Resistance exercise training (RET) is well-known to counteract negative age-related changes in both muscle and tendon tissue. Traditional RET consists of both concentric (CON) and eccentric (ECC) contractions; nevertheless, isolated ECC contractions are metabolically less demanding and, thus, may be more suitable for older populations. However, whether submaximal (60% 1RM) CON or ECC contractions differ in their effectiveness is relatively unknown. Further, whether the time course of muscle and tendon adaptations differs to the above is also unknown. Therefore, this study aimed to establish the time course of muscle and tendon adaptations to submaximal CON and ECC RET. Twenty healthy young (24.5 ± 5.1 years) and 17 older males (68.1 ± 2.4 years) were randomly allocated to either isolated CON or ECC RET which took place 3/week for 8 weeks. Tendon biomechanical properties, muscle architecture and maximal voluntary contraction were assessed every 2 weeks and quadriceps muscle volume every 4 weeks. Positive changes in tendon Young’s modulus were observed after 4 weeks in all groups after which adaptations in young males plateaued but continued to increase in older males, suggesting a dampened rate of adaptation with age. However, both CON and ECC resulted in similar overall changes in tendon Young’s modulus, in all groups. Muscle hypertrophy and strength increases were similar between CON and ECC in all groups. However, pennation angle increases were greater in CON, and fascicle length changes were greater in ECC. Notably, muscle and tendon adaptations appeared to occur in synergy, presumably to maintain the efficacy of the muscle–tendon unit.

众所周知，阻力运动训练 (RET) 可以抵消肌肉和肌腱组织中与年龄相关的负面变化。传统的 RET 包括向心 (CON) 和离心 (ECC) 收缩；尽管如此，孤立的 ECC 收缩对代谢的要求较低，因此可能更适合老年人群。然而，次极量 (60% 1RM) CON 或 ECC 收缩的有效性是否不同尚不清楚。此外，肌肉和肌腱适应的时间过程是否与上述不同也不得而知。因此，本研究旨在确定肌肉和肌腱适应次极量 CON 和 ECC RET 的时间过程。20 名健康年轻人（24.5 ± 5.1 岁）和 17 名年长男性（68.1 ± 2.4 岁）被随机分配到隔离 CON 或 ECC RET，每周 3 次，持续 8 周。每 2 周评估一次肌腱生物力学特性、肌肉结构和最大自主收缩，每 4 周评估一次股四头肌体积。4 周后，在所有组中观察到肌腱杨氏模量的积极变化，此后年轻男性的适应趋于平稳，但老年男性继续增加，这表明随着年龄的增长适应率下降。然而，CON 和 ECC 在所有组中导致肌腱杨氏模量的总体变化相似。在所有组中，CON 和 ECC 之间的肌肉肥大和力量增加相似。然而，CON 中的羽状角增加更大，ECC 中的束长度变化更大。值得注意的是，肌肉和肌腱的适应性似乎协同作用，可能是为了维持肌肉-肌腱单元的功效。每 2 周评估一次肌肉结构和最大自主收缩，每 4 周评估一次股四头肌体积。4 周后，在所有组中观察到肌腱杨氏模量的积极变化，此后年轻男性的适应趋于平稳，但老年男性继续增加，这表明随着年龄的增长适应率下降。然而，CON 和 ECC 在所有组中导致肌腱杨氏模量的总体变化相似。在所有组中，CON 和 ECC 之间的肌肉肥大和力量增加相似。然而，CON 中的羽状角增加更大，ECC 中的束长度变化更大。值得注意的是，肌肉和肌腱的适应性似乎协同作用，可能是为了维持肌肉-肌腱单元的功效。每 2 周评估一次肌肉结构和最大自主收缩，每 4 周评估一次股四头肌体积。4 周后，在所有组中观察到肌腱杨氏模量的积极变化，此后年轻男性的适应趋于平稳，但老年男性继续增加，这表明随着年龄的增长适应率下降。然而，CON 和 ECC 在所有组中导致肌腱杨氏模量的总体变化相似。在所有组中，CON 和 ECC 之间的肌肉肥大和力量增加相似。然而，CON 中的羽状角增加更大，ECC 中的束长度变化更大。值得注意的是，肌肉和肌腱的适应性似乎协同作用，可能是为了维持肌肉-肌腱单元的功效。