20110114080127 measurements of fitness & exercise performance

8/3/2019 20110114080127 Measurements of Fitness & Exercise Performance

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PART 4

Measurements of Fitness and Exercise

Performance


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Chapter 14

Measuring Endurance and AnaerobicCapacity


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Metabolic Determinants of

Physiological Capacities

Certain activities/sports are reliant on high skeletal

muscle metabolic capacities.

If the metabolic demands and related physiology of

given activities are known, then laboratory tests can be

developed to measureorbe dependenton that metabolic

pathway.

As will be shown, the metabolic needs of activitiesdiffer most in terms of their exercise intensity/duration.


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Figure 13.1

Prolonged Endurance

Short Term Intense

Oxygen Delivery Maximal Steady State

VO2max Lactate Threshold Economy

Others

Muscle Size MU Recruitment Buffering Capacity Anaerobic Capacity Others

Muscle Strength Isokinetics Wingate Test AOD

It is important to note that other non-

physiological factors also contribute to

performance


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VO2max

Traditionally, the maximal rate of oxygen consumption

(VO2max) is interpreted as a measure of the maximalcapacity of the bodys cardiorespiratory function.

The test of VO2max is arguably the most performed test

of human physiological function in exercise physiology.LimitationsAdditional variables are also important for performance

Does not explain who performs well among individualswith similar training

Requires sophisticated equipment

Difficult to measure a true maximal value is some people


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Testing Procotols

The time constraints for the duration of a protocol suited

to measure VO2max necessitates the need to tailor aprotocol to suit a given individual.

The steps to follow in determining a protocol are:

determine the subjects cardiorespiratory fitnessand training status by interview, and estimate a

workload at VO2max.

Select suitable stage and total test durations.

Calculate the increment needed for each stage


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Criteria Description

Protocol

Test duration 8-12 min

Stage duration Ramp, or 1-3 min

Intensity increment Based on stage duration and

cardiorespiratory fitness of subjects

Mode Subject specific on the basis of

training, disease states, and

musculoskeletal concerns

Data Interpretation

Criteria for max vs. peak Plateau in VO2RER > 1.1

Hrmax < 10 b/min from predicted

Table 13.1: Criteria for a valid protocol to measure VO2max


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Predicting Steady State VO2

Steady state VO2 can estimated using one of severalequations (Table 13.2).

It is recommended that theACSM equations be used for

treadmill walking and running.

For cycle ergometry, the equation of Latin should be used.


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Criteria Equation

Treadmill Walking

ACSM (mL/kg/min) [0.1 (m/min)] + [(grade fraction) (m/min) (1.8)] + 3.5

Treadmill Running

ACSM (mL/kg/min) [0.2 (m/min)] + [(grade fraction) (m/min) (0.9)] + 3.5

Cycle Ergometry

ACSM (mL/min) [2 (kgm/min)] + [3.5 (wt,kg)]

Latin (mL/min) [1.9 (kgm/min)] + [3.5 (wt,kg)] + 260

Summary of submaximal VO2 prediction equations (simplified)


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Predicting Cardiorespiratory and Muscular Endurance

VO2max can be predicted from either maximal or

submaximal exercise tests (Table 13.2).

Typically, submaximal tests are shorter in duration, and

can used for more elderly subjects due to reduced risks

for musculoskeletal and cardiovascular injury.

Maximal tests, despite the added time and effort required

by the subject, arefar more accurate

VO2max


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Criteria Equation

Maximal Tests - Treadmill

Bruce (mL/kg/min) 6.7 [2.82 (gender)] + [0.056 (time)]

Foster (mL/kg/min) 14.76 [1.38 (time)] + 0.451 (time2)] [0.12 (time3)]

Maximal Tests CycleErgometry

Storer (mL/min)

- male-female

[10.51 (Wmax)] + [6.35 (wt, kg)] [10.49 (age, yr)] + 519.3

[9.39 (Wmax)] + [7.7 (wt, kg)] [5.88 (age, yr)] + 136.7

Summary of prediction equations for VO2max (simplified)


