I have seen a lot of people using all different types of bicycles during a triathlon race including mountain bikes, hybrid bikes and touring bikes. Whether you are a serious triathlete or just a weekend warrior, it pays to use clip-in pedals on your bicycle. I can understand if you are hesitant to spend extra money to have your bicycle outfitted with clip-in pedals. After all, that means you need to purchase bike shoes with cleats so that they can be clipped onto the pedals. Or, you may use your bicycle for other purposes and you may not want to modify it. Or, you may be afraid to have your feet secured to the pedals. I know, because that's how I felt when I first started out. I used a mountain bike on my first triathlon. Not only was it humiliating to have just about everyone zoom past me on their road bikes, but my legs felt like rubber by the time I got to the run. So, my first suggestion would be to invest in a good racing bicycle if you are even remotely serious about participating in triathlons. There are a number of decent road bicycles available and the prices range from about $700 on up to about $4000. It goes without saying that the bicycle should be equipped with clip-in pedals. Here's why.With regular pedals, you can only push down on each pedal stroke. Your legs and knees will take a pounding and you just can't generate even power throughout the entire pedal stroke. It's like a 4-cylinder engine running on only one cylinder. You are making the front of your upper thighs do all the work.You can add toe-clips to your pedals. Using toe clips is better than not using them, but you can't really pull up on the back side of the pedal stroke (between (B-C) because your feet will come out of the toe clips. Plus, I have found that I have to pull the strap on the toe clip so tight that it hurts my foot and makes my toes go numb.With clip-in pedals, your shoe has a cleat on the bottom that snaps into the clip-in pedal. There are a number of different pedal and cleat options to choose from (check this link to see our reviews here). The bottom line is, with clip-in pedals, you can generate smooth power throughout the entire pedal stroke. You will be engaging your hamstring muscles and your calf muscles in addition to your thigh muscles. You will be able to go faster longer. You will be able to cruise up hills. Your legs will be "spinning" through the entire pedal stroke.One of the best ways to train with clip-in pedals is on an indoor trainer. I have a trainer that lets me use my bike indoors by lifting the rear wheel off the ground. In order to create resistance, there is a roller that contacts the back wheel and has adjustable tension on it. There are a number of types of indoor trainers - some provide tension by using a fan, others with magnets and others with sealed fluid (hydraulic). There are also dual-roller trainers where you ride your bike on rollers that are about 18 inches wide. See our reviews of indoor bicycle trainers for more information.At any rate, there are a number of exercises you can do on an indoor trainer that can help you develop a smooth, powerful and efficient pedal stroke.One-legged drillsThe best exercise that I know of is called the one-legged drill. Essentially, you pedal with only one leg at a time with resistance applied to the wheel. For this drill, I will place 2 chairs on either side of my bike. I will take one foot out of the pedal and let it rest on the chair and leave the other foot clipped into the pedal. Proceed to concentrate on pulling and pushing evenly through the entire pedal stroke. At the very top of the stroke, you will push your foot forward as if kicking a ball. Then you push down through the front of the stroke. At the bottom of the stroke, you pull your foot back and up, like scraping mud off the bottom of your shoe. On the back part of the stroke, pull your foot up and forward back to the top of the stroke again.As you first try this exercise, try an easy gear and/or low resistance on your indoor trainer. The very first time I tried this drill, I literally could not get my foot up the back and over the top. I had to use my hands to pull my thigh upwards just to get my foot to come up the backside of the stroke! You will be engaging muscles that hardly ever get used, with the exception of maybe climbing stairs. When you first try to pull up hard on the back side of the stroke, it would be like climbing stairs with a heavy weight attached to your shoe.As you begin to develop strength throughout the entire stroke, pay attention to the sound that your indoor trainer makes. You will notice that the trainer will hum throughout the stroke. If you notice that the hum gets significantly louder during the down-stroke, then your stroke is not evenly-powered throughout the entire stroke. The goal is to have your indoor trainer humming smoothly no matter where your foot is in the stroke cycle. If you can get to the point where you are generating smooth, even power throughout the entire stroke, then you will be "spinning". When you take your bike out on the road, try to remember to spin there as well. It's often easy to forget and revert back to the "only-push-down" stroke.