Department of Physiotherapy, School of Primary Health Care, Monash University, Melbourne, Victoria, Australia.
Department of Rehabilitation, Nutrition and Sport, School of Allied Health, La Trobe University, Melbourne, Victoria, Australia.
Br J Sports Med. 2015 Oct;49(19):1277-83. doi: 10.1136/bjsports-2014-094386. Epub 2015 May 15.
Few interventions reduce patellar tendinopathy (PT) pain in the short term. Eccentric exercises are painful and have limited effectiveness during the competitive season. Isometric and isotonic muscle contractions may have an immediate effect on PT pain.
This single-blinded, randomised cross-over study compared immediate and 45 min effects following a bout of isometric and isotonic muscle contractions. Outcome measures were PT pain during the single-leg decline squat (SLDS, 0-10), quadriceps strength on maximal voluntary isometric contraction (MVIC), and measures of corticospinal excitability and inhibition. Data were analysed using a split-plot in time-repeated measures analysis of variance (ANOVA).
6 volleyball players with PT participated. Condition effects were detected with greater pain relief immediately from isometric contractions: isometric contractions reduced SLDS (mean±SD) from 7.0±2.04 to 0.17±0.41, and isotonic contractions reduced SLDS (mean±SD) from 6.33±2.80 to 3.75±3.28 (p<0.001). Isometric contractions released cortical inhibition (ratio mean±SD) from 27.53%±8.30 to 54.95%±5.47, but isotonic contractions had no significant effect on inhibition (pre 30.26±3.89, post 31.92±4.67; p=0.004). Condition by time analysis showed pain reduction was sustained at 45 min postisometric but not isotonic condition (p<0.001). The mean reduction in pain scores postisometric was 6.8/10 compared with 2.6/10 postisotonic. MVIC increased significantly following the isometric condition by 18.7±7.8%, and was significantly higher than baseline (p<0.001) and isotonic condition (p<0.001), and at 45 min (p<0.001).
A single resistance training bout of isometric contractions reduced tendon pain immediately for at least 45 min postintervention and increased MVIC. The reduction in pain was paralleled by a reduction in cortical inhibition, providing insight into potential mechanisms. Isometric contractions can be completed without pain for people with PT. The clinical implications are that isometric muscle contractions may be used to reduce pain in people with PT without a reduction in muscle strength.
很少有干预措施能在短期内减轻髌腱病（PT）的疼痛。离心运动既痛苦又在竞技赛季期间效果有限。等长和等张肌肉收缩可能会对 PT 疼痛产生即时影响。
这项单盲、随机交叉研究比较了单次等长和等张肌肉收缩后的即时和 45 分钟效果。主要结局指标为单腿下蹲测试（SLDS，0-10）中的 PT 疼痛、最大自主等长收缩（MVIC）时的股四头肌力量，以及皮质脊髓兴奋性和抑制性的测量。使用时间重复测量方差分析（ANOVA）的分割图进行数据分析。
6 名患有 PT 的排球运动员参与了该研究。结果显示，等长收缩即刻产生更大的疼痛缓解效果：等长收缩使 SLDS（均值±标准差）从 7.0±2.04 降至 0.17±0.41，等张收缩使 SLDS（均值±标准差）从 6.33±2.80 降至 3.75±3.28（p<0.001）。等长收缩释放皮质抑制（比值均值±标准差）从 27.53%±8.30%升至 54.95%±5.47%，但等张收缩对抑制没有显著影响（预 30.26±3.89，后 31.92±4.67；p=0.004）。条件与时间分析显示，等长收缩后的疼痛缓解在 45 分钟后仍持续，但等张收缩后则不然（p<0.001）。等长收缩后疼痛评分平均降低 6.8/10，而等张收缩后则降低 2.6/10。等长收缩后 MVIC 显著增加 18.7±7.8%，且明显高于基线（p<0.001）和等张收缩（p<0.001），45 分钟后也更高（p<0.001）。
单次抗阻训练等长收缩即刻减轻肌腱疼痛至少 45 分钟，同时增加 MVIC。疼痛减轻与皮质抑制减少平行，为潜在机制提供了新的见解。患有 PT 的人可以无痛地完成等长收缩。临床意义在于，等长肌肉收缩可用于减轻 PT 患者的疼痛，而不会降低肌肉力量。
