Chapter 1 Common Measurements in Exercise

Metric system

The standard system of measurement used by scientists to express mass, length, and volume

Common prefixes

mega, kilo, centi, milli, micro, nano

Force

mass * acceleration

Acceleration

Rate of change of velocity over time (change in velocity / change in time)

Work

force * distance

Power

work/time

Ergometry

Measurement of work output

Ergometer

Device to measure work

Direct Calorimetry

Measurement of EE via measurement of body heat production (gold standard)

Energy expenditure commonly measured in calories

Indirect calorimetry

Measurement of EE by measuring VO2 (people are more familiar with this)

Determines VO2 by measure amount of O2 consumed

1 MET

3.5 ml/kg/min

Efficiency of exercise

Ratio of work output to energy input

A more efficient individual uses less energy to perform the same tasks/amount of work

Concept of net efficiency

Ratio of work output/energy input (above rest)

% Net efficiency

(work output / energy input) x 100

Exercise intensity

Curvilinear relationship between work rate and energy expenditure

Efficiency decreased at high exercise intensities due to higher energy cost of very heavy exercise

Speed of movement (reflective of power output)

An optimum speed of movement exists and deviation from it reduces efficiency

Muscle fiber types

Slow muscle fibers (Type I) more efficient in using ATP, more fatigue resistant than fast muscle fibers (Type II)

Factors impacting exercise effciency

Exercise intensity, speed of movement, muscle fiber type

Force vs Velocity of movement curve

As velocity increases, the less force you produce

Speed of movement: power curve

There will be a speed with optimal power

Around 30-60% of 1 rep max

Running Economy (RE)

Measured as VO2 of running at a specific speed

-lower VO2 at the same speed indicated better RE

-measure RE at a submaximal "steady state"

Type I fibers are more efficient than Type II

Elite runners are more efficient than non-runners

Main determinants of endurance performance

VO2 max, lactate threshold, economy of movement (RE)

Peak vs relative

Relative divide value by body weight

Advanced ergometers

Wahoo KICKR Bike, Biodex Isokinetic Testing, SEGR Fv 1 Electric Leg Press, AccuPower Force Plates, Treadmetrix Treadmill