G Model JSAMS-1109; No. of Pages 6
ARTICLE IN PRESS Journal of Science and Medicine in Sport xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Journal of Science and Medicine in Sport journal homepage: www.elsevier.com/locate/jsams
Original research
The effect of the addition of hip strengthening exercises to a lumbopelvic exercise programme for the treatment of non-specific low back pain: A randomized controlled trial Karen D. Kendall a,e,∗ , Carolyn A. Emery b,c , J. Preston Wiley b , Reed Ferber a,d a
Running Injury Clinic, Faculty of Kinesiology, University of Calgary, Canada Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Canada c Departments of Community Health Sciences and Pediatrics, Faculty of Medicine, University of Calgary, Canada d Faculty of Nursing, University of Calgary, Canada e School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, Australia b
a r t i c l e
i n f o
Article history: Received 5 February 2014 Received in revised form 10 August 2014 Accepted 7 November 2014 Available online xxx Keywords: Exercise therapy Chronic disease Rehabilitation Kinematics
a b s t r a c t Objectives: To compare the efficacy of two exercise programmes in reducing pain and disability for individuals with non-specific low back pain and to examine the underlying mechanical factors related to pain and disability for individuals with NSLBP. Design: A single-blind, randomized controlled trial. Methods: Eighty participants were recruited from eleven community-based general medical practices and randomized into two groups completing either a lumbopelvic motor control or a combined lumbopelvic motor control and progressive hip strengthening exercise therapy programme. All participants received an education session, 6 rehabilitation sessions including real time ultrasound training, and a home based exercise programme manual and log book. The primary outcomes were pain (0–100 mm visual analogue scale), and disability (Oswestry Disability Index V2). The secondary outcomes were hip strength (N/kg) and two-dimensional frontal plane biomechanics (◦ ) measure during the static Trendelenburg test and while walking. All outcomes were measured at baseline and at 6-week follow up. Results: There was no statistical difference in the change in pain (¯x = −4.0 mm, t = −1.07, p = 0.29, 95%CI −11.5, 3.5) or disability (¯x = −0.3%, t = −0.19, p = 0.85, 95%CI −3.5, 2.8) between groups. Within group comparisons revealed clinically meaningful reductions in pain for both Group One (¯x = −20.9 mm, 95%CI −25.7, −16.1) and Group Two (¯x = −24.9, 95%CI −30.8, −19.0). Conclusion: Both exercise programmes had similar efficacy in reducing pain. The addition of hip strengthening exercises to a motor control exercise programme does not appear to result in improved clinical outcome for pain for individuals with non-specific low back pain. © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
1. Introduction The World Health Organization reports low back pain as a leading cause of disability worldwide.1 Eighty-five percent of low back pain cases are classified as non-specific (NSLBP) meaning a definitive diagnosis has not been found.2 Systematic reviews investigating the use of exercise for the treatment of NSLBP are unable to support any one type of exercise therapy over another.3 Motor control exercise targeting the transversus abdominus, lumbar multifidus, and pelvic floor musculature is commonly
∗ Corresponding author. E-mail address: [email protected] (K.D. Kendall).
