背景與目的：先前研究多探討溫度刺激活化大腦皮質與肢體動作功能之改善，較少研究探討溫度刺激對脊髓神經迴路傳導與肌肉特性之影響。本研究目的比較冷和熱溫度刺激對健康人下肢神經肌肉特性之立即影響效應。方法：徵召30位健康成年人受試者，每位參與研究個案在前後2天依隨機順序分別給予受測小腿一般冷(23~24°C)及疼痛冷(2~3°C)或一般熱(40~41°C)及疼痛熱(46~47°C)各別15分鐘溫度刺激介入。並在四種不同溫度刺激前及刺激結束後，進行比目魚肌神經肌肉特性評估，使用Myoton®PRO儀器量測比目魚肌肌肉張力、彈性和僵硬度；並紀錄比目魚肌最大H反射與M波之比值以評估神經脊髓興奮性。結果：接受一般與疼痛冷溫度刺激後，比目魚肌肉彈性皆顯著下降，而接受一般熱溫度刺激後，僵硬度和最大H反射與最大M反應比值皆顯著降低(p=0.03;p=0.02)，疼痛冷刺激於比目魚肌彈性改變量顯著大於疼痛熱刺激(F[3,1]=3.09,p=0.03)。結論：健康成年人接受15分鐘一般或疼痛冷溫度刺激後有降低比目魚肌彈性的立即效應，而接受一般熱刺激介入後能降低比目魚肌α運動神經元興奮性及肌肉僵硬度。這些結果可以提供治療師選擇冷熱因子治療改善關節活動度的參考。

Background and Purpose: Previous studies mostly explored the effects of thermal stimulation (TS) on brain activation and motor function recovery of limbs. However, the investigation of TS on spinal circuit transmission and muscle characteristics is insufficient. This study aimed to compare the immediate effects of cold and heat stimulation on the neuromuscular properties of lower limbs in healthy adults. Methods: Thirty healthy subjects were recruited. Each subject was instructed to receive either the innocuous cold (23–24 °C) and noxious cold (2–3 °C) or the innocuous heat (40–41 °C) and noxious heat (46–47 °C) TS for 15 minutes on the calf in 2 different days in a random order. The neuromuscular properties of the soleus were evaluated before and after TS stimulation at each temperature. The Myoton®PRO device was used to measure the soleus muscle tone, elasticity, and stiffness. The maximum H-reflex/ maximum M-wave (Hmax/Mmax) ratio was measured to assess the spinal circuit excitability of the soleus. Results: Compared with the baseline, significant decreases on soleus elasticity were found in both innocuous and noxious cold TS. The stiffness and Hmax/Mmax ratio were significantly decreased after innocuous heat TS (p = 0.03; p = 0.02). The change score from the baseline on soleus elasticity for noxious cold TS was significantly higher than that of noxious heat TS (F[3,1] = 3.09, p = 0.03). Conclusion: A 15-minute innocuous TS or noxious cold TS could result in immediate effects on decreasing soleus muscle elasticity in healthy adults. The innocuous heat TS decreased the alpha motor neurons excitability and the stiffness of soleus muscle. The results of this study may provide therapists with the insights into choosing heat and cold agents to improve joint range of motion.