急性神經肌肉疲勞對於連續跳躍測驗之影響

Acute effects of neuromuscular fatigue on continuous jump test

緒論：神經肌肉疲勞會影響運動表現，有效監控疲勞狀態成為運動科學的重要課題。垂直跳躍測驗，例如下蹲跳（countermovement jump，CMJ）與落下跳（drop jump，DJ），為監控神經肌肉疲勞的方式之一，但單次的跳躍測驗可能無法有效反映急性疲勞造成的變化。連續性的跳躍測驗，例如連續垂直跳測驗（continuous jump，CJ），似乎具有評估神經肌肉疲勞的潛力。因此，本研究旨在透過遞增負荷運動測驗（graded exercise test，GXT）誘發急性疲勞，並探討其對於垂直跳躍測驗及生理指標的影響。方法：12名大專甲組男性籃球選手配戴慣性感測器、肌電儀與近紅外線光譜儀，依序進行3次30公分箱高的DJ與CJ（連續15次的CMJ）測驗，記錄跳躍過程的肌電反應與肌肉氧飽和度，並以加速度換算跳躍高度。垂直跳測驗結束後，受試者接續進行腳踏車測功儀GXT，以每分鐘增加30 W的負荷持續踩踏直到衰竭，並於GXT前後採集血乳酸濃度。GXT結束後立即進行第二次的DJ與CJ測驗，並以跳躍高度計算GXT前後之運動表現下降率（performance decrement score，PDs）與CJ百分比（percentage CJ，pCJ）。結果：GXT後之血乳酸濃度（GXT前vs. GXT後，2.47±0.72 vs. 8.13±3.29 mmol·L-1，p < .05）、去氧合速度（GXT前vs. GXT後，3.11±1.44 vs. 3.60±1.48 %·s-1，p < .05）、肌電圖中位頻率（GXT前vs. GXT後，9.24±2.26 vs. 11.19±1.85 Hz，p < .05），以及PDs（GXT前vs. GXT後，13.50±7.17 vs.17.15±6.61 %，p < .05）皆顯著高於GXT前。CJ的平均跳躍高度（GXT前vs. GXT後，36.57±9.16 vs. 34.97±8.46 cm，p < .05）與pCJ則於GXT後顯著下降（GXT前vs. GXT後，87.53±8.41 vs. 80.49±2.14 %，p < .05）。結論：本研究發現，CJ在疲勞監測中具有足夠的敏感性，尤其是PDs和pCJ可作為有效的疲勞評估指標。此外，去氧合速度亦能提供額外的疲勞監測資訊。

Introduction: Monitoring the exercise neuromuscular fatigue induced by exercise is becoming an important issue in sports science. Vertical jumping tests, such as countermovement jump (CMJ) and drop jump (DJ), have been suggested as effective methods for evaluating neuromuscular fatigue. However, single jump test might not effectively reflect the changes induced by acute fatigue. Continuous jumping tests, such as the continuous jump (CJ), appear to have potential to evaluate neuromuscular fatigue. Therefore, this study aimed to investigate the effects of acute fatigue induced by a graded exercise test (GXT) on vertical jump performance and physiological indicators. Methods: Twelve male college division I basketball players wore inertial measurement units, electromyography (EMG) and near-infrared spectroscopy (NIRS) to perform three DJs from a 30 cm box and CJ (15 continuous CMJ). During the jumping tests, the EMG activity and muscle oxygen utilization were monitored, and the jump height was calculated by acceleration data. Following the jump tests, participants performed a GXT on a cycling ergometer with an increasing workload of 30 W/min until exhaustion. Blood lactate concentrations were collected before and after the GXT. Immediately after the GXT, participants performed a second round of DJ and CJ tests to monitor their performance decrement score (PDs) and CJ percentage (pCJ) based on jump height. Results: The blood lactate concentration (before vs. after: 2.47±0.72 vs. 8.13±3.29 mmol·L⁻¹, p < .05), deoxygenation rate (before vs. after: 3.11±1.44 vs. 3.60±1.48 %·s⁻¹, p < .05), EMG median frequency (before vs. after: 9.24±2.26 vs. 11.19±1.85 Hz, p < .05), and PDs (before vs. after: 13.50±7.17 vs. 17.15±6.61 %, p < .05) was significantly increased after GXT. The average jump height of CJ (before vs. after: 36.57±9.16 vs. 34.97±8.46 cm, p < .05) and pCJ (before vs. after: 87.53±8.41 vs. 80.49±2.14 %, p < .05) was significantly decreased after GXT. Conclusion: This study demonstrated that CJ might be used as sensitive indicators for monitoring fatigue, particularly through the assessment of PDs and pCJ. Furthermore, alterations in the deoxygenation rate might offer supplementary insights into fatigue monitoring.