Thigh muscle activation patterns and dynamic knee valgus at peak ground reaction force during drop jump landings: Reliability, youth competitive alpine skiing-specific reference values and relation to knee overuse complaints
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Date
2021-12
Publication Type
Journal Article
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yes
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Abstract
Objectives
(1) To evaluate the reliability of quantifying thigh muscle activation patterns and dynamic knee valgus during drop jump landings, (2) to provide reference values for female and male youth alpine skiers, and (3) to study their associations with age, anthropometrics, biological maturation and knee overuse complaints.
Design
Cross-sectional biomechanical experiment including questionnaires.
Methods
One hundred fourteen skiers of the under 16 category (main experiment) and twelve healthy participants (reliability experiment) volunteered. Quadriceps-to-hamstring-activation ratio and medial knee displacementat peak ground reaction force during drop jump landings were measured using marker-based motion analysis, force plates and electromyography. Additionally, age, anthropometrics, biological maturation and knee overuse complaints were assessed.
Results
There were good test–retest reliabilities and moderate standardized typical errors for both quadriceps-to-hamstring-activation ratio (intraclass correlation coefficient(3,1) = 0.84 [95% confidence interval: 0.69, 0.94]; standardized typical errors = 0.43 [0.35, 0.56]) and medial knee displacement (intraclass correlation coefficient(3,1) = 0.87 [0.74, 0.95]; standardized typical errors = 0.39 [0.32, 0.50]). Male skiers had a significantly higher quadriceps-to-hamstring-activation ratio (3.9 ± 2.0 vs. 2.9 ± 1.4, p = 0.011), whilst medial knee displacement was comparable to females (12 mm ± 11 mm vs. 13 mm ± 9 mm; p = 0.419). In male skiers, medial knee displacement correlated with anthropometrics and maturity offset; in female skiers, quadriceps-to-hamstring-activation ratio and medial knee displacement were associated with knee overuse complaints (p < 0.05).
Conclusions
Female and male youth skiers use different thigh muscle activation strategies, but show comparable dynamic knee valgus motions during drop jump landings. In females, a combination of increased relative quadriceps activity and medial knee displacement may favour knee overuse complaints.
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published
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Journal / series
Volume
24 (12)
Pages / Article No.
1230 - 1234
Publisher
Elsevier
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Edition / version
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Date collected
Date created
Subject
Athletes; Exercise; Physical functional performance; Testing; Electromyography; Injury prevention
Organisational unit
03822 - Snedeker, Jess G. / Snedeker, Jess G.