If you are a lifting novice (e.g.not already squatting twice your bodyweight), focused effort to gain strength requires a simple training plan consisting of squats, deadlifts and presses (bench or standing, alternating each workout). Three hard sets of five of each, three times a week. Increase weight incrementally, each workout (like, 5-10 lbs per workout). No other supplemental lifting is required, but some chinups are allowed. When you start lifting heavier weights, there will be some perfunctory warmup sets at lighter weights required, and these don't count toward your standard three sets of five reps.
This will work if you eat way more food than you think you should, and get lots of sleep. If you let it run its course, you will increase your working sets of five to something along the lines of 1.75x to 2x bodyweight in squat, 1.25x to 1.5x bench press, and 2x deadlift. This can be continued until the linear gains (consistent increase each workout) slow down a bunch, and that won't happen until you hit the numbers above. None of your pants will fit.
This will not work if you do not consume (or wear, in the form of lots of excess fat) lots and lots of food, get less than lots of sleep, or force your body to share resources (e.g. recovery from your little exercises) instead of dedicating all of them to recovery from your strength training.
Litany of Excuses for Not Getting Strong:
1. "Oooooh! I'll get too fat!" No schidt, you will gain fat weight. It burns off nearly as easily as it goes on once you change your strength work to maintenance, change your diet, and add back your little cardio exercises.
2. "I don't want to give up my super-duper-primo cardio conditioning." If you want it back, you can train it back, and it will come back a whole lot more quickly than it took to gain the strength. Maybe your neat little long distance run times suffer a little, but you're now twice as strong or more as you were. Strap a load on and see if you notice a change then.
3. "I walked an NFL linebacker into the ground on a hunt so I don't need to get strong; muscle just gets in the way." You are possessed of unfixable stupid.
