B2L2 寫:I dont buy your idea of controlling muscles. My understanding of human skeleton, muscle and joint don't work the way you describe.
Muscle's main function is to control joint movement. So whatever how you control different part of one muscle, your movement still limited by your joint.
B2L2 寫:About your experience, u have been using rental boots and skies that didn't fit you. How could u feel the proper force giving from the equipment?
U have also been skiing in a slower speed. Again, how could u experience all the acceleration force, 離心力，去心力？
So how did you correct your son? Did you teach him how to properly use his muscles? No, right. Yes, "coordination and timing" is a much better word. One need to do the proper movement at the right time.
norman 寫:裝備只要適應一下軟硬及鋼邊弧度及長度就行了，邊滑邊適應邊套上要做的動作就行了。只是裝備太糟糕的話，就要多花一天時間適應而已，動作反而影響不大。
Look at your own skiing, I don't see the proper "coordination and timing" at slow speed. Once you're skiing at higher speed or steeper slope or use different equipment or 1000 more or, everything changed.
You could claim "影響不大", but I said everything effects your skiing. Without experiencing all these and I wouldn't trust you managed to "create" your own learning method correctly. I would still recommend to just pick a teaching system and follow it instead.
norman 寫:速度慢就沒有離心力跟向心力了嗎？
PS. 忘了講加速力/acceleration force，反問，什麼是加速力？雪板上有加裝推進器嗎？加速力會憑空產生嗎？基於什麼條件才會出現？真的有加速力嗎？
Gravity is the major acceleration force. That's why the steeper the slope, the higher acceleration the skier experience. Yes, ski rebound is a measurable force. With proper use, skier (racer) could use it for acceleration. I agree as a recreational skier, we prefer to control this force instead of using it for acceleration. We "control" it to help us skiing effortlessly.
速度慢就沒有離心力跟向心力了嗎？ Yes, those exists in any turn. The infamous equation: ac= v^2/r. Centripetal acceleration increase by the square of velocity. That's when you speed double, the centripetal acceleration is 4 times higher.
All your moving and timing needs to be adjusted accordingly.
#48 回覆: cross-under 應該是在做 down-unweighting
發表於 : 週二 3月 31, 2015 3:58 am
由 B2L2
norman 寫:對，所以動作的「正確與否」及「運用」離心力跟向心力跟速度快慢是無關。
If it is really 無關, then after you learn all the "correct" movement and understand how to "use" them, then you should able to win an Olympic medal.
norman 寫:如同你舉的這個例子，三歲小孩來推我，我很好抵擋，甚至我還可以用比他更大的力量反推回去。100公斤的人來推我，我抵擋就很吃力，如果我的力量比他大，一樣可以反推回去，如果我的力量小，我一定抵擋不住。
How to push back a 三歲小孩 and how to push back 100公斤的人 could be different. How to push back the same person walking towards you and running towards you could be different.
norman 寫:問題就在於滑雪的技巧不是在互相比力氣，而是在如何綜合平衡壓力及建立更高的平衡能力，所以速度慢，一樣可以在慢速上仔細練習及體會的，甚至很好改變自己的策略去多方嚐試，要是在高速下，應付平衡跟速度都來不及了，我們還會有多餘的心力放在自己的動作上體會嗎？當然，如果一直在練錯誤的動作，那體會也是沒有用的，只有腦筋變通開通改變後才有機會把動作導向正確的動作。
真正的問題 is how to prove what you think is correct. I actually agree to practice everything in slow speed and then gradually increased your speed. Then come back to practice the next thing.
norman 寫:至於加速力的問題，我認為沒有這種東西，以前我也被誤導以為有，事實上那是錯誤的感覺(這是我在野澤時體會到的想法)，就跟「反彈」是一樣是錯誤的感覺，當重心質量跟雪板交叉錯移時，錯移的速度夠快又正確時，就會產生「反彈力」跟「加速力」的錯覺。事實上只要降低阻力，速度上就提升了，而阻力有很多種方式會出現，如風阻，如重心移動沒有正確的移動，如雪板接解雪面面積越多，或雪板的軟硬功能….等影響，這些都會增加阻力，速度自然就慢下來了。所以「加速力」應該是建立在「降低阻力」才會變相成有增加速度。
There is a force. When you bend a ski and release your hand, there is a force to straighten the ski back. Where is the 錯覺? I said before, it is up to the skier how to use this force. For racers, their intention is go faster and they use certain movement to use this force. For beginner or usual recreational skier, their intention is to slow down or control their speed. That's why there are beginner level equipment (ski, ski boots, etc) which gave less force which is easier to control. However, for experienced recreational skier, they could use this force to achieve what they want and that's why there are higher end equipment to suit what they need.
All the remaining about 阻力 that you said isn't all wrong. If you couldn't feel and use the ski rebound, using your own word, it is only because you haven't feel it yet. We couldn't able to explain to you. If you learn what's missing, your created "correct movement" (lean, absorb, etc) could be a lot different. Work on improving if you could.
#49 回覆: cross-under 應該是在做 down-unweighting
發表於 : 週二 3月 31, 2015 8:55 am
由 norman
B2L2 寫:So how did you correct your son? Did you teach him how to properly use his muscles? No, right. Yes, "coordination and timing" is a much better word. One need to do the proper movement at the right time.
Look at your own skiing, I don't see the proper "coordination and timing" at slow speed. Once you're skiing at higher speed or steeper slope or use different equipment or 1000 more or, everything changed.
You could claim "影響不大", but I said everything effects your skiing. Without experiencing all these and I wouldn't trust you managed to "create" your own learning method correctly. I would still recommend to just pick a teaching system and follow it instead.
B2L2 寫:If it is really 無關, then after you learn all the "correct" movement and understand how to "use" them, then you should able to win an Olympic medal.
How to push back a 三歲小孩 and how to push back 100公斤的人 could be different. How to push back the same person walking towards you and running towards you could be different.
真正的問題 is how to prove what you think is correct. I actually agree to practice everything in slow speed and then gradually increased your speed. Then come back to practice the next thing.
There is a force. When you bend a ski and release your hand, there is a force to straighten the ski back. Where is the 錯覺? I said before, it is up to the skier how to use this force. For racers, their intention is go faster and they use certain movement to use this force. For beginner or usual recreational skier, their intention is to slow down or control their speed. That's why there are beginner level equipment (ski, ski boots, etc) which gave less force which is easier to control. However, for experienced recreational skier, they could use this force to achieve what they want and that's why there are higher end equipment to suit what they need.
All the remaining about 阻力 that you said isn't all wrong. If you couldn't feel and use the ski rebound, using your own word, it is only because you haven't feel it yet. We couldn't able to explain to you. If you learn what's missing, your created "correct movement" (lean, absorb, etc) could be a lot different. Work on improving if you could.
