Hip flexor stretching exercises
Lack of mobility in the hip flexors and ankles can lead to incorrect movement mechanics and prevent you from jumping. Keep your hip flexors active so that your hip extensors can be used to their maximum without slowing down your hip flexors during jumping movements.
Mobility is also necessary to be able to squat deeper, and squats are the main training to increase vertical jump height.
Don’t let poor flexibility be a limiting factor in your performance.