Modern mountain bikes are amazing.
The geometry, suspension and tyres let you ride up almost any trail.
The only thing is, that the modern MTB encourages you to sit and spin, letting the bike do the work.
This is fine if efficiency is the number one priority, but by rarely standing to pedal you are missing out on strengthening the standing pedalling muscles.
You will not be powerful and explosive out of the saddle if you never stand.
In this video I explain why I believe that spending more time standing to pedal will make you a better, stronger rider, whether you race or simply enjoy trail riding.
By climbing out of the saddle you strengthen the legs, core and upper body and build a foundation of muscular endurance that can then be used for sprint training and power work in the future.