Form: You Were Not Born With It
Often ignored but something to think about. Yes, you can change your form. Natural form is a myth. Some quirks you may have are ways your body deals with asymmetric differences. They may be necessary, but good form can be learned. Here are a few things to try on your next run.
1. Shorten your stride length. Most people over stride. Over striding causes more impact and uses more energy. A great place to play with stride length is on a treadmill but you can also do it on the road.
2. Arm carry. Your fore-arm and hand should be about nipple high on your chest. Try carrying your arms down unusually low and notice that your pace drops. It is better to carry your arm too high than too low. It actually takes less energy to carry your arms higher. Don't ask me why. Your arm swing should be straight forward and back. Your legs follow your arm movement. Try running with your arms swinging back and forth across your chest. Notice that your legs cross over behind you. You might even start to kick yourself. It is what we used to call, running like a girl, back in grade school. (Thank goodness we don't use lame macho expressions like that anymore because in running, being a girl is certainly not a disadvantage!)
3. Hill Running. Lean into the hill slightly and shorten your stride. Mentally think about pulling yourself up by a rope, this will give you the proper arm carry. Remember to run over the top, or through the hill. People have a ten dency to slow up as the crest a hill.