used.4 A recent systematic review concluded that motor control exercise is more efficacious at reducing pain and disability than minimal intervention but no better than any other types of exercise therapy.5 To justify the continued use of motor control exercise and to improve its treatment efficacy, further research is necessary to determine optimal methods of exercise prescription. Despite their anatomical link to the pelvis, surprisingly little focus has been placed on the contribution of the hip musculature to lumbopelvic support. The function of the hip musculature in lower body mechanics is an important part of musculoskeletal health. Weak hip abductor muscles have been linked to atypical lower extremity mechanics,6 and injuries such as patellofemoral pain.7 Associations between low back pain and hip extensor muscle weakness8 and hip muscle fatigability9 have also been
http://dx.doi.org/10.1016/j.jsams.2014.11.006 1440-2440/© 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Kendall KD, et al. The effect of the addition of hip strengthening exercises to a lumbopelvic exercise programme for the treatment of non-specific low back pain: A randomized controlled trial. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.006
G Model
ARTICLE IN PRESS
JSAMS-1109; No. of Pages 6
K.D. Kendall et al. / Journal of Science and Medicine in Sport xxx (2014) xxx–xxx
2
shown. Finally, a simple hip abductor muscle strengthening programme resulted in significant decreases in pain for individuals with NSLBP.10 To date, interventions for NSLBP have been primarily focused on the trunk musculature. The addition of hip exercises to motor control exercise programmes may help to better support hip, pelvis and lumbar spine mechanics whereby reducing pain and disability for individuals with NSLBP. The primary objective of this study was to compare the efficacy of two exercise therapy programmes for the treatment of non-specific low back pain. It was hypothesized that the addition of specific hip strengthening exercises to a lumbopelvic exercise programme would result in greater reductions of pain and disability. The secondary objective of the study was to explore changes in strength and biomechanics thus examining the underlying mechanical factors related to pain and disability. 2. Methods Participants were recruited via eleven community-based medical practices and a newspaper article. Participants contacted the research coordinator for an initial screening for entry (Table 1) and if eligible for the trial, were given an information letter and asked to visit a general practitioner to obtain a referral for participation. Once the referral was received, participants attended the research laboratory for a clinical screening appointment to verify all inclusion and exclusion criteria (Table 1). The sample size estimation was based upon the minimal clinical important difference value of 15 units (mm) on the 0–100 mm VAS identified for individuals with NSLBP11 and the variance estimate based on the work of Williams et al.12 Forty participants per group were required to power the study accounting for an estimated 25% drop out. The trial was approved by the Conjoint Health Research Ethics Board and was registered with ClinicalTrials.gov. Eighty participants were randomized into two groups using a simple randomization involving a computer-generated table of random numbers. An administrator, not involved in the recruitment or evaluation of trial participants, was responsible the randomization schedule and creating the sequentially numbered concealed opaque envelopes. The randomization was concealed from the research personnel. All participants signed an informed consent prior to commencing the trial. The PI and the laboratory research technician (RT) completed all baseline and follow-up testing and were blinded to group allocation. A rehabilitation specialist (RS), a Certified Exercise Physiologist was responsible for delivering the exercise programmes. The primary dependent variables were the change in pain and disability calculated at follow up for the VAS (mm) and Oswestry Disability Index (ODI) (%) scores. Participants were asked to rate
their average pain over the preceding 7 days on the 0–100 mm VAS as a measure of their ‘usual’ pain status. This measure of average weekly pain is a valid and practical measure of pain intensity over a one week period and represents a meaningful measure of ‘usual’ pain in back pain patients.13 The ODI assesses disability as a result of low back pain.14 The test–retest reliability (r = 0.99 within day, ICC: 0.83 within week) have been reported.15 The secondary dependent variables included four bilateral measures of hip abductor, extensor, external rotator, and internal rotator strength, and seven frontal plane biomechanical measures including, trunk lean, pelvic drop, and hip adduction measured during the Trendelenburg test (TT), and trunk, pelvis, and hip excursions measured while walking. Hip strength was measured using a force dynamometer (Lafayette Instruments, Model 01163, Lafayette, IN). For each measure, participants were asked to perform one submaximal trial, and three maximal trials with a 30-s rest period between. The order of testing was randomized to limit potential order bias. The participant’s testing position was secured with straps and using the “make” test method according to methods that have been previously described.7,16 All force (kg) measures were converted into newtons, normalized to body mass, and averaged for both the right and left limbs for use in the statistical analysis. Test–retest reliability of the