
Filip started with 2 x 10 minutes a week. After two months, he "got into the rhythm." Today, he says, "If I don't do it, I feel like I'm missing a dot in my day."
What can you do today (child/parent/teacher)
Child: Schedule a “power window” (Mon, Wed, Fri after school for 10–15 minutes).
Parent: Set a family reminder and join in on one series – examples speak louder than words.
Teacher: fixed activation slot in the lesson plan (e.g. after a long break).
CONCLUSION: This is a decision about your own body
"I give my body 30 minutes of intelligent strength a week. Not for results. For health, courage, and freedom."
Bibliography
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