so I have this yonex super rd tour 90 leaded up to 13.6 oz (My Dad gave me this racquet). I just can't generate any power with this thing without swinging it like hell. I don't think it is too heavy for me to swing because I lift 35 lb weights for bicep curls. I tried experimenting with different strings, but still no power. What can I do to get more power? My technique is solid and I am a 4.0 ntrp. Apparently it has 4.5 grams of lead in the bumper fyi.