Physiological Tendon Thickness Adaptation in Adolescent Elite Athletes: A Longitudinal Study

Abstract

Increased Achilles (AT) and Patellar tendon (PT) thickness in adolescent athletes compared to non-athletes could be shown. However, it is unclear, if changes are of pathological or physiological origin due to training. The aim of this study was to determine physiological AT and PT thickness adaptation in adolescent elite athletes compared to non-athletes, considering sex and sport. In a longitudinal study design with two measurement days (M1/M2) within an interval of 3.2 ± 0.8 years, 131 healthy adolescent elite athletes (m/f: 90/41) out of 13 different sports and 24 recreationally active controls (m/f: 6/18) were included. Both ATs and PTs were measured at standardized reference points. Athletes were divided into 4 sport categories [ball (B), combat (C), endurance (E) and explosive strength sports (S)]. Descriptive analysis (mean ± SD) and statistical testing for group differences was performed (α = 0.05). AT thickness did not differ significantly between measurement days, neither in athletes (5.6 ± 0.7 mm/5.6 ± 0.7 mm) nor in controls (4.8 ± 0.4 mm/4.9 ± 0.5 mm, p > 0.05). For PTs, athletes presented increased thickness at M2 (M1: 3.5 ± 0.5 mm, M2: 3.8 ± 0.5 mm, p < 0.001). In general, males had thicker ATs and PTs than females (p < 0.05). Considering sex and sports, only male athletes from B, C, and S showed significant higher PT-thickness at M2 compared to controls (p ≤ 0.01). Sport-specific adaptation regarding tendon thickness in adolescent elite athletes can be detected in PTs among male athletes participating in certain sports with high repetitive jumping and strength components. Sonographic microstructural analysis might provide an enhanced insight into tendon material properties enabling the differentiation of sex and influence of different sports.

Motor Control and Achilles Tendon Adaptation in Adolescence: Effects of Sport Participation and Maturity

“…The increase in tendon thickness and length with sport participation, at an earlier time from PHV may be an adaptive response to specific training-induced increase in muscle mass and strength ( Falk and Eliakim, 2003 , Waugh et al, 2014 , Granacher et al, 2011 ). Our findings are consistent with Cassel et al (2017) who reported greater tendon cross sectional area in athletes than non-athletes in specific sport activities. Nevertheless, our findings are in odds with other studies, which show that sports participation had no significant relationship with cross sectional area ( Waugh et al, 2014 , Neugebauer and Hawkins, 2012 ).…”

“…One study, found that the patellar tendon CSA increased 27% from mid to late adolescence (16-18 years) ( Mersmann et al, 2017a ), whereas others report reductions in tendon cross sectional areas in early adolescence ( Neugebauer and Hawkins, 2012 ). These controversial reports about the tendon’s hypertrophy in childhood to adulthood could be attributed to the age cohort and the inclusion of adolescents who participated in sports or not ( Mersmann et al, 2017b , Cassel et al, 2017 ), and gender ( Intziegianni et al, 2017 ). Our findings from this longitudinal study show that athletes had greater cross-sectional area and longer resting length of the Achilles tendon than non-athletes.…”

Muscle‐tendon morphology and function following long‐term exposure to repeated and strenuous mechanical loading

“…The fact that no differences between civilians and cadets were found for the AT agrees with a series of past findings pertaining to tendon‐specific structural and functional adaptations resulting from short‐term resistance training and long‐term habitual overloading. Combined evidence from a number of studies in athletic populations with controls suggest that the mechanical loading threshold for adaptations in the AT is somewhat higher than that of the PT in the same populations 4,10,11,13,14,29,45,50 . We can therefore deduce that the load exerted on the AT in the group of cadets was not sufficient to produce any changes in tendon thickness and CSA.…”

The Anterior Cruciate Ligament Can Become Hypertrophied in Response to Mechanical Loading: A Magnetic Resonance Imaging Study in Elite Athletes

“…In this new oblique-sagittal view, the slice running through the midportion of the patellar tendon was identified, from which the longitudinal axis of the tendon was defined. The AP patellar tendon diameter was measured perpendicular to this longitudinal axis at a distance of 2 cm distal to the patella 7,8 on the slice displaying the thickest part of the tendon at that height (Figure 2).…”