ABSTRACT

The Effects of a Six-week Passive Stretching Protocol on the Iliotibial Band ComplexT. Bowersock, S. Gaydos, B. Hagan, S. Sprockett, D. Cade, PhD.

Ohio University School of Physical Therapy - Athens, OH

OBJECTIVE: To determine whether the administration of a 30-second passive stretching protocol to the iliotibial band (ITB) complex could decrease tightness, therefore increasing the amount of hip adduction in both the straight leg Ober (SLO) and bent leg Ober (BLO) tests with the hip in the flexed (Flex) and extended (Ext) positions.

HYPOTHESIS: A six-week passive stretching protocol to the ITB complex will increase hip adduction as measured by the Ober tests.

SUBJECTS: Twenty female graduate students were recruited in accordance with the Institutional Review Board of Ohio University to participate as subjects in this study. Ten subjects served as the experimental group receiving the stretching exercise while the other ten subjects served as the control group.

RESULTS: The Ober test positions were adequately reliable (ICC: 0.83 – 0.87). The mean gain for hip adduction in the experimental group was 3.1° at four weeks and 3.8° at six weeks. Repeated measures ANOVA showed significant differences after six weeks (p = .003) for three of the four tests (BLO Flex/Ext & SLO Flex). Post-Hoc analysis utilizing the Least Significant Difference test showed a significant difference between pretest and four weeks and six weeks (p = 0.00 – 0.004), but no difference from four weeks to six weeks. Paired t-tests were performed to look at how different hip positions influenced the Ober test. The control group demonstrated no changes across the three test periods, except for SLO Ext which improved and did not represent any significant difference between the control and experimental group.

CONCLUSION: Ober test performance improved as the result of a 30-second stretch once a day, four times per week over four weeks. Non-significant improvement continued to week six. Differences in the Ober test due to hip position indicate that clinicians should be consistent with the hip position they employ during the Ober test. It does not appear necessary to maintain full hip extension while performing the test.

INTRODUCTION

• The iliotibial band (ITB) is a collagenous structure crossing both the hip and knee joints on the lateral thigh. ITB tightness has been associated with numerous musculoskeletal pathologies of the lower extremity and other orthopedic problems.2

• The first procedure to assess ITB length was described by Ober in 1936.5 In the years following, the Bent Leg Ober (BLO) position has become the most frequently used method to determine ITB length. Since then, Kendall created the modified Ober test or straight leg Ober test (SLO) that involves holding the knee of the tested lower extremity in full extension.3

• ITB stretching techniques are commonly incorporated into treatment programs.1 However, research has not addressed whether the ITB has the capability of being stretched or the amount of lengthening that may result. Even though the ITB plays a crucial role in proper lower extremity biomechanics, a void in clinical research arises when looking at stretching or the capabilities of stretching the ITB complex.

•The purpose of this study was to assess the effects of a six-week passive stretching protocol on the ITB complex of female graduate students.

METHOD

Subjects:• Twenty females (24.2 ± 2.1 years old) with a height of 161.3 ± 5.3 cm and a weight of 61.1 ± 7 kg volunteered participation. This study was approved by Ohio University’s Institutional Review Board, and all subjects gave written informed consent prior to participation.

Testing Protocol:• The experimenters took 4 separate measurements including: SLO with the hip in 10° of flexion, SLO with the hip in 10° of extension, BLO with the hip in 10° of flexion and BLO with the hip in 10° of flexion. Measurements were recorded prior to implementation of the stretching protocol, at 4-weeks and after 6-weeks. Two trials of each test was completed.

Stretching Protocol: • Both groups standing posture were examined by the experimenters and an experienced physical therapist to determine which lower extremity was more abducted to be used as the test leg. • The subjects assumed a side-lying position with the non-tested leg against the plinth, and a two-pound cuff weight was secured to the test ankle. The leg was then passively abducted and slightly extended and allowed to fall into adduction while the experimenter stabilized the pelvis.

• A single 30-second stretch was performed four times per week for six weeks.

CONCLUSION

Previous reports in the literature fail to look at the effects of long-term stretching on the TFL/ITB. Findings from this study support the use of TFL/ITB stretching. This study showed that a stretch of the ITB 30sec/day, 4 days per week for 4 weeks produced a significant change in ITB length. Such increase in length may provide relief to numerous LE orthopedic conditions including but not limited to: CMP, ITB friction syndrome, etc. In addition, clinicians must remain consistent when incorporating the Ober test. They must maintain the same hip and knee positions during the test in order for measures to correlate with previous findings. Future research should include replicating this study with a larger number of subjects. This would not only increase the power of the statistics but also the relevance of such findings. In addition, a study needs to be performed on persons with ITB restrictions who have the orthopedic pathologies stated previously in order to determine if the stretch provides any relief.

REFERENCES

1. Gajdosik, R., M. Sandler and H. Marr 2003. Influence of Knee Positions and Gender on the Ober Test for Length of the Iliotibial Band. Clinical Biomechanics 18: 77-79.

2. Gose, J. and P. Schweizer 1989. Iliotibial Band Tightness. The Journal of Orthopedic and Sports Physical Therapy 4: 399-407.

3. Kendall, F., E. MCreary and P. Provance 1993. Muscles Testing and Function. Baltimore, Williams and Wilkins.

4. Kubo, K., et al 2001. Influence of Static Stretching on Viscoelastic Properties of Human Tendon Structures In Vivo. Journal of Applied Physiology. 90: 520-527.

