I have been asked numerous times if racing flats should be worn in races and ‘will it make me faster’. So, I’m going to share some common statements and scientific-based information about this topic along with some recent research. Then I’ll add my practical observations and advice on who, what and when to wear racing flats.
- Bob Wischnia writing on the Mizuno blog states that you could get 3-4 seconds per mile boost with racing flats. “Research shows that for every ounce that you shave off the weight of a training shoe, you will run one second per mile faster.“
- According to Ed Frederick, a biomechanist at the Nike Sports Research Laboratory in the early 1980s you could save two and a half to three minutes in a marathon with a shoe that is four ounces lighter than your trainers. [However it is important to note his statements say this …”may influence energy efficiency.” But it does not say it DOES influence it.]
- According to Jack Daniels PhD, you expend 1% more energy per 100 grams of weight on a shoe – 4 ounces reduction would yield a three-minute drop in your marathon time.
Wait (or should I say weight?) not so fast!
Problem #1, the seconds-per-mile estimates does not take into consideration a runner’s speed, weight or biomechanics. Are we supposed to believe that Bernard Lagat (5-8, 134 pounds) with 15-plus years of elite running erases 12 seconds on his 5k with his racing flats (12:53.6 PR) and so does my neighbor (6-4, 200 pounds) who has a 24 minute 5k PR? Always be skeptical of blanket statements!
Problem #2, training and individual power output, efficiency and biomechanics are not taken into consideration in these figures. It is true with most racing shoes that they have a less dramatic heel lift, tighter fit and narrower last. These promote a change in foot strike, push off and potentially ground contact time. But these come at a cost. That cost is impact. For a fit runner who can accommodate the added stress for the entire length of a race – they may benefit. However, a weaker runner will suffer the consequences and fatigue earlier and in fact slow down!
Problem #3, the initially quoted data above may in fact be wrong! Much more recent research found in the Medicine & Science in Sports & Exercise performed at the University of Colorado counters these claims. I won’t go into the details – you can read a nice article on this here. The researchers wanted to answer the question does wearing shoes require more energy than going barefoot? Their findings: “When barefoot runners and shod runners carried the same weight on their feet, barefoot running used almost 4 percent more energy during every step than running in shoes.” It means that the cushioning effect – if not in the shoes – is taken up in the leg muscles, which costs energy.
This can of course be extrapolated to racing shoe use. The fact that a shoe is lighter does not mean you will necessarily gain time because you are carrying less weight. Less weight means less cushioning. Less shoe cushioning means more leg cushioning. More leg cushioning means more fatigue. [It appears that the former studies may have been more hypothetical (i.e. using formulas and biomechanical statistics on weight at the end of a lever for instance) than applied.]
Who shouldn’t be wearing racing shoes?
I agree with conventional wisdom that says: if you are a heavier runner; if you require stability shoes; if you are prone to impact-related injuries (stress fractures, shin splints); if you need cushioning in your shoes; and if you are a beginning runner, then you should avoid racing flats.
- Bob Wischnia states that if your race pace is slower than seven minutes per mile you should not use racing flats. I don’t know where he came up with that figure but I completely agree. Though you may be “in shape” by most standards, in the running world this is not indicative of the amount of running-specific strength and power to benefit from racing flats.
- If you are running half-marathons and marathons – the great majority of runners should not even think about a racing flat. The pounding is cumulative and will results in some ugliness late in the race. The hours of trauma to your lower legs will leave you feeling like you have ground meatloaf for legs. You will lose in the end.
And while I’m at it, these conclusions go for track spikes too! Distance spikes are even less supportive than racing flats and the spikes are set into a hard plastic plate in your forefoot, which only exacerbates the pounding problem. Beginning track runners or those who are not in the upper competitive positions are not exerting enough power from their legs to the track to benefit from the spikes! Since races are shorter in track (longest is 2 miles in HS and 5K in most college meets) you can survive just fine with racing flats. Save your money.
Who really should use racing flats and will benefit from them most?
- If you are a competitive runner finishing in the top 10 or so of your age group in races 10k and shorter.
- For those of you running marathons under three hours – you might think about wearing them. However, see all the conditions stated above (under conventional wisdom).
- Ok, if you just need a psychological boost – I’ll give that to you. Racing flats do have a certain “feel” to them that can create or promote and support a self-image of being fast. If it keeps your head in the race and pushing to the finish-line then it is working!