Run-specific strength is another reason to hit the trails, specifically trails with hills. One of the primary benefits is that it will help strengthen your postural muscles. Running uphill requires more activity in the posterior chain muscles (the erector spinae and the gluteal group). Couple this with the need for shorter, more explosive steps when you are running uphill and you have the makings of a great sport-specific strength workout. Physiologically, off-road running is an amazing way to increase effort without the high impact loads that occur on flatter terrain and on pavement. Long, consistent uphill terrain allows you to sustain higher efforts with less impact on your body. On the flip side, running downhill can help you handle the impact your body has to deal with during every step, especially at the end of long races. Your heart and lungs are rarely the limiter in long endurance events. The limitation most athletes experience is handling impact, especially in events like an Ironman. When your muscles break down it doesn’t matter how fit your heart and lungs are – you simply won’t be able to go as fast. The varied terrain you encounter off-road groups all of these benefits up into one nice package.