strength measures was completed on a sample of five healthy controls prior to the commencement of the trial and revealed good to excellent (ICC2,1 , 0.72–0.99) reliability.17 Two-dimensional frontal plane biomechanics were calculated from 3-dimensional marker coordinate data collected using an 8-camera motion capture system (Vicon MX, Vicon Motion Systems Ltd. Centennial, CO, USA), and analysis software (Vicon Nexus 1.6.1, Vicon Motion Systems Ltd, Centennial, CO, USA) using 14 mm retro-reflective markers. The participants first performed a static standing trial, followed by two 30-s Trendelenburg tests (right and left standing legs), and a 2–3 min walking trial during which three, 30-second data collections were recorded. The static TT was performed as per methods previously described by Hardcastle and Nade.18 The raw marker coordinates were used to calculate the frontal plane variables of interest using MATLAB software (Mathworks Inc. Natick, MA, USA). For the TT trials, the biomechanical variables of interest included contralateral pelvic drop (cPD:◦ ), ipsilateral hip adduction angle (iHADD:◦ ), and trunk lean (TRUNK:◦ ). TRUNK was calculated as a segmental angle resulting from the sum of the angles formed by the line between the right and left AC markers and the line between the right and left PSIS markers. cPD was calculated as a segmental angle subtended by the line between the right and left PSIS markers and the horizontal (global) reference plane of the laboratory. iHADD was calculated as a relative angle resulting from
Table 1 Inclusion and exclusion criteria: initial and clinical screening. Initial screening criteria
Clinical screening criteria
Inclusion
Exclusion
Inclusion
• Age between 18 and 65 years
• ‘Red Flag’ symptoms including, a history of major trauma, persistent night pain, bladder or bowel dysfunction, and/or lower extremity neurological deficit. • Scoliosis or Discogenic pathology
• A minimum ‘usual pain’ score 50 mm measured on the 0–100 mm VAS Scale
• Previous surgery to the lumbar spine, abdomen, pelvis, or hip • Use of any radiological interventions or injections in the past 3 months
• Equal leg length (
ARTICLE IN PRESS Journal of Science and Medicine in Sport xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Journal of Science and Medicine in Sport journal homepage: www.elsevier.com/locate/jsams
Original research
The effect of the addition of hip strengthening exercises to a lumbopelvic exercise programme for the treatment of non-specific low back pain: A randomized controlled trial Karen D. Kendall a,e,∗ , Carolyn A. Emery b,c , J. Preston Wiley b , Reed Ferber a,d a
Running Injury Clinic, Faculty of Kinesiology, University of Calgary, Canada Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Canada c Departments of Community Health Sciences and Pediatrics, Faculty of Medicine, University of Calgary, Canada d Faculty of Nursing, University of Calgary, Canada e School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology, Australia b
a r t i c l e
i n f o
Article history: Received 5 February 2014 Received in revised form 10 August 2014 Accepted 7 November 2014 Available online xxx Keywords: Exercise therapy Chronic disease Rehabilitation Kinematics
a b s t r a c t Objectives: To compare the efficacy of two exercise programmes in reducing pain and disability for individuals with non-specific low back pain and to examine the underlying mechanical factors related to pain and disability for individuals with NSLBP. Design: A single-blind, randomized controlled trial. Methods: Eighty participants were recruited from eleven community-based general medical practices and randomized into two groups completing either a lumbopelvic motor control or a combined lumbopelvic motor control and progressive hip strengthening exercise therapy programme. All participants received an education session, 6 rehabilitation sessions including real time ultrasound training, and a home based exercise programme manual and log book. The primary outcomes were pain (0–100 mm visual analogue scale), and disability (Oswestry Disability Index V2). The secondary outcomes were hip strength (N/kg) and two-dimensional frontal plane biomechanics (◦ ) measure during the static Trendelenburg test and while walking. All outcomes were measured at baseline and at 6-week follow up. Results: There was no statistical difference in the change in pain (¯x = −4.0 mm, t = −1.07, p = 0.29, 95%CI −11.5, 3.5) or disability (¯x = −0.3%, t = −0.19, p = 0.85, 95%CI −3.5, 2.8) between groups. Within group comparisons revealed clinically meaningful reductions in pain for both Group One (¯x = −20.9 mm, 95%CI −25.7, −16.1) and Group Two (¯x = −24.9, 95%CI −30.8, −19.0). Conclusion: Both exercise programmes had similar efficacy in reducing pain. The addition of hip strengthening exercises to a motor control exercise programme does not appear to result in improved clinical outcome for pain for individuals with non-specific low back pain. © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
1. Introduction The World Health Organization reports low back pain as a leading cause of disability worldwide.1 Eighty-five percent of low back pain cases are classified as non-specific (NSLBP) meaning a definitive diagnosis has not been found.2 Systematic reviews investigating the use of exercise for the treatment of NSLBP are unable to support any one type of exercise therapy over another.3 Motor control exercise targeting the transversus abdominus, lumbar multifidus, and pelvic floor musculature is commonly
∗ Corresponding author. E-mail address: [email protected] (K.D. Kendall).
