Childhood and Adolescent Muscle Strength: A Lifelong Health Indicator

We had previously mentioned the importance of cardiorepiratory endurance for the child's health, its impact on its future health, as well as its evolution in the past 20 years. Muscle strength, another essential component of physical condition, is also a marker of health, from an early age.

[Article issu de The Conversation, écrit par Vanhelst Jérémy, Maître de conférences en STAPS, Université Sorbonne Paris Nord, Jean-Michel Oppert, PUPH et chef de service de Nutrition à l’hôpital Pitié-Salpêtrière, Sorbonne Université]

While we have shown a drop in the child's cardiorepiratory capacities (-18.4 %) over the past 20 years, the evolution of muscle strength in young people in France remains little studied, despite its determining role for health . A recent study attempts to fill this gap by carrying out an analysis of national trends in muscle strength between 1999 and 2023. What exactly?

Muscle shape, an excellent marker for health

The muscular form can be defined according to three components: maximum strength, muscle endurance and power. In addition, the muscular strength of the lower and upper limbs are dissociated. Muscular strength is strongly associated with health (cardiometabolic diseases such as cardiovascular pathologies and type 2 diabetes, bone health, or mental health) throughout life, in young people, adults and elderly subject.

Large cohort studies have shown that a low muscle force during adolescence is associated with an increased risk of premature death, all causes combined as well as mortality linked to cardiovascular disease and adulthood cancers. It has also been shown that a low muscle force was strongly associated with the presence of physical inability in adulthood and obtaining a disability pension.

Through these solid scientific evidence, international physical condition and health experts in children highlight the importance of measuring and monitoring the muscle strength of young people. This is the object of our study among young French people.

Two simple tests to assess it in young people

Evaluating muscle strength in young people can be easily done thanks to simple, accessible, reproducible and scientifically validated tests. The two most commonly used tests are: (i) the “leap without momentum” test allowing to assess the muscular strength of the lower limbs and (ii) the test of the manual grip force, commonly called in English “Handgrip” test which makes it possible to assess the muscular strength of the upper limbs.

• The “leapless jump” test test: this first test is to position the child behind a marked line on the ground with the width of the shoulders (shoulders), the tips of the feet just behind the starting line, and Ask him to jump as far as possible by taking off and landing his feet attached. The child has the right to use the arms during the jump by making a pendulum movement. We note the distance made in cm. This test is fast, requires no expensive equipment, and provides reliable results.
• The manual grip force: it is measured using a manual dynamometer, a simple to use device. The child is asked to tighten the dynamometer as loud as possible for 2-3 seconds while standing, spread out width of the pelvis and the arm along the body. The result displayed is expressed in kilograms of pressure. Unlike the previous test, the latter requests the purchase of a device whose price ranges from 50 to 300 euros.

These two tests are inexpensive in terms of realization, without risk and adapted to the use of land for example in schools. Their simplicity and efficiency make them key tools to monitor and promote the physical form of young people and their use was recommended by the conclusions of a group of 169 international experts.

In France, growing inequalities between students

A recent study based on data of more than 53,000 French children and adolescents aged 6 to 16 assessed the evolution of muscle strength between 1999 and 2023 thanks to the two tests previously described.

The results show a slight decrease in jumping performance (about – 2 cm per decade), but an improvement in the grip force (+0.6 kg per decade). These trends are similar to those observed in other countries.

However, this study also noted an increase in performance differences between the best and the less good students, reflecting increasing inequalities. These disparities could potentially be linked to access to sports associations and different infrastructures depending on the socio-economic level of children and their families, thus reflecting an inequity of access.

The muscular strength constituting an essential indicator in the surveillance of the state of health of the population of the population, the trends observed in this recent study provide very important data on the general health state of our young French.

They also make it possible to indirectly judge the effect of public health recommendations as well as programs and initiatives in terms of promoting physical activity. The drop in physical activity, the increase in time spent in front of screens, and the decrease in registration for sports clubs can most certainly contribute to the results found in this study.

What solutions to reverse these trends?

To improve and reverse these trends, it seems essential to act on several axes:

• Strengthen school programs : The implementation of the program of 30 minutes of daily physical activity (APQ) in primary schools, in connection with the heritage of the Olympic and Paralympic Games in Paris 2024, is a first initiative that can impact muscle strength. However, it remains to be defined how and when to generalize such a prevention program and consider its evaluation.
• • Increase the sports offer within local communities : previous studies show that the inscription of a child in a sports club can have a beneficial effect on improving muscle strength.
  • Reduce access inequalities : Municipalities could develop sports infrastructure accessible to everyone and encourage policies promoting the participation of children from lower socio-economic backgrounds.
  • Encourage physical activity and reduce sedentary lifestyle : These two life behaviors will have a direct impact on the muscular strength of children in France.
  • Promote favorable environments : Secure urban development (cycle paths, parks and green spaces, accessible gymnasiums) as well as the development of public transport has a demonstrated effect to increase the usual physical activity and will impact the general physical condition of the child.

  Mobilize educators, teachers, parents, political and health professionals

  The promotion of physical condition requires general mobilization on the part of educators, teachers, as much as parents and families, but also political decision -makers and health professionals.

  Even if current trends do not demonstrate major negative evolution in terms of change with the time of the muscular strength of our young people, these recent French data highlight the importance of implementing prevention strategies focused on promoting the 'Physical activity and the reduction of sedentary lifestyle in order to preserve the health of future generations.