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The purpose of this study was to compare the incremental running tests performed by young soccer players on a treadmill (Tr) and in the field (FT cod : 100 m change of direction and FT cir : 100 m circle). Nineteen players (average age 17.4 ± 1.1 years; body height 172.0 ± 5.7 cm; body mass 68.9 ± 6.7 kg) volunteered to perform incremental Tr , FT cod and FT cir running tests. In all three tests, players ran for 3 min at 8, 10, 12 and 14 km∙h -1 and were given a 1 min rest interval between subsequent stages. Blood lactate concentrations (La - ) were measured at 1 min rest intervals and the heart rate (HR) responses of players were recorded during the tests. After a 5 min recovery period, the second part of the test started; players ran at 15 km∙h -1 with velocity increments of 1 km∙h -1 every 1 min until exhaustion. This part was performed to determine maximum HR, maximum La - and the players' final velocities. The results showed that players had significantly lower La - (F = 6.93, p = 0.07, η 2 = 0.46, 95%CI (TR-FTcir) = -1.91/-0.34, 95%CI (TR-FTcod) = -1.59/-0.05) and HR (F = 9.08, p = 0.02, η 2 = 0.53, 95%CI (TR-FTcir) = -6.98/-1.68, 95%CI (TR-FTcod) = -7.19/1.08) responses in the Tr test than in the FT cir and FT cod tests at 14 km∙h -1 . It was also found that players completed the Tr test (F = 58.22, p = 0.00, η 2 = 0.87) at higher final running velocities than the FT cir (95%CI (TR-FTcir) = 1.67/2.78) and FT cod (95%CI (TR-FTcod) = 1.69/2.85) tests. In conclusion, when coaches or sports scientists plan to train at higher running velocities or according to the final velocity in the test, it is advisable to carry out testing in the circumstances under which training will be carried out (in the field or on a treadmill)., (© 2020 Yusuf Köklü, Utku Alemdaroğlu, Ramazan Demirhan, Yunus Arslan, published by Sciendo.)

Tendons are dense connective tissues that attach muscles to bone with an indispensable role in locomotion because of their intrinsic properties of storing and releasing muscle- generated elastic energy. Tenomodulin (Tnmd) is a well-accepted gene marker for the mature tendon/ligament lineage and its loss-of -function in mice leads to a phenotype with distinct signs of premature aging on tissue and stem/progenitor cell levels. Based on these findings, we hypothesized that Tnmd might be an important factor in the functional performance of tendons. Firstly, we revealed that Tnmd is a mechanosensitive gene and that the C-terminus of the protein co-localize with collagen I-type fibers in the extracellular matrix. Secondly, using an endurance training protocol, we compared Tnmd knockout mice with wild types and showed that Tnmd deficiency leads to significantly inferior running performance that further worsens with training. In these mice, endurance running was hindered due to abnormal response of collagen I cross-linking and proteoglycan genes leading to an inadequate collagen I fiber thickness and elasticity. In sum, our study demonstrates that Tnmd is required for proper tendon tissue adaptation to endurance running and aids in better understanding of the structural-functional relationships of tendon tissues., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)