Fábio Viadanna Serrão

The effect of additional strengthening of hip abductor and lateral rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot study

Objectives: To study the effect of additional strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise rehabilitation programme for patients with the patellofemoral pain syndrome. Design: Randomized controlled pilot trial. Setting: Clinical setting with home programme. Participants: Fourteen patients with patellofemoral pain syndrome. Intervention: The subjects were randomly assigned to the intervention group (strengthening of quadriceps plus strengthening of hip abductor and lateral rotator muscles) or to the control group (strengthening of quadriceps). Both groups participated in a six-week home exercise protocol. Main outcome measures: The perceived pain symptoms, isokinetic eccentric knee extensor, hip abductor and lateral rotator torques and the gluteus medius electromyographic activity were assessed before and after treatment. Parametric and non-parametric tests were used to compare the groups before and after treatment with α=0.05. Results: Only the intervention group improved perceived pain symptoms during functional activities (P=0.02—0.04) and also increased their gluteus medius electromyographic activity during isometric voluntary contraction (P=0.03). Eccentric knee extensors torque increased in both groups (P=0.04 and P=0.02). There was no statistically significant difference in the hip muscles torque in either group. Conclusion: Supplementation of strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise programme provided additional benefits with respect to the perceived pain symptoms during functional activities in patients with patellofemoral pain syndrome after six weeks of treatment.

Trunk, Pelvis, Hip, and Knee Kinematics, Hip Strength, and Gluteal Muscle Activation During a Single-Leg Squat in Males and Females With and Without Patellofemoral Pain Syndrome

STUDY DESIGN Controlled laboratory study using a cross-sectional design. OBJECTIVES To determine whether there are any differences between the sexes in trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during the performance of a single-leg squat in individuals with patellofemoral pain syndrome (PFPS) and control participants. BACKGROUND Though there is a greater incidence of PFPS in females, PFPS is also quite common in males. Trunk kinematics may affect hip and knee function; however, there is a lack of studies of the influence of the trunk in individuals with PFPS. METHODS Eighty subjects were distributed into 4 groups: females with PFPS, female controls, males with PFPS, and male controls. Trunk, pelvis, hip, and knee kinematics and gluteal muscle activation were evaluated during a single-leg squat. Hip abduction and external rotation eccentric strength was measured on an isokinetic dynamometer. Group differences were assessed using a 2-way multivariate analysis of variance (sex by PFPS status). RESULTS Compared to controls, subjects with PFPS had greater ipsilateral trunk lean (mean ± SD, 9.3° ± 5.3° versus 6.7° ± 3.0°; P = .012), contralateral pelvic drop (10.3° ± 4.7° versus 7.4° ± 3.8°; P = .003), hip adduction (14.8° ± 7.8° versus 10.8° ± 5.6°; P<.0001), and knee abduction (9.2° ± 5.0° versus 5.8° ± 3.4°; P<.0001) when performing a single-leg squat. Subjects with PFPS also had 18% less hip abduction and 17% less hip external rotation strength. Compared to female controls, females with PFPS had more hip internal rotation (P<.05) and less muscle activation of the gluteus medius (P = .017) during the single-leg squat. CONCLUSION Despite many similarities in findings for males and females with PFPS, there may be specific sex differences that warrant consideration in future studies and when clinically evaluating and treating females with PFPS.

Effects of Functional Stabilization Training on Pain, Function, and Lower Extremity Biomechanics in Women With Patellofemoral Pain: A Randomized Clinical Trial

