Your information is a bit too vague.
A 12% to 20% body fat percentage (BFP) range is like saying your weight is between 50kg and 100 kg. For a guy, 12% body fat is in the athletic range and very close to a professional athlete's level of BFP, but 20% is average for someone who does almost no forms of exercise.
And you need to be more specific about what you mean by getting stronger overall. What you stated does not saying anything. To achieve a goal, you have to define it. The better defined it is, the better chance you have to reach it. Just a general vague description means you will not achieve anything and even if you somehow lucked out and did reach a goal you would not even realize it.
Re-read what your wrote and you will see that not having a well defined goal pretty much is the reason why you thought of getting a weighted vest. What was it suppose to do for you? Was carrying extra weight suppose to magically make your entire body more fit? If that were so, all overweight people would be fit.
Weighted vests are a pretty useless piece of kit. They place too much stress on limbs and joints, and don't really add any resistance to the upper body.
About the only thing I can think of is that might help in doing certain plyometric exercises..
As the other post above notes... Looks to me like you're going about all this in a very unorganized and scattershot way.
First, establish some goals. What do you want? You say you're involved in martial arts... If you want increased performance in martial arts you need to only do some supplemental strength training in addition to the MA workouts.
Do some serious research into exercise physiology.
I'd say that a weight vest will restrict your movement way too much to do good martial art techniques especially Kung Fu where agility and flexibility matter greatly. I think that there will be too much difference in balance if you are used to the weight of a weighted vest which would physically lower your center point of balance and then find you have to do the techniques without the weighted vest which will inevitably raise your center point of balance point and change your techniques. this can land you in a heap of trouble.
I think you need to just train and never mind the weighted vest. If others can build muscles without weighted vests why would you not be able to. Besides good techniques do not come from strength but from good techniques.
...and I agree with John. You would be much better off picking one martial art and doing 3 hour classes per week in that and then spend the gym time practicing at home what you learned in class. Then your martial arts training might actually amount to something.
There are so many wrong in your question.
1. You're not fat. You didn't say that specifically but that's what you implied. You're current BMI is at around 24.
2. There is a big difference between 12% and 20% fat. You can not give that interval.
3. Personally when it comes to martial arts I think you should either do it properly or not do it at all. 1 hour of kung fu weekly serves you almost no purpose. Kung fu is not known for it's physical exercises. I just think paying for something and doing it so little is pointless. Same thing with kendo.
4. Going to the gym for 20 min is ridiculous. That is barely enough to get warmed up. You need to be at the gym at least an hour. You can do like I do. One day you do exercises and the next day you run either on the treadmill or outside. It is summer now after all.
5. Weighted vests are mostly used for running. There really is not much point in wearing one just for the heck of it. The con is that it puts a strain on your joints. But if you are ok with that then go for it.
But you need to work out smarter. What you're doing now is completely wrong. I would try and find a gym that is physically tough and if you go to the gym stay there for at least an hour.
12-20% BFP is a huge disparity. Weighted vests will do you much more harm than good and if you think that wearing one all day and exercising with it is going to help your body "get used to the additional weight," like in an anime cartoon, then you're incredibly naive. They may be useful for anaerobic exercises but not to be worn for long periods of time.
personally id ask a doc if it can harm your back.. cause u are carrying that exstra weight on your spine.. I thank that you can add it into your training saftley but I wouldn't do it all the time ya kno?
That I never thought of.
Am 15 years old, approx 80kg.
Looking to just, get stronger - overall.
Was thinking about purchasing a 30KG (adjustable) weighted vest that I can just wear around.
Am currently 6ft, are there any growth-related effects?
I'm also quite a big build for my height, broad (ish), etc. Currently at about 12-20% fat.
I do Kung Fu - weekly (1 hour)
and Kendo - weekly (2 hours).
Gym (20 minutes daily - 5 times a week)
Was thinking about starting at 10-15kg and slowly getting up to 30kg as to not wear out ligament.
Currently using 12.5kg when curling in the gym.
Opinions/suggestions?