5. Ober, F. 1936. The Role of the Iliotibial Band and Fascia Latae as a Factor in Causation of Low Back Disabilities and Sciatica. Journal of Bone Joint Surgery 18: 105-110.

Picture 1: Subject in stretching position with Experimenter bracing pelvis.

RESULTS

•An ICC statistic ranging from (0.83 – 0.87) demonstrated that the group had good test-retest reliability when repeating the Ober tests. With a good reliability, any change in the experimental group should be a result of the intervention.

•Both groups began at similar baseline measurements. The experimental group showed a significant improvement in Ober test performance at the four and six-week measurements (p < .001). The mean gain in Ober test improvement was 3.1 deg at 4 weeks and 3.8 degs at 6 weeks. Post Hoc Analysis revealed a non-significant difference from 4 to 6 weeks (p =.751-.837) in the experimental group demonstrating a plateau. The control group showed no significant change at either the 4 or 6 week measurement (p = .600 - .840).

•Initially (An initial independent t-test demonstrated that), there were no significant differences between the groups (p = ???). At the 4 and 6 wk measurements, the experimental group was significantly different from the control in 3 of 4 Ober test including BLO flex, BLO ext, and SLO flex (see Fig. B) (p = ???). The difference between SLO ext failed to reach significance (p = .079).

•A paired t-test was performed to look at how different hip positions influence the Ober test (i.e. SLO flex vs. SLO ext). From baseline to post-test, there was a significant correlation in the amount of change in the SLO positions (r = .932; p < .001) as well as the BLO positions (r = .745; p < .001 ). However, the average difference between SLO flex and ext was 2.95 deg and 4.012deg between the BLO positions.

DISCUSSION

• The ITB has been described as a long, nonelastic collagen structure. 2 This interpretation leads readers to believe that the ITB length remains unchanged even after stretching. Consequently, if the ITB length remains the same length, Ober test performance improvements may come from increased length of the attached musculature. …………

• Our stretching protocol was established in part by previous research indicating the increase in length of the hamstrings with static stretching.4 A two-pound cuff weight was added to the ankle to increase the force of the stretch. The pelvis was stabilized prior to stretching to reduce involvement of the lateral trunk flexion and other passive or active structures……..

•Clinicians find ITB tightness by using the Ober test. With our study they can assume that they will find improvements in the Ober test after 4-weeks of stretching. We found a statistical difference in Ober test improvements in the experimental group after 4-weeks, but we cannot determine whether the 3-4 deg difference is a result of increased ITB length or increase TFL and/or Glut max length. In addition, performing this study on a healthy population prevents us from determining if the improvement will make a clinical difference. In relative terms, if you consider the normal ITB length measurements (0° for the bent-leg version and -10° adduction for the straight-leg version), the few degree difference is substantial.

•When evaluating ITB length, clinicians need to consider the position of the hip when performing the Ober test. The results suggest that the number of degrees of Ober test improvements between hip flexion and extension have a strong correlation. However, the degrees of difference between the position suggest that clinicians need remain consistent with the position of the hip during the following evaluations to get a reliable measurement.

• Limitations of the study include the small sample size (n = 20), variability in goniometric measurement (± 3°), possible experimenter bias, and the absence of a long term follow-up assessment to determine if results were maintained.

A) Amount of hip abduction (+)/adduction (-) in the control test group performing the various positions of the Ober test at pre-test, 4 weeks, and 6 weeks. There is no significant change in hip adduction (p >.05). B) Amount of hip abduction(+)/adduction (-) in the experimental test group performing the various positions of the Ober test at pre-test, 4 weeks, and 6 weeks. There is significant change in hip adduction (p>.05) with BLO Flex/Ext and SLO Flex. C) Comparison of BLO Ext control group vs. experimental group hip abduction values. There is significant change in hip adduction (p >.05). D) Comparison of SLO Ext control group vs. experimental group hip adduction values. There is no significant change in hip adduction (p <.05).

Ober Test Means (in Degrees) with SD

Experimental Group Control Group

Pretest 4-weeks 6-weeks Pretest 4-weeks 6-weeks

SLO ext 3.3 + 3.6 -1.5 + 3.5 -1.8 + 2.7 1.2 + 5.0 1.3 + 3.3 -.15 + 2.3

SLO flex 0.9 + 4.7 -5.0 + 4.8 -5.6 + .2.7 -2.7 + 5.0 -1.3 + 1.7 -2.1 + 1.2

BLO ext 7.7 + 3.71 1.3 + 4.0 0.9 + 2.2 5.6 + 4.5 5.7 + 2.9 4.9 + 2.8

BLO flex 3.7 + 3.3 -2.7 + 4.0 -2.4 + 3.1 1.8 + 4.2 2.5 + 2.7 1.0 + 2.5

C. BLO Extension.

0

1

2

3

4

5

6

7

8

9

Pre-Test Week 4 Week 6

Experimental Group

Control Group

D. SLO Extension

-6

-5

-4

-3

-2

-1

0

1

2

Pre-Test Week 4 Week 6

Experimental Group

Control Group

B. Ober Test Performance - Experimental Group

-8

-6

-4

-2

0

2

4

6

8

10

Pre-Test Weeks 4 Week 6

Ob

er

Te

st

Hip

Po

siti

on

SLO Flex

SLO Ext

BLO Flex

BLO Ext

A. Ober Test Performance - Control Group

-4

-3

-2

-1

0

1

2

3

4

5

6

7

Pre-Test Week 4 Week 6

Ob

er

Te

st

Hip

Po

siti

on

SLO Flex

SLO Ext

BLO Flex

BLO Ext