Gait and Posture has published a study which found that almost all beginner runners who wore standard running shoes showed signs of heel strike. The study, which analyzed 903 novice runners, used the adidas Supernova Glide 3 on indoor tracks. What makes these individuals "new" runners is that none of them ran more than ten kilometers total within the previous twelve months.
456 men were studied, which returned results of a whopping 96.9% being rearfoot heel strikers. As for the ladies, 447 were analyzed, and 99.3% of them were found to be heel strikers. Meanwhile, studies in the past have suggested that experienced runners show far less (as little as 75%) tendencies of heel striking.
So, what does this mean for you? Researcher Michael Bertelsen spoke with Runner's World and had this to say:
"Shoe choice may explain the differences in foot strike patterns across the studies/populations. Conventional shoes are typically thicker, more cushioned, have a greater heel-to-toe drop, and are heavier. Studies have shown runners to be more likely to [forefoot strike or midfoot strike] when wearing minimalist running shoes. This is why it’s very important to stress that our results are found in novice runners wearing conventional running shoes. The foot strike pattern among novice runners wearing minimalist shoes or running barefoot has, to my knowledge, not be investigated yet. To my knowledge, it has not been proven that forefoot strike and midfoot strike is more effective than rearfoot strike. A study from 2012 found no significant difference in running economy between runners with [a forefoot strike and rearfoot strike]. I would, therefore, be very careful to conclude anything regarding association between foot strike type and running efficiency."
There you have it. Although there may be negative connotations associated with heel strike, the experts say that it isn't actually a negative factor in running efficiency.