Sometimes, you will not know what your weakness is until you try something new. There are some events you'll be naturally gifted at, but others will require a lot of work before you're even competent. If you change your workout often enough and actually try something new, you may have found a new love for something or have found a weakness you were not aware of. Rarely is someone great at ALL the elements of fitness: Speed, stamina, agility, strength/power, technique, endurance, flexibility, or mobility -- to name a few.
Here is a workout I like to do to check progress, or lack thereof, in a variety of running styles and benchmark distances:
All Kinds of Running (speed, endurance, agility) 1 mile jog / easy dynamic stretches / recover / hydrate. 1 mile fast as you can – timed followed by easy ¼ mile to half mile walk with some dynamic stretches added in to prepare for full sprint build up. Run 5 x 100m sprints - build up to full speed – How fast are you these days? Try a 40yd dash as well for kicks. Run a hill, steps, or bleachers for 5 minutes nonstop. Set up cones or ladder drills for 5-10 minutes of different events. Illinois Agility Test, shuttle runs, etc. Repeat 5 times
1/4 mile goal pace of your timed run (i.e., 1.5 mile run at 9 min = 90 sec ¼ mile pace) 20 squats 10 lunges / leg
After you do this work out, you may find something you like doing and challenge yourself to get better at it. Or you may want to do this again another day the following week but in different order as your running stamina / endurance is lacking and you failed to score at your goal pace in the last workout due to fatigue.