Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 May;42(5):977-987.
doi: 10.1002/jum.16105. Epub 2022 Sep 29.

Adolescent Marathon Training: Prospective Evaluation of Musculotendinous Changes During a 6-Month Endurance Running Program

Alexandra F DeJong Lempke  1   2   3 , Sarah B Willwerth  2   3 , Danielle L Hunt  2   3 , William P Meehan 3rd  2   3   4 , Kristin E Whitney  2   3   4
Affiliations
Free article

Adolescent Marathon Training: Prospective Evaluation of Musculotendinous Changes During a 6-Month Endurance Running Program

Alexandra F DeJong Lempke et al. J Ultrasound Med. 2023 May.
Free article

Abstract

Objectives: Assess changes in lower extremity musculotendinous thickness, tissue echogenicity, and muscle pennation angles among adolescent runners enrolled in a 6-month distance running program.

Methods: We conducted prospective evaluations of adolescent runners' lower extremity musculotendinous changes at three timepoints (baseline, 3 months, and 6 months) throughout a progressive marathon training program. Two experienced researchers used an established protocol to obtain short- and long-axis ultrasound images of the medial gastrocnemius, tibialis anterior, flexor digitorum brevis, abductor hallicus, and Achilles and patellar tendons. ImageJ software was used to calculate musculotendinous thickness and echogenicity for all structures, and fiber pennation angles for the ankle extrinsic muscles. Repeated measures within-subject analyses of variance were conducted to assess the effect of endurance training on ultrasound-derived measures.

Results: We assessed 11 runners (40.7% of eligible runners; 6F, 5M; age: 16 ± 1 years; running experience: 3 ± 2 years) who remained injury-free and completed all ultrasound evaluation timepoints. Medial gastrocnemius muscle (F2,20 = 3.48, P = .05), tibialis anterior muscle (F2,20 = 7.36, P = .004), and Achilles tendon (F2,20 = 3.58, P = .05) thickness significantly increased over time. Echogenicity measures significantly decreased in all muscles (P-range: <.001-.004), and increased for the patellar tendon (P < .001) during training. Muscle fiber pennation angles significantly increased for ankle extrinsic muscles (P < .001).

Conclusions: Adolescent runners' extrinsic foot and ankle muscles increased in volume and decreased in echogenicity, attributed to favorable distance training adaptations across the 6-month timeframe. We noted tendon thickening without concomitantly increased echogenicity, signaling intrasubstance tendon remodeling in response to escalating distance.

Keywords: hypertrophy; intrinsic foot muscles; lower extremity; running; ultrasound imaging.

PubMed Disclaimer

References

    1. Hulteen RM, Smith JJ, Morgan PJ, et al. Global participation in sport and leisure-time physical activities: a systematic review and meta-analysis. Prev Med 2017; 95:14-25. https://doi.org/10.1016/j.ypmed.2016.11.027.
    1. Fakhouri THI, Hughes JP, Burt VL, Song M, Fulton JE, Ogden CL. Physical activity in U.S. youth aged 12-15 years, 2012. NCHS Data Brief 2014; 141:1-8.
    1. National Federation of State High School Associations. 2018-2019 High School Athletics Participation Survey. Accessed August 31, 2018. https://www.nfhs.org/media/1020412/2018-19_participation_survey.pdf
    1. Lubans DR, Morgan PJ, Cliff DP, Barnett LM, Okely AD. Fundamental movement skills in children and adolescents: review of associated health benefits. Sports Med 2010; 40:1019-1035. https://doi.org/10.2165/11536850-000000000-00000.
    1. Kalkhoven JT, Watsford ML, Impellizzeri FM. A conceptual model and detailed framework for stress-related, strain-related, and overuse athletic injury. J Sci Med Sport 2020; 23:726-734. https://doi.org/10.1016/j.jsams.2020.02.002.