A stronger runner, is a better runner

Running is an endurance sport and not a strength-based sport, but it can for you as running pays to be a strong runner.
If we compare the two runners of the same height, weight, fitness, lactate threshold, running economy, etc. then it comes to the run the runner with the greatest strength runs faster.
Imagine that for every step you take; you're using a small portion of your maximum muscle strength - let's just say 10%. It's hardly something you notice, but when running you take a lot of steps, then even 10% quietly UTTERLY EXHAUST your muscles, and at some point, your muscles will be so tired that it hinders your performance.
Let say that you train specific strength training and you get stronger. So it may be that you instead of 10% maximum strength now only uses 5% of your maximum strength, every time you take a step.
When you use only 5%, then it will obviously take longer (vs. 10%) before your muscles get so tired that it hinders your performance.

Strength training for Increase Power

In other words, it may pay off to do strength training to become stronger. And it will take help a lot. You must first of become stronger than you need to train your "muscle endurance," which is typically what runners train when they start strength training.
It is my experience that the effect of three sets of 12 repetitions is minimal, while the effect of the five sets of 2-5 repetitions is magnificent.
So you must learn how to train "massive resistance" where the weight is so heavy you are challenged by a maximum of four-five repetitions.

5 × 5 - simple method, high-impact

A secure training protocol, to begin with, is to do five sets of five repetitions
To avoid overloading, I have a basic rule that says you must start EASY and increase SLOWLY. You can, therefore, consider the first few weeks of strength training as habituation, since in the period will feel easy to do five sets of five reps.
For training to be effective over time, then the progression from one workout to the next a necessity, why you should increase the weight 2.5 to 5.0 kg when you perform five sets of five reps.

Increases your weight for each workout, then you will before you know have reached a serious weight and when you can no longer manage five sets of five reps in the first workout.

Instead, it may be you are doing 5, 4, 4, 3, 2, 2 reps rather than the planned 5 × 5th When it happens, it keeps you stuck in the same weight subsequent times until you stack 5 × 5th Then you increase again and build repetitions again.

For you to get enough weight on your exercises, and thus the optimal training benefits, it requires in most cases that you have access to a barbell and different weight plates. This by far most gyms offer, but you do not want to train at a center, so if you do not like "the gym" that you must invest from 200 to 500 euro in a barbell, dumbbells and a squat rack or a couple of good sandbags widths are the great tool for all-round training and strength.
In return, you can then train your 30 minutes of strength training when it suits you, without having first to transport you to the gym.

For only runners, two strength exercises are enough, but for OCR you need more.

You want to be stronger; it requires only that you take 2-3 times per week of about 30 minutes for your strength, and you can make do with two drills if your only are running.
The first day you du squat (front squat if you can), and for the second you do deadlift, and then switch between squat and deadlift, and in the first several weeks, on 5 × 5

Exercise: squat or deadlift
 Method: 5 × 5 Do 2-4 warm up sets where you gradually increase the weight until you reach today's "target weight" then take 2-4 minute break between each set.

Bonus Tips

Have a simple workout diary of your strength. You should see what you performed last time, so you know what to do today. Do not try to remember your training, and if you do so, you will quickly discover that it is hard to remember what you trained last time.
It is also a great motivation to see over time become how stronger you have become.

The vast majority of runners (and endurance athletes in generally) is often impatient people who find it difficult to keep long breaks. Do you belong to one of them - and probably do - then it is fine to have some additional exercises for example. Core/abs in your pauses between two sets of deadlifts/squats.
Becoming stronger demand far less than what most people think, you just do it right. In fact, it requires so little that most tend to do too much (too many exercises to short breaks and too many sets and repetitions), resulting in too little to no benefit. less = more.
Running and weight training is almost like yin and yang. Use energy and be super active when you run and use your powers, but take it easy when you train strength.
Starts easy, you increase slowly and be persistent, then you will in 3-6 months will become stronger, which will surely result in faster running.