The last 4 years i was having a very hard time trying to keep locked elbows during straddle planche. Ive tried to strengthen every part of the back, shoulder and still my elbows didnt locked fully.
Then in july of last year i saw a video of Jordan Jovtchev doing flyes pushups in rings and saying that this pushups increase the elbow and biceps strength for straight arm exercises especially for maltese, then i think if helps for maltese may help for planche and so i have nothing to lose doing this exercise in a regular basis so i included them in my weekly routine doing 3x10rep 2 times per week.
After 3 months of constant effort on strengthening my elbows(the pain becomes my friend
) i was able to hold a locked elbow straddle planche with very less effort then my bent arm straddle planche(something over my head before this training), so this post serves as a tip for those who are feeling difficult to lock elbows in the planche especially if you have long arms.
The flyes pushups consists in doing pushups with elbows straight so you move the hands to the side, can be done in rings or with some dumbell on floor i guess (never tried)