time and power output over 15m wheelchair sprint
TRANSCRIPT
Center for Human Movement Sciences
Wheeled mobility in sports
15m overground sprint
Field test to assess wheelchair-specific anaerobic capacity?
Jan van der ScheerSonja de GrootRiemer Vegter
Dirk-Jan VeegerLuc van der Woude
vrijdag 3 mei 13
Center for Human Movement Sciences
Wheelchair-specific anaerobic capacity?
• Capacity for short, intense wheelchair exercise
• ‘Explosive’ sprint power
• High capacity required in:
Source photos: www.paralympic.org & frontlinepictures.photoshelter.com
vrijdag 3 mei 13
Center for Human Movement Sciences
Testing wheelchair-specific anaerobic capacity
• Why? Training status, selection
• Best available test: Wingate in lab
• Wheelchair ergometer or roller
• 30s all-out with relatively high resistance
• Outcomes: power output
• Disadvantage: lab-based equipment
• Needed: valid alternative field test
vrijdag 3 mei 13
Center for Human Movement Sciences
Field alternative for Wingate
• 15m overground sprint
• Test from wheelchair skill battery
• Short (5-15s) and all-out
• Simple: stopwatch time
• Overground sprint tests in other surroundings
• Track: time 100m (r=-0.7 to -0.9)
• Basketball court: 24m sprints for 30s (r=0.9)
vrijdag 3 mei 13
Center for Human Movement Sciences
Relationship time-15m and Wingate
• Stopwatch time over 15m sprint: valid field alternative for Wingate outcomes?
• Potential confounder: skill for high handrim velocities in 15m
• >2 m/s
• Resistance 15m < Wingate
• Skill 15m > Wingate
• Between-subject differences in skill may confound relationship with Wingate
• Potential confounder: body mass
• E.g. heavier: more rolling resistance, more time needed
• Power output Wingate less affected than time-15m
vrijdag 3 mei 13
Center for Human Movement Sciences
Relationship P5-15m and Wingate• Power output during 15m sprint
• Measurement wheel
• P5-15m
• Similar to Wingate outcome
• Mean power output first 5s
• Lower than P5 of Wingate due to lower resistance
• P5-15m (vs. time-15m) less affected by between-subject differences in:
• Body mass
• Skill (only first 5s when velocity is relatively low due to inertia)
• P5-15m: valid alternative field outcome for Wingate outcomes?
vrijdag 3 mei 13
Center for Human Movement Sciences
Research question and hypotheses
• 15m overground sprint outcomes: valid field alternatives for Wingate outcomes?
• Stopwatch time over 15m
• Relationship with Wingate possibly confounded by skill and body mass
• P5-15m
• Relatively little influence of skill and body mass
• P5-15m lower than P5 of Wingate
vrijdag 3 mei 13
Center for Human Movement Sciences
Subjects: novice able-bodied persons
• Why? No disability-related factors
• N=19 (9 men)• Age: 23 ±2y
• Body mass: 69 ±12 kg
• Wheelchair experience: 1 ±2h
vrijdag 3 mei 13
Center for Human Movement Sciences
2 days, 2 tests(1) 15m overground sprint
• ADL wheelchair
• Stopwatch
• Measurement wheel (Optipush)
(2) 30s-Wingate test
• Similar to 15m:
• Wheelchair configuration
• Start velocity = 0 m/s and inertia simulated
• In contrast to 15m:
• Resistance higher and standardized (<2 m/s)
vrijdag 3 mei 13
Center for Human Movement Sciences
• 15m sprint• Time-15m: stopwatch
• MeanVelocity-15m: 15m / Time-15m
• P5-15m: highest mean power output of successive 5s intervals
Outcomes
• Wingate test (WAnT)• P5-WAnT: highest mean power output of successive 5s intervals
• P30-WAnT: highest mean power output over 30s
