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Tendinous tissue properties after short‐ and long‐term functional overload: Differences between controls, 12 weeks and 4 years of resistance training
Author(s) -
Massey G. J.,
Balshaw T. G.,
MadenWilkinson T. M.,
Folland J. P.
Publication year - 2018
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.13019
Subject(s) - aponeurosis , tendon , patellar tendon , medicine , quadriceps tendon , quadriceps femoris muscle , patella , anatomy , cardiology , isometric exercise
Abstract Aim The potential for tendinous tissues to adapt to functional overload, especially after several years of exposure to heavy‐resistance training, is largely unexplored. This study compared the morphological and mechanical characteristics of the patellar tendon and knee extensor tendon‐aponeurosis complex between young men exposed to long‐term (4 years; n = 16), short‐term (12 weeks; n = 15) and no (untrained controls; n = 39) functional overload in the form of heavy‐resistance training. Methods Patellar tendon cross‐sectional area, vastus lateralis aponeurosis area and quadriceps femoris volume, plus patellar tendon stiffness and Young's modulus, and tendon‐aponeurosis complex stiffness, were quantified with MRI , dynamometry and ultrasonography. Results As expected, long‐term trained had greater muscle strength and volume (+58% and +56% vs untrained, both P < .001), as well as a greater aponeurosis area (+17% vs untrained, P < .01), but tendon cross‐sectional area (mean and regional) was not different between groups. Only long‐term trained had reduced patellar tendon elongation/strain over the whole force/stress range, whilst both short‐term and long‐term overload groups had similarly greater stiffness/Young's modulus at high force/stress (short‐term +25/22%, and long‐term +17/23% vs untrained; all P < .05). Tendon‐aponeurosis complex stiffness was not different between groups ( ANOVA , P = .149). Conclusion Despite large differences in muscle strength and size, years of resistance training did not induce tendon hypertrophy. Both short‐term and long‐term overload demonstrated similar increases in high‐force mechanical and material stiffness, but reduced elongation/strain over the whole force/stress range occurred only after years of overload, indicating a force/strain specific time‐course to these adaptations.