Tennis Warehouse: Zepp Tennis Sensor Playtest

[julian]

Data for baseball

http://www.zepp.com/baseball/
shows what can be done for baseball
------> a quotation from the Web site above

ARM YOURSELF WITH HELPFUL DATA

BAT SPEED
Track your hand speed throughout your swing. More speed equals a faster reaction time and more power.
HAND SPEED
Track how fast you swing and work on increasing your speed. More speed equals more power and distance.
IMPACT ANGLES
Capture the angle of your bat at impact and where in the hitting zone you make contact with the ball.

RESULT TAGGING
Tag your hit results and input radar data to identify successful swing characteristics. Use this data to set new swing goals.
SWING PLANE
Discover the shape of your swing and view the position of your bat in 3D space from any angle.
TIME TO IMPACT
Measure reaction time from the start of your
-----> the end of the quotation

 

[julian]

Potential errors

http://link.springer.com/article/10.1007/s12283-012-0084-9#page-1
addresses an issue of potential errors for baseball measurements
A similar technique applicable for tennis
@gzhpcu -I will provide more details on this subject

 

[julian]

Ball speeds

http://www.tennisindustrymag.com/articles/2006/07/wrist_snap_in_the_serve.html
provides the number 115 miles per hour for a college player

I believe that a Zepp number would be around 60 percents of the number above

 

[julian]

Review of a serve of Javier Molina

A review of a serve of Javier Molina is difficult
because a video provided to me was from behind and trajectory is basically
"done" perpendicularly to a long axis of a court.
Therefore it is difficult to compare a contact point from a video to a contact point obtained from a trajectory.

 

[jc_rex]

So this happened to my sensor today after flying out of the pro mount.

Sucks

 

[Backhanded Compliment]

got mine and found the app difficult. I registered 3 serves but I could only get it to record those three. in 3d serve mode when it says hit a ball and I do it it usually does nothing. I turned sensor on and off too.


If I can get it to work I can see this being pretty cool... I hit some pretty wimpy half hearted second serves and still got 44 power. Curious about what happens when I go full out.

***Update a new sensor is on the way and I gear the app will have an extensive revamp next week. good communication with this company.

 

[gzhpcu]

Look at the 3D swing example on the Zepp website, start the video and look at the starting image:

http://www.zepp.com/tennis/

As a tennis player it makes no sense to me: A weird swing and impact is way below and not at the highest point in the swing.

 

[julian]

Trajectory was produced May 5

Look at the 3D swing example on the Zepp website, start the video and look at the starting image:

http://www.zepp.com/tennis/

As a tennis player it makes no sense to me: A weird swing and impact is way below and not at the highest point in the swing.

I have a very minor point which is related more or less to a software process,
not to the merit of your post above.
As you see from the date of the trajectory it was produced May 5th.
It was 2 point releases ago.
Whether it matters I do NOT know.

I do NOT know what trajectory would be produced with the current version 1.2.2 for the iphone (I think 1.2.2 is the latest greatest -released around July 17th).
Whether this particular marketing material is the best choice-I do NOT know.
I am just a tennis coach,as you know.

I believe that a trajectory from a side would give better information
if a "side" video is available.
A good example will be
http://www.tennis.com/gear/2014/06/product-review-zepp-tennis/51908/#.U-Yb-PldVCg

I understand that in majority of clubs the side view is NOT available.
Video cameras in US are positioned mostly at the back of courts from one reason or another.
regards,
Julian

 

[julian]

Please read my E-mail

Look at the 3D swing example on the Zepp website, start the video and look at the starting image:

http://www.zepp.com/tennis/

As a tennis player it makes no sense to me: A weird swing and impact is way below and not at the highest point in the swing.

Please read my e-mail

 

[gzhpcu]

Actually, the tennis 3D serve trajectories make very little sense to me. Sometimes the racket points in weird directions the trajectory is not much better. Anybody have any good experiences with the 3D serve trajectories? Do you think they are realistic?

I personally think that Zepp has underestimated the complexity involved in a serve trajectory, and they also do not interpret the movement of the racket along the trajectory correctly. Think I will stick to a video camera for serve analysis... at least you see what you get...

 

[Backhanded Compliment]

I got the new sensor and updated the ap and firmware

3d serve works better now and spin on my flatter 1st serves is now usually 6 instead of 10. My american twist seconds serves register from 8-9 spin. Both seem in keeping but it only records serves where I pause for about 2 seconds.... this interrupts serve practice flow so the 3d thing is just kind of a novelty.

Much better was tracking mode. It tackede nearly every serve forehand and backhand. It seemed mnore accurate in terms of power too. Actually this now seems very useful. I paln to use it wh Im just hitting and doing warmups. Would be great if tracking mode tracked amount of spin per stroke like 3d serve mode does. A fun comparative practice tool. That should get improved as R&D progresses to tune this.

 

[julian]

Please elaborate

I got the new sensor and updated the ap and firmware

3d serve works better now and spin on my flatter 1st serves is now usually 6 instead of 10. My american twist seconds serves register from 8-9 spin. Both seem in keeping but it only records serves where I pause for about 2 seconds.... this interrupts serve practice flow so the 3d thing is just kind of a novelty.

