kmurdick wrote: ↑
Sat Jul 22, 2017 2:08 pm
A passive rebound is a contraction, but it's a contraction of a different sort.
Sure. That's what I was getting at by contrasting it with an active contraction.
kmurdick wrote: ↑
Sat Jul 22, 2017 2:27 pm
Jouve's video is very good, and it looks exactly like my 'i' finger when I repeat it at 140 mm. These videos really prove nothing as to when or if there is any relief in the free stroke.
I don't think the rebound theory means more relief. If it is correct, then the extensor of the MCP has to be tense while the MCP is being flexed by he lumbricals. If it is wrong and the return is active, then extensor is relaxed during the flexion phase but works during the extension phase, rather than just springing back. Either way it works for half the cycle. Equally, the lumbricals only work for half the cycle, but they are working a lot harder if the return is just a rebound, because in that case the opposing muscle is actively resisting them.
I think some of the videos do provide a few clues about the return. If you go back a few pages and look at Kyuhee Park's tremolo - especially her a finger - it doesn't look at all like a rebound. The rebound effect is being swamped by an explosive muscular contraction.
It seems logical to me that the natural release is responsible for some or all of the extension process.
I don't see how you could prevent the rebound from happening even if you wanted to - the issue is only whether it is the whole story.
And if what I just said is true, I don't think one should should consciously extend (or reach or straighten) from the middle joint while flexing from the knuckle joint. Notice I said "consciously".
I don't think so either (I'm not sure you should be consciously attending to any of these details of the movement in ordinary playing). I don't understand how this point relates to the release though. Also, I don't think you can equate conscious movement with active contraction. We don't consciously instruct all the muscles involved in walking to contract just the right amount at just the right time, but that doesn't mean that this is achieved by a catapult effect rather than by controlled active contraction. We are only conscious of a tiny part of what our brains are doing.
BTW, I'm am not a pro-planting guy. Planting is useful for learning certain things, but I don't think one should base an entire technique around it. The free stroke is one smooth movement and I believe it should be practiced as such.
I just needed a word for the part of the stroke where the MCP is flexing and the PIP is extending. I was also thinking that, for someone who believes a controlled plant is important, it might make sense to use a technique that limits the speed of the flexion but gives you a faster extension, which is just what pre-tensioning would do.