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No Slide Title - Ironbark (xtelco)
Chapter 10
Energy Expenditure During Walking,
Jogging, Running, and Swimming
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Gross Versus Net Energy
Expenditure
• Energy expenditure estimates
– Gross energy expenditure
• Total energy required for an activity
– Net energy expenditure
• Gross energy expenditure – Resting energy
expenditure
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Economy of Human Movement
• Economy of movement refers to the energy
required to maintain a constant velocity of
movement.
• More skilled athletes perform the same
activity with a reduced energy requirement.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Mechanical Efficiency
• Mechanical efficiency
– Ratio of energy output / energy input
– Reflects the amount of energy transferred into
doing work
– External work is measured as F × D
• Ft-lb
• Kg-m
• kCal
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Walking
• Influence of body mass
– Equations may be used to calculate energy
expenditure.
– Speed or pace is an important factor.
– Mass is factored in as resistance.
– Individuals with a larger mass expend more
energy at the same pace.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Walking
• Terrain and walking surface
– Energy expenditure is greater on soft surfaces.
• Sand
• Snow
– Slope or grade influences energy expenditure.
• Downhill walking requires less energy.
• Very steep downhills require energy to “brake.”
• Uphill grades require more energy.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Walking
• Footwear
– Added weight to feet or legs increases energy
requirements.
– Shoes need to balance cushioning effects with weight.
• Handheld and ankle weights
– Increase energy expenditure
– Used during walking, increase energy expenditure closer
to that of running
– Have less of an impact on energy expenditure while
running
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Competition Walking
• Economy is not good in this type of walking.
– Energy expenditure increases at a faster rate or a
greater slope for competitive walking compared
to running.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Running
• Economy of running fast or slowly
– Net energy cost values for running a set distance are similar
for different speeds.
• Stride length, stride frequency, and speed
– Running
• Speed is dependent upon stride length & stride frequency.
– Competition walking
• Speed is increased mainly by increasing stride frequency.
– Optimum stride length
• Level of minimum effort
• No “best” style
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Running
• Running economy: Children and adults
– Children have lower running economy than adults.
– Children require 20 – 30% more oxygen per unit
of mass to run at the same pace as an adult.
• Air resistance
– Factors that effect air resistance
• Air density
• Runner’s projected surface area
• Square of runner’s velocity
– Drafting
• Decreases resistance
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Running
• Treadmill versus track running
– Have similar energy requirements at the same
speed
– Elite athletes at top speeds on the track may
encounter increased air resistance.
• Marathon running
– To be successful requires the ability to maintain
pace for an extended period of time
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Swimming
• Methods of measurement
– Portable metabolic systems may be worn.
– Subjects may be tethered.
– Subjects may swim in a flume.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Swimming
• Energy cost and drag
– Total drag force
• Wave drag
• Skin friction drag
• Viscous pressure drag
– Ways to reduce effects of drag force
• Wet suits
• Drafting
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Swimming
• Energy cost, swimming velocity, and skill
– Skilled swimmers are more efficient.
• More of their effort provides forward movement.
– The stroke used influences energy cost.
• Freestyle or front crawl is more efficient than back
crawl or breaststroke.
• Breaststroke is less efficient than freestyle or back
crawl.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Swimming
• Effects of water temperature
– Cold water adds additional energy costs.
– Optimal temperature is ~ 82 – 86°F.
• Effects of buoyancy: Men versus women
– The leaner an individual, the less buoyant.
– Women tend to be more economical due to
added buoyancy.
– Endurance swimming is influenced by economy
and thermal insulation provided by body fat.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition

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