Lower Limb Muscle Strength and Running Performance in ...
Transcript of Lower Limb Muscle Strength and Running Performance in ...
AUTHORS: E.M. Beckman (1), Y.C. Vanlandewijck (2); M.J. Connick (1); S.M.
Tweedy (1).
AFFILIATIONS: (1) University of Queensland, School of Human Movement
Studies, Queensland, Australia; (2) Catholic University Leuven, Department
Rehabilitation Sciences, Leuven, Belgium
Evaluating the validity of lower limb muscle
strength tests for classification of runners
with ataxia, athetosis and hypertonia
IPC Athletics Classification System for Physical
Impairments
Purpose of classification –
To minimize the impact of impairment on the
outcome of competition
Classify athletes based on how much
impairment impacts on performance
Background – Classification in Paralympic sport
• Evidence-based classification mandated by IPC – empirical evidence is
required
•IPC Concept map – Athletics classification (Tweedy & Vanlandewijck, 2011)
STRENGTH OF
ASSOCIATION
Coordination
Strength
Range of Movement
(active and passive)
Wheelchair – sprint
performance
Running – sprint performance
Standing Throw performance
Seated throw performance
Tests of Impairment Tests of Performance
Aim
Evaluate the validity of lower limb muscle strength tests for
classification of runners with hypertonia, ataxia, and athetosis.
1. Determine whether AWD are significantly different from
ND athletes on tests of strength
2. Determine the strength of association between tests of
strength and performance in AWD
3. Determine the strength of association between tests of
strength and performance in ND
Methods - Participants
Athletes with disabilities
• n = 13 male athletes: clinically diagnosed hypertonia, ataxia, athetosis
• Competitive runners
• Mean age 25.89 (± 10.37) years
Non-disabled athletes
• n = 28 male athletes
• regularly active in competitive sport
• Mean age 23.1 (± 4.1) years
Methods – Strength tests
Isometric, slow build up of force, standardised positions (measured in Newtons)
Leg flexion Leg extension Plantarflexion
Methods – Performance tests
Acceleration: 0-15m
(seconds)
Top Speed: 30-60m
(seconds)
Statistical Analysis
1. Determine whether AWD were significantly different from ND
athletes on tests of strength
Independent t-test
2. Determine the strength of association between strength
measures and performance in AWD
Pearson’s Correlations
3. Determine the strength of association between strength
measures and performance in ND
Pearson’s Correlations
Results
• AWD significantly slower compared to ND
• AWD significantly weaker in most affected side
compared to ND
• Low to Moderate correlations between
strength and top speed, and low correlations
between strength and acceleration
Difference between AWD and ND ?
AWD Mean (SD)
ND mean(SD)
Top speed (secs)
4.31(0.64)
3.76** (0.27)
Acceleration (secs)
3.18(0.33)
2.76**(0.19)
AWD Mean (SD)
ND mean(SD)
Flexion more affected side
176.46(68.82)
253.48**(83.82)
Flexion less affected side244.98(65.87)
242.99(76.73)
Extension more affected side
992.72(337.37)
1660.64**(363.60)
Extension less affected side
1398.86(234.30)
1663.84 (426.63)
Plantarflexion more affected side
823.54(266.58)
1508.45**(309.31)
Plantarflexion less affected side
1071.98(264.37)
1457.19**(280.21)
Pearson’s Correlations: strength vs running
performanceTopspeed
AWDAcceleration
AWDTopspeed
NDAcceleration
ND
Flexion more affected side
Pearson Correlation -.131 .174 -.493** -.481**
Sig. (2-tailed) .686 .589 .008 .009
Flexion less affected side
Pearson Correlation -.237 .077 -.331 -.239
Sig. (2-tailed) .459 .813 .085 .221
Extension more affected side
Pearson Correlation -.148 .218 -.089 -.172
Sig. (2-tailed) .646 .496 .653 .382
Extension less affected side
Pearson Correlation -.291 .085 -.062 -.111
Sig. (2-tailed) .359 .793 .756 .574
Plantarflexion more affected side
Pearson Correlation -.318 .133 -.086 -.014
Sig. (2-tailed) .290 .665 .664 .944
Plantarflexion less affected side
Pearson Correlation -.427 -.061 -.111 -.098
Sig. (2-tailed) .146 .843 .573 .621
Discussion
Correlations strength vs performance
R² = 0.119
R² = 0.0124
3.00
3.50
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0.00 500.00 1000.00 1500.00 2000.00 2500.00
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Plantarflex strength
AWD
ND
Linear (AWD)
Linear (ND)
Discussion
• Low associations between strength and
performance may be related to slow isometric
force build up
• Plantarflexion on less affected side potentially
the best predictor of performance (more affected
side important too)
• Stronger trend in top speed: is acceleration
related to coordination or range of motion?
Conclusions
• Early indications that these tests are potentially
valid for use in classification in athletes with
ataxia, athetosis, hypertonia
• More athletes are required to demonstrate the
relative weighting of each test to performance