Will strength training enhance my 5K performance?

In a word, ABSOLUTELY! First my "how", then some proof.
 
You don't have to do massive squats or deadlifts or anything overly intimidating. However, you do have to push yourself. Strength training your entire body will help you through a run, of any distance. You need a strong upright core to insure proper and efficient running form and breathing. Without a strong core, as your fatigue increases, your form suffers and you become less efficient, and your fatigue increases more! Strength training your lower body has a number of positive effects. You will decrease your risk of injury, your recover times will be faster, and your actual running will improve. Upper body training is equally important. As you fatigue, if you don't have a strong back and shoulders to maintain proper posture, you could begin to slouch, which could prevent you from getting good air into your lungs, it could also limit your hip flexor range of motion, which would prevent efficient running technique. I would suggest single leg training. We don't have to load our backs with super heavy weights to gain muscle in our legs. Plus single leg exercises help with balance and works the smaller stabilizing muscles. Plyometrics are equally important, but I would incorporate these in the later stages of training, after you have built up a good base of strength, otherwise you increase your risk of injury.

Now, how do I know this??? Well, I have a little bit of knowledge from research and experience, and I've trained runners. Most recently I have been working with an ultra-marathoner (100 milers!!). We have been training his legs very heavy. His last run, he said a lot of elite runners were saying this is one of the hardest 100's out there; he wasn’t sore AT ALL the next day! Usually you're a walking mess the day after. Also, he only runs about twice a week! And one day of strength training with me. THAT is amazing, and none of the other runners believes that's all he runs. He said his recovery times are down (See above), and his injuries have lessened or gone away or don't return. And his hill climbing is amazing compared to where it was. His downhill speed is increasing and he feels more stable coming down as well.

Granted he is an elite runner, but strength training will help any runner get better.

A properly designed strength training program will enhance 5k performance by increasing stabilization strength of the surrounding tissue complex around the foot, knee, hip, and spine areas. If an athlete can curb fatigue they have increased the probability for a faster run time, and also decrease the chance of injury. A systematic strength training program will support the tissues to enhance muscular strength endurance, balance, and mobility.

100% strength training can improve your 5K performance. If you want to cover all of your bases, then incorporate several types of fitness training into your exercise program. Make sure to include the following types of training; flexibility, core, balance, and plyometrics as well. Research studies are providing good evidence that each of these components of a fitness program can not only decrease risk of running injuries but improve running economy and improve running performance. 

Exercises that help to improve the coordination throughout the entire body and are progressed on a regular basis may give the best returns. Keeping exercise routines fresh can challenge the nervous system and help you to avoid plateaus and repetitive injuries. Remember to always warm up and cool down with flexibility training to keep healthy!

Not only will strength training enhance your 5K performance, it will benefit your overall fitness! Strength training is important to runners because strong arms help you pump your way to the finish line, and solid core and leg muscles keep your gait steady and your body aligned. Train your muscles with resistance exercises two to three times per week in addition to running and you'll reap the rewards at your next 5K race. Happy training!

Strength training can be beneficial for your muscular strength, cardio endurance, and reducing injuries, which will enhance your performance.

Increasing your overall body strength and conditioning, will help you recover quicker from the physical stress the 5K will have on your body. Also weight lifting at a fast pace with little rest between sets is an effective cardio training tool that will increase your cardio endurance. 

Be careful to maintain proper control of your weights and posture during your workout.

Strength training is a category of resistance training. I must say, performing entire body resistance training would be a great addition to any goal. Sure squats, leg press/curls and calf raises will increase strength, but also muscle. In order to be able to push one foot off the ground while the other is rising, both simultaneously at a faster speed, you’re inevitably increasing muscle through the strength gained from resistance training.

If considering strength training, think outside the box. Try using a sprinting parachute, weighted sled or vest to concentrate more on resisting the run and increase the necessary strength to enhance performance. All other exercises will definitely be an added bonus to reduce fatigue and risk of injury. Don’t forget to adjust your nutrition to accommodate your added routine.

Yes, IF you do the right kind of strength training. You have two types of muscle fibers referred to as quick twitch and slow twitch. Fast twitch is good for sprints -- they have lots of power but exhaust quickly due to fewer mitochondria than slow twitch which has lots of staying power and is what you need to strengthen for marathons.

To develop quick twitch muscle fibers, you do fewer reps with max weights. To develop slow twitch, you need lower weights, but lots of reps lots of sets. To strengthen muscles for a marathon, I would select a weight that enables you to do 30 to 40 reps and 5 to 6 sets. In a marathon you need stamina so you should mirror that in your strength training.