maurice101 thank you for sharing the training clip.
First of your stroke looks good and i wouldnt change equipment.
May i ask why you want to straighten your arm ? a more closed arm is fine on the backswing.
while your movement overall looks good it seems to be a little out of sync. it looks like you use up alot of energy with your stroke. you may stiffen up your body too early so you lose power.
is your forearm relaxed when swinging? you arm looks a little bit stiff while accelerating.
if you keep your ellbow a little closer to your body you can rotate and snap faster into the ball.
also you seem to backswing pretty late and a little bit to excessive. which could screw the contact point in a match by taking the ball to late.
if you take such a long stroke you need a lot of hip and arm acceleration to generate needed energie. you want you hip to rotate and swing your arm with your hip. it looks like you move your hip but you dont generate power from it. your swing is coming from the upper body not in sync with the hip.
- loosen up the upper body (dont grip you blade to tight if you do)
- move your elbow closer to the body work more with the legs
- use your hip to lead the arm and upper body
- accelerate and snap faster with arm and forearm.
in this video you can see how the stroke is pretty short but because of the arm closer to the hip, the hip leading the movement and a shorter faster acceleration the power is still there. the upper and lower body are in sync.
i hope you you understand what i mean and i could help a little. keep up the work !