文/耐力網/莊茗傑
《鐵人三項訓練聖經》的作者喬福瑞在Triathlon Science這本編著中以科學的角度回答了這個問題:
游泳選手最常發生的運動傷害部位莫過於肩膀,而訓練強度、訓練量和距離的上升是受傷的主因。因為肩膀是擁有一個淺籃狀凹槽–肩盂腔(glenoid cavity)和球狀的肱骨頭(humeral head)所組成,被稱為肩盂肱骨關節(glenohumeral joint),這個關節的兩個結構彼此大小不相配,較大的肱骨總是只有1/3的肩盂所包覆,所以肩關節比實際人體其他關節的活動角度都還來得大,但也因此造成肩膀容易因為重複性的壓力而受傷。平均而言,競賽型的游泳選手一個禮拜大約游6萬到8萬公尺。以每游25公尺需要划水8到10次來計算,每邊肩膀一個禮拜需要轉動3萬次。雖然此訓練量可能比大多數的鐵人三項選手還來得多,但若能了解發生在肩膀上有多少次動作,便能幫助我們想像出為何游泳選手那麼容易因過度使用肩膀而造成運動傷害。
最常發生於游泳的運動傷害是「肩關節夾擠症候群」,這種症候群通常診斷原因包括:
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肩旋轉肌肌腱炎 (rotator cuff tendinitis or tendinosis)
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滑囊炎( bursitis)
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肱二頭肌肌腱長頭肌腱炎(long head of the biceps tendinitis or tendinosis,
疼痛常出現於手掌過頭的動作,像是自由式游泳的入水和抓水的階段。另外,肩膀受傷的患者在睡覺時也會無法用患側(茗傑註:例如右肩受傷,便無法倚靠右側側睡)。通常,這些傷害的原因是因為自然的生物力學動作,可以藉由修正划水動作模式或是某些運動員的生物力學限制來改善。當治療這些肩膀傷害時,運動員應該要避免使用划手板或是划槳。
對自由式來說,造成肩膀傷害的原因如下:
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提臂入水時超過身體轉動的中線
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拇指入水
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不對稱的身體轉動
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單邊換氣。
除了按照適當的游泳動作指導,運動選手應該要增強脊椎活動性和保持良好的旋轉軸肌(rotator cuff) 和肩膀的穩定力量。
以下介紹三種對肩膀有幫助的運動可以在游泳前或後來施作。
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胸椎伸展上半部滾筒運動
將滾筒垂直放置於你的上背。伸展你的脊椎和在滾筒上滑動,並且舉起你的雙手過頭。持續1分鐘、重複3-5組,每一組泡棉滾筒的滾動位置都可以略微上移。
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旋轉肌肌力加強
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姿勢1:將毛巾擠壓置於手肘與腰部之間,並且隨時保持手肘在90度(茗傑註:可以使用啞鈴或是其他有點重量的負重器具)。
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姿勢2:舉起你擠壓毛巾的手(茗傑註:量力而為,到自己可以接受的範圍即可),並且不要移動肩膀。
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最後慢慢放下手回到起始動作
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在瑜珈球上作TS動作
把你的臀部和腹部核心肌群放在瑜珈球上,並且將你的雙腳放在地板上以維持平衡。注視著地板並且保護你的頸部。讓肩膀保持上抬到耳朵的位置,同時使大拇指面對天花板。專注於將你的肩膀靠攏並且觸碰在一起。
以上譯文與圖片摘自:Joe Friel,Jim Vance, editors (2013). Triathlon science.,462, 463, 464. United States of America: Human Kinetics.,下面為原文:
Shoulder Injuries
Shoulder injuries are the most common injury among swimmers, typically resulting from increases in training intensity, volume, and distance. Because the shoulder is a ball-and-socket(glenohumeral) joint with a shallow socket and relatively large ball, it allows tremendous range of motion. This degree of mobility permits the shoulder to perform more movement than virtually any other joint, but it also makes the shoulder prone to breakdown under repeated stress. The average competitive swimmer swims approximately 60,000 to 80,000 meters per week. With a typical count of 8 to 10 strokes per 25-meter lap, each shoulder performs 30,000 rotations each week. Although this training volume may be more than the typical triathlete performs, an understanding of how much movement is occurring in the shoulder is helpful in creating a picturte of why it is so susceptible to overuse injury.
The most common swimming-related injury is describled as impingement syndrome(generlized diagnosis that may include rotator cuff tendinitis or tendinosis, bursitis, long head of the biceps tendinitis or tendinosis, and so on) and presents as pain with overhead activity, pain at water entry or catch phase, and inability to sleep on the affected side.
Typically, these injuries are biomechanical in nature and can be addressed by modifying stroke pattern or in some cases by correcting the athlete’s biomechanical restrictions. When dealing with an injured shoulder the triathlete should avoid the use of paddles and kickboards. Contributors to shoulder injury in the swim stroke are hand entry crossing midline, thumb down entry, asymmetric body roll, and unilateral breathing. Besids obtaining proper swim stroke instuction, the triathlete need to increase spinal mobility and maintain good rotator cuff and scapular stabilizer strength. The following three exercises before or after each swim session can be helpful.
Thoracic Extension Half Foam
Place the foam roll perpendicular to your midback. Extend your spine over the foam roll and lift both arms above your head. Hold for 1 minute and repeat three to five time, moving the foam roller to higher segments of your thoratic spine.
Rotatot Cuff Strengthening
Position 1:Squzzse the towel roll down with the elbow and keep the elbow at 90 degrees at all times. Position 2: Lift your hand while squeezing the towel roll and not moving the shoulder back. Slowly lower back to the starting position.
TS on a Physioball
Place your hips and core onto a physiball and place your feet on the ground for balance. Look at the ground to protect your neck. Keep your shoulders from rising up toward your ears. Concentrate on squeezing your shoulder blades together. Keep your thumbs facing the ceiling.
游泳選手最可能發生的過度運動型傷害在肩膀:
對於游泳選手來說,最大比例的運動傷害部位為肩膀。因為內文中有提到:「一個競賽型的游泳選手一個禮拜大約游6萬到8萬公尺。以每游25公尺需要划水8到10次來計算,每邊肩膀一周需要轉動3萬次」。雖然大部分的人一個禮拜的訓練量不會到達6萬公尺,可是單就游泳自由式這項運動而言,肩膀仍是使用最頻繁的部位。
除了譯文中介紹的三種輔助運動(胸椎滾桶運動、旋轉肌肌力加強和TS動作),我也推薦施作增強肩膀柔軟度的動作:請參考youtube上有關使用彈力帶增進肩膀柔軟度的五個動作示範
因為當我們肩膀柔軟度增強時,便能更流暢地作出划水的動作,並且減少肩膀因為動作受限( biomechanical restrictions)而造成的韌帶損傷。
最後幫讀者們附上游泳選手常見的肩關節運動傷害有:
- 「肩關節夾擊症候群」(shoulder-impingement-syndrome):肩關節夾擊症候群的成因是因為肩旋轉袖肌群的損傷可能導致肱骨頭往上位移,使肩關節的空間變小造成夾擊
- 「肩關節滑囊炎」(Bursitis)的簡圖與簡介:反覆的肩膀拉扯或手臂高舉過頭的動作,會使位於肱骨頭的滑囊受壓迫與發炎。
(摘自DK Publishing:《運動傷害圖解聖經》,台北市:旗標,2012,頁72)
圖片來源:Triathlon Science
耐力網相信訓練是科學也是藝術,而訓練的藝術,是科學化的極致表現。