Morphological features of MTJ in control and trained rats.

<p>TEM images of MTJs which reveal the different complexity between control (<b>A</b>) and trained groups (RUN-F, <b>B</b>). At high magnification (13500x), tenocytes, located strictly close to MTJ (mtj), display, in comparison to control (<b>C</b>), a growing presence of rough endoplasmic reticulum (►) in trained groups (RUN-F, <b>D</b>). Bars <b>A</b>,<b>B</b>,<b>C</b>,<b>D</b>: 0.5μm.</p

Contractile force levels developed in rat muscles of the three experimental conditions.

<p>Evaluation of muscle strength in response to single twitch (<b>A</b>) and tetanus (<b>B</b>) in CTRL, RUN-S and RUN-F. *p < 0.05; **p < 0.01.</p

Morphometric analysis of MTJ complexity.

<p>Morphometric analysis of MTJ base (B) and interface length (IL), and study of muscle-tendon interpenetration (MID) (<b>A</b>). MTJ complexity investigated by means of a modified Sholl analysis (<b>B</b>). m: muscle; t: tendon.</p

mRNA levels of IGF-1 receptor, TbR1, BmpR-1b and Betaglycan in tendon.

<p>Effect of exercise protocols on IGF-1 receptor (<b>A</b>), TbR1 (<b>B</b>), BmpR-1b (<b>C</b>) and Betaglycan (<b>D</b>) mRNA expression in EDL tendon, assessed by real-time PCR. Gene expression is represented as fold-change compared to untrained rats. Data are representative of three independent experiments. *p < 0.05.</p

mRNA levels of PGC-1α, Vinculin, IGF-1Ea and TGF-β in muscle.

<p>Effects of exercise protocols on PGC-1α (A), Vinculin (B), IGF-1Ea (C) and TGF-β (D) mRNA expression in EDL muscle, assessed by real-time PCR. Gene expression is represented as fold-change compared to untrained rats. Data are representative of three independent experiments. *p < 0.05.</p

mRNA levels of IGF-1Ea and TGF-β in tendon.

<p>Effect of exercise protocols on IGF-1Ea (<b>A</b>) and TGF-β (<b>B</b>) mRNA expression in EDL tendon, assessed by real-time PCR. Gene expression is represented as fold-change compared to untrained rats. Data are representative of three independent experiments. *p < 0.05; **p < 0.001.</p

Morphometric results on MTJ complexity.

<p>IL/B ratio (<b>A</b>), maximum insertion depth (<b>B</b>) and Sholl analysis (<b>C</b>) have been evaluated in the MTJs of CTRL, RUN-S and RUN-F. *p < 0.05; **p < 0.01.</p