Hi, I asked a question about what the effects of sliced and reverse sliced shots on the shuttle's flight path are and how to most effectively use these techniques more than a decade ago on this forum. At the time, it quickly became apparent that very few people really know what happens to a shuttle cock during its flight and that even people who design shuttle cocks have very limited understanding of their aerodynamics or behavior whether sliced or not. In fact, there was almost no research available and most of what could be discerned was based on opinion rather than scientific fact. As I have restarted playing badminton recently I have found that much more information is now available and there are actual wind tunnel studies of shuttle cock aerodynamics. I have summarized what I have found on my blog, but there are still many unknowns and I would greatly appreciate any feedback or pointers to relevant articles or actual research that people can point me to. The full 2,000 words essay on natural, straight and reverse spin is on my blog, but a quick summary of the summary of what I've found for discussion is below: feather shuttle cocks are constructed to "naturally" spin counterclockwise this is due to the way that the air passes over the overlapping feathers this stabilizes the shuttle cock much like a spinning top when traveling at speed so even "straight" shots acquire counterclockwise spin by moving the racket face over the shuttle in a clockwise direction, the natural counterclockwise spin of the shuttle can be increased (as the shuttle reverses) if this rotation is fast/ strong enough it can lead to the skirt of the shuttle deforming outwards thus greatly increasing drag and slowing the shuttle down much faster this "straight slicing" action can be exploited to slow the shuttle down quicker and make it travel a shorter distance it can also be used to hit the shuttle harder while still keeping it in the court; the average speed of the shuttle and thus its total speed are then higher but it moves at the same speed in the later stages of its flight when the natural rotation speed takes over again There's pretty good evidence for everything so far, but then we come to the reverse slice I can find nothing scientific and everything becomes pure speculation on my part. hitting the shuttle in a counter-clockwise motion will impart it with clockwise rotation along its axis, the so called "reverse slice" left-handed players naturally produce "reverse slice" because they move their racquets clockwise over the shuttle right handed players can produce reverse slice, just as left handed players can produce "straight" slice, but the body mechanics make it much harder. As far as I can see: reverse sliced shuttles will decelerate for a shorter amount of time because the natural spin will counteract its clockwise spin quickly more energy will need to be expended to produce a strong enough rotational force to cause skirt deformation the shuttle will be less stable towards the middle of its flight path as the clockwise rotation stops and the counterclockwise rotation reasserts itself, possibly making the shuttle tumble the shuttle will travel further than with the "straight slice" as it is decelerated for less time the big unknown is whether clockwise rotation produces the same, more or less skirt deformation than counterclockwise rotation; all of the above is incorrect if the deformation is significantly greater I then try to apply all this to my shot selection for clears, drives, smashes, half smashes, etc. As I said, I would appreciate any feedback and further information about both the theoretical and the practical application of spins!
That's an interesting piece of analysis, well done. It's great to see people apply their minds to the sport in this way. I think the big difficulty here is the giant gulf between theory and practical application; and the theory itself has some inherent issues too. The aerodynamics of the shuttle are extremely complex. I enjoyed your thoughtful analysis and I think it's well argued, but I don't think it qualifies as scientific. Here's what makes something scientific: can you verify or refute it by testing against the observable world? Yes? Science. No? Superstring theory. I don't think we have much, if any, good scientific data on this subject. And in the absence of that, it's ever so easy to fall into untested assumptions based on personal experience or speculation about how the shuttle might or should be behaving. And it is very subjective. In practice, different players have different experiences using these shots. It's common for players to like reverse slice more than "normal" slice, or the other way around. One player will feel he gets more/better slice with "normal" slice; another will feel she gets more/better slice with reverse slice. Who is right? Both of them. The shuttle's natural spin direction may be affecting this, but the player's own style of hitting makes a much bigger difference. For example, if you have an overhead style like Peter Gade's, there's a fairly good chance you will find reverse slice more natural than "normal" slice. On top of that, everyone just has stronger and weaker shots, even at the professional level. At the amateur level the difference between a player's strong and weak shots can be huge. In practical terms, it's worth remembering that slice generally comes with an accuracy penalty. The more heavily you slice the shuttle, the harder it will be to control the placement of your shot. This is a trade off. In some situations it makes sense to use heavy slice; in others, it makes sense to use a smaller amount of slice; in others, it makes sense to avoid using slice. Usually the main thing that can make heavy slice worthwhile is deception. A good example is the attacking clear, which you mention in your article. While it's certainly possible to play a sliced clear, I feel the benefit is dubious, especially when you consider the importance of accurate placement. This is not a shot I've ever taught, or seen taught; whereas a sliced smash is definitely worth using. I can really see the appeal of the kind of analysis you have done. It feels like deriving badminton from first principles. It's the sort of thing I could easily get into myself. But I feel there is too little connection between the theory and the reality. And with so little contact between the theory and practical play, there's a big risk of the theory becoming a burden to developing your play instead of helping it. Ask yourself this: does the theory help you discover useful ideas for your badminton? Does it help you learn a shot technique, for example? Of course, theory is interesting for it's own sake too, and well-written, intelligent pieces like your article enrich the community. Keep up the good work.
