Havent been playing drums for a while .. roughly a year and a half .. because im tryna work on Keys and Bass more .. But Thanks and all Glory to God, I been gettin Gigs and Offers playing drums for Choirs and Bands and Churches.. God has been blessing me.. But I have a slight problem... When i play, after a while.. I Hand, mainly my left hand, the weakest, get really weak to the point where i feel like im not grippin the stick and i feel like the stick about to slip right outta my hands..... What exercises can I do to keep my hands from gettin weak...??? Thanks in advance for the response..