Basicly To Make A Effect To Player You Can Use "/effect give <player> <effect name> <Time> <Amplifier>"
To Make Jump Boost Effect You can Do "/effect give <player> Jump_Boost 10 1"
After Do The Command You Will Get 10 Second Of Jump Boost 1.
But How To Make Youre Player Can't Jump?, Its Actually Very Easy And Simple
You Can Do "/effect give <player> jump_boost 10 128" Command And Then Its Will Make You Cant Jump For Ten Second
The Max Amplifier Is 255 that Make You Jump Normally, But If You Change It To 128 It Will Make You Cant Jump

To Make Cant Jump Command:
/effect Give <player> Jump_boost 10 128

Thank You :)