used.4 A recent systematic review concluded that motor control exercise is more efficacious at reducing pain and disability than minimal intervention but no better than any other types of exercise therapy.5 To justify the continued use of motor control exercise and to improve its treatment efficacy, further research is necessary to determine optimal methods of exercise prescription. Despite their anatomical link to the pelvis, surprisingly little focus has been placed on the contribution of the hip musculature to lumbopelvic support. The function of the hip musculature in lower body mechanics is an important part of musculoskeletal health. Weak hip abductor muscles have been linked to atypical lower extremity mechanics,6 and injuries such as patellofemoral pain.7 Associations between low back pain and hip extensor muscle weakness8 and hip muscle fatigability9 have also been
http://dx.doi.org/10.1016/j.jsams.2014.11.006 1440-2440/© 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Kendall KD, et al. The effect of the addition of hip strengthening exercises to a lumbopelvic exercise programme for the treatment of non-specific low back pain: A randomized controlled trial. J Sci Med Sport (2014), http://dx.doi.org/10.1016/j.jsams.2014.11.006
G Model
ARTICLE IN PRESS
JSAMS-1109; No. of Pages 6
K.D. Kendall et al. / Journal of Science and Medicine in Sport xxx (2014) xxx–xxx
2
shown. Finally, a simple hip abductor muscle strengthening programme resulted in significant decreases in pain for individuals with NSLBP.10 To date, interventions for NSLBP have been primarily focused on the trunk musculature. The addition of hip exercises to motor control exercise programmes may help to better support hip, pelvis and lumbar spine mechanics whereby reducing pain and disability for individuals with NSLBP. The primary objective of this study was to compare the efficacy of two exercise therapy programmes for the treatment of non-specific low back pain. It was hypothesized that the addition of specific hip strengthening exercises to a lumbopelvic exercise programme would result in greater reductions of pain and disability. The secondary objective of the study was to explore changes in strength and biomechanics thus examining the underlying mechanical factors related to pain and disability. 2. Methods Participants were recruited via eleven community-based medical practices and a newspaper article. Participants contacted the research coordinator for an initial screening for entry (Table 1) and if eligible for the trial, were given an information letter and asked to visit a general practitioner to obtain a referral for participation. Once the referral was received, participants attended the research laboratory for a clinical screening appointment to verify all inclusion and exclusion criteria (Table 1). The sample size estimation was based upon the minimal clinical important difference value of 15 units (mm) on the 0–100 mm VAS identified for individuals with NSLBP11 and the variance estimate based on the work of Williams et al.12 Forty participants per group were required to power the study accounting for an estimated 25% drop out. The trial was approved by the Conjoint Health Research Ethics Board and was registered with ClinicalTrials.gov. Eighty participants were randomized into two groups using a simple randomization involving a computer-generated table of random numbers. An administrator, not involved in the recruitment or evaluation of trial participants, was responsible the randomization schedule and creating the sequentially numbered concealed opaque envelopes. The randomization was concealed from the research personnel. All participants signed an informed consent prior to commencing the trial. The PI and the laboratory research technician (RT) completed all baseline and follow-up testing and were blinded to group allocation. A rehabilitation specialist (RS), a Certified Exercise Physiologist was responsible for delivering the exercise programmes. The primary dependent variables were the change in pain and disability calculated at follow up for the VAS (mm) and Oswestry Disability Index (ODI) (%) scores. Participants were asked to rate
