Document Detail

The influence of reduced hamstring length on patellofemoral joint stress during squatting in healthy male adults.
MedLine Citation:
PMID:  19818627     Owner:  NLM     Status:  MEDLINE    
Increased patellofemoral joint (PFJ) stress has been implicated in the development of PFJ pathologies. Previous studies have identified a relationship between reduced hamstring length and patellofemoral pain syndrome. Hamstring stretching is also recommended in the management thereof. However, the relationship between reduced hamstring length and PFJ stress has not been explored in vivo during activities that load the PFJ, such as squatting. The objective of this study was to determine if persons with reduced hamstring length demonstrate increased PFJ stress during squatting compared with individuals without reduced hamstring length. Eight participants with, and eight participants without, reduced hamstring length were assessed to determine their PFJ contact area using magnetic resonance imaging, and their PFJ reaction force during squatting using motion analysis. Data collected were entered into a biomechanical model to calculate medial, lateral and total PFJ stress. It was found that participants with reduced hamstring length had significantly greater total (393.39 Pa/kg vs. 213.01 Pa/kg) and lateral (311.23 Pa/kg vs. 142.55 Pa/kg) PFJ stress at 60 degrees knee flexion during squat descent and ascent (427.75 Pa/kg vs. 255.64 Pa/kg and 337.75 Pa/kg vs. 170.63 Pa/kg, respectively). This was due to significantly increased PFJ reaction force at 60 degrees knee flexion during squat descent (12.18 N/kg vs. 7.21 N/kg) and ascent (13.03 N/kg vs. 8.72 N/kg), and lower medial PFJ contact area at 60 degrees knee flexion (88 mm(2) vs. 160 mm(2)). The results of this study demonstrate a relationship between reduced hamstring length and increased PFJ stress during squatting due to increased PFJ reaction force and reduced medial PFJ contact area.
Enda F Whyte; Kieran Moran; Conor P Shortt; Brendan Marshall
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Publication Detail:
Type:  Journal Article     Date:  2009-10-08
Journal Detail:
Title:  Gait & posture     Volume:  31     ISSN:  1879-2219     ISO Abbreviation:  Gait Posture     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2010-02-03     Completed Date:  2010-05-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9416830     Medline TA:  Gait Posture     Country:  England    
Other Details:
Languages:  eng     Pagination:  47-51     Citation Subset:  IM    
Copyright Information:
Copyright 2009 Elsevier B.V. All rights reserved.
School of Health and Human Performance, Dublin City University, Collins Avenue, Glasnevin, Dublin 9, Ireland.
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MeSH Terms
Analysis of Variance
Femur / physiology*
Imaging, Three-Dimensional / instrumentation
Knee Joint / physiology*
Magnetic Resonance Imaging
Movement / physiology*
Muscle, Skeletal / physiology*
Patella / physiology*
Range of Motion, Articular / physiology
Stress, Mechanical

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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