PWC
170
2
The purpose of this section of the lab is to:
1.
Gain experience in assessing HR, BP, and RPE during exercise.
2.
Determine sub-maximal fitness level using a standardized cycle ergometer test.
3.
Determine a prediction of peak oxygen consumption determined by HR responses to submaximal steady state exercise responses.
Sub-maximal exercise responses are a useful tool for evaluating not only HR and BP responses in general, but to estimate fitness in larger settings than is possible with maximal exercise testing. Submaximal testing is less costly and obviously involves a much lower risk of complications in the population at large. Many sub-maximal tests have been developed over the years to estimate peak oxygen consumption including the YMCA bike test, the Harvard Step test, and the 6-min walk test to name a few.
The PWC
170
test is one of the most popular of the standardized cardiorespiratory fitness tests. The test was first developed as a tool to estimate work capacity in actual work settings (i.e. clearance).
The test has been criticized in the past, but can be a useful tool in a budget with limited funds and resources. This test is based on steady-state exercise responses (HR) during three or four submaximal work rates. The loads are incremental and should approximate between 25 to 75% of an individual's peak aerobic capacity. The test is performed on a stationary ergometer and the HR should be taken during the last 30 seconds on every minute of a 4 to 5 minute stage. The last two heart rates should be averaged and they will represent the HR for that particular workload.
For the Astrand prediction of the subject’s VO
2 pk, the HR and work rate data from one of the stages of the PWC
170
test will be sued along with data on gender (M, F) to predict the maximal value for your subject. This is done first by taking the work rate and HR (the average of min 3-4 or 4-5 for a level of the PWC
170 test and inspecting a standard VO
2 pk prediction table or nomogram that has been developed to show predictions for men or women. Once the predicted VO
2 pk may then be interpreted according to normative data bases (population tables) to determine the person’s age and gender adjusted fitness level. The nomogram is included with this lab material, as are some of the tables and figures that you will need to score and interpret the test results. Norms for men and women for predicted VO
2 pk will be provided in class.
Procedures
For these tests it is usually advisable to use 4 workloads so that you will have more points for predicting PWC
170
. Today use 3 submaximal workloads on the Monark ergometer, each lasting at least 4 minutes. In other words, you may use results from lab #1A to calculate results .
The steady state heart rates should be between 120 and 160 bts • min -1
1.
Weigh the subject, with exercise clothing, but without shoes.
2.
Adjust the seat height such that the subject is able, at pedal down stroke, to almost fully extend the knee. Record the seat height.
3.
Use and electronic metronome when need to set the pace of the exercise. For 60 rpm, use 120 clicks/min.
1

4.
Warm the subject up at the above pace with .5 kg of tension for 2 minutes.
5.
Turn the tension control to apply the correct resistance for the first workload (~0.5 kg for women and ~1.0 kg for men) and check the load scale frequently to maintain the desired resistance.
Without any rest interposed between loads, the tension is increased at the end of 4 minutes to begin the second load. Next, the third load, etc.
6.
Use methods from lab 1A to measure BP and RPE.
7.
Measure the HR during the last 10-sec of each minute of exercise.
8.
Heart rates are recorded during each minute. Determine the HR for each stage as the average for the last 2 minutes (3-4) in which the values differed by no more than 4 bts • min -1 . In the event HR values at minutes 4 and 5 are more than 4 bts different stay at that workload for 1 more minute.
9.
For workloads that go to 5 minutes, only increase the resistance by 0.5 kg. For individuals who reach a steady state within 4 minutes, you may increase 1.0 kg.
10.
Record RPE during the first 30-sec of the 4 th minute in each work stage, using the Borg scale.
Interpretation of results:
1.
Plot PWC
170
results on the attached chart by plotting the average of the last two minutes of each stage with the corresponding workload (kg-m/min or W). Record the PWC
170
for your subject.
2.
Use one of the workloads between 120 and 160 bts • min -1 to predict peak aerobic capacity using the Astrand nomogram for men and women, respectively.
3.
Find and record the aerobic fitness category for the person you measured using the attached
ACSM fitness category ratings.
PWC
170 workload:
Astrand-Rhyming Predicted VO2 pk:
Fitness Score (Percentile Rank) (Table 4-5):
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3

Exercise Testing Sheet
BIKE TEST
Age:
Name
Date:
Name of partner:
Ht (in): Wt (kg): Medications:
Age-pred. peak HR 85% age-pred max HR:
Resting HR (supine) BP (supine)
BP (sitting)
1
2
3
4
5
6
7
8
9
10
11
12
13
Time (kgm/min) METs HR (bts
• min
-1
) BP
(mmHg)
14
15
16
17
RPP
(-10)
RPE Signs/Symptoms
4