Is Hamstring Flexibility Affected in Chronic Ankle Instability
Conditions: Chronic Ankle Instability
Sponsor: Cairo University

 
 
 
 
 
Official Title: Is hamstring flexibility affected in 
chronic ankle instability 
 
Date of document: January 12, 2016 
 
 
 
 
 
 
 
 
 
 
 

Flexibility Deficit in Chronic Ankle Instability 
 
  On Anatomical and Joint Physiological point of view. The ankle complex 
comprises 3 articulations: the talocrural joint, the subtalar joint, and the tibioﬁbular 
joints. These joints work in concert to allow coordinated movement of the rearfoot 
(Hertel, 2002; levangie, 2005). Proximal and distal tibiofibular joints closely linked 
to each other and to the talocrural joint movements (Levangie, 2005). Proximal and 
Distal tibiofibular is plane synovial joint allow gliding movement and the fibula can 
move upward, downward and rotate (Sperber, 2006).  
       This suggests that investigating alterations in arthrokinematics such as the 
proximal tibiofibular joint (mechanical impairment) and its associated structure as 
biceps femoris (functional impairment) may provide greater insight into meaningful 
changes associated with CAI. 
    Payne et al., 1997 conducted that there is lack in the studies that 
consider the aspect of flexibility in CAI cases , Most prospective studies on 
flexibility and injury have focused on larger muscle groups and other types of 
injuries, such as muscle strains Therefore the third purpose of this study is to 
assess the flexibility status in CAI. 
Purposes of the Study  
       This study is aiming to compare the flexibility Deficit between patients with 
Chronic Ankle Instability and non-injured ankle participants 
Hypothesis of the study :  
There will be no flexibility deficit of hamstring in CAI  
 
Methodology 
This study will be conducted at outpatient clinic in faculty of physical therapy in 
Cairo University. 
Design of the study: 
Observational- Case control study 
 

Subjects: 
This study will be conducted on 42 participants, 21 subjects as study group had 
inversion ankle sprain and followed criteria of instability and recruited from 
outpatient clinic at faculty of physical therapy, Cairo University and 21 subjects as 
control group. Their age range from 18-35 years old. All subjects will be asked to 
sign a consent form for confidential issues which approved by research ethical 
committee of faculty of Physical Therapy Cairo University under number 
P.T.REC/012/001312. 
Inclusion Criteria: Based on functional ankle instability questionnaire that was 
modified from one developed by Hubbard and Kaminski, 2002.  
 Generally healthy between age of 18-30 years old. 
  Self-report a past history of unilateral ankle inversion injury within previous 
2 years which had required a period of protected weight bearing and/or 
immobilization 
 The subject perceives that the ankle was chronically weaker, more painful, 
and/or less functional than the other ankle or than before first injury 
 The subject reports a tendency for the ankle to give way or repeatedly turn 
over during functional activity and/or recurrent ankle sprain.  
Exclusion Criteria: 
 No significant history of lower extremity conditions, knee injury, or low 
back dysfunction that required medical or surgical intervention within the 
last year. 
 Current participation in supervised physical rehabilitation. 
 History of hamstring strain injury  
 Bilateral ankle sprain injury  
 Ankle injury within 3 months of participation 
 History of ankle fracture 
 
Instrumentation used for evaluation during the study: 
Flexibility assessment  
     Inclinometer  

    The pendulum (gravity) dependent goniometer was used to measure the angular 
displacement of the hip or knee, depending on the test .The inclinometer was set 
total knee extension recorded as 0 (fig.1) 
 
 
 
Assessment procedures  
    All subjects will be assessed for Hamstring flexibility using knee extension 
test knee extension test has been shown to be a reliable measure of hamstring 
flexibility (Sullivan et al., 1992) found the intratester reliability of the knee 
extension test to be 0.99 by using the inclinometer method. Webright et al., 1997 
also found high intratester (0.98) and intertester (0.98) reliability with the knee 
extension test by using a universal goniometer. (fig.2) 
   The subjects will be in the supine lying position and hip joint will be 
maintained while an inclinometer was placed on the leg 5 cm below the inferior 
border of the patella in line with the tibia (fig.2). The examiner then slowly and 
passively extend the leg while maintaining the thigh against the vertical wooden 
board. The lower extremity not being tested was maintained flat on the table. The 
range of restricted extension in the knee joint was measured by reading the 
inclinometer (ie, total knee extension was recorded as 0").End point is firm 
resistance to further motion will felt and the subject stated that maximum knee 
extension has been reached. (Cajdosik, 1993). The test will be repeated 3 times and 
take highest score (fig.3). 
 

 
Fig 2. O’Sullivan, K., Murray, E., & Sainsbury, D. (2009). The effect of warm-up, static stretching and 
dynamic stretching on hamstring flexibility in previously injured subjects. BMC Musculoskeletal 
Disorders, 10(1), 37. http://doi.org/10.1186/1471-2474-10-37 
 
Fig.3 measuring the end point by inclinometer 
Statistical analysis:  
   Data will be checked for normality using Shapiro-Wilk test and homogeneity. 
Independent t-test will used to analyze the difference in hamstring flexibility 
between the tested groups. Statistical analysis was conducted using the statistical 
package for social studies (SPSS) for windows, version 21 (SPSS, Inc., Chicago, 

IL). The data are presented as Mean ±SD. Significance will determined at p < 0.05. 
and power will set 80.