Tomonobu Ishigaki1, Keitaro Kubo2. 1. Department of Life Science (Sports Sciences), The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan. 2. Department of Life Science (Sports Sciences), The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan. kubo@idaten.c.u-tokyo.ac.jp.
Abstract
PURPOSE: The purpose of the present study was to compare the effects of eccentric training with different training frequencies on the blood circulation, collagen orientation, and mechanical properties of the human Achilles tendon in vivo. METHODS: Ten healthy males completed 12 weeks of a unilateral eccentric training program {(15 repetitions with knee straight and 15 repetitions with knee slightly bent) × 6 sets in a single session} for the plantar flexor muscles. They performed training three times per week on one side (3TW) and six times per week on the other side (6TW). Before and after training, changes in blood volume, coefficient of variation (CV) of echogenicity (reflects collagen fiber orientation), and stiffness of the Achilles tendon were compared by two-way analysis of variance. RESULTS: The tendon blood volume tended to increase after 3TW and 6TW (p = 0.064). Tendon stiffness did not change after 3TW and 6TW, whereas the elongation of tendon structures at three force levels (50, 100, and 150 N) significantly decreased with 3TW, but not 6TW. The CV of echogenicity significantly decreased after 3TW and 6TW. However, no significant differences were observed in the relative changes in these measured variables between 3TW and 6TW. CONCLUSION: The present results demonstrated an increase in blood volume, the alignment of collagen fibers, and unchanged stiffness of the Achilles tendon after 12 weeks of eccentric training. Furthermore, the training frequency did not influence these training-induced changes in the tendon properties.
PURPOSE: The purpose of the present study was to compare the effects of eccentric training with different training frequencies on the blood circulation, collagen orientation, and mechanical properties of the human Achilles tendon in vivo. METHODS: Ten healthy males completed 12 weeks of a unilateral eccentric training program {(15 repetitions with knee straight and 15 repetitions with knee slightly bent) × 6 sets in a single session} for the plantar flexor muscles. They performed training three times per week on one side (3TW) and six times per week on the other side (6TW). Before and after training, changes in blood volume, coefficient of variation (CV) of echogenicity (reflects collagen fiber orientation), and stiffness of the Achilles tendon were compared by two-way analysis of variance. RESULTS: The tendon blood volume tended to increase after 3TW and 6TW (p = 0.064). Tendon stiffness did not change after 3TW and 6TW, whereas the elongation of tendon structures at three force levels (50, 100, and 150 N) significantly decreased with 3TW, but not 6TW. The CV of echogenicity significantly decreased after 3TW and 6TW. However, no significant differences were observed in the relative changes in these measured variables between 3TW and 6TW. CONCLUSION: The present results demonstrated an increase in blood volume, the alignment of collagen fibers, and unchanged stiffness of the Achilles tendon after 12 weeks of eccentric training. Furthermore, the training frequency did not influence these training-induced changes in the tendon properties.
Entities:
Keywords:
Blood volume; Coefficient of variation of echogenicity; Tendon stiffness; Ultrasonography
Authors: H T M van Schie; R J de Vos; S de Jonge; E M Bakker; M P Heijboer; J A N Verhaar; J L Tol; H Weinans Journal: Br J Sports Med Date: 2009-08-06 Impact factor: 13.800