energy consumption

The famous hypothesis is wrong

Complete Walker IV P.59

In 1953 the successful Mount Everest expedition came to the conclusion that in terms of physical effort 1 pound on the feet is equivalent to 5 pounds on the back. A consensus of informed opinion now seems to support that assessment.

「1953年のエヴェレスト遠征隊は足の1ポンドの重さは荷物5ポンドの重さに該当すると結論した。今ではこの結論についてコンセンサスが得られたと思う。」

Dear Robert

It may be my turn, because I am the exceptional man, wearing mountain boots.

Confronted to the boots vs shoes discussion, I searched several

scientific papers. And I found several important points.

1. "one pound on your foot equals five on your back" is wrong. This

wrong idea was found in "Complete Walker I, and IV", and Townsend's "

the backpacker's handbook", because they cited the classical

experiments, carried out with very heavy boots ( 5 Kg and backpack

weight was 25 Kg ). These are very different from recent boots. Many

boots weight less than 1 kg.

2. According to the recent research, the energy consumption of boots

is equal to that of shoes when we are walking at 4-5Km/hour speed,

because our walking is described by the dynamic walking model. Most of

the time, our leg behave as like inverted pendulums.

3. High-top boots reduced peak Achilles tendon tension by an average

of 9.9% when compared with low-top shoes. This research design was

ideal one. So, This may be a firm scientific evidence.

4. But boots affect gait, and increased the joint loading at the knee.

So if you wear boots, you need a slight modification of walking style.

5. There is no evidence of ankle support for boots. Townsend denied.

But, I think there is some support. So, I am always wearing boots. If

you wear high-top boots, you feel more supports.

6. The training at the rough ground may strengthen your ankle, but it

may take several years, or ten more years.

My recommendation is:

1. Light weight high-top boots.

2. The training on the rough ground with the boots.

荷物の重さ

体重の15%の荷重は歩行エネルギーを増大させない、振り子運動的歩行は歩行エネルギーを減少させるという研究から推論すると、振り子運動的歩行が可能な範囲(急勾配を除く)では体重の20%程度の荷重は歩行エネルギーに影響しないのではないか。Ergonomicsは面白い。

体重の15%を担がせ、トレッドミルを歩く実験がある。PDFが公開された。興味深い点は、空身の方が、荷物を持つ場合よりもエネルギー消費が大きいこと。荷物が重くなればエネルギー消費が単純に増えるというのは間違い。また、担ぐ位置は、背中の高い位置の方が低い位置よりも優れているようだ。荷物の重さが体重の20％を超える場合は、Front loadingも検討した方がよい。

There are ergonomic experiments concerning load carriage: I found the

article( Abea et al. 2007, Applied Ergonomics) last year.

Interesting points:

1. The energy cost of walking significantly decreased during walking

with load than without load at slower speeds. This means that the

energy cost does not increase as the load increase, contrary to the

expectation:

2. A significant decrease in the energy cost of walking was also

observed while carrying the load on the upper back than on the lower

back at 60-80 m/min. The load on the upper back is superior to the

lower back load.

Please see Fig.2

My conclusion is:

\begin{itemize}

\item The footwear weight is important for the speed hiker (6 Km/hr or more).---スピードハイキングの場合、靴の重量の影響が大きいので、軽い方がよい。

\item The footwear weight is not so important as previously expected for adequate walking speed ( 3.6 - 4.8 Km/hr )---疲労の少ない速度で歩く場合、靴の重量の影響は小さいので、神経質になることはない。

\item More slower walking speed resulted more energy consumption.---歩く速度が遅すぎると返って疲労を招く。

\end{itemize}