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Note the

variability

Note the curvilinear

response - see

equation of Foster


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Submaximal Tests For Predicting Cardiorespiratory and

Muscular Endurance

The most accurate and widely used protocols forestimating VO2max from submaximal exercise are;

ACSM equation (treadmill or cycle ergometer)

YMCA cycle ergometer protocol

Astrand-Rhyming nomogram

Modifications of YMCA and Astrand-Rhyming

nomogram


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ACSM Equation

1. Complete steady state exercise for between 4-6 min for

two exercise intensities. (ideally between 60-85% HR-reserve)

2. Measure the steady state HR for each condition.

3. Calculate VO2 for each condition using the most accurate

equation (Table 13.2).

4. Calculate the VO2-HR slope (b)

5. Calculate HRmax (220 - age)

6. Calculate VO2max

b = (BVO2 - AVO2) / (BHR - AHR)

VO2max = BVO2 + [b (HRmax - BHR)]


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YMCA Cycle Ergometer Protocol Figure 13.3


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VO2 (L/min)

Power output (kgm/min)

Women Men

Kg weight

Heart Rate (b/min)

Women Men

Women Men

VO2max = 3.3 L/min

Age Correction Factors

Age (yrs) Multiply VO2max by

15 1.10

25 1.00

35 0.87

40 0.78

60 0.68

Astrand-Rhyming

Nomogram

VO2max

(L/min)


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Heart rate

(b/min)Power Output

kgm/min

VO2

(L/min)

Watts

VO2max

(L/min)

Bannister-Legge

Nomogram


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Lactate and Ventilatory Thresholds

The exercise intensity at the lactate threshold (LT) or

ventilatory threshold (VT) provides the bestmeasurement that can predict athletic performance in

middle to long distance (duration) events.

There are currently no universally accepted guidelines for

measuring the LT, and several methods existfor

documenting a threshold change in blood lactate.

More concrete guidelines exist for the VT, with one of two

methods being acceptable in research (see Figure 8.10):

ventilatory equivalents (VE/VO2 vs VO2)

V-Slope (VCO2 vs VO2)


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Subject 1Subject 2

Note the curvilinear responses


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Subject 1Subject 2

LT ?

LT ?

LT

R i E


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VO2 = 0.35 + 0.0113 (Watts)

Running Economy


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Other Tests of Cardiorespiratory and Muscular Endurance

VO2 Kinetics

The more rapid the increase in VO2 during a rest-exercisetransition, the greater the cardiorespiratory and muscular

endurance of the subject.

The increase in VO2 to steady state is represented by amonoexponential equation:

VO2 = A (1 - e-Bx) + EA = magnitude of change, e = natural log base, B = rate constant,

E = beginning VO2, x = time

see Figures 6.9 and 6.13


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Heart Rate Threshold

Heart rate does not increase in a linear manner to VO2max

in all individuals. The exercise intensity where HR-VO2deviates from linearity has been termed theheart rate

threshold(HRT orfc).

Thefc has been shown to coincide with the LT, butadditional studies have not confirmed this association.

Furthermore, afc may only occur in ~50% of healthy

individuals.

See Figure 7.7


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Predicting Maximal Muscle Power and Anaerobic Capacity

The muscles capacity for non-mitochondrial (anaerobic)

ATP regeneration is impossible to measure accurately. Dueto this, several laboratory tests have been developed that

rely heavily on anaerobic ATP regeneration, or indirectly

provide a measure of the anaerobic capacity.

Short-Term Tests Intermediate-Term Tests

Sargeants Jump and Reach Wingate Test

Margaria Power Test Isokinetic Tests

Muscle Metabolite Accumulation

Accumulated Oxygen Deficit


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Accumulated Oxygen Deficit

Measured VO2

5.15 L/min

393 Watts

Note the linear extrapolation to

non-steady state conditions

Approximately 120% VO2max


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Accumulated oxygen deficit (mL O2/kg)

Control

Distance

Middle Distance

Sprinters

20110114080127 measurements of fitness & exercise performance

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