Jumping rope is a great cardio exercise for mountain bikers because it builds lower leg power and endurance and forces you to maintain good posture in the process.While some groups do appreciate it (boxers and MMA fighters for instance) most people don't realize just how great a tool it really is. Since you can get a jump rope for less than $10 (although I recommend spending a bit more if you can) it is something you can easily add into your routine tomorrow.The first benefit is the lower leg specific power and endurance it builds. I get a lot of questions about how to deal with calf cramps and fatigue and nothing beats the jump rope for addressing those issues. It also builds trail flow as it works on foot speed and coordination, an important part of lower body athleticism.The other benefit is that jumping rope forces you to stand up straight and maintain a tall spine. This is extremely important for mountain bikers as it combats the caved chest/ forward sloping shoulder syndrome so common in our ranks. In fact, this is thereason that jumping rope feels so awkward at first – most riders simply don't know how to achieve and move with a tall spine and instead collapse, which throws the whole movement off balance.By choosing an activity that forces you to learn proper posture and then maintain it as you fatigue you'll be able to build cardio while avoiding overuse injuries common in riders who don't get off the bike. Plus, since the tall spine posture is important for stand up pedaling you'll be reinforcing proper movement for that all important task. When you look at all the benefits of jumping rope the real question becomes why wouldn’t you use it?When getting started with jumping rope I recommend starting with a regular double leg jump. Remember that double jumping between turns of the rope is fine when you're 5, but you want to work on being able to jump rope like a big kid. We've all seen someone who knows how to turn a rope and that's what you want to look like – fluid, fast and effortless.When you can bang out 100 jumps with ease then it is time to move on to some other techniques. I like to run through the following sequence as a warm up before going into my foam rolling and stretching prior to a strength training session.- Double Leg X 100 jumps- Single Leg X 50 jumps each leg- Alternating Legs X 100 jumps- Split Stance X 50 jumps each wayI'll do 100 total jumps for each technique (50 each for the Single Leg and Split Stance variations). You may find that you need to start at 50 total jumps and build from there, but when you can get to the point that you can run through this whole routine without stopping you'll feel a big difference on the trail.Watch this video to see me demonstrate proper jump rope form and how to apply it to these different techniques.As I've mentioned before I also like to use the jump rope for cardio training. They work great for intervals ranging from 30-90 seconds and you can count your jumps during each interval. This lets you see if you're slowing down in later rounds and acts as a great source of feedback on how your cardio is improving.Hopefully you're starting to see why that simple piece of rope or plastic that has probably been sitting in your closet for a few years deserves to get dusted off. The truth is that the jump rope delivers better trail specific results than any of the fancy pieces of cardio training equipment sitting in your local gym.James Wilson is the owner MTB Strength Training Systems, the world's only company dedicated to developing strength and conditioning programs for the unique demands of mountain biking. James owns a training facility in Grand Junction, CO and is the strength coach for the Yeti World Cup Team. Visit his blog www.bikejames.com to sign up for your free mini-course 10 Steps to Instantly Improve Your Riding, plus a bonus bodyweight workout.