Old fashion method to determine stroke consistency

What is stroke consistency?

It is the ability to hit the shuttle within the a small area on the string bed, shot after shot.

We have seen video of the professional players under-going training using several high speed cameras with computers performing body motion analysis in order to optimise their competitive performance. This includes hitting the shuttlecock within the sweet spot to optimise the transfer of energy  from the arm via the racquet, to the shuttlecock.

Unfortunately for us (aka the non-professional), we will never have access to such facilities nor can we afford to purchase such specialise equipment for a single purpose.

Luckily there is the old fashion methodology for the non professionals.

PRO is the cost of a restring.

CON is will take a while before we can see the results - not within the few minutes as per for the professionals with the high tech setup.

The methodology in-question involves reviewing the areas of fraying on the racquet stringbed.

The following pix is my own racquet. String brand is Gosen and the string thickness is 0.63mm. Used for about 12 badminton sessions so far.

Fraying on my own racquet stringbed

The following are the idealogy behind the fraying.

If the fraying occurs within a small area in the sweet spot, your stroke timing is consistent. Professionals will have a small round spot of about 3.5-5cm diameter within the sweet spot on their racquet stringbed.

If the fraying occurs within a larger area in the sweet spot, your stroke timing is good.

If the fraying is larger than the sweetspot, your stroke timing is not as consistent as it should or could be.

If the fraying is outside the sweet spot, your stroke timing need to be changed.

Recommend you restring with a darker string if you wish to determine where you are hitting the shuttle on the stringbed.

Why?

Since the head of the shuttlecock is white, the shuttlecock will leave white residues on the dark colour string upon contact. Hence you can then see the residues. This will provide an idea where you are hitting the shuttlecock on your racquet stringbed.

ISBS study of relation between tension and speed of shuttlecock leaving stringbed

ISBS conducted a study of the relationship between the tension used on a badminton racquet and the speed of the shuttlecock leaving that stringbed.

The following chart summarizes their findings. The article is at this weblink with the full details available for download as PDF.

Basically, the results are shuttles leave the stringbed at a higher velocity at the lower range of tension tested. Automation was used to swing the racquet consistently.

How to determine sweet spot on your racquet?

The sweet spot is the area of the racquet stringbed which permits the optimum transfer of energy from the stroke of your arm, to the shuttlecock via the stringbed.

In general, the sweetspot is usually on the upper half of a ISO frame vs in the center for a BOX frame (aka Yonex Carbonex series).

Here's how you can determine the sweetspot for your racquet.

Basically listen for a change in the sound pitch. If you hit the stringbed against the base of your palm, at the location of the sweetspot, the pitch will increase and produce a nice lively tone vs the dull sound, if otherwise.

Please came back on November to discuss how to determine if you are hitting the shuttlecock in the sweetspot aka  maxising the transfer of energy from your stroke to the shuttlecock.

Unfortunately those affordable "stuck-on" monitoring tools from China or Hong Kong can not inform if you are hitting on the sweetspot - bought one to try after reading the marketing material ... provides other useful statistics though. Will provide that review in the near future

Possible non strip grommet replacement for ZF2

Discovered a bad grommet on a clients ZF2.

If the bad grommet were not at the end of the strip, you would need to replace the entire strip. And unfortunately (for you), Yonex only sells them as an ENTIRE set for the ZF2 (as well as several other models)!!!

Luckily in this case, I could just remove the bad grommet on the last position of the strip; replace with a normal grommet. In the pix, the offending strip is nearest to my finger on the frame of the racquet.

Upper strip with last grommet removed from the end of strip and replaced with normal grommet

Please take note of the string alignment towards the top of the picture - you can then avoid string overlapping the cutoff strip, if the vertical tie-off is on the other side of the frame.

Reasons for using high tension on racquet

Always wonder why players want to use higher and higher tension on their racquet.

Guess there is 2-sides of the coin.

Players would revert.
- hit further
- better control
- sounds nice when hit shuttle
- thin strings produce nice high pitch sound
- feel more "professional" as they would be using tensions closer to the world ranking players ??

IF I own a sports shop, I would say the following instead, as it would provide  more regular revenue opportunities
- higher tension strings break faster
- racquets would be easily damaged at higher tensions, especially when they clash
- racquets tend to turn soft after several restrings at higher tensions
- thinner strings at higher tension tend to snap faster

Does anyone ever ask if you experience any elbow pain, recent pain on the upper arm or pain in the neck area after you started using a higher tension? Never heard anyone in the shop asking such questions ... I do when the client wants to use a higher tension.

All you hear in the shops are  ... wow you still using such low tension???

You as the client need to ask yourself ... do they have your interest at heart, or, are you just an atm for them?

Same string diff thickness

Was quite surprised when I performed a comparison of the Yonex BG66 Ultimax string actual physical thickness.

The red string appear to be thinner than the yellow. Also find the red string composition to be more solid when compared to the yellow.

Bought from the same wholesaler in UK as the Yonex agent for South East Asia, Sunrise apparently does not sell strings in reel form when I made the inquiry.

Could this be evidence of an OEM activity eg Yonex contracts a 3rd party to manufacture for them, since Yonex does not confirm nor deny if they have factories which produces strings?

Gosen and Ashaway proudly confirms their manufacturing facilities.

Carlton 3.7X - 1st generation non-wooden racquet

Recently acquire the Carlton 3.7X for a collector.

