Department of Kinesiology, University of Connecticut, Storrs.
School of Kinesiology, University of Michigan, Ann Arbor.
J Athl Train. 2020 Jun 23;55(6):608-614. doi: 10.4085/1062-6050-27-19.
After knee-joint injury, pain, effusion, and mechanoreceptor damage alter afferent signaling, which can result in quadriceps inhibition and subsequent weakness. The individual contributions of each factor to inhibition remain unclear due to confounding knee-joint injuries and indirect experimental models.
To characterize the influence of naturally occurring knee damage and pain on quadriceps neuromuscular function in individuals with patellar tendinopathy.
Cross-sectional study.
Research laboratory.
Twenty participants who self-reported patellar tendinopathy (PT) and 10 healthy control individuals underwent ultrasonic tendon assessment. Injured participants were dichotomized by an orthopaedic surgeon into groups with (1) pain and structural tendon abnormality and (2) regional pain alone.
MAIN OUTCOME MEASURE(S): Quadriceps inhibition was assessed with the Hoffman reflex and the central activation ratio via the superimposed-burst technique. Normally distributed measures were analyzed using a 1-way analysis of variance and post hoc independent t tests. Kruskal-Wallis tests with post hoc Mann-Whitney U tests were used to analyze nonnormally distributed data. An a priori α level of P ≤ .05 was set.
Control participants presented with more spinal-reflex excitability (0.37 ± 0.23) than the PT (0.10 ± 0.06; P = .03) and regional-pain (0.18 ± 0.05; P = .02) groups. Knee-extension strength was greater in the control (3.37 ± 0.59 Nm/kg) than in the PT (2.41 ± 0.67 Nm/kg; P = .01) group but not the regional-pain group (3.05 ± 0.66 Nm/kg; P = .24). Control individuals presented with more quadriceps activation (97.93% ± 3.12) than the PT (84.44% ± 16.98; P < .01) and regional-pain (91.17% ± 10.56; P = .01) groups. No differences were present for any measures between the PT and regional-pain groups (P values > .05).
Deficits in spinal-reflex excitability, quadriceps activation, and strength were present in both the PT and regional-pain groups. A combination of pain and structural damage appeared to have the greatest negative effect on quadriceps function, as only the PT group presented with neuromuscular outcomes that failed to meet clinical thresholds.
膝关节损伤后，疼痛、积液和机械感受器损伤改变传入信号，导致股四头肌抑制和随后的无力。由于膝关节损伤和间接实验模型的混杂，每种因素对抑制的单独贡献仍不清楚。
描述自然发生的膝关节损伤和疼痛对髌腱病患者股四头肌神经肌肉功能的影响。
横断面研究。
研究实验室。
20 名自报髌腱病（PT）的参与者和 10 名健康对照组接受了超声肌腱评估。受伤的参与者由骨科医生分为两组：（1）疼痛和结构肌腱异常，（2）局部疼痛。
通过叠加爆发技术，使用 Hoffmann 反射和中央激活比评估股四头肌抑制。正态分布的测量值采用单因素方差分析和事后独立 t 检验进行分析。非正态分布数据采用 Kruskal-Wallis 检验和事后 Mann-Whitney U 检验进行分析。预先设定的α水平为 P ≤.05。
对照组参与者的脊髓反射兴奋性（0.37 ± 0.23）高于 PT 组（0.10 ± 0.06；P =.03）和局部疼痛组（0.18 ± 0.05；P =.02）。对照组的膝关节伸展力量（3.37 ± 0.59 Nm/kg）大于 PT 组（2.41 ± 0.67 Nm/kg；P =.01），但不大于局部疼痛组（3.05 ± 0.66 Nm/kg；P =.24）。对照组参与者的股四头肌激活度（97.93% ± 3.12）高于 PT 组（84.44% ± 16.98；P <.01）和局部疼痛组（91.17% ± 10.56；P =.01）。PT 组和局部疼痛组之间的任何测量值均无差异（P 值均>.05）。
PT 组和局部疼痛组均存在脊髓反射兴奋性、股四头肌激活和力量的缺陷。疼痛和结构损伤的结合似乎对股四头肌功能有最大的负面影响，因为只有 PT 组的神经肌肉结果未能达到临床阈值。
