Puerto Vallarta, Mexico - If I had gone to sleep in Bristol, England, and woke up here, in the mountainous jungle of the Sierra Madre, the first place that would come to mind would have been the Amazon rain forest. It is that wild, that exciting, and that unexpected.

We had stopped at the El Salto waterfall, in a low, craggy ravine, after an intense ride through the dense jungle. The water cascading down the rocks poured into a clear pool. In the deepest parts you could jump from the rocks into the crispy cold water and in the sandy shallows the silvery fish swam at your feet.

I had jumped in off the rocks several times feeling the rush of the fresh water enveloping and energizing my skin as I let the strong current push me back onto the shore. Jenny had swum and jumped too. The rest of the guys - there were four of us on the tour - lazed on the side. Sonora, the dog, chewed a stick. She had been following us since the village and our guide told us she did it on nearly every El Salto tour. We tore off pieces of the energy bars provided and fed her. I had given her a little piece of ham and cheese croissant, and then she followed me around at the waterfall looking up with her big brown eyes.

Then we were riding again and our guide, a man with great, wavy, shoulder length hair and popping calves like tennis balls, said we were going back the same way. I was surprised because it seemed completely different. I think now there were two reasons for this: the lack of landmarks in the thick, impenetrable vines, and that the track was like a line on a ECG machine connected to someone with a strong heart so that we were going up what we had ridden down and going down what we had ridden up.

This El Salto Waterfall tour really is for advanced riders only, as it says on the EcoRide website. I had chosen to ignore this, or at least over-estimated my ability, for one of the downhill portions was so steep and jagged with rocks and boulders that, firing down with bugs in my eyes and stones pinging off the spokes, I started to say my prayers. All the same, as with any dangerous thrill, you come out the other side feeling like saying, "what was all the fuss about" and "let's do that again!" It was certainly very exhilarating and the only thing coming to mind that compares is perhaps a roller coaster.

Besides the technical aspect of the tour there is also the fitness side. I am twenty-two years old and back home in England I go lane swimming once a week, ride my bike leisurely but often, play football occasionally and do some long sweaty fights with a punching bag that has a photograph taped on the front; yet I was always at the back of the group with my light blue t-shirt turned dark. Several of the hills I had to push up, too.

We stopped on a high piece of land looking out on the mountains baked in the sun and some screeching macaws flew overhead. You could just make out the etchings of their wonderful plumage. They were very handsome birds. A cold beer would have been nice with your back up against a tree, but the water that EcoRide provided did the job. That is important. Even though EcoRide generously gives you two bottles of water, you should bring at least one extra. You should also bring snacks, a camera and insect repellent. I had bites afterward that went yellow and lumpy.

'Cow!' Jenny screamed as we dropped round a corner and saw a wild-looking bull taking up nearly the whole of the track. We were going too fast to brake efficiently and squeezed behind the bull with his ruddy red hide. Then there was more animal madness when Sonora chased some hens that went clucking and flapping toward us in a flurry of feathers. And then we were back in the little villages of Paso Ancho, Paso del Guayabo and Los Almacenes that we had passed through earlier except now they felt calmer because we were exhausted.

Sonora had left us. Nobody knew if she was a stray or whatever. She was a curious and excitable little dog. We went on bumping over the cobbled stone streets that carried us on to Viejo Vallarta, where nestles the quaint EcoRide shop. Our guide, a man with a cool, mellow attitude and flowing dark hair, told us to enjoy life as we thanked him for such a great trip.

About EcoRide:

EcoRide have operated mountain bike and hiking tours since 2002. They mission is "not only to promote mountain bike and hiking to all we meet, but also to improve ecological awareness and respect for our beautiful planet." Their tours include: Vallejo, San Pedro, El Salto Waterfall, El Salto 3000, Yelapa and La Herradura, ranging between $45 to $105 USD. Their hiking tours are El Salto and Las Animas. You can more or less choose from a good selection of well-maintained bikes and can expect knowledgable, cheerful guides and challenging yet rewarding rides. The Vallejo tour is suitable for most riders, however. Their shop is located on Calle Miramar, two streets behind the church, where you can drop by and book a tour or have a friendly chat. Learn more at ecoridemex.com.