title: Muscle and tendon adaptation in adolescent athletes: A longitudinal study.
abstract: There is evidence that a non-uniform adaptation of muscle and tendon in young athletes results in increased tendon stress during mid-adolescence. The present longitudinal study investigated the development of the morphological and mechanical properties of muscle and tendon of volleyball athletes in a time period of 2 years from mid-adolescence to late adolescence. Eighteen elite volleyball athletes participated in magnetic resonance imaging and ultrasound-dynamometry sessions to determine quadriceps femoris muscle strength, vastus lateralis, medialis and intermedius morphology, and patellar tendon mechanical and morphological properties in mid-adolescence (16 ± 1 years) and late adolescence (18 ± 1 years). Muscle strength, anatomical cross-sectional area (CSA), and volume showed significant (P < 0.05) but moderate increases of 13%, 6%, and 6%, respectively. The increase of patellar tendon CSA (P < 0.05) was substantially greater (27%) and went in line with increased stiffness (P < 0.05; 25%) and reduced stress (P < 0.05; 9%). During late adolescence, a pronounced hypertrophy of the patellar tendon led to a mechanical strengthening of the tendon in relation to the functional and morphological development of the muscle. These adaptive processes may compensate the unfavorable relation of muscle strength and tendon loading capacity in mid-adolescence and might have implications on athletic performance and tendon injury risk.
authors.affiliation: Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.|Berlin School of Movement Science, Berlin, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Mersmann
authors.affiliation: Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.|Berlin School of Movement Science, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Bohm
authors.affiliation: Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.|Berlin School of Movement Science, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schroll
authors.affiliation: Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Boeth
authors.affiliation: Berlin School of Movement Science, Berlin, Germany.|Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: G N
authors.initials: GN
authors.lastname: Duda
authors.affiliation: Department of Training and Movement Sciences, Humboldt-Universität zu Berlin, Berlin, Germany.|Berlin School of Movement Science, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Arampatzis
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D056352:Athletes; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology; D009929:Organ Size; D017847:Patellar Ligament / Q000000981:diagnostic imaging* / Q000502:physiology; D052097:Quadriceps Muscle / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology; D013710:Tendons / Q000000981:diagnostic imaging / Q000502:physiology; D014463:Ultrasonography; D054798:Volleyball
keywords: Muscle size; growth; imbalance; jumper's knee; knee joint; maturation; tendinopathy