Much better was tracking mode. It tackede nearly every serve forehand and backhand. It seemed mnore accurate in terms of power too. Actually this now seems very useful. I paln to use it wh Im just hitting and doing warmups. Would be great if tracking mode tracked amount of spin per stroke like 3d serve mode does. A fun comparative practice tool. That should get improved as R&D progresses to tune this.

Please elaborate what do you mean by
"Both seem in keeping"

 

[Backhanded Compliment]

Please elaborate what do you mean by
"Both seem in keeping"

By that I feel like the spin ratings were in the right ballpark of what I experienced. The onethat was a 9 was a ball I chased and spun it in, It jumped severely whenit hit the ground. The others are all seemed right.My first serves were all intentionally flatterstyle and typically had a spin of 6. My second serve is an american twist.

 

[gzhpcu]

Question I have is do you consider the 3D trajectories realistic to your serve motion?

 

[Backhanded Compliment]

Question I have is do you consider the 3D trajectories realistic to your serve motion?

Short answer... about half of the time. Others it is just waaay wierd. I've found the sensor has improved my serve practices becayse I can see what gives me that extra increase in pace and or spin and replicate it. It keeps things from being anecdotal.

 

[Backhanded Compliment]

http://www.zepp.com/baseball/
shows what can be done for baseball
------> a quotation from the Web site above

ARM YOURSELF WITH HELPFUL DATA

BAT SPEED
Track your hand speed throughout your swing. More speed equals a faster reaction time and more power.
HAND SPEED
Track how fast you swing and work on increasing your speed. More speed equals more power and distance.
IMPACT ANGLES
Capture the angle of your bat at impact and where in the hitting zone you make contact with the ball.

RESULT TAGGING
Tag your hit results and input radar data to identify successful swing characteristics. Use this data to set new swing goals.
SWING PLANE
Discover the shape of your swing and view the position of your bat in 3D space from any angle.
TIME TO IMPACT
Measure reaction time from the start of your
-----> the end of the quotation

impact angles in the tracking mode for groundstrokes might be interesting for tennis. Itcertainly realates to Slice flat and topspin but it might be cool to break down the angle of incidence on the various types of shots. Also results tagging would be great for tennis too.

 

[boojay]

I just got the sensor a couple weeks ago and finally found time to try it out. It's pretty cool and I'm guessing fairly accurate(?), it seems that way.

Anyway, I'm having trouble interpreting the results and was wondering if someone could fill me in on what it means. In particular, if there are any concrete figures that can be derived from the numbers given by the sensor.

During a fairly casual to average hitting session with my weekly partner, I struck about 400 balls in half an hour after warming up and obtained the following stats:

FOREHAND
Avg 65
Max 88

BACKHAND
Avg 59
Max 88

SERVE
Avg 91
Max 100

Based on the description in Zepp's online manual, 100 represents pro level. I can accept the numbers on my groundstrokes, but I find it hard to believe I have near a pro level serve. It's pretty good for club level, but no way am I hitting bombs all the time, at least I don't think so.

I'll try another session sometime and maybe up the intensity to see if I can max out the groundstrokes. Only then will I think the sensor is possibly not lying to me. I'll use it the next time I play with a teaching pro who just loves to wail on the ball, so every stroke should be fairly high.

 

[Backhanded Compliment]

I just got the sensor a couple weeks ago and finally found time to try it out. It's pretty cool and I'm guessing fairly accurate(?), it seems that way.

Anyway, I'm having trouble interpreting the results and was wondering if someone could fill me in on what it means. In particular, if there are any concrete figures that can be derived from the numbers given by the sensor.

During a fairly casual to average hitting session with my weekly partner, I struck about 400 balls in half an hour after warming up and obtained the following stats:

FOREHAND
Avg 65
Max 88

BACKHAND
Avg 59
Max 88

SERVE
Avg 91
Max 100

Based on the description in Zepp's online manual, 100 represents pro level. I can accept the numbers on my groundstrokes, but I find it hard to believe I have near a pro level serve. It's pretty good for club level, but no way am I hitting bombs all the time, at least I don't think so.

I'll try another session sometime and maybe up the intensity to see if I can max out the groundstrokes. Only then will I think the sensor is possibly not lying to me. I'll use it the next time I play with a teaching pro who just loves to wail on the ball, so every stroke should be fairly high.

It is all relative and based mostly on head speed. If tou use a heavy racquet with a slower swing speed it can register lower #'s even though it is a heavier and faster ball.

I like using mine for serve practice. Ive found that just 4 points can constitute a huge difference in how hard a serve is.

 

[boojay]

I received a reply from Zepp in regards to the power number:

"The power measurement is relative with the racket speed. Due to the difference of racket sizes and shapes, we index the speed of the sensor to the ?power? number from 0-100. A power of 100 represents a pro men player that uses full power to play forehand/backhand/serve."

That's pretty encouraging because I've always said I only put in about 70% effort when I hit my groundies during rallies and I do feel like I'm hitting the ball better than ever (and still improving), so this is quite validating.

Even my hitting partner who's no slouch himself (58 on his groundies) has said every once in a while we have pro-level rallies when we both zone in. I'm starting to believe him.