The sprint key appears to tire me out quick and even when i am sprinting i am still not fast enough. Some players are able to leap far and wide I cannot do that. Am new at this game and i cannot understand it
Letre, Tremulous runs on the Quake 3 engine. As such, the direction your mouse is pointing affects your speed.
You have to spin the mouse up to get more speed. For example, in ATCS human base you can leap from the raised platform that your spawn is on to the other raised platform.
Face the ledge.
Hold sprint
Angle your view slightly downwards
Press forward
(You begin running)
As you reach the very tip of the ledge, press JUMP.
As soon as you jump, begin spinning the mouse from looking forward & down at the floor to upwards.
Your character will gain extra momentum from this mouse-spin and you will cross the gap.
Additionally, I believe that all characters move in a double-chorded fashion -- so if you press up + left you get 2 vector boosts instead of your speed being completely split between the 2 angles.
If this human jumping is very difficult, there's a test you can do as a

to demonstrate the power of mouse jumping.
Spawn as

and venture to hallway on ATCS.
Look straight ahead (floor level)
Hold forward
Observe your movement speed -- count seconds it takes to hit a wall, for example.
Now return to your starting position
Look upwards at headbite level
Hold forward
Observe your movement speed -- you are moving slower horizontally than you did before.
See, with the

you are putting momentum upwards but your game state is grounded so you don't leave the ground.
When you jump with the mouse spinning, those momentum gains push you further into the air allowing you to cross the gap. I believe it is not possible to cross the ATCS gap as a human by simply sprinting and running straight at. (Perhaps with pixel perfect timing but I have not been able to achieve this). With a bit of practice the sprint + mousespin in the air is possible.
Additionally, I suggest you check your menu options and enable "always run". When it's off, you walk by default and that can be very slow.
Good luck out there.