Whether the cross-sectional area (CSA) and mechanical properties of the @entity1 Achilles tendon change in response to habitual exercise remains largely unexplored. The present study evaluated the CSA and contraction-induced displacement of the @entity924 in 11 untrained subjects before ( @entity5482 ) and after (test 3) approximately 9 mo of regular running ( approximately 78 training sessions). Displacement of the @entity924 complex obtained by ultrasonography; electromyography of the gastrocnemius, soleus, and dorsiflexor muscles; and joint @entity717 were recorded during graded isometric plantarflexion ramps. Tendon CSA and moment arm were measured by using MRI, and tendon force was calculated from joint moments and tendon moment arm. A treadmill test was used to determine submaximal @entity26 consumption ( @entity4962 ) at a given speed and maximal Vo2. The total running duration was approximately 43 h, distributed over 34 wk. Maximal Vo2 increased 8.6% (P < 0.01), and submaximal Vo2 decreased 6.2% (P < 0.05). @entity924 during maximal @entity2472 was unchanged (tests 1-3, 5.2 +/- 0.6, 5.2 +/- 0.5, and 5.3 +/- 0.4 mm, respectively) and yielded a structural stiffness of 365 +/- 50, 358 +/- 40, and 384 +/- 52 N/mm for tests 1-3, respectively (P > 0.05). Tendon CSA also remained unchanged (tests 1-3, 34.2 +/- 2.2, 33.9 +/- 2.2, and 33.8 +/- 2.1 mm2, respectively). In conclusion, a total training stimulus of approximately 9 mo of running in previously untrained subjects was adequate to induce significant cardiovascular improvements, although it did not result in any changes in the mechanical properties of the triceps surea @entity924 .

Effect of habitual running on XXXX Achilles tendon load-deformation properties and cross-sectional area.

@entity1 :: ('9606', 'Species') :: ['human'] @entity4962 :: ('CHEBI:30046', 'Chemical') :: ['Vo2'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity924 :: ('MESH:D052256', 'Disease') :: ['tendon-aponeurosis complex or in the dimensions of Achilles tendon', 'tendon-aponeurosis', 'Tendon-aponeurosis displacement', 'aponeurosis-tendon complex of the triceps surae'] @entity5482 :: ('10942', 'Gene') :: ['tests 1 and 2'] @entity717 :: ('MESH:D009069', 'Disease') :: ['angular rotation'] @entity2472 :: ('MESH:C536214', 'Disease') :: ['voluntary contraction']
@entity1 :: (9606,Species) :: ['human']
