Supplementary information files for "Urinary N-terminal titin fragment concentration as a non-invasive biomarker of exercise-induced muscle damage in males and females"

Supplementary files for article "Urinary N-terminal titin fragment concentration as a non-invasive biomarker of exercise-induced muscle damage in males and females"<br><br><b>Purpose</b> To examine the effects of muscle-damaging exercise on urinary N-terminal fragments of titin (UTF) in males and females, and its association with markers of exercise-induced muscle damage.<br><b>Methods</b> 27 males (n = 16) and females (n = 11) (height: 1.74 ± 0.10 m; body mass: 72.2 ± 11.4 kg; age: 22 ± 3 years) performed 200 eccentric contractions of the knee extensor on an isokinetic dynamometer. Urine and serum samples were collected pre-, post- and 48 h post-exercise to quantify UTF and creatine kinase (CK). Additionally, knee extensor maximal voluntary isometric force (MVIF), voluntary activation (VA), time to peak twitch (TTP), evoked maximal rate of force development (RFD_max), potentiated twitch force (Twpot), and delayed-onset muscle soreness (DOMS) were recorded.<b>Results</b> UTF (2.3 ± 1.8 to 3.3 ± 3.4 nmol/mg/dL) and CK (9.7 ± 4.8 to 14.5 ± 8.7 units/L) concentrations were elevated 48 h after exercise (p &lt; 0.01). DOMS was greater at all post-exercise time points vs. pre-exercise (<i>p</i> &lt; 0.01). MVIF, evoked RFD_max, VA, and Twpot all decreased after exercise (<i>p</i> &lt; 0.01). The pre- to 48 h post-exercise change in UTF strongly correlated with CK (rs = 0.73; p &lt; 0.01), TTP (r_s = -0.77; <i>p</i> &lt; 0.01) and evoked RFD_max (r_s = -0.62; p &lt; 0.01) and moderately correlated with MVIF (r_s = -0.45; <i>p</i> &lt; 0.01). Moderate strength correlations were found between the pre- to 48 h post-change in CK with DOMS (r = 0.47; <i>p</i> = 0.03). There were no sex differences for any variables (<i>p</i> &gt; 0.05).<b>Conclusion</b> UTF was similarly increased post- and 48 h post-exercise in males and females and was moderately to strongly correlated to CK and some markers of neuromuscular function, but not DOMS.

论文《尿液N末端肌联蛋白片段浓度作为男女运动诱导肌肉损伤的无创生物标志物》补充材料<br><br>**研究目的** 本研究旨在探讨肌肉损伤性运动对男女尿液中肌联蛋白（titin）N末端片段（UTF）的影响，及其与运动诱导肌肉损伤相关标志物的关联。<br><br>**研究方法** 本研究共纳入27名受试者（男性16名，女性11名；身高1.74±0.10 m；体质量72.2±11.4 kg；年龄22±3岁），所有受试者在等速测力仪（isokinetic dynamometer）上完成200次膝伸肌离心收缩。分别于运动前、运动后即刻及运动后48 h采集尿液与血清样本，以定量检测肌联蛋白N末端片段（UTF）与肌酸激酶（CK）。此外，本研究还记录了膝伸肌最大自主等长肌力（MVIF）、自主激活（VA）、单收缩峰时间（TTP）、诱发最大肌力上升速率（RFD_max）、增强型单收缩肌力（Twpot）以及延迟性肌肉酸痛（DOMS）。<br><br>**研究结果** 运动后48 h，受试者尿液UTF浓度（2.3±1.8 升至3.3±3.4 nmol/mg/dL）与血清CK浓度（9.7±4.8 升至14.5±8.7 U/L）均显著升高（p<0.01）。所有运动后时间点的延迟性肌肉酸痛（DOMS）评分均显著高于运动前（p<0.01）。运动后，膝伸肌最大自主等长肌力（MVIF）、诱发最大肌力上升速率（RFD_max）、自主激活（VA）以及增强型单收缩肌力（Twpot）均显著下降（p<0.01）。运动前至运动后48 h的UTF变化量与CK（rs=0.73；p<0.01）、单收缩峰时间（TTP）（rs=-0.77；p<0.01）及诱发最大肌力上升速率（RFD_max）（rs=-0.62；p<0.01）呈强相关，与最大自主等长肌力（MVIF）呈中等程度相关（rs=-0.45；p<0.01）。运动前至运动后48 h的CK变化量与延迟性肌肉酸痛（DOMS）呈中等程度相关（r=0.47；p=0.03）。所有观测指标均未发现显著的性别差异（p>0.05）。<br><br>**研究结论** 本研究结果表明，无论男性还是女性，运动后即刻及运动后48 h的UTF浓度均显著升高，且UTF浓度变化与CK及部分神经肌肉功能标志物呈中至强相关，但与延迟性肌肉酸痛（DOMS）无显著关联。