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Muscle strength, size, and neuromuscular function before and during adolescence.
Eur J Appl Physiol. 2019 Jul; 119(7):1619-1632.EJ

Abstract

PURPOSE

To compare measurements of muscle strength, size, and neuromuscular function among pre-adolescent and adolescent boys and girls with distinctly different strength capabilities.

METHODS

Fifteen boys (mean age ± confidence interval: 13.0 ± 1.0 years) and 13 girls (12.9 ± 1.1 years) were categorized as low strength (LS, n = 14) or high strength (HS, n = 14) based on isometric maximal voluntary contraction strength of the leg extensors. Height (HT), seated height, and weight (WT) determined maturity offset, while percent body fat and fat-free mass (FFM) were estimated from skinfold measurements. Quadriceps femoris muscle cross-sectional area (CSA) was assessed from ultrasound images. Isometric ramp contractions of the leg extensors were performed while surface electromyographic amplitude (EMGRMS) and mechanomyographic amplitude (MMGRMS) were recorded for the vastus lateralis (VL). Neuromuscular efficiency from the EMG and MMG signals (NMEEMG and NMEMMG, respectively) and log-transformed EMG and MMG vs. torque relationships were also used to examine neuromuscular responses.

RESULTS

HS was 99-117% stronger, 2.3-2.8 years older, 14.0-15.7 cm taller, 20.9-22.3 kg heavier, 2.3-2.4 years more biologically mature, and exhibited 39-43% greater CSA than LS (p ≤ 0.001). HS exhibited 74-81% higher NMEEMG than LS (p ≤ 0.022), while HS girls exhibited the highest NMEMMG (p ≤ 0.045). Even after scaling for HT, WT, CSA, and FFM, strength was still 36-90% greater for HS than LS (p ≤ 0.031). The MMGRMS patterns in the LS group displayed more type I motor unit characteristics.

CONCLUSIONS

Neuromuscular adaptations likely influence strength increases from pre-adolescence to adolescence, particularly when examining large, force-producing muscles and large strength differences explained by biological maturity, rather than simply age.

Authors+Show Affiliations

Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA.Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA.Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA.Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA.Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA.Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 211 Ruth Leverton Hall, Lincoln, NE, 68583, USA. jcramer@unl.edu.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31087141

Citation

Gillen, Zachary M., et al. "Muscle Strength, Size, and Neuromuscular Function Before and During Adolescence." European Journal of Applied Physiology, vol. 119, no. 7, 2019, pp. 1619-1632.
Gillen ZM, Shoemaker ME, McKay BD, et al. Muscle strength, size, and neuromuscular function before and during adolescence. Eur J Appl Physiol. 2019;119(7):1619-1632.
Gillen, Z. M., Shoemaker, M. E., McKay, B. D., Bohannon, N. A., Gibson, S. M., & Cramer, J. T. (2019). Muscle strength, size, and neuromuscular function before and during adolescence. European Journal of Applied Physiology, 119(7), 1619-1632. https://doi.org/10.1007/s00421-019-04151-4
Gillen ZM, et al. Muscle Strength, Size, and Neuromuscular Function Before and During Adolescence. Eur J Appl Physiol. 2019;119(7):1619-1632. PubMed PMID: 31087141.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Muscle strength, size, and neuromuscular function before and during adolescence. AU - Gillen,Zachary M, AU - Shoemaker,Marni E, AU - McKay,Brianna D, AU - Bohannon,Nicholas A, AU - Gibson,Sydney M, AU - Cramer,Joel T, Y1 - 2019/05/13/ PY - 2018/12/22/received PY - 2019/04/24/accepted PY - 2019/5/16/pubmed PY - 2019/11/28/medline PY - 2019/5/16/entrez KW - Electromyography KW - Isometric strength KW - Mechanomyography KW - Youth SP - 1619 EP - 1632 JF - European journal of applied physiology JO - Eur. J. Appl. Physiol. VL - 119 IS - 7 N2 - PURPOSE: To compare measurements of muscle strength, size, and neuromuscular function among pre-adolescent and adolescent boys and girls with distinctly different strength capabilities. METHODS: Fifteen boys (mean age ± confidence interval: 13.0 ± 1.0 years) and 13 girls (12.9 ± 1.1 years) were categorized as low strength (LS, n = 14) or high strength (HS, n = 14) based on isometric maximal voluntary contraction strength of the leg extensors. Height (HT), seated height, and weight (WT) determined maturity offset, while percent body fat and fat-free mass (FFM) were estimated from skinfold measurements. Quadriceps femoris muscle cross-sectional area (CSA) was assessed from ultrasound images. Isometric ramp contractions of the leg extensors were performed while surface electromyographic amplitude (EMGRMS) and mechanomyographic amplitude (MMGRMS) were recorded for the vastus lateralis (VL). Neuromuscular efficiency from the EMG and MMG signals (NMEEMG and NMEMMG, respectively) and log-transformed EMG and MMG vs. torque relationships were also used to examine neuromuscular responses. RESULTS: HS was 99-117% stronger, 2.3-2.8 years older, 14.0-15.7 cm taller, 20.9-22.3 kg heavier, 2.3-2.4 years more biologically mature, and exhibited 39-43% greater CSA than LS (p ≤ 0.001). HS exhibited 74-81% higher NMEEMG than LS (p ≤ 0.022), while HS girls exhibited the highest NMEMMG (p ≤ 0.045). Even after scaling for HT, WT, CSA, and FFM, strength was still 36-90% greater for HS than LS (p ≤ 0.031). The MMGRMS patterns in the LS group displayed more type I motor unit characteristics. CONCLUSIONS: Neuromuscular adaptations likely influence strength increases from pre-adolescence to adolescence, particularly when examining large, force-producing muscles and large strength differences explained by biological maturity, rather than simply age. SN - 1439-6327 UR - https://www.unboundmedicine.com/medline/citation/31087141/Muscle_strength_size_and_neuromuscular_function_before_and_during_adolescence_ L2 - https://dx.doi.org/10.1007/s00421-019-04151-4 DB - PRIME DP - Unbound Medicine ER -