0 1 2 3 4 5 6 7 8-100
-50
0
50
100
150
200
Time (s)
Unila
tera
l PO
(W)
Pstart -15m
P5 -15m
PO (W)Push startPush stopPOpeak-15m0 5 10 15 20 25 30
-100
-50
0
50
100
150
200
Time (s)
Unila
tera
l PO
(W)
P5-WAnT
P30-WAnT
vrijdag 3 mei 13
Center for Human Movement Sciences
Time-15m and MeanVelocity-15m: relationship to Wingate outcomes
5.5 6 6.5 7 7.5 8 8.5 9 9.5 1020
30
40
50
60
70
80
90
Time−15m (s)
P5−W
AnT
(W)
• Time-15m correlation
• P5-WAnT: r=-0.6
• P30-WAnT: r=-0.6
1.4 1.6 1.8 2 2.2 2.4 2.6 2.820
30
40
50
60
70
80
90
MeanVelocity−15m (m/s)
P5−W
AnT
(W)
• Theoretical error
• t=0, power output ≠ infinite
• MeanVelocity-15m with no intercept in regression model
• P5-WAnT: r=0.4
• P30-WAnT: r=0.4
vrijdag 3 mei 13
Center for Human Movement Sciences
• Time-15m and MeanVelocity-15m not valid alternatives for Wingate outcomes
• Velocity in 15m >2 m/s -> skill differed between subjects
• Peak velocity 15m: 3.1 ±0.4 m/s • Peak velocity Wingate: 1.5 ±0.4 m/s
• Effects body mass differences
0 1 2 3 4 5-100
-50
0
50
100
150
200
Unila
tera
l PO
(W)
Time (s)
0 1 2 3 4 5-0.5
0
0.5
1
1.5
2
2.5
Velo
city (
m/s)
Time (s)
15m sprintWAnT
15m sprintWAnT
Time-15m and MeanVelocity-15m: relationship to Wingate outcomes
vrijdag 3 mei 13
Center for Human Movement Sciences
P5-15m: relationship to Wingate outcomes
20 25 30 35 40 45 50 55 60 65 7020
30
40
50
60
70
80
90
P5−15m (W)
P5−W
AnT
(W)
P5-15m correlation
• P5-WAnT: r=0.8
• P30-WAnT: r=0.8
vrijdag 3 mei 13
Center for Human Movement Sciences
20 25 30 35 40 45 50 55 60 65 7020
30
40
50
60
70
80
90
P5−15m (W)
P5−W
AnT
(W)
• P5-15m: 38.1 ±14.0W
• P5-WAnT: 56.5 ±18.9W
Between-subject differences in skill (r=0.8)
0 1 2 3 4 5-100
-50
0
50
100
150
200
Unila
tera
l PO
(W)
Time (s)
0 1 2 3 4 5-0.5
0
0.5
1
1.5
2
2.5
Velo
city (
m/s)
Time (s)
15m sprintWAnT
15m sprintWAnT
P5-15m: relationship to Wingate outcomes
vrijdag 3 mei 13
Center for Human Movement Sciences
Discussion• 15m overground sprint outcomes:
valid field alternatives for Wingate outcomes?
• Stopwatch time over 15m• Not acceptable (r<0.7) • Due to differences between subjects in skill and body mass
• P5-15m
• Acceptable (r=0.8)• Relatively little influence of skill and body mass• P5-15m < P5-WAnT due to lower resistance
• Future developments• Low-cost technology for power output in overground sprint• Combine this technology with accessible ‘in-field’ roller
vrijdag 3 mei 13
Center for Human Movement Sciences
Take home messages based on this study
(1) Time over 15m overground sprint: not an outcome of wheelchair-specific anaerobic capacity
(2) Power output over 15m overground sprint: field alternative for wheelchair-specific anaerobic capacity
vrijdag 3 mei 13
Center for Human Movement Sciences
Acknowledgements and further info
Thanks for your attention!
• Acknowledgements
• Data collection: Tom Gakes and Marlies Bouma
• Data analysis: Helco van Keeken
• Data interpretation: Bert Otten
• Financing: ZonMW, FondsNutsOhra
• Further information
• www.scionn.nl
vrijdag 3 mei 13
Center for Human Movement Sciences
20 25 30 35 40 45 50 55 60 65 7020
30
40
50
60
70
80
90
P5−15m (W)
P5−W
AnT
(W)
• P5-15m: 38.1 ±14.0W
• P5-WAnT: 56.5 ±18.9W
Difference varied between subjects (r=0.8)
0 1 2 3 4 5-100
-50
0
50
100
150
200
Unila
tera
l PO
(W)
Time (s)
0 1 2 3 4 5-0.5
0
0.5
1
1.5
2
2.5
Velo
city (
m/s)
Time (s)
15m sprintWAnT
15m sprintWAnT
P5-15m: relationship to Wingate outcomes
vrijdag 3 mei 13