STUDY DESIGN Randomized clinical trial. OBJECTIVES To compare the effects of functional stabilization training (FST) versus standard training on knee pain and function, lower-limb and trunk kinematics, trunk muscle endurance, and eccentric hip and knee muscle strength in women with patellofemoral pain. BACKGROUND A combination of hip- and knee-strengthening exercise may be more beneficial than quadriceps strengthening alone to improve pain and function in individuals with patellofemoral pain. However, there is limited evidence of the effectiveness of these exercise programs on the biomechanics of the lower extremity. METHODS Thirty-one women were randomized to either the FST group or standard-training group. Patients attended a baseline assessment session, followed by an 8-week intervention, and were reassessed at the end of the intervention and at 3 months after the intervention. Assessment measures were a 10-cm visual analog scale for pain, the Lower Extremity Functional Scale, and the single-leg triple-hop test. A global rating of change scale was used to measure perceived improvement. Kinematics were assessed during the single-leg squat. Outcome measures also included trunk endurance and eccentric hip and knee muscle strength assessment. RESULTS The patients in the FST group had less pain at the 3-month follow-up and greater global improvement and physical function at the end of the intervention compared to those in the standard-training group. Lesser ipsilateral trunk inclination, pelvis contralateral depression, hip adduction, and knee abduction, along with greater pelvis anteversion and hip flexion movement excursions during the single-leg squat, were only observed in the FST group after the intervention. Only those in the FST group had greater eccentric hip abductor and knee flexor strength, as well as greater endurance of the anterior, posterior, and lateral trunk muscles, after training. CONCLUSION An intervention program consisting of hip muscle strengthening and lower-limb and trunk movement control exercises was more beneficial in improving pain, physical function, kinematics, and muscle strength compared to a program of quadriceps-strengthening exercises alone.

Hip and knee kinematics are associated with pain and self-reported functional status in males and females with patellofemoral pain.

Altered hip and knee kinematics in the frontal and transverse planes may increase patellofemoral joint stress and contribute to the development of patellofemoral pain. The purpose of this cross-sectional study was to evaluate the association among hip and knee kinematics, pain, and self-reported functional status in males and females with patellofemoral pain. 20 males and 20 females with patellofemoral pain participated in this study. 3-dimensional hip and knee kinematics were quantified while performing a step-down task. A visual analogue scale was used to evaluate usual knee pain. The anterior knee pain scale was used to evaluate the knee functional score. For both groups combined, greater usual pain was associated with greater peak hip adduction, hip internal rotation and knee abduction (r=0.54-0.57, P<0.001). Also, modest to low correlations (r=-0.48 to - 0.37, P=0.03-0.08) were found among hip and knee kinematics and functional score. Stepwise regression revealed that peak hip internal rotation and hip adduction were significant predictors of pain, while peak hip adduction was the only predictor of function. Greater hip adduction, hip internal rotation and knee abduction are associated with higher levels of pain and reduced function in males and females with patellofemoral pain.

Effect of functional stabilization training on lower limb biomechanics in women.

PURPOSE This study aimed to verify the effects of functional stabilization training on lower limb kinematics, functional performance, and eccentric hip and knee torques. METHODS Twenty-eight women were divided into a training group (TG; n = 14), which carried out the functional stabilization training during 8 wk, and a control group (CG; n = 14), which carried out no physical training. The kinematic assessment of the lower limb was performed during a single-leg squat, and the functional performance was evaluated by way of the single-leg triple hop and the timed 6-m single-leg hop tests. The eccentric hip abductor, adductor, lateral rotator, medial rotator, and the knee flexor and extensor torques were measured using an isokinetic dynamometer. RESULTS After 8 wk, the TG significantly reduced the values for knee abduction (from -6.86° to 1.49°), pelvis depression (from -10.21° to -7.86°) and femur adduction (from 7.08° to 5.19°) as well as increasing the excursion of femur lateral rotation (from -0.55° to -3.67°). Similarly, the TG significantly increased the values of single-leg triple hop (from 3.52 to 3.92 m) and significantly decreased the values of timed 6-m single-leg hop tests (from 2.43 to 2.14 s). Finally, the TG significantly increased the eccentric hip abductor (from 1.31 to 1.45 N · m · kg(-1)), hip lateral rotator (from 0.75 to 0.91 N · m · kg(-1)), hip medial rotator (from 1.45 to 1.66 N · m · kg(-1)), knee flexor (from 1.43 to 1.55 N · m · kg(-1)), and knee extensor (from 3.46 to 4.40 N · m · kg(-1)) torques. CONCLUSIONS Strengthening of the hip abductor and lateral rotator muscles associated with functional training improves dynamic lower limb alignment and increases the strength and functional performance.

