Verified answer

It's all about leg strength and you'll find out soon.

Do power cleans because it's really one of the most important lifts.. It works out explosiveness which you need for hitting harder and being faster.

Do weighted calf raises and squats or even non weighted if you want but with weights is the most effective.

Do sprinting exercises such as Sprinting 30 yards, jogging 10, sprint 30, jog 10.. it helps..

And do some agility training such as ladder exercises and figure 8.

Don't neglect upper body strength though cause it also helps.

Do dumbbell rows, bench press, jammers (works out legs too), incline press, wrist and bicep curls, and others that you want like lat pulls.. but if you can use weights.. just do pushups and tricep pushups..

lastly.. do situps a lot because you need a strong core for hard hits

new football players think upper body makes you a beast.. well it does but having a strong lower body helps a hell of a lot too.. remember.. the strongest muscles in your body are lower body muscles.

if you arent agile i can guarantee you WILL NOT start linebacker

push ups

Note: there's another excercise I'm thinking of, but I can't remember the name of it. Here's what you do:

You lay down on the opposite end of the bench press. Then, you take the bench bar and do 5 reps, but when you go up on the 5th rep you bring it back behind your head and then over your head until the bar is on your chest. Do that a couple times and it'll really help your arms.