Lori A. Bolgla

Hip Strength and Hip and Knee Kinematics During Stair Descent in Females With and Without Patellofemoral Pain Syndrome

STUDY DESIGN Cross-sectional. OBJECTIVE To determine if females presenting with patellofemoral pain syndrome (PFPS) from no discernable cause other than overuse demonstrate hip weakness and increased hip internal rotation, hip adduction, and knee valgus during stair descent. BACKGROUND Historically, PFPS has been viewed exclusively as a knee problem. Recent findings have indicated an association between hip weakness and PFPS. Researchers have hypothesized that patients who demonstrate hip weakness would exhibit increased hip internal rotation, hip adduction, and knee valgus during functional activities. To date, researchers have not simultaneously examined hip and knee strength and kinematics in subjects with PFPS to make this determination. METHODS AND MEASURES Eighteen females diagnosed with PFPS and 18 matched controls participated. Strength measures were taken for the hip external rotators and hip abductors. Hip and knee kinematics were collected as subjects completed a standardized stair-stepping task. Independent t tests were used to determine between-group differences in strength and kinematics during stair descent. RESULTS Subjects with PFPS generated 24% less hip external rotator (P = .002) and 26% less hip abductor (P =. 006) torque. No between-group differences (P > .05) were found for average hip and knee transverse and frontal plane angles during stair descent. CONCLUSION Subjects with PFPS had significant hip weakness but did not demonstrate altered hip and knee kinematics as previously theorized. Additional investigations are needed to better understand the association between hip weakness and PFPS etiology.

A literature review of studies evaluating gluteus maximus and gluteus medius activation during rehabilitation exercises

Recently, clinicians have focused much attention on the importance of hip strength for the rehabilitation of not only patients with low back pain but also lower extremity pathology. Properly designing a rehabilitation program for the gluteal muscles requires careful consideration of biomechanical principles, such as length of the external moment arm, gravity, and subject positioning. Understanding the anatomy and function of these muscles also is essential. Electromyography (EMG) provides a useful means to determine muscle activation levels during specific exercises. Descriptions of specific exercises, as they relate to the gluteal muscles, are described. The specific performance of these exercises, the reliability of such EMG measures, and descriptive figures are also detailed. Of utmost importance to practicing clinicians is the interpretation of such data and how it can be best used in exercise prescription when formulating a treatment plan.

Patellofemoral Pain: Proximal, Distal, and Local Factors - 2nd International Research Retreat.

Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.P ain under the kneecap, also known as anterior knee pain or patellofemoral pain, is one of the most common reasons why active people seek healthcare. Each year, 2.5 million runners are diagnosed with patellofemoral pain. Unfortunately, 74% of people with this problem will decrease their overall physical activity levels for at least 5 years after the initial injury, and 70% to 90% of them will experience more than 1 episode of pain. Recently, a panel of 50 experts from 9 countries gathered in Belgium to discuss the potential causes of and best treatments for this condition. A synopsis of this meeting is published in the June 2012 issue of JOSPT and provides new insights and discussion of evidence-based treatments for those who have knee pain.

Patellofemoral Pain: proximal, distal, and local factors

Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.P ain under the kneecap, also known as anterior knee pain or patellofemoral pain, is one of the most common reasons why active people seek healthcare. Each year, 2.5 million runners are diagnosed with patellofemoral pain. Unfortunately, 74% of people with this problem will decrease their overall physical activity levels for at least 5 years after the initial injury, and 70% to 90% of them will experience more than 1 episode of pain. Recently, a panel of 50 experts from 9 countries gathered in Belgium to discuss the potential causes of and best treatments for this condition. A synopsis of this meeting is published in the June 2012 issue of JOSPT and provides new insights and discussion of evidence-based treatments for those who have knee pain.

Reliability of electromyographic methods used for assessing hip and knee neuromuscular activity in females diagnosed with patellofemoral pain syndrome

Patellofemoral pain syndrome (PFPS) is one of the most common, yet misunderstood, knee pathologies. PFPS is thought to result from abnormal patella tracking caused from altered neuromuscular control. Researchers have investigated neuromuscular influences from the gluteus medius (GM), vastus medialis (VM), and vastus lateralis (VL) but with inconsistent findings. A reason for these discrepancies may be from varying methodology. The purpose of this study was to determine the reliability of electromyographic (EMG) methods used to assess amplitudes and timing differences of the GM, VM, and VL in subjects with PFPS. Seven females with PFPS participated. GM, VM, and VL activity was assessed during the stance phase of a stair descent task on two separate occasions. Amplitudes during the different intervals of stance were recorded and expressed as a percent of each muscles maximum voluntary isometric contraction. Muscle onsets at the beginning of stair descent were also determined. VM-GM, VL-GM, and VL-VM onset timing differences were quantified. Intraclass correlation coefficients (ICCs) and standard errors of measurement (SEMs) were calculated to assess between-day reliability. Most EMG measures had acceptable reliability (ICC(3,5)>or=0.70). Although some measures had moderate reliability (ICC<0.70), they had low SEMs, which suggested high measurement precision. These findings support using these methods for examining neuromuscular activity in subjects with PFPS.

