School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Australia.
Scand J Med Sci Sports. 2022 Apr;32(4):728-736. doi: 10.1111/sms.14111. Epub 2021 Dec 18.
This study aimed to investigate short-interval intracortical inhibition (SICI) and muscle function in the triceps surae of runners with mid-portion Achilles tendinopathy (AT).
Runners with (n = 11) and without (n = 13) AT were recruited. Plantar flexor isometric peak torque and rate of torque development (RTD) were measured using an isokinetic dynamometer. Triceps surae endurance was measured as single-leg heel raise (SLHR) to failure test. SICI was assessed using paired-pulse transcranial magnetic stimulation during a sustained contraction at 10% of plantar flexor isometric peak torque.
Triceps surae SICI was 14.3% (95% CI: -2.1 to 26.4) higher in AT than in the control group (57.9%, 95% CI: 36.2 to 79.6; and 43.6% 95% CI: 16.2 to 71.1, p = 0.032) irrespective of the tested muscle. AT performed 16 (95% CI: 7.9 to 23.3, p < 0.001) fewer SLHR repetitions on the symptomatic side compared with controls, and 14 (95% CI: 5.8 to 22.0, p = 0.004), fewer SLHR repetitions on the non-symptomatic compared with controls. We found no between-groups differences in isometric peak torque (p = 0.971) or RTD (p = 0.815).
Our data suggest greater intracortical inhibition for the triceps surae muscles for the AT group accompanied by reduced SLHR endurance, without deficits in isometric peak torque or RTD. The increased SICI observed in the AT group could be negatively influencing triceps surae endurance; thus, rehabilitation aiming to reduce intracortical inhibition should be considered to improve patient outcomes. Furthermore, SLHR is a useful clinical tool to assess plantar flexor function in AT patients.
本研究旨在探讨中段跟腱腱病（AT）跑者的皮质内短程抑制（SICI）和小腿三头肌功能。
招募了 11 名有 AT 和 13 名无 AT 的跑者。使用等速测力计测量跖屈等长峰值扭矩和扭矩发展率（RTD）。单腿提踵（SLHR）至力竭测试测量小腿三头肌耐力。在跖屈等长峰值扭矩的 10%持续收缩期间，使用成对脉冲经颅磁刺激评估 SICI。
AT 组的小腿三头肌 SICI 比对照组高 14.3%（95%CI：-2.1 至 26.4）（对照组为 57.9%，95%CI：36.2 至 79.6；和 43.6%，95%CI：16.2 至 71.1，p=0.032），而与测试肌肉无关。与对照组相比，AT 组在患侧的 SLHR 重复次数少 16 次（95%CI：7.9 至 23.3，p<0.001），在非患侧少 14 次（95%CI：5.8 至 22.0，p=0.004）。我们发现两组间等长峰值扭矩（p=0.971）或 RTD（p=0.815）无差异。
我们的数据表明，AT 组的小腿三头肌 SICI 增加，同时 SLHR 耐力降低，但等长峰值扭矩或 RTD 无缺陷。在 AT 组中观察到的 SICI 增加可能对小腿三头肌耐力产生负面影响；因此，应考虑减少皮质内抑制的康复措施来改善患者的预后。此外，SLHR 是评估 AT 患者跖屈肌功能的有用临床工具。
