Following is a great video created by Cycling Secrets that explains the different phases of a pedal stroke. When you hear "apply equal pressure to your pedals" or "find your circles" during our workouts, what is meant is you should be thinking about the clock in the video and your toes touching each number. So if you had a marker attached to your shoe that could draw on air, it would draw a perfectly round circle - whether or not you have a square bottom bracket ... just in case you were wondering.
As we are starting to do harder workouts and our legs are fatiguing, it is common to "mash" on the pedals, forcibly push down, or "pedal in squares" in an attempt to find more power. I prefer to think of the down stroke as a push forward stroke for the sake of imagery. If you look at the clock you will see that the 3 is farther east then the 1 and 2, so in order for your toes to "connect the numbers" (remember we have a marker on our shoe), it needs to feel like you are pushing your foot forward, like a leg press, or a lunge forward. As we get tired, feet start to "drop" down from the 1 to the 5, creating a dead spot, or a spot where we are not applying any force and therefore missing an opportunity to propel ourselves forward.
The pull back phase, in general, is done well by Cycling Centre athletes, until they stand up. Especially as we get tired, it is common to "rest" at the bottom of the stroke, so when you are standing it is important to remember pedalling technique, to scrape through the bottom of the pedal stroke and push forward through the set up - which will be touched on 2 paragraphs down. Remember, every time you lack force to the pedal you lose momentum, speed, power .... and when you are standing it is usually because we are looking for extra speed and power, whether it is on a hill or a sprint finish, or to get back up to speed. By having an efficient pedal stroke you will maintain momentum and save energy.
The lift up phase is done very well by riders who have done fixed gear riding, whether it's on a track bike or at a spin class. The idea behind this part is to pull up and as you go from the 8 to the 9, through to the 10 and 11, to drop your heal. So as you move from the end of the lift up and in to the set up, you should have a flat foot, which for many means that you will feel like your toes are much higher then your heal, like you are in a calf stretch position when you start the set up phase.
Then there is the infamous set up, the part of the pedal stroke that many people don't think about as it's not part of the up or down; and if you've been reading from the beginning hopefully you have clued in that there really is no up and down, it is around and around. We touched on foot position in the lift up phase and if done correctly you should be in good shape for the set up, or the "push forward". The key to the set up is to have a flat foot. If you are a "toe rider" or have a more vertical then horizontal foot at the top of your pedal stroke then it is too big a movement to correctly place your foot for the next phase and you are losing a lot of push, or forward propulsion.
The video talks about ankling, which many people do automatically, what you need to be aware of is how flat your foot is. The flatter your foot, the bigger the lever, so the more power you can generate. When pedalling at a high cadence you rely more on momentum and due to leg speed, there is not sufficient time for ankling or big changes in foot position; so you'll find that your foot is not as flat, it is simply about smooth circles.
When looking for more power, as we are in the current phase of training, having a flatter foot, really working on having lower heals in the set up phase and pushing forward and out to the 3 o'clock will result in more power, hence speed, at the same heart rate and cadence. So it is a gained benefit with minimal change in effort. Body position also plays a role, so when you are at a lower cadence, big gear and looking for big watts, slide your bum back in the saddle, feel like you have a bit of an arch in your back to ensure you are bending from your hips rather then your waist (pelvic tilt), relax your shoulders and drop them while keeping your back straight, bend your elbows and have them in line with your shoulders (going in to the drops can help you achieve this position), and keep your head up to stay aware of what is going on in front of you. This body position will help get your glutes and quads in to pushing your feet forward and the lower centre of gravity of your body will help with aerodynamics and strength.
So we talked a lot about pushing big gears, and touched on high cadence, but what about when we are riding at our "normal" cadence, or optimal cadence. All of the principles will be the same, you still want equal pressure your pedals as you do your circles, you just may not be pushing as hard. You still want more of a flat foot rather then a pointed foot, but it may not be as flat as when you are digging in a harder gear and this may be when ankling works for you.
The following diagram was found on several other websites and I'm sorry proper credit is not given as I'm not sure who the original creator was, but it helps describe which muscles you are using during a proper pedal stroke. This is a great time of year to get in the gym and work on single leg exercises to help balance out your legs and improve muscle discrepancies and weaknesses.