Theresa H. Nakagawa

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.

Frontal Plane Biomechanics in Males and Females with and without Patellofemoral Pain

PURPOSE The studys purpose was to compare trunk, pelvis, hip, and knee frontal plane biomechanics in males and females with and without patellofemoral pain syndrome (PFPS) during stepping. METHODS Eighty recreational athletes were equally divided into four groups: female PFPS, female controls, male PFPS, and male controls. Trunk, pelvis, hip, and knee frontal plane kinematics and activation of the gluteus medius were evaluated at 15°, 30°, 45°, and 60° of knee flexion during the downward and upward phases of the stepping task. Isometric hip abductor torque was also evaluated. RESULTS Females showed increased hip adduction and knee abduction at all knee flexion angles, greater ipsilateral trunk lean and contralateral pelvic drop from 60° of knee flexion till the end of the stepping task (P = 0.027-0.001), diminished hip abductor torque (P < 0.001), and increased gluteus medius activation than males (P = 0.008-0.001). PFPS subjects presented increased knee abduction at all the angles evaluated; greater trunk, pelvis, and hip motion from 45° of knee flexion of the downward phase till the end of the maneuver; and diminished gluteus medius activation at 60° of knee flexion, compared with controls (P = 0.034-0.001). Females with PFPS showed lower hip abductor torque compared with the other groups. CONCLUSIONS Females presented with altered frontal plane biomechanics that may predispose them to knee injury. PFPS subjects showed frontal plane biomechanics that could increase the lateral patellofemoral joint stress at all the angles evaluated and could increase even more from 45° of knee flexion in the downward phase until the end of the maneuver. Hip abductor strengthening and motor control training should be considered when treating females with PFPS.

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.

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.

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.

The relationship between external knee moments and muscle co-activation in subjects with medial knee osteoarthritis

PURPOSE External knee moments are reliable to measure knee load but it does not take into account muscle activity. Considering that muscle co-activation increases compressive forces at the knee joint, identifying relationships between muscle co-activations and knee joint load would complement the investigation of the knee loading in subjects with knee osteoarthritis. The purpose of this study was to identify relationships between muscle co-activation and external knee moments during walking in subjects with medial knee osteoarthritis. METHODS 19 controls (11 males, aged 56.6±5, and BMI 25.2±3.3) and 25 subjects with medial knee osteoarthritis (12 males, aged 57.3±5.3, and BMI 28.2±4) were included in this study. Knee adduction and flexion moments, and co-activation (ratios and sums of quadriceps, hamstring, and gastrocnemius) were assessed during walking and compared between groups. The relationship between knee moments and co-activation was investigated in both groups. FINDINGS Subjects with knee osteoarthritis presented a moderate and strong correlation between co-activation (ratios and sums) and knee moments. INTERPRETATION Muscle co-activation should be used to measure the contribution of quadriceps, hamstring, and gastrocnemius on knee loading. This information would cooperate to develop a more comprehensive approach of knee loading in this population.

92 Hip, Knee And Ankle Torques In Subjects With And Without Patellar Tendinopathy: A Pilot Study

Introduction Patellar tendinopathy is a common musculoskeletal dysfunction in athletes and it is considered an important cause for physical disability. Previous studies have demonstrated that athletes with patellar tendinopathy present diminished torque generation capacity for knee extension in comparison to asymptomatic athletes.2 Therefore, quadriceps muscle strengthening exercises have been recommended for the rehabilitation of athletes presenting this dysfunction. It is important to consider, however, that the hip and ankle joints are also involved in the dissipation of the ground reaction force during closed kinetic chain activities such as jump-landings. Thus, weakness of the muscles surrounding these joint might result in excessive overload of the knee extensor mechanism. However, to date, no study evaluated the torque generation capacity of the hip and ankle joints of subjects presenting patellar tendinopathy. Therefore, the purpose of this study was to compare the hip, knee and ankle isometric torque between athletes with patellar tendinopathy and asymptomatic controls. Methods Young male and female athletes, 18 to 30 years of age, were recruited from local volleyball, basketball and handball teams. They were submitted to an ultrasonographic (US) evaluation of both patellar tendons by an experienced radiologist. Subjects presenting history or current symptoms in the patellar tendon during tendon-loading tasks (i.e., jumping, squatting) for at least 3 months and presenting patellar tendon abnormalities (PTA)1 were included in the patellar tendinopathy group (PTG; n = 6, 5M and 1F). Asymptomatic subjects with no PTA were included in the control group (CG; n = 6, 4M and 2F). The subjects were submitted to a torque evaluation during isometric hip extension, knee extension and ankle plantar flexion. Straps were used to stabilise the subjects and the handheld dynamometer (Lafayette Instruments, Lafayette, IN, USA). The hip extensor torque was evaluated with the subject lying in prone with the knee in 90º of flexion.3 The knee extensor torque was measured with the subject in supine lying with 30° of knee flexion.4 The ankle plantar flexor torque was evaluated with the subject in prone lying with his foot positioned outside the examining table in a neutral position.3 For each test, 1 practice and 3 experimental trials were performed for 5 seconds, with 15 seconds of rest between contractions. The average normalised peak-force values produced during the 3 trials was normalised to the subject’s body mass and height. Independent t-tests were used for statistical analysis with a significance level of 5%. Results Results demonstrated that the PTG presented smaller torque for hip extension when compared to the control group. No group differences were observed for knee extension and ankle plantar flexion torques (Table 1). Abstract 92 Table 1 Hip, knee and ankle torque (N.m.kg-1.m-1) of subjects with and without patellar tendinopathy. Tendinopathy Group Control Group P Hip 0.77 ± 0.15* 0.98 ± 0.17 0.05 Knee 1.03 ± 0.19 1.18 ± 0.10 0.13 Ankle 0.57 ± 0.11 0.55 ± 0.09 0.75 Data presented as mean ± standard deviation. *p ≤ 0.05 Discussion Previous research has shown that athletes with patellar tendinopathy have smaller knee extensor torque in comparison to asymptomatic controls.2 However, the strength of the hip and ankle joints had not yet been investigated in this population. Our preliminary results showed that athletes with patellar tendinopathy have diminished hip extensor torque in comparison to healthy athletes. This diminished hip strength may be a consequence of a ‘quadriceps dominant’ jump-landing strategy, involving less hip flexion. This strategy increases the demand for ground reaction force dissipation at the knee joint and diminishes the demand at the hip joint.5 Hip strengthening exercises should be encouraged in the rehabilitation of subjects with patellar tendinopathy. References 1 Cook, et al . Scand J Med Sci Sport. 2001;11:321–7 2 Crossley, et al. J Orthop Res. 2007;25:1164–75 3 Fukuchi, et al. Clin Biomech. 2014;29:304–10 4 Willson, Davis J. Sport Rehab. 2009;18:76–90 5 Zhang, et al. Med Sci Sports Exerc. 2000;32:812–9