Trunk biomechanics and its association with hip and knee kinematics in patients with and without patellofemoral pain

Patellofemoral pain (PFP) is a common lower extremity condition observed in sports clinics. Recently, it has been suggested that trunk motion could affect hip and knee biomechanics in the frontal plane. Thus, the purpose of the study was compare trunk kinematics, strength and muscle activation between people with PFP and healthy participants. In addition, the associations among trunk biomechanics, hip and knee kinematics were analysed. Thirty people with PFP and thirty pain-free individuals participated. The peak ipsilateral trunk lean, hip adduction, and knee abduction were evaluated with an electromagnetic tracking system, and the surface electromyographic signals of the iliocostalis and external oblique muscle were recorded during single-leg squats. Trunk extension and trunk flexion with rotation isometric strength and side bridge tests were quantified using a handheld dynamometer. Compared with the control group, the PFP group demonstrated increased ipsilateral trunk lean, hip adduction and knee abduction (p = 0.02-0.04) during single-leg squat accompanied with decreased trunk isometric strength (p = < 0.001-0.009). There was no between-group difference in trunk muscle activation. Only in the control group, ipsilateral trunk lean was significantly correlated with hip adduction (r = -0.66) and knee abduction (r = 0.49); also, the side bridge test correlated with knee abduction (r = -0.51). Differences in trunk, hip and knee biomechanics were found in people with PFP. No relationship among trunk, hip and knee biomechanics was found in the PFP group, suggesting that people with PFP show different movement patterns compared to the control group.

Variations in dynamic knee valgus and gluteus medius onset timing in non-athletic females related to hormonal changes during the menstrual cycle ☆

It has been suggested that activities of daily living could contribute to the occurrence of ACL injury in females. Currently, no studies have focused on the lower extremity behavior of a non-athletic population to compare or understand the lower extremity adeptness towards daily movements that mimic athletic tasks. Our hypothesis was that increased knee valgus angles would occur during the late follicular phase of the menstrual cycle accompanied by different onset timing of the gluteus medius muscle. In a controlled laboratory study, 23 non-athletic collegiate females participated and 15 subjects comprised the final sample for statistical analysis. Subjects performed a single leg drop landing maneuver while 3-D knee kinematics and gluteus medius muscle onset timing were assessed throughout three distinct phases of the menstrual cycle, confirmed by blood hormone analysis. In general, knee valgus angles were significantly less in the luteal phase compared to both follicular phases (p<0.005), while differences were not observed for gluteus medius onset timing (p=0.936). As a decreased knee joint valgus angle was observed during the luteal phase, it was hypothesized that the hormone progesterone could significantly influence knee kinematics during a dynamic task. However, such influence was not observed for gluteus medius EMG onset timing as a significant correlation between gluteus medius onset timing and knee valgus angle could not be determined.

Rehabilitation of Patellar Tendinopathy Using Hip Extensor Strengthening and Landing-Strategy Modification: Case Report With 6-Month Follow-up

