Family Plank Challenge: 21 Days With Fair Scoring

Here is a challenge that needs no kit, takes under five minutes a day and works for a 6-year-old, a teenager and a tired parent at the same time. A family plank challenge is simple: everyone holds a plank once a day for 21 days, and everyone has their own target. The trick is making it fair, so the youngest is not crushed by the 14-year-old and the parent does not end up on the floor wondering why they agreed to this. Below you will find a 21-day plan, kid-sized targets, a tracker you can copy onto paper and a scoring system that keeps mixed ages competitive.

Why planks work for a family challenge

• Everyone can do a version. Knees down, hands on a sofa or full plank on toes.
• No space needed. The length of a body on the living room floor.
• Short and measurable. Kids love watching the timer go up.
• Quiet. No jumping, so you can do it after tea in a flat without upsetting the neighbours.

It also nudges everyone towards more movement. The NHS physical activity guidelines for children and young people say children aged 5 to 18 should do activities that strengthen muscles and bones across the week, alongside an average of at least 60 minutes of moderate or vigorous activity a day. A plank on its own will not get them there, but it is a fun daily habit to build on.

How to plank properly (for all ages)

1. Forearms on the floor, elbows under shoulders.
2. Legs straight back, toes tucked (or knees down for the easier version).
3. Body in a straight line from head to heels, or head to knees. No bum in the air, no sagging hips.
4. Squeeze your bum and tummy, and keep breathing.
5. The plank is over when the shape breaks, not when you collapse.

That last rule is important for kids. A 20-second plank with a straight body beats a 60-second banana shape. Parents get to be the “form judges”, which children take extremely seriously.

Family plank challenge targets by age

These are starting points, not rules. Children vary a lot. Let each person do a test plank on day 1 and adjust.

Who	Version	Day 1 target	Day 21 target
Ages 5 to 7	Knees down or hands on the sofa	10 seconds	20 to 30 seconds
Ages 8 to 11	Knees down, moving to toes	15 seconds	30 to 45 seconds
Ages 12 to 16	Full plank on toes	20 seconds	45 to 60 seconds
Parents	Whatever version you can hold with good form	Your test time	Test time plus 20 to 30 seconds

For under-5s, keep it as play. Let them do a “bear” on hands and feet or copy you for a few seconds. No targets needed.

The 21-day plan

• Days 1 to 7: 2 planks a day at your starting target, with 30 seconds rest between.
• Days 8 to 14: add 5 seconds to your target. Still 2 planks.
• Day 15: rest day. Do a family walk instead.
• Days 16 to 20: add another 5 seconds. Try 1 side plank each side (knees down for younger ones) as a bonus.
• Day 21: test day. One all-out plank with good form. Compare it to day 1.

If anyone is ill, skip the day. Missing a day does not reset the challenge.

A tracker you can copy

Draw this on a sheet of paper and stick it on the fridge. Each person gets a row, and each day gets a box.

Name	Target	Days 1 to 7	Days 8 to 14	Days 16 to 20	Day 21 result
Parent		7 boxes	7 boxes	5 boxes
Child 1		7 boxes	7 boxes	5 boxes
Child 2		7 boxes	7 boxes	5 boxes

Younger kids can colour or sticker a box each time. Teens may prefer a note on their phone. Either works.

Fair scoring for mixed ages

Comparing raw seconds is unfair. The 14-year-old will win every time and the 6-year-old will lose interest by day 3. Score effort instead:

• 1 point for every day you complete your plank.
• 1 bonus point for every day you hit your personal target with good form.
• 5 points on day 21 for beating your own day 1 time.
• Percentage prize: whoever improves their time by the biggest percentage wins the final round. A child going from 10 to 25 seconds beats a parent going from 40 to 60.

Pick a reward that is not food: choosing the weekend activity, the film, or what the family does on the rest day.

A note for parents

If you are pregnant, have recently had a baby, have a tummy gap after pregnancy or have back pain, check with your GP or a physio before doing planks. You can still be the timer and the form judge. My guide to plank progressions for beginners has gentler starting points, and if you are wondering whether this kind of exercise is fine for younger kids, see is strength training safe for children.

Where a class fits

Once the 21 days are done, keep the habit going. For more ideas, see my list of family fitness challenges. For your own training, a bootcamp class builds the strength around your core that makes planks feel easier. If you are often running on empty, my SYP Recharge energy and focus class is a good one to start with.

FAQs

How long should a child hold a plank?

For most young children, 10 to 30 seconds with good form is plenty. Older children and teens can work up to around a minute. Form matters more than time.

Are planks safe for kids?

Short bodyweight planks are generally fine for healthy children when done with good form. Stop if anything hurts, and check with your GP if your child has a health condition.

What is a good plank time for a beginner adult?

20 to 30 seconds with a straight body is a solid start. Build up slowly rather than holding a poor position for longer.

How do you make a plank challenge fun?

Give everyone their own target, score effort rather than raw time, let kids judge form and finish with a test day and a non-food reward.

Book your first class

The kids are planking. Now it is your turn. SYP Bootcamp runs 45-minute small-group classes indoors in a church hall in Archway N19, max 10 people, £15 a class, for all fitness levels. Book your £15 class here or call or WhatsApp me on 07301 512215. If you want a fully structured 1-1 plan for yourself, take a look at my transformation programme.

About the author

Artem Olekhnovych is a personal trainer in Archway and the founder of SYP Fitness and SYP Bootcamp. He has coached clients in Archway, Highgate and across North London for over 10 years, and runs small-group bootcamp classes for busy mums and dads. Read reviews from his 1-1 clients.