Strengthening of the Hip and Core Versus Knee Muscles for the Treatment of Patellofemoral Pain: A Multicenter Randomized Controlled Trial

CONTEXT Patellofemoral pain (PFP) is the most common injury in running and jumping athletes. Randomized controlled trials suggest that incorporating hip and core strengthening (HIP) with knee-focused rehabilitation (KNEE) improves PFP outcomes. However, no randomized controlled trials have, to our knowledge, directly compared HIP and KNEE programs. OBJECTIVE To compare PFP pain, function, hip- and knee-muscle strength, and core endurance between KNEE and HIP protocols after 6 weeks of rehabilitation. We hypothesized greater improvements in (1) pain and function, (2) hip strength and core endurance for patients with PFP involved in the HIP protocol, and (3) knee strength for patients involved in the KNEE protocol. DESIGN Randomized controlled clinical trial. SETTING Four clinical research laboratories in Calgary, Alberta; Chicago, Illinois; Milwaukee, Wisconsin; and Augusta, Georgia. PATIENTS OR OTHER PARTICIPANTS Of 721 patients with PFP screened, 199 (27.6%) met the inclusion criteria (66 men [31.2%], 133 women [66.8%], age = 29.0 ± 7.1 years, height = 170.4 ± 9.4 cm, weight = 67.6 ± 13.5 kg). INTERVENTION(S) Patients with PFP were randomly assigned to a 6-week KNEE or HIP protocol. MAIN OUTCOME MEASURE(S) Primary variables were self-reported visual analog scale and Anterior Knee Pain Scale measures, which were conducted weekly. Secondary variables were muscle strength and core endurance measured at baseline and at 6 weeks. RESULTS Compared with baseline, both the visual analog scale and the Anterior Knee Pain Scale improved for patients with PFP in both the HIP and KNEE protocols (P < .001), but the visual analog scale scores for those in the HIP protocol were reduced 1 week earlier than in the KNEE group. Both groups increased in strength (P < .001), but those in the HIP protocol gained more in hip-abductor (P = .01) and -extensor (P = .01) strength and posterior core endurance (P = .05) compared with the KNEE group. CONCLUSIONS Both the HIP and KNEE rehabilitation protocols produced improvements in PFP, function, and strength over 6 weeks. Although outcomes were similar, the HIP protocol resulted in earlier resolution of pain and greater overall gains in strength compared with the KNEE protocol.

Electromyographic Analysis of Hip Abductor Exercises Performed by a Sample of Total Hip Arthroplasty Patients

Weakness of the hip abductors after total hip arthroplasty may result in pain and/or functional limitation. Non-weight-bearing (NWB) exercises are often performed to target the hip abductors; however, muscle activation of NWB exercises has not been compared to weight-bearing (WB) exercises. Our purpose was to evaluate gluteus medius activation during 2 WB and 2 NWB hip abductor strengthening exercises. Fifteen patients at least 6 weeks post unilateral total hip arthroplasty volunteered for the study. Electromyographic amplitude for each exercise was normalized to each patients maximal voluntary isometric contraction. There were no significant differences in gluteus medius electromyographic amplitudes between the 4 exercises (P = .15). Based on our results, NWB exercises provided no clear benefit in terms of gluteus medius activation when compared to potentially more functional WB exercises in the early postoperative period.

Relative electromyographic activity in trunk, hip, and knee muscles during unilateral weight bearing exercises: Implications for rehabilitation

ABSTRACT Background: Clinicians routinely prescribe unilateral weight bearing exercises to strengthen the lower extremity. Researchers have primarily examined thigh muscle activation with minimal attention to the hip and trunk muscles. The purpose of this study was to quantify trunk, hip, and thigh muscle activation during these types of exercises. Methods: Electromyographic (EMG) activity was collected for the abdominal obliques (AO), lumbar extensors (LE), gluteus maximus (GMX), gluteus medius (GM), and vastus medialis (VM) as subjects performed four unilateral weight bearing exercises. Data were expressed as 100% of a maximum voluntary isometric contraction (% MVIC). Separate analyses of variance with repeated measures were used to identify muscle activity differences across exercise. The sequentially-rejective Bonferroni test was used for all post-hoc analyses. Results: EMG activity for the AO, LE, and GMX was low (5.7–18.9% MVIC) during all the exercises. The GM activity was moderate (21.4–26.5% MVIC) while VM activity was high (40.0–45.2% MVIC). Conclusion: Lower AO and LE activation most likely resulted from subjects maintaining a vertical trunk position over the stance limb during each exercise. The fact that the exercises required greater frontal plane control (from balancing on a single limb) most likely accounted for lower GMX activity. The exercises would provide little, if any, benefit for individuals with AO, LE, or GMX weakness. The unilateral weight bearing exercises would be beneficial for GM neuromuscular re-education and endurance and VM strengthening.

Gender Differences in Core Strength and Lower Extremity Function During the Single-Leg Squat Test

This chapter discusses the principles of core stability in terms of its importance on lower extremity function. The use of the single-leg squat test to measure core stability is described, which is a practical tool that can easily be used in the clinical setting. The test protocol and methods for interpretation of the results are provided. Reliability and validity data are cited. Associations between core strength, neuromuscular activity, and lower extremity function during the test are described. Differences in core strength, lower limb position, and posture between male and female subjects depicted by the single-leg squat are summarized.

Patellofemoral Pain: Proximal, Distal, and Local Factors—2nd International Research Retreat, August 31–September 2, 2011, Ghent, Belgium

Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.P ain under the kneecap, also known as anterior knee pain or patellofemoral pain, is one of the most common reasons why active people seek healthcare. Each year, 2.5 million runners are diagnosed with patellofemoral pain. Unfortunately, 74% of people with this problem will decrease their overall physical activity levels for at least 5 years after the initial injury, and 70% to 90% of them will experience more than 1 episode of pain. Recently, a panel of 50 experts from 9 countries gathered in Belgium to discuss the potential causes of and best treatments for this condition. A synopsis of this meeting is published in the June 2012 issue of JOSPT and provides new insights and discussion of evidence-based treatments for those who have knee pain.