Primary Schools

The Complete Guide to Child Fitness (AKA How to Grow Up Strong!)

Little Boy Playing on a Slide

These days, it’s hard to get away from the need to be physically fit. Whether it’s celebrity slimming plans, spiralling obesity statistics, gym promotions, or rows over food labelling, we’re constantly bombarded with one message. Get fit or suffer the consequences.

And we’re well aware of what this means. Heart disease, diabetes, strokes, cancer, high blood pressure, joint pain, depression. It’s become a well-worn chorus, a dogeared refrain repeated endlessly in newspapers and TV shows like Embarrassing Bodies. Eat right and move regularly or risk early death.

Yet, the numbers keep climbing. In the UK, 29% of girls under 18 are overweight or obese. The number is only slightly lower for boys, at 26%. So, perhaps our understanding of what it means to be fit needs work. There’s no shortage of guidance on foods to avoid and how regularly we should exercise, but few insights on WHAT makes a person physically fit.

The Fantastical World of Fundamental Fitness

Many people (parents and teachers included) are unaware that physical fitness covers two categories – health and skill. Health related fitness is essential for everyday activities. It allows a person to get through the day without struggling. For kids, this means getting out of bed, paying attention at school, doing homework, playing with friends, and enjoying life.

Skill related fitness is a consequence of health related fitness. With a healthy body, you can run faster, jump higher, and feel stronger. Healthy kids harness their energy to play sports, exercise, run from danger, and move safely through different environments. You don’t need to be fast or strong to be physically fit but being physically fit makes both possible.    

Health Related Fitness

There are six components of health related fitness. Healthy bodies tick all of the following boxes:


The ability to use, move, and extend the joints through a broad range of movements. Some kids will be more flexible than others. However, they should all be able to touch their toes with straight legs, fully extend their arms, and rotate their legs at the hips.

Body Composition

This is the most familiar component and the one that attracts most attention. It measures the percentage of fat, in relation to height and weight. Healthy ranges can vary wildly among children because they grow so quickly. It means there’s lots of wiggle room, but kids between the 85th and 94th percentiles are generally considered overweight. Kids above the 95th percentile are considered obese.

Cardiovascular Endurance

Healthy kids tend to excel in this area without giving it much thought. They can run, swim, climb trees, and kick footballs for hours on end. This is because they have strong hearts and efficient lungs that pump oxygen around the body at speed.

Muscular Endurance

Muscular endurance is at its highest potential during childhood, because kids are constantly on the move. The more they bend, twist, throw, kick, and race, the stronger the muscles become. This type of endurance is very much ‘use it or lose it’ - do five push ups today and you can probably do eight tomorrow.


Strength is the amount of force your muscles can produce. The easiest way to test this is to lift or push against heavy objects. The definition of ‘strong’ is different for everybody, but kids should be able to support the weight of their own body. Mastering the monkey bars, for example, comes pretty easy to most.  


For a long time, power was equated with strength. In recent years, however, it has been defined as the ability to use strength quickly and precisely. For example, a child leaping over a log demonstrates physical power. They can jump high or break into a sprint almost instantly.  

Skill Related Fitness

There are five components of skill related fitness. Children with a high level of health related fitness can develop the following abilities:


The ability to stabilise the body in a preferred position. The most obvious example is balancing on one leg, but free handstands and crawling require stability too. Balancing is useful for all sports but particularly valuable in gymnastics, football, and squash.


Coordination is used to combine multiple movements. Juggling is a great example, as it only works if a person can move two arms and hands in sync. Hitting or catching balls – football, tennis, netball – requires coordination. The brain converts data from the eyes and ears into messages about how and where to move.


The ability to perform movements very quickly. We tend to think of running as the only demonstration of speed, but some kids have faster arms than legs. They can throw a ball exceedingly fast and excel at batting sports.


Agility is hugely beneficial, because it allows kids to switch smoothly between movements. It brings together speed, coordination, flexibility, and balance. Even simple primary school games involve complex sequences of jumping, stretching, kicking, and bending, so agility develops early for most.  

Reaction Time

Finally, reaction time describes the ability to move fast, in response to external triggers. This could be a whistle, an incoming ball, or a friend barrelling towards you in the playground. Reaction time is important for sports, as there’s little time to plan how and where to move.      

It’s never too late to improve general fitness or develop movement skills. With the right training and support, ALL children have the opportunity to grow up big and strong.   

Join Our Healthy Schools Programme for FREE!

We want every child to feel healthy, be active and live life to the full! It's why we launched the Amaven Healthy Schools Programme.

It aims to increase physical activity in schools and provide pupils with a deeper understanding of fitness, movement, healthy eating, emotional wellbeing and more. Alongside FREE access to Amaven software, you'll receive:

  • Wellness Kickstart Day Hosted by Amaven Coaches
  • Onsite and Online CPD for Teachers
  • Impact Reports for Evidencing PE Spending
  • Exclusive Lesson Plans & Resources 
  • Personalised Home Activities for Pupils
  • Bespoke Health & Wellbeing Strategy


Join our Healthy Schools Programme

Please select a convenient time and date *
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.