One group pretest post-test
design
One Group Pre-Post Design
Methodology
• A common example of
Pre-Experimental Designs
– No control group
– No random selection of
participants
– Little power to
establish causation
• One Group Study Design
–
–
–
–
Select/recruit volunteers
Administer pre-test
Provide Treatment
Administer post-test
Development of Race Profiles for
the Performance of a Simulated
2000-m Rowing Race
Kennedy & Bell, 2003
• Research Purpose
-To create race profiles of men and women rowers
before and after training using a simulated 2000-m
rowing race.
-To observe the effect of:
-Men vs. women
-Before vs. after training
Study Design and Methodology
• Subject characteristics
– Recruited from local rowing
clubs
– Actively training for preceding
3 months
– 7 male, 11 female novice
rowers
– 12 male, 8 female experienced
rowers
Informed consent & Ethics approved
by U of Alberta and Faculty of Phys.Ed.
Study Design and Methodology
• Race Simulation Structure
– 2000 meter race in lowest time
– Performed on a Concept II Model C
– Time, distance, stroke rate, 500-m split time
displayed for rowers
– HR, split time/500-m time & stroke rate
recorded every 200-m.
Study Design and Methodology
• Testing Protocol (Before & after training)
• 2000-m simulated race time
• Combined VT/VO2max test
–Horizon metabolic cart
–Polar Heart Rate monitor
• Multiple Repetition Maximum tests
Study Design and Methodology
• Training Treatment Specifics
• Ten week program:
– Individually prescribed and periodized
– Progressive overload
• Strength Component: 2x/week
– Upper and lower body exercises
– 65-90% predicted 1-RM
• Aerobic Component: 4x/week
– Three continuous and one interval workout
– Performed on Concept II Model C
Data Analysis
• All variables collected manually from the
Concept II display (stroke rate, time,
distance, 500-m. split time)
• Used to calculate velocity, mean race
velocity (MRV), deviation from MRV, and
standard deviation of MRV every 200-m.
Data Analysis
• Mean Race Velocity (MRV)
– Average of all race velocities taken at 200-m. intervals
• Deviation from MRV
– Specific race velocities taken at 200-m. intervals
minus MRV
• Standard Deviation from MRV
– Average deviation of all participants from their mean
race velocity at a given interval
Data Analysis
• Race Profile Definition:
– Provides a descriptive graphical illustration of
spontaneous pacing behavior
– Is a known factor in sport performance that
has received little attention in the sport of
rowing
– Deviation from MRV plotted against MRV
Major Findings
• Physiological Improvements
Female
Pre
Female
Post
Male Pre
Male Post
VO2
Max
37
ml/kg·m
45
46
56
2000m
539 sec.
496
458
426
Leg Press 148 kg.
187
297
348
Bench
20
78
84
18 kg.
Race Profile (Male Pre-test)
Deviation from MRV over 2000-m.
0.2
0.15
0.1
0.05
Deviation from MRV
-0.1
80
0
10
00
12
00
14
00
16
00
18
00
20
00
60
0
-0.05
40
0
20
0
0
Race Profile (Male Post-test)
Deviation from MRV over 2000-m.
0.15
0.1
0.05
Deviation from MRV
-0.1
80
0
10
00
12
00
14
00
16
00
18
00
20
00
60
0
-0.05
40
0
20
0
0
“Constant Pace” (Fast Male Post)
Deviation from MRV over 2000-m.
0.035
0.03
0.025
0.02
0.015
Deviation from MRV
0.01
0.005
2000
1800
1600
1400
1200
800
600
1000
-0.01
400
-0.005
200
0
“All-Out” (Fast Female Post)
Deviation from MRV over 2000-m.
80
0
10
00
12
00
14
00
16
00
18
00
20
00
60
0
Deviation from MRV
40
0
20
0
0.3
0.25
0.2
0.15
0.1
0.05
0
-0.05
-0.1
-0.15
-0.2
Major Findings
• Differences in pacing with training
– Moved toward a constant pace model and improved
pace
• Differences in pacing between genders
– Fastest males adhered most closely to the constant
pace strategy
– Fastest females adhered to an all-out strategy not
adopted by any other groups
Discussion
• All-out pace profile (fastest women)
– Close to higher intensity sports
– Unknown if adhering to a constant pace
would have resulted in improved performance
• Constant pace profile (fastest men)
– Close to similar well-documented sports
• Short duration cycling (4000-m.)
Critique
• Pre-post inability to establish causation
– has no control group
• Learning effect (author’s critique)
• Possible that fastest female rowers were novice
• During 2000 m test verbal encouragement used
– could affect final results
• Compared group vs. 3 fastest rowers of each sex
– should have compared novice vs. experienced rowers
Critique cont’d
• Tested during off-season
– rowers not in physical or mental shape of race
• Transferability not good
– test is on rowing ergometer vs. boat in water
– racing strategy often dependent on situation relative
to competitors
Suggestions/Future Considerations
• Need to assess elite level competition to
•
•
•
strongly establish nature of optimal race
strategy etc.
Done on water (author’s suggestion)
Compare matched groups using alternate
approaches
Compare all out strategy vs. constant for
2000 m race
Other Possible Questions for Similar
Research
• Specific to rowing
– what is psychologically
going on during the
race
• General for Pre-Post
design
– add a control group
– eg. Choosing own
method of rowing vs.
racing strategy