I have been playing table tennis for over 6 years in which I have taken some breaks and got a little extra fat.

Now I am going to the gym at least 3 days a week in which I do classic weightlifting (8 reps, heavy weights and normal pace) and doing functional training (which is a 45 minute hiit circuit) which involves plyometrics, isotermic exercises, explosive push ups and a little bit of jogging at the end.

I know that for the lower body plyometrics, sprints and explosive lateral movement are good ways to increase footwork potential, however, I was curious of what can be done to improve the upper body at table tennis, because when I train my upper body at the gym I feel my body gets "dumb" when playing as there is a lack of control and feeling of the ball. 

What kind of training do you do for upper body?

How frequent do you do it?

Do you include weights?

Do you believe that training with a 5lb weight strap on the arm would improve your arm speed?

I mostly work on leg exercises and hip exercises-- but not even to the extend you are doing it.

On the FH side if you do a traditional loop (more brush than drive) you should be working the hips to generate speed and power, not using your arms (or chest/shoulders) as the initiator.  If you don't already I would add in hip exercises and work on shadow swings with your blade or something a bit heavier and just keep your arms loose (and your wrist not rigid) during the swing.  (use a video to make sure you are using your hips and you are not moving your head too much during the swing)

You don't need to engage your arm muscles too much during the FH swing.  Just by having more muscle mass will add the power when you make contact with the ball--->>> but only if you can keep your swing speed the same as when you had less muscle.  On the BH you are using more of the arm but the key on the backhand is the timing and bat angle rather than strength.  I still keep my arm and wrist very relaxed for a BH loop or drive.

Personally I'm not into bulking up, and from your routine it sounds like you are not looking to get huge-- but you must balance the extra muscle mass with the same or greater flexibility which you probably are doing by looking at your routine.

I would just make sure you are doing enough hip work and keeping very flexible.

**as a side note-- there are lots of very, very good amateur players that do no gym work whatsoever. 

I did everything in the gym: Arm, shoulder, chest, back, leg, hip, and run....

After 2 months, I and all my friends in table tennis club see I improvement as moving faster and playing time longer and during the match my level stay as same as beginning (that is my major problem). I know I did like that is not right as professional table tennis player but I am very happy with the way I did and I am not professional anyway.

https://youtu.be/Bq2IWko31tI?t=48s" rel="nofollow - https://youtu.be/Bq2IWko31tI?t=48s

It's called the Front Rotary Scoop Toss and it's an excellent drill to train your body to generate power from the lower body up through the arms. Do not use a weighted paddle or dumbbell to mimic your stroke as this will compromise the integrity of your technique. 

Give it a try and let me know what you think!

Sorry, must of missed this. Here's a full body warmup you can use:

https://www.youtube.com/watch?v=_gHUQiKmmdI

You don't necessarily have to do the whole thing each time. Pick and choose based on what seems tight or on how well you're moving that particular day.