Was curious how heavy it would be - answer in the pix below (in grams).

The 3.7X is quite collectable as it has a midway tapered shaft. The 3.7X also differ from the 3.7 as it was an all stainless steel frame vs the 3.7 frame which does corrode and easily cracked.

I lost my own then newish 3.7X at Narita airport in the late 1980's during a stopover flight from Singapore to LA. Was pretty disappointed as the authorities was never able to locate the missing racquet.

Racquet with designed Non-traditional stringing pattern

Unique stringing pattern for a Hart Infinite OV-3000, the grommet layout facilitates a top-down approach.

Overall view before last row tensioned

Top portion of frame

Bottom portion of frame

Using phone app to monitor string tension (Part-2/2)

Based upon testing using CARLTUNE (IPhone and android), the app will display a frequency of approximately (+/-10Hz) 1144Hz if you hit the sweet-spot on your racquet against the base of your palm, for tension of 22lbs. Basically is the average after several such hits.

Approximate CarlTune reading for 22lbs tension

Verifying tension on the newly strung Yonex Aerosonic

Please perform the action as close as possible to the phone mic for best results. I did discovered the phone can be further away if you are in a enclosed and closed room. In this scenario I try to keep a shuttle in the air gently via tapping, with the app monitoring the Hz of the hits.

Tested the procedure with racquets strung with Yonex Aerosonic (0.61mm), Yonex BG66 Ultimax (0.65mm), Gosen Pro66 (0.66mm) and Ashaway Zymax62 (0.62mm) which seem to provide similar results.

In addition, I had reverified the tension using the Tension-O-Meter since I just restrung one of my racquets with Yonex Aerosonic @ 22lbs - app shows 1144.xx Hz. Sometimes the result would be within a few Hz of the above. Irregardless, the percentage of error would be small and hence negligible for the purpose of (free) monitor facility.

Thus we can use the following simple formula to determine tension via the frequency readout on the app.

1144 Hz = 22lbs

1 Hz       = 22 / 1144

               = 0.01924

Thus a x Hz  readout would mean tension of approximately = 0.01924 * frequency shown on app (tension in lbs)

True this methodology is not 100% accurate as it is meant to provide a means for monitoring, not provide absolutely accurate readings. There are such commercial app and/or tools but they won't be free!

Using phone app to monitor string tension (Part-1/2)

Before I describe my layman version of the authors technique, please assist to review the original article at Badmintoncentral - give credit where credit is due.

They provide a technical in-depth discussion of the technique and the science behind it. 

Do you know how to make use of the information presented to actually monitor the tension on your badminton racquet?

If not, tune back next month and I will reveal how the average Joe can monitor their racquet tension without any expensive tools.

FYI Grommet replacement for Yonex Z-Force 2 (and alike)

Recently had to help a client replace the "in-line" grommets at the upper half of a Yonex Z-force 2, as it seem to be cutting into the string. 

Now for the shocking news - I called the local Yonex distributor as well as various local shops and they tell me to go order the replacement from overseas myself, as they would charge a processing fee for the item.

Why is it shocking, you say? 

If you try ordering it, the "in-line" grommet is not available as a single item. You must buy the entire set of grommets for the Z-Force2 at about USD$12 per set!!! This is before cost for shipping etc.

KUDOS to Yonex for this easy money making scheme!

So owners of the Z-Force2 and some models of ArcSaber/NanoRay/Voltaric be aware of these impending future expenses.

Sweet spot difference on ISO vs box frames

Found the following pix on the net which illustrates the sweet spot difference between a traditional box shape and a modern ISO frame - easier to show using the below than trying to explain it.

Another fake racquet from PRC

A friend recently purchased the following fake from PRC via TaoBao after using my Dunlop Biomimetic Evolution. I purchased my pair in 2010.

The below pix shows the fake with yellow strings - looks ok right? Even the skin effect of the Biomimetic series was well cloned.  Upon closer inspection, there are differences.

1. Racquet is 675mm for the FAKE (YELLOW string) vs 670mm of the original and of the specifications printed on the shaft of both the original and the fake.

2. Finger over the wordings on the frame of the FAKE (YELLOW string) feels lumpy (aka printed) vs smooth feel on the original

3. Smear of the BIOMIMETIC on one side of the frame of the racquet on the FAKE (YELLOW string) vs the original

4. Difference of the cap over the handle

5. Grommet layout of the original vs the FAKE (YELLOW string) which is alike an older racquet I bought in 2009.

Fake version in Yellow string

Closeup of bottom grommets on the fake

Fake (YELLOW string) vs original (BLUE string)

Note the difference in the grommets on the 12th position from the shaft. The grommet layout of the fake is as per normal racquets whilst the original has 2 micro-grommets at the same location.

Grommets at top of frame. Fake in YELLOW vs original in BLUE string

Minimal difference here with the fake (YELLOW string) having only a single large grommet. The original has 2.

More grommets on the side of the original

Both the fake (YELLOW string) and the original (BLUE string) have 6 transparent micro-grommets on each side of the frame. However on the original, there is a additional micro-grommet after the last transparent micro-grommet on the top of the frame.

Difference in string layout - overlay of fake (YELLOW string)  over the original (BLUE string)

String pathing differs on the fale (YELLOW string)

Different handle top of the fake (middle)

Pix of grommet layout of friends racquet from same series. He bought his racquet from Malaysia., Grommet structure is as per my racquets in BLUE and WHITE strings.