Many times with trail running the inconsistent nature of the terrain can alter the mechanics of your natural running style. It sounds as if you may have a tendinopathy of the ankle/foot flexors as a result of the constant gripping of the foot for stability on this uneven terrain. A strengthening routine would benefit, however, do not limit to one direction but all directions of the ankle and foot as well as calf stretching. Also, regular icing of the irritated areas after exercise will help to decrease the inflammation caused by the activity itself. For any further questions do not hesitate to comment again.
Best in Health,
JAG
Icing should be done 2-3 times per day for 15 min and immediately after any form of vigorous exercise. Also there are many different ways to strengthen the ankle including resistance band exercises up/down and towards both sides. A piece of elastic called a theraband is often used to perform these. You can also perform balance exercises standing on one leg with progression onto unlevel surfaces and performing a ball toss in order to create more difficulty which targets the stabilizers of the ankle which can in turn create less tension on the tendons. I would try to limit overuse of the ankle and foot by performing strengthening and balance on the days you are not running and on the days that you do run be sure to warm up and cool down with stretching.
Best in Health,
JAG
Thanks John! This answer really helped me. It makes alot of sense and I feel that it confirms what I was thinking.
I just have some specific questions about your recommendations:
1 - Icing afterwards - What would you suggest as reasonable guidelines for this? How long to ice for and how many sessions? Ie 20 minutes on, 20 minutes x 3?
2 - Besides calf raises, are there other specific exercises to target the other directions of the ankle and foot?
3 - I need direction on frequency of the strengthening routine. I run on Tuesdays, Fridays and Sundays. Sundays are my longest day. Also, where in the week should I slot the routine - pre workout, post workout or on another day?