Unless you’ve been living in a cave for the last few years (sometimes I wish I had) you’ve probably come across one of the countless news stories and online articles about the barefoot running craze. While I can’t tell you when this actually started as I haven’t run a lap since I was forced to in junior high, it seems like a 2010 article in the scientific journal Nature stirred up the renewed interest.
Put you in my Delorean and gun it to ’88
It might seem like a current fad, but the basis for this craze stems from way back in the day, when there were no Nikes, Adidas, or New Balance, and it was socially acceptable to run around in a loin cloth. Skipping the finer details, the study found that people who run without shoes use a different foot strike strategy than their shoe-wearing counterparts. To minimize the high impact and potentially injurious forces that occur with the heel strike during running, where the heel of the foot contacts the ground before any other part of the foot, shoeless runners tend to land on a forward (anterior) position of the foot. In doing so these runners don’t generate the high ground impact forces that occur with a heel strike, and instead produce a more gradual impact profile with a lower rate of force development during the impact of foot contact (1).
Obviously the blogosphere and news sites caught on to this (not unlike myself), and while experienced runners probably took the results in moderation, I envisioned hordes of weight-loss seekers starting and ending their running careers by ditching their shoes and running wild and free, finally rid of the shackles of their Nike Shox or their ridiculous Sketchers Shape-Ups. Once I came back to reality and considered the different foot-strike strategies, I wondered how these same principles could apply to some of the more interesting hybrid conditioning techniques used by many of us of the weight-lifting persuasion (ie: weighted sled drags and prowler pushes).
Pushing heavy stuff = forefoot strike pattern
If you focus on the foot during a heavy sled drag or view someone pushing a sled like the prowler, when the body’s centre of mass is in front of the feet, it’s apparent that they contact the ground with the mid to forefoot similar to barefoot running, as opposed to the heel as in traditional running. The video below shows an excerpt from the EliteFTS Prowler ad that features a nice view demonstrating the mid to fore-foot contact pattern that occurs when pushing a sled. In fact, during the short clip you don’t see the heel contact the ground for the entire clip.
Thinking about weight loss, a client that is likely naive to exercise in the first place and left to their own devices might take up running and punish the pavement and their shins with some high-impact heel strikes. Fast forward a few weeks and more often than not, the pain of running will derail their fat-loss efforts and they’ll be trapped in an endless cycle of injury and weight gain/regain. By turning to sled pushing/dragging, you can provide the metabolic stimulus these clients need while minimizing the potentially injurious heel strikes they would encounter with running. It’s not that sled pushing is necessarily producing lower forces overall, this is probably still dependent on the weight of the individual and their sled pushing technique, however it will provide a different point of impact between the ground and foot with a gradual impact force profile, similar to what would be seen in barefoot running. Looking at the bigger picture you’ve also managed to recruit significantly more muscle mass than you would during a run, deriving a wicked metabolic advantage, and the increased loading provided by the sled could be a stimulus for increased strength and muscle hypertrophy, at least in relatively untrained clients.
Can heavy sled drags/pushing keep weight-loss clients injury free?
Given the potentially high-rate of injury with running (2) and the environmental inability to run barefoot (asphalt, broken glass, etc.), it might be worth introducing structured intervals of sled dragging and pushing into your conditioning programs as an alternative to running. Granted the equipment costs are obviously higher than a barefoot run (although pushing a car is always an option), and at this point we don’t have conclusive data on the forces generated or injury rates, but the results might just be worth it. At the very least it provides some variety to everyday programming outside of running in circles around the block. Opinions?
- Lieberman et al (2010). Nature 463(7280):531-535.
- ven Gent et al (2007). Br J Sports Med 41:469-480.