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Updated: Oct 6, 2025
3D Ultrasound Imaging: Fast and Cost-effective Morphometry of Musculoskeletal Tissue
Published on: November 27, 2017
Associations between physical fitness components with muscle ultrasound parameters in prepuberal children
Yesenia García-Alonso1, Antonio García-Hermoso1, Alicia M Alonso-Martínez1
1Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA, Pamplona, Spain.
Insights
Physical fitness in children is linked to lower muscle fat and subcutaneous fat. Fit children show better muscle composition, indicating fitness impacts body composition from an early age.
Area of Science:
- Pediatric Exercise Science
- Musculoskeletal Ultrasound
- Body Composition Analysis
Background:
- Muscle ultrasound is a non-invasive tool for assessing muscle tissue in real-time.
- Previous studies linked muscle ultrasound parameters to physical performance in adults, but not in children.
- The relationship between physical fitness and muscle ultrasound in prepuberal children is unexplored.
Purpose of the Study:
- To investigate the association between physical fitness components and muscle ultrasound parameters in prepuberal children.
- To explore how fitness levels relate to muscle thickness, echo-intensity, and fat content in young children.
Main Methods:
- 282 children (aged 5-9 years) participated.
- Muscle ultrasound of the rectus femoris captured muscle thickness, subcutaneous adipose tissue (SAT), and intramuscular adipose tissue (IMAT).
- Physical fitness was assessed for cardiorespiratory fitness, strength, speed-agility, and overall levels.
Main Results:
- Higher physical fitness was inversely associated with echo-intensity (EI), IMAT, and SAT.
- Fit children exhibited significantly lower EI, IMAT, and SAT compared to unfit children across various fitness components.
- These associations remained significant after adjusting for sex and age.
Conclusions:
- Physical fitness components are inversely associated with muscle and adiposity ultrasound parameters in prepuberal children.
- This study highlights that physical fitness influences muscle and fat composition even in early childhood.
- Muscle ultrasound is a valuable tool for assessing body composition in relation to fitness in pediatric populations.
Background/Objectives:
Muscle ultrasound is a convenient technique to visualize normal and pathological muscle tissue as it is non-invasive and real-time. This technique is related to several physical performance parameters and body composition components in adults; however, this relationship remains unexplored in early aged. We aimed to evaluate the association between physical fitness components with muscle ultrasound parameters in prepuberal children.
Methods:
A sample of 282 prepuberal children aged 5-9 years (144 boys) participated in the study. A trained sonographer obtained six B-mode images from femoral rectus for muscle thickness, subcutaneous adipose tissue (SAT) and area of the muscle of interest, were captured, and muscle ultrasound parameters (echo-intensity: EI uncorrected, EI correct equations) and intramuscular adipose tissue (IMAT) were extracted. Lean muscle tissue has low EI, whereas intramuscular fat and connective tissue have high EI. Physical fitness components (cardiorespiratory fitness, upper and lower muscle strength, speed-agility, and overall fitness levels) were also evaluated. Children were categorized as fit or unfit for each specific fitness test.
Results:
After adjustment for sex and age, higher physical fitness components and overall fitness (z-score) levels were negatively associated with EI, IMAT, and SAT (cardiorespiratory fitness β range = -0.264 to -0.298; upper-muscular strength β range = -0.389 to -0.457; and lower-muscular strength β range = -0.202 to -0.279; and speed-agility β range = -0.257 to -0.302). Children categorized as fit according to four physical fitness components had lower EI uncorrected, EI correct equation 1-2, IMAT, and SAT than unfit children for each respective tests (all Ps < 0.001).
Conclusion:
Physical fitness components are inversely associated with EI, IMAT, SAT after adjusting for potential confounders, including sex and age, in prepuberal children. The present study strengthens the idea that muscle and adiposity parameters is affected by physical fitness even from early childhood.