their average pain over the preceding 7 days on the 0–100 mm VAS as a measure of their ‘usual’ pain status. This measure of average weekly pain is a valid and practical measure of pain intensity over a one week period and represents a meaningful measure of ‘usual’ pain in back pain patients.13 The ODI assesses disability as a result of low back pain.14 The test–retest reliability (r = 0.99 within day, ICC: 0.83 within week) have been reported.15 The secondary dependent variables included four bilateral measures of hip abductor, extensor, external rotator, and internal rotator strength, and seven frontal plane biomechanical measures including, trunk lean, pelvic drop, and hip adduction measured during the Trendelenburg test (TT), and trunk, pelvis, and hip excursions measured while walking. Hip strength was measured using a force dynamometer (Lafayette Instruments, Model 01163, Lafayette, IN). For each measure, participants were asked to perform one submaximal trial, and three maximal trials with a 30-s rest period between. The order of testing was randomized to limit potential order bias. The participant’s testing position was secured with straps and using the “make” test method according to methods that have been previously described.7,16 All force (kg) measures were converted into newtons, normalized to body mass, and averaged for both the right and left limbs for use in the statistical analysis. Test–retest reliability of the strength measures was completed on a sample of five healthy controls prior to the commencement of the trial and revealed good to excellent (ICC2,1 , 0.72–0.99) reliability.17 Two-dimensional frontal plane biomechanics were calculated from 3-dimensional marker coordinate data collected using an 8-camera motion capture system (Vicon MX, Vicon Motion Systems Ltd. Centennial, CO, USA), and analysis software (Vicon Nexus 1.6.1, Vicon Motion Systems Ltd, Centennial, CO, USA) using 14 mm retro-reflective markers. The participants first performed a static standing trial, followed by two 30-s Trendelenburg tests (right and left standing legs), and a 2–3 min walking trial during which three, 30-second data collections were recorded. The static TT was performed as per methods previously described by Hardcastle and Nade.18 The raw marker coordinates were used to calculate the frontal plane variables of interest using MATLAB software (Mathworks Inc. Natick, MA, USA). For the TT trials, the biomechanical variables of interest included contralateral pelvic drop (cPD:◦ ), ipsilateral hip adduction angle (iHADD:◦ ), and trunk lean (TRUNK:◦ ). TRUNK was calculated as a segmental angle resulting from the sum of the angles formed by the line between the right and left AC markers and the line between the right and left PSIS markers. cPD was calculated as a segmental angle subtended by the line between the right and left PSIS markers and the horizontal (global) reference plane of the laboratory. iHADD was calculated as a relative angle resulting from
Table 1 Inclusion and exclusion criteria: initial and clinical screening. Initial screening criteria
Clinical screening criteria
Inclusion
Exclusion
Inclusion
• Age between 18 and 65 years
• ‘Red Flag’ symptoms including, a history of major trauma, persistent night pain, bladder or bowel dysfunction, and/or lower extremity neurological deficit. • Scoliosis or Discogenic pathology
• A minimum ‘usual pain’ score 50 mm measured on the 0–100 mm VAS Scale
• Previous surgery to the lumbar spine, abdomen, pelvis, or hip • Use of any radiological interventions or injections in the past 3 months
• Equal leg length (
