KP 322 Lab 7 - LT and VT1
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Wilfrid Laurier University *
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Course
322
Subject
Health Science
Date
Dec 6, 2023
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docx
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5
Uploaded by KidRock7053
LABORATORY
SEVEN
LACTATE
&
VENTILATORY
THRESHOLD
Required Readings:
Course Text - 12
th
ed. – Chapters 4, 10 & 19
pp. 89-92 (Lactate threshold)
pp. 279-280 (Ventilatory control during heavy and very heavy exercise)
pp. 512-513 (Intermediate-length performances)
Course Text - 11
th
ed.
pp. 86-87 (Lactate threshold and Figure 4.8)
pp. 265-266 (Ventilatory control during heavy and very heavy exercise)
pp. 499-500 (Intermediate-length performances)
Introduction:
As an incremental exercise test progresses in intensity, reliance on anaerobic energy
production also increases and blood lactate levels will inevitably increase. Although there
is debate as to the exact mechanism causing this increase, when blood lactate levels start
to rise in a sudden and systematic fashion during progressive exercise testing, we label
that point as being the lactate threshold. Lactate threshold is an important determinant in
aerobic sport performance (particularly in intermediate-length events) and some would
argue it is a better predictor of athletic end performance than VO
2
max
.
Purpose:
The purpose of this laboratory is two-fold:
(i)
To understand what lactate threshold is versus what ventilatory threshold is,
(ii)
To be able to graph and interpret each from collected data
Subjects:
2
subjects per lab are required. The rest of the class will help collect data and observe.
One subject will have blood lactate taken at the end of each stage, the other will not.
Note: the protocol outlined below is a typical biking VO
2max
test protocol, although we
are not measuring that specifically in today’s lab.
Test Administration:
Equipment:
-
Metabolic cart
-
Face mask and bonnet
-
Heart rate monitor/ECG
-
Gloves
-
Alcohol swabs and Fingertip Bandaids
-
Lactate Scout Portable Lactate Analyzer (including test strips)
-
Single-use lancets
-
Monark bicycle ergometer
-
Data collection form
Protocol:
1.
The lab instructor will calibrate the metabolic cart for data collection prior to the lab.
2.
Have the subject warm up for approximately 3 minutes at .5 kg, and allow the
subject to choose the pedaling speed at which they want to run the test (between
50-85 rpm). They will maintain this rpm for the entire test.
3.
Fit the subject with breathing apparatus, ensuring no air is leaking from the mask.
4.
Have the subject begin cycling at 1 kg of resistance for females and 1.5 kg of
resistance for males at their self-selected rpm. Continue for 2.5-3 minutes. Note
that pertinent data will be recorded at the end of each stage including a blood
lactate analysis (if applicable) over the duration of the experiment and some
information will be displayed on the monitors.
5.
Continue to increase the resistance by .5 kg every 2 - 2.5 min. (rpm constant).
**Note: ideally stages in a progressive maximal test like this would be 2
minutes, but due to measurements we are obtaining (La+) we cannot move on
to the next stage until those measurements have been obtained. We will strive
to get as close to 2 min. stages as possible.
6.
Loudly encourage the subject to continue exercising as the workload increases.
7.
Terminate exercise test when the subject can no longer continue at their self-
selected rpm (#2 above) or an increase in workload does not result in a
significant increase in VO
2
from the previous workloads. (Note: the subject may
voluntarily terminate the test at any time.)
8.
Remove face mask and headpiece from the subject and allow the subject to cool
down for 3 - 5 minutes by cycling at .5-1 kg of resistance at 30-50 rpm. Allow for
an active recovery.
Results:
-
Use data collection forms below with the VO
2
, HR, Blood La
+
and
VE’s of all the stages performed by the subjects (readings during last 30s of stage)
2
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