Study Design Case report. Background Although eccentric exercises have been a cornerstone of the rehabilitation of athletes with patellar tendinopathy, the effectiveness of this intervention is sometimes less than ideal. Athletes with patellar tendinopathy have been shown to have different jump-landing patterns and lower hip extensor strength compared to asymptomatic athletes. To our knowledge, the effectiveness of an intervention addressing these impairments has not yet been investigated. Case Description The patient was a 21-year-old male volleyball athlete with a 9-month history of patellar tendon pain. Pain was measured with a visual analog scale. Disability was measured with the Victorian Institute of Sport Assessment-patella questionnaire. These assessments were conducted before and after an 8-week intervention, as well as at 6 months after the intervention. Hip and knee kinematics and kinetics during drop vertical jump and isometric strength were also measured before and after the 8-week intervention. The intervention consisted of hip extensor muscle strengthening and jump landing strategy modification training. The patient did not interrupt volleyball practice/competition during rehabilitation. Outcomes After the 8-week intervention and at 6 months postintervention, the athlete was completely asymptomatic during sports participation. This favorable clinical outcome was accompanied by a 50% increase in hip extensor moment, a 21% decrease in knee extensor moment, and a 26% decrease in patellar tendon force during jump landing measured at 8 weeks. Discussion This case report provides an example of how an 8-week intervention of hip muscle strengthening and jump-landing modification decreased pain and disability and improved jump-landing biomechanics in an athlete with patellar tendinopathy. Level of Evidence Therapy, level 4. J Orthop Sports Phys Ther 2015;45(11):899-909. Epub 21 Sep 2015. doi:10.2519/jospt.2015.6242.

Electromyographic preactivation pattern of the gluteus medius during weight-bearing functional tasks in women with and without anterior knee pain

BACKGROUND Proximal factors have been proposed to influence the biomechanics of the patellofemoral joint. A delayed or diminished gluteus medius (GM) activation, before the foot contact on the ground during functional activities could lead to excessive femur adduction and internal rotation and be associated with anterior knee pain (AKP). There are few studies on this topic and the results were inconclusive, therefore, it is necessary to investigate the GM preactivation pattern during functional activities. OBJECTIVE To compare the GM electromyographic (EMG) preactivation pattern during walking, descending stairs and in single leg jump task in women with and without AKP. METHODS Nine women clinically diagnosed with AKP and ten control subjects with no history of knee injury participated in this study. We evaluated GM EMG linear envelope before the foot contact on the ground during walking and GM onset time and EMG linear envelope during descending stairs as well as in a single leg vertical jump. Mann-Whitney U tests were used to determine the between-group differences in GM EMG preactivation pattern. RESULTS No between-group differences were observed in GM linear envelope during walking (P=0.41), GM onset time and linear envelope during descending stairs (P=0.17 and P=0.15) and single leg jump (P=0.81 and P=0.33). CONCLUSIONS Women with AKP did not demonstrated altered GM preactivation pattern during functional weight bearing activities. Our results did not support the hypothesis that poor GM preactivation pattern could be associated with AKP.

Test–retest reliability of three-dimensional kinematics using an electromagnetic tracking system during single-leg squat and stepping maneuver

The electromagnetic tracking system (ETS) has been used to analyze three-dimensional (3D) lower limb kinematics. The single-leg squat and stepping maneuver are useful tasks to evaluate lower extremity alignment in a clinical setting. The purpose of this study was to evaluate the test-retest reliability of trunk, pelvis, hip, and knee 3D kinematics using an ETS during single-leg squat and stepping maneuver and compare 3D kinematics between tasks. Twenty healthy volunteers (10 males and 10 females) completed two test sessions 3-5 days apart. Three-dimensional kinematics using an ETS was assessed during single-leg squat and stepping maneuver. Overall, intrarater-intrasession reliability (ICCs=0.83-1.00) and intersession reliabilities (ICCs=0.82-0.97) were high during single-leg squat and stepping maneuver. The intrasession minimal detectable change (MDC) ranged from 1.3° for the knee frontal plane range of motion for single-leg squat to 6.2° for the pelvic transverse range of motion for the stepping maneuver. Intersession MDC values ranged from 1.2° for the ipsilateral trunk lean for the single-leg squat to 8.3° for hip flexion for the stepping maneuver. Healthy participants exhibited greater anterior pelvic tilt, more hip flexion, and less contralateral pelvis forward excursion (p<0.05) during single-leg squat compared with the stepping maneuver. These findings suggest that the 3D kinematics of the trunk, pelvis, hip, and knee using an ETS is reliable during single-leg squat and the stepping maneuver. Minimal detectable change values were low during the evaluated activities. Intertask comparisons revealed differences in hip and pelvis kinematics.