footwear

This topic was frequently discussed in PCT-L. I had already bored about this topic, since I had wrotten and published "Hiking Handbook" in Japan. I will state my opinion briefly.

1. "in terms of physical effort 1 pound on the feet is equivalent to 5 pounds on the back." is a wrong concept.

This is a famous concept, which was written by Colin Fletcher( Complete Walker IV P.59 ). This hypotheis was proved to be wrong by many scientific experiments. The most recent experiments was carried out by Abe et al. ( Abe, D., Yanagawa, K, & Niihata, S. 2004 Effects of loadcarriage, load position, and and walking speed on energy cost of walking. Applied Ergonics, 35, and 329-335.} 8 young men who wore lightweight shoes and attached ancle weights of 1, 1.5, and 3 kg to both feet ( Then, they executed experiments with 0, 2, 3, 6 kg weight conditons ), and walked treadmeill at various speed. The energy consumptions of 0, 2, and 3 kg conditon were almost equal at around 5 km/h speed. Their result was repeatedly verified. Therefore, the weight of boots is not important factor, because many boots weigh lesser than 2 kg.

2.Energy consumption of walking is mainly determined by step length. I cited dynamic walking model as a representative. ( Kuo, A.D. 2007 The six determinants of gait and the inverted pendulum analogy:A dynamic walking perspective. Human Movement Science, 26, 617-656.)

The energy consumption is predictable mathematically by the following formula,

WR =(1/8)f^3s^4

WR is work rate (energy consumption per weight and time), f is standardized frequency of pitch, and s is standardized step length.

This model was proved by the walking experiments. The mathematical estimation of energy consumption was very similar to the real energy consumption.

When you carry your backpack with ideal way ( on the waist bones ), you can stand without energy consumption. The backpack weight can be combined with your body weight. Then, based on a simple calculation, influence of pack weight is lesser than 5% of the toal energy consumption.

3.Boots reduce the shock of the Achilles tendon.

( Rowson et al. 2010 Can footwear affect Achilles tendon loading? Clinical Journal of Sport Medicine, 20, and 344-349.)

They measured the influence of the type of shoes (a high cut / low cut) and shoelace ( not fastened / fastened ) using man's dead real leg. As a result, the high cut shoes reduce the maximum shock of the Achilles tendon average 9.9 %.

4. Do boots provide ankle support? I think high-cut boots my provide ancle support.

(Dizon,J.M., Reyes, J.J. 2010 A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players. Journal of Science and Medicine in Sport, 13, and 309-317.)

They did a systemtic review based on the meta analysis of seven reliable researches. The shoe braces and taping reduced the risk of re-injury. The restricted motion of an ankle my prevent injury, although the detailed mechanism is unknown, they said. Therefore, it is natural to think that high-cut boots have an effect of prevent ancle injury.

5. Which is safer, boots or shoes?

I think this depend where you walk.

(Anderson, L.S. Jr, Rebholz, C.M., White, L.F., Mitchell, P., Curcio,E.P. 3rd, Feldman, J.A., & Kahn, J.H. 2009 The impact of footwear and packweight on injury and illness among long-distance hikers. Wilderness Environtal Medicine, 20, and 250-256.)

They investigated 128 persons who walked along AT and PCT 805 km or more, and discovered that there were many abnormalities in feeling among the persons who wore boots. However, when the weight of the load was controlled statistically, the effect of footware disappeared. The true cause was the weight of the load. There is no difference of injury rate.

( Jardine, R. 2009 Trail life. Ray Jardine's lightweight backpacking. AZ: AdventureLore Press)

I think Jardine's assertion that boots is dangerous is based on a misunderstanding or confirmation bias.

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I was stimulated by this mailing list and searched scientific papers. I found many important findings, and I wrote them in my hiking handbook ( it will be published in April, sorry it was all written in Japanese ). If you want to try shoes, you need to train calf muscles and Achilles' tendon. I will cite simplified several conclusions of itemized section in my book.

// clear points

Boots reduce the shock of the Achilles' tendon around 10 %. ---Rowson S., McNally C.,& Duma S.M. 2010 Can footwear affect Achilles tendon loading? {\it Clinical Journal of Sport Medicine}, 20, 344-349.}

Boots reduce the burden of the ankle, but increase the burdens of the knee joint. ---B\"{o}hm, H.,& H\"{o}sl, M. 2010 Effect of boot shaft stiffness on stability joint energy and muscular co-contraction during walking on uneven surface.

{\it Journal of Biomechanics, 43, 2,472} 2467-}

Thick, soft shoes are the most unstable, and thin, firm shoes are the most stable. ---Robbins, S., Waked, E., Gouw, G.J. ,& McClaran, J. 1994 Athletic footwear affects balance in men.{\it British Journal of Sports Medicine}, 28, 117-122.}

// not clear, but the answer may be positive

Do the boots support an ankle? In this respect, there is no strong evidence, but the answer may be positive based on the meta analyzes of 7 reliable studies . As Dan Jacobs posted, aircast was proved to have supportive function. ----Dizon, J.M., Reyes, J.J. \ \ 2010 \ \ A systematic review on the effectiveness of external ankle supports in the prevention of inversion ankle sprains among elite and recreational players. { \it Journal of Science and Medicine in Sport}, 13, 309-317.}

// not clear, it may be no difference

Which are safe, boots or shoes? --- Anderson, L.S. Jr, Rebholz, C.M., White, L.F., Mitchell, P., Curcio, E.P. 3rd, Feldman, J.A., \& Kahn, J.H. 2009 The impact of footwear and packweight on injury and illness among long-distance hikers. {\it Wilderness Environtal Medicine}, 20, 250-256.} They studied AT and PCT hikers and found no difference.

no difference, refined prospective randomized study --- Hamonko, M.T., McIntosh, S.E., Schimelpfenig, T., \& Leemon, D. \ \ 2011 \ \ Injuries related to hiking with a pack during National Outdoor Leadership School courses: a risk factor analysis. {\it Wilderness Environmental Medicine}, 22, 2-6.

Those results are negative to Jardine, R. 2009 {Trail life. Ray Jardine's lightweight backpacking}. AZ: AdventureLore Press}

// not clear, no study

Does Gortex needed for footwear? ---no study.

// clear point

Boots are generally heavier than shoes. I had already posted the effect of weight of footwear. If you are an average man and the weight of your footwear is within 2kg, you need not to be nervous about the weight. If your walking speed exceed 7km/h, the lighter footwear is better.