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Measuring Neuromuscular Junction Functionality
Published on: August 6, 2017
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Muscle strength, size, and neuromuscular function before and during adolescence
Zachary M Gillen1, Marni E Shoemaker1, Brianna D McKay1
1Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA.
European Journal of Applied Physiology
|May 16, 2019
Summary
Muscle strength differences between adolescent boys and girls are linked to neuromuscular adaptations and biological maturity, not just age. High-strength individuals show greater muscle size and efficiency.
Area of Science:
- Human physiology
- Sports science
- Developmental biology
Background:
- Muscle strength, size, and neuromuscular function are critical components of physical performance.
- Understanding developmental changes in these parameters is essential for optimizing training and development in young athletes.
- Significant variations in strength exist among pre-adolescent and adolescent youth.
Purpose of the Study:
- To compare muscle strength, size, and neuromuscular function between pre-adolescent and adolescent boys and girls with differing strength levels.
- To investigate the relationship between biological maturity, muscle characteristics, and strength capabilities in youth.
- To differentiate between age and biological maturity as factors influencing strength development.
Main Methods:
- Categorized participants into low strength (LS) and high strength (HS) groups based on isometric leg extensor strength.
- Measured anthropometric data (height, weight) and estimated body composition (percent body fat, fat-free mass).
- Assessed muscle cross-sectional area (CSA) using ultrasound and recorded electromyographic (EMG) and mechanomyographic (MMG) signals during isometric contractions to evaluate neuromuscular responses and efficiency.
Main Results:
- High-strength individuals were significantly older, taller, heavier, more biologically mature, and possessed greater quadriceps femoris muscle CSA compared to low-strength individuals.
- High-strength individuals demonstrated significantly higher neuromuscular efficiency (NME) in both EMG and MMG measures.
- Even after accounting for anthropometric and muscle size differences, high-strength individuals remained significantly stronger, suggesting intrinsic neuromuscular factors contribute substantially to strength disparities.
Conclusions:
- Neuromuscular adaptations play a crucial role in the increase of muscle strength from pre-adolescence to adolescence.
- Biological maturity is a more significant determinant of strength differences than chronological age alone, especially in large, force-producing muscles.
- These findings highlight the importance of considering maturity status when assessing and training young individuals for strength development.
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