长期储存和释放的弹性应变能,远端肌腱如跟腱在运动过程中允许肌肉力量放大以及减少运动能量成本:因为远端肌腱在反冲过程中执行机械工作,足底屈肌纤维可以在较小的长度范围内工作,在较慢的缩短速度下,和较低的激活水平。很少有证据表明,长远肌腱在人类中进化(或从我们更遥远的人类祖先中保留)主要是为了允许高肌肉肌腱功率输出,事实上,与许多其他物种相比,我们仍然相对无能为力。相反,大多数证据表明,这种肌腱的演变,以减少总的运动能源成本。然而,许多额外的,往往不被认可,长腱的优势推测可能具有更大的进化优势,包括由较短和较轻的肌肉提供的减少的肢体惯性(减少近端肌肉力量的要求),减少地面碰撞过程中的能量耗散,储存和重复使用肌肉工作的能力,以抑制脚底碰撞引发的振动,减少肌肉产热(从而减少核心温度),和减轻工作引起的肌肉损伤。累计,这些效果应该减少神经运动疲劳和运动力的感觉,允许人类选择以更快的速度移动更长时间。由于这些好处在更快的运动速度下更大,它们与我们祖先使用的跑步步态可能对跟腱长度施加了巨大的进化压力的假设一致。因此,长跟腱可能是一个单一的适应,提供了许多生理,生物力学,和心理上的好处,从而影响了多个任务的行为,包括和附加于运动。虽然能源成本可能是运动研究中感兴趣的变量,未来的研究应该考虑影响我们运动能力的更广泛的因素,包括我们决定以特定的速度移动给定的距离,为了更全面地了解跟腱功能的影响以及这种功能对身体活动的反应的变化,不活动,废用和疾病,运动性能。
Elastic strain energy that is stored and released from long, distal tendons such as the Achilles during locomotion allows for muscle power amplification as well as for reduction of the locomotor energy cost: as distal tendons perform mechanical work during recoil, plantar flexor muscle fibres can work over smaller length ranges, at slower shortening speeds, and at lower activation levels. Scant evidence exists that long distal tendons evolved in humans (or were retained from our more distant Hominoidea ancestors) primarily to allow high muscle-tendon power outputs, and indeed we remain relatively powerless compared to many other species. Instead, the majority of evidence suggests that such tendons evolved to reduce total locomotor energy cost. However, numerous additional, often unrecognised, advantages of long tendons may speculatively be of greater evolutionary advantage, including the reduced limb inertia afforded by shorter and lighter muscles (reducing proximal muscle force requirement), reduced energy dissipation during the foot-ground collisions, capacity to store and reuse the muscle work done to dampen the vibrations triggered by foot-ground collisions, reduced muscle heat production (and thus core temperature), and attenuation of work-induced muscle damage. Cumulatively, these effects should reduce both neuromotor fatigue and sense of locomotor effort, allowing humans to choose to move at faster speeds for longer. As these benefits are greater at faster locomotor speeds, they are consistent with the hypothesis that running gaits used by our ancestors may have exerted substantial evolutionary pressure on Achilles tendon length. The long Achilles tendon may therefore be a singular adaptation that provided numerous physiological, biomechanical, and psychological benefits and thus influenced behaviour across multiple tasks, both including and additional to locomotion. While energy cost may be a variable of interest in locomotor studies, future research should consider the broader range of factors influencing our movement capacity, including our decision to move over given distances at specific speeds, in order to understand more fully the effects of Achilles tendon function as well as changes in this function in response to physical activity, inactivity, disuse and disease, on movement performance.