Thanks. You are of course right in all your points. There is very little actual data available and there's far too much speculation. For those interested, there are about a dozen peer-reviewed scientific articles available at the ScienceDirect academic portal. The gap between theory and practice is of course huge, but my interest was piqued by the fact that nobody could tell me whether a reverse slice shot actually has a different flight path to a straight sliced drop shot. Is one faster than the other? Does it land further or shorter? Does it drop faster? How then to decide whether you want to invest time in learning it or not? As for the sliced attack clear, it's one of my favorite strokes. I play it just under the reach of my opponent, bang into the backhand corner (for right hand player) and with 95% smash power and very heavy (straight) slice. It certainly feels like it is very much faster than the normal clear and I can play it much more precisely than my straight clear. It is also after a 10 year absence from the court, one of my only rock solid strokes at the moment . The fact that it is low means that the cork doesn't have much time to drop before my opponent has to play it and is thus not yet fully stable. More often than not, at least at our club level, people are forced to play a backhand, which even for our best club players is a huge disadvantage and usually results in a either very short clear (smash-able) or more likely a slow drop shot that I can then take high and spin. It's one of my staple preparation shots. I have seen in multiple places that it makes no sense to slice clears and it is not something that is often done or indeed taught. When I watch professional players such as Lin Dan, however, I certainly think that I can see them slice pretty much every last clear, but since it is such a fast paced sport it's not even 100% clear in slow motion shots.. thus again my interest in the question of should one slice one's attack clears? does it make an actual difference?
Interesting topic. For LD, he does seem to slice some clears to decelerate the shuttle, possibly to keep it from going out. And re left handed players, like LD, FHF, TBH, I think along with many others somehow the lefty smash ends up being more powerful than righty simply due to a faster spin imparted.
I could see it having some use when you're late to the shuttle, in the same manner as a neutralising shot that can require slice to keep the shuttle from going wide. The problem would be losing a lot of power in a situation where power production is already difficult. If you are Lin Dan, that problem may be less of an issue.
I don't quite follow. You said straight slicing moves racket face over shuttle clockwise, so shuttle spins more counterclockwise. Ok so far... But then you said lefties naturally do reverse slicing, because they move racket face over shuttle clockwise? Clockwise again? Do you mean counterclockwise? For racket movement, is your stated direction from the perspective of the player looking up at the shuttle? For shuttle spinning, is your stated direction from the perspective of the player looking from the back of the departing shuttle?
Sorry, that was wrong I did mean counter clockwise for lefties. The spin direction of the shuttle that I mean is when it moves away from the player who executed the shot. So a clockwise racket motion becomes a counter clockwise shuttle spin after the shuttle flips.
So...does anyone know someone who can put the feathers on 'backwards'? That would most easily control for the reverse vs. straight action since the action will be the same. It will give you a direct trajectory comparison, but for the 'why?', we'd need some slow-mo footage of the shuttle as it leaves the racquet face, and possibly mid-flight too. That could be a start of a scientific approach to solving this question.
Presumably you would also need to make sure that, rather than just putting the feathers on backwards, you also made sure you used feathers from the right wing of the bird, rather than just the left wing. I have always assumed that the shuttle trajectory is most affected by the way the feathers are overlapped, and the fact that it comes only from one of the wings of a bird, and not both.
