Exercises for trail running

I can see tons of exercises online, to promote hype, to promote views, to trigger something of a wow, that is awesome feeling. Just like the ridge running of Killian. Hill bouding, uphill bouncing on the toes on a highly graduated treadmill. Multi-directional lunge jumps, with each hop landing and balancing on one leg. Box jumps up and down, or weight wested reverse backwards lunges downhill. 

High risk, high value, low volume. The injury risk is way too high. The recovery aspect is way too high. Post workout real running delay is way too high. 

We as runners must privilege running as the most important form of exercise. We should not build muscle, habits or structures, with anything else than running. Otherwise, we'll end up with a body designed to do a lot of stuff, except running. 
What I just said, does simply mean, that when you do reinforce your body, it should be a sort of microstimulation, so your body can call on it, when trail running. This can be for instance a series of lunges, deep enough, with poles at a speed, followed by or mixed with medium to high step ups. Or core training, what is most likely focused on bomb proof lower back. Like 10 dynamic planks front, side and back, followed by hyper-extensions and back-wards leg lifts, or called reverse-hyper. Dynamic swiss ball bridges, followed by excentric ham curls. If you prepped for an ultra, where you'll use poles, I recommend to do of course some biceps, triceps, chest and back, but most importantly, weighted or elastic band, high rep wrist exercises. Pronation, supination, rise, cupping and so on. If I had to do just one single sort of upper body exercises that would be more likely than the rest. Loads of armwrestling routines, mixed with elastic exercises for the legs, especially ankles and achilles tendon. 

What you want to do either ways are routines that do not perturbe but reinforce your running. For instance do only 5 to 10 to 15 minutes max at time, but do it every single day for your lifetime. It ill bring way more benefits, then doing like 30 to 90minutes 3 times a week, that you stop in August for a month, stop for the spring vacation and you don't follow through during the 2 to 4 weeks christmas break. 10minutes twice a day is 140minutes a week. Lets's call that two hours. That will add 104 hours of training a year !!! I mean, if you trained only 400 a year and now you are at 500, that is just superb. 

If you did train 60minutes a day of mobility and strength, yes, that is 365 hours of extra movement a year, besides your 5 to 30 hours of  running and cycling.