體育研究：有關「我們的知識有一半是不正確的」

Research in Sports: Regarding ＂Half of What We Know is Wrong＂

郭家驊(Chia-Hua Kuo)

《大專體育學刊》 21卷3期 (2019/09) Pp. i-iv

https://doi.org/10.5297/ser.201909_21(3).0000

摘要

研究工作主要是在回答重要問題與滿足人類好奇心。中立無偏見的研究結果經過符合邏輯的解釋，可累積新知，讓人類更有能力瞭解世界、改善自身生存品質。研究價值的高低也通常在於工作是否能有效回答重要問題，即直接與間接攸關生存品質的問題。雖然人類已透過各類觀察產生大量的知識與經驗，對自己生存環境的瞭解仍極為不足。大部分的重要問題仍無法被正確與完整的回答。哈佛大學教授Burwell曾對學生說：在數年後，你們學到的知識半數都將被證明是錯誤的，而老師未必能夠告訴您。另一位化學專長的猶太科學家Kornberg，1959年諾貝爾生理與醫學獎獲獎人，又重複提到「Half of what we know is wrong: the purpose of science is to determine which half」，說明了需要自己培養科學素養以辨認哪一半的知識是錯的。科學素養最重要的兩個關鍵詞為證據（evidence）與邏輯（logic）。兩位學者說明了現代知識的不確定性，以及我們認為正確的觀念經過更多驗證後可能發現未必正確。因此，養成以科學證據與邏輯判斷能力不斷挑戰傳統知識的習慣，成為社會進步的動力。知識的不確定性使我們必須重新思考幾個關鍵問題：在教育體系如何讓知識更穩固與快速的拓展？當標準答案未必正確時，考試篩選制度應如何設計？教育出優秀學生的方法為何？優秀學生要如何定義？教師應如何接受與鼓勵學生自由挑戰課堂知識？在體育知識上，有許多重要問題的答案經過科學驗證後發現是錯誤的。早期受關注的重要問題包括運動員一個星期應該訓練幾次，最能有效增加有氧體能（aerobic power），在1970年前傳統看法是訓練頻率愈高愈好。之後Fox比較每星期訓練2天、4天高強度的訓練（100-m或200-m這類的無氧衝刺訓練）13週後，發現每星期訓練2天的改善效果最好（Fox et al., 1975），推翻訓練頻率愈高越好的迷思。最近的研究也發現，重量訓練有利人類生存率，但如果每星期超過3次，對生存的影響比不訓練更差（Liu et al., 2019）。這些科學證據共同暗示恢復時間的重要性。另外一個體育的重要問題是什麼強度的運動減脂效果較好，一般的看法是中低強度有氧運動。這是基於人體能量消耗上中低強度以燃脂為主、強度愈高逐漸以醣類無氧代謝為主，但經過過去的大量試驗發現強度較高、能量使用偏向無氧的運動效果減脂效果反而較好、中低強度沒有太明顯的減脂效果（Vissers et al., 2013）。減脂必需靠燃脂是一個看似合理、根深蒂固的猜想：但這些科學證據讓我們認識對看似合理的推論，仍應保持懷疑態度，進行科學驗證。挑戰現有知識是進步的必要行為。研究結果與自己的研究假設不同、比較介入結果並無預期顯著差異的研究，都是研究工作的常態，具有參考價值，能讓知識向前拓展。學術期刊應特別鼓勵挑戰傳統思維與觀念的研究，也很願意接受實驗介入後沒有顯著差異的研究發現。

並列摘要

The purpose of research is to answer important questions and to satisfy our curiosity. Unbiased scientific data with logical explanation helps knowledge expansion for humans, particular for those beneficial in optimizing life quality. Ignorance is the major barrier of human survival. Thus, knowledge expansion allows us to understand the world for better survival chance. Therefore, value of research is mainly judged by whether novel, important questions are correctly answered. It seems like we have learned tons of knowledge in the past. We are still ignorant as most of important questions regarding survival have not been correctly answered. Dr. Burwell delivers speech in a Harvard Medical School graduation during the late 1940s, ＂half of what we have taught you is wrong. Unfortunately, we don't know which half.＂ Dr. Kornberg, the Nobel laureate in Physiology and Medicine in 1959, also strengthens the point as ＂half of what we know is wrong: the purpose of science is to determine which half.＂ The two keywords of science are evidence and logics. Both scholars highlight the uncertainty of human knowledge and implicates that constant challenges against existing knowledge is the way to consolidate knowledge. Inherent uncertainty of human knowledge leads us to reconsider several key questions: how would you design test to evaluate students if answers of the question may be uncertain in the future? How do you judge academic excellence to select students? How faculty members should prepare and encourage scientific challenge against class content? Similarly, in the area of sports science, there were many answers of important questions are proven wrong at the beginning. For example, what is the optimal weekly frequency of high intensity exercise to increase aerobic power? It was conventionally believed that fitness improvement should be proportional to training frequency. Fox designed a study to challenge this idea by allocating subjects into groups with frequency of 2 days and 4 days per week of sprinting training for 13 weeks. The result show that 2 days per week produced the superior improvement than 4 days per week (Fox et al., 1975). Furthermore, high frequency weight training will do more harm than good in survival (Liu et al., 2019). Both outcomes suggest the importance of recovery time for high intensity training. Another example is the question on what exercise intensity is the best for fat loss outcome? Conventional concept is low-to-moderate intensity of exercise, not higher intensity. This is largely because of greater energy reliance on carbohydrate with less fatty acid oxidation as exercise intensity increases. However, fat loss outcome, measured by Dual-energy X-ray absorptiometry (DEXA) and magnetic resonance imaging (MRI), is neglectable at low-to-moderate intensity of exercise training compared with higher intensity (Vissers et al., 2013). The major flaw of the old concept is based on an intuitive thought that the only way to lose fat is fatty acid oxidation. Aforementioned examples let us realize that we should maintain certain level of skeptics on conventional wisdom, which is instrumental to advance the current knowledge further. It is common to witness discrepancy between study hypothesis and outcomes, as well as lack of meaningful difference on those we thought it supposes to be different. Journal should welcome and encourage those studies that challenges conventional wisdom based on evidence.

參考文獻

Fox, E. L., Bartels, R. L., Billings, C. E., O’Brien, R., Bason, R., & Mathews, D. K. (1975). Frequency and duration of interval training programs and changes in aerobic power. Journal of Applied Physiology, 38(3), 481-484. doi:10.1152/jappl.1975.38.3.481

Liu, Y., Lee, D. C., Li, Y., Zhu, W., Zhang, R., Sui, X., ... Blair, S. N. (2019). Associations of resistance exercise with cardiovascular disease morbidity and mortality. Medicine and Science in Sports and Exercise, 51(3), 499-508. doi:10.1249/MSS.0000000000001822

Vissers, D., Hens, W., Taeymans, J., Baeyens, J. P., Poortmans, J., & Van Gaal, L. (2013). The effect of exercise on visceral adipose tissue in overweight adults: A systematic review and meta-analysis. PLoS One, 8(2), e56415. doi:10.1371/journal.pone.0056415