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

Women with patellofemoral pain show changes in trunk and lower limb sagittal movements during single-leg squat and step-down tasks

BACKGROUND

Changes in the trunk and lower limbs' sagittal movements may cause patellofemoral pain (PFP) because they influence the forces acting on this joint.

OBJECTIVES

To compare trunk and lower limb sagittal kinematics between women with and without PFP during functional tests and to verify whether sagittal trunk kinematics are correlated with those of the knees and ankles.

METHODS

A total of 30 women with PFP and 30 asymptomatic women performed single-leg squat (SLS) and step-down (SD) tests and were filmed by a camera in the sagittal plane. The trunk inclination angle, forward knee displacement, and ankle angle were calculated.

RESULTS

The PFP group exhibited less trunk flexion (SLS, p = .006; SD, p = .016) and greater forward knee displacement (SLS, p = .001; SD, p = .004) than the asymptomatic group; there was no significant difference in ankle angle (SLS, p = .074; SD, p = .278). Correlation analysis revealed that decreased trunk flexion was associated with increased forward knee displacement (SLS, r = -0.439, p = .000; SD, r = -0.365, p = .004) and ankle dorsiflexion (SLS, r = -0.339, p = .008; SD, r = -0.356, p = .005).

CONCLUSION

Women with PFP present kinematic alterations of the trunk and knee in the sagittal plane during unipodal activities. Furthermore, the trunk and lower limb sagittal movements were interdependent.

Motor alterations along the kinetic chain in amateur volleyball and handball athletes with shoulder pain: An observational comparative study

Overhead sports overload the shoulder complex due to movement repetition and the great amount of force created during the athletic motion, which may cause adaptations in the shoulder and lead to shoulder pain. However, overhead movements include the kinetic chain, and alterations in some of the structures throughout the kinetic chain may increase stress on the shoulder complex and be associated with shoulder pain.

PURPOSE

To compare kinetic chain components in overhead athletes with and without shoulder pain.

METHODS

Forty-one volleyball and handball athletes (21 with and 20 without shoulder pain) were included and assessed for hip internal (IR) and external rotation (ER) range of motion (ROM), hip and trunk isometric strength, trunk endurance and neuromuscular control of the lower and upper limbs (Y balance test).

RESULTS

Athletes with shoulder pain showed smaller IR ROM in both hips, lower endurance time for trunk extensors and flexors, decreased reach distance in the anterior and posteromedial direction, as well as a smaller composite score in the Y balance test (p < 0.05).

CONCLUSION

Volleyball and handball athletes with shoulder pain showed changes in ROM throughout the kinetic chain in addition to lower core endurance, and decreased neuromuscular control of lower limbs.

Core stabilisation exercises reduce chronic low back pain in Air Force fighter pilots: a randomised controlled trial

BACKGROUND

There is evidence that core stabilisation, strength and endurance training contribute to reduce low back pain in the general population. However, we are not aware of the effect of these exercises on fighter aviation pilots. Therefore, the present study aims to investigate the effects of an exercise protocol on chronic low back pain in Brazilian Air Force fighter pilots. Changes in neck pain, lumbar disability, range of motion, strength and resistance were also investigated.

METHODS

Fourteen participants with chronic low back pain were randomised into two groups: stabilisation exercise group (SEG-n=7), exercise protocol twice a week for 12 weeks) and the regular exercise group (REG-n=7), which performed their own usual exercise routine. The evaluations were carried out before and after the training period. The primary outcome was the intensity of low back pain and the secondary outcomes were cervical pain, functional disability, range of motion, maximum isometric strength and trunk muscle resistance.

RESULTS

The SEG had a significant reduction in low back pain compared with the REG (difference of 2.3 points, p=0.04) and a lower rate of cervical pain (difference of 2.5 points, p=0.01) at the end of the protocol. Maintenance of trunk muscle strength was also observed in the SEG over the period, while the REG presented a decrease in flexural strength to the right side (difference between groups: -3.7%, p=0.04). There were no differences in the rates of disability, range of motion or resistance to fatigue between groups.

CONCLUSIONS

The stabilisation exercise programme focused on the core muscles was successful in decreasing the fighter pilots' chronic lumbar pain. Pilots are normally active; however, our results indicate that specific trunk training programmes should be offered considering the work needs of these subjects.

CLINICAL TRIALS

'Exercise protocol for pilots with back pain' (registered: 09 October 2018)-NCT03713814 (https://clinicaltrials.gov/ct2/show/NCT03713814).

Unlocking the Potential: Increasing Muscle Strength in Lower Limbs of Youth Soccer Players over Five Weeks through Mat Pilates Training-A Pilot Study

The interest in soccer generally starts during childhood, with children and young people often looking for opportunities in sports. New exercise techniques can be effective in improving training. The aim of this study was to compare the effects on the strength and physical posture of a group practicing Pilates with another not practicing Pilates, both undergoing continuous football training. In this controlled randomized clinical trial, the participants were 15 soccer club members, who had a training frequency of least three times weekly. The sample was divided into a control group (n = 7) of players who did not undergo any therapeutic intervention (only the usual training) and a Pilates group (n = 8) of players who participated in the mat Pilates program. The intervention consisted of fifteen sessions. Postural evaluations were performed using biophotogrammetry and force analysis. Significant improvements were obtained in terms of increased muscle strength (p = 0.001) for the Pilates group, but there were no significant postural alterations when comparing the two groups. Five weeks of mat Pilates was sufficient to increase lower limb muscle strength in young football players. This pilot study indicates that Mat Pilates as a method that could be planned to be included in training.

Persons with patellofemoral pain exhibit altered hip abductor muscle recruitment while performing hip abductor exercises

INTRODUCTION

Strengthening of the hip abductors has been advocated for persons with patellofemoral pain (PFP). It is not clear if these individuals activate the hip abductor muscles appropriately to achieve the desired therapeutic effects.

OBJECTIVE

To compare activation of the hip abductor muscles between persons with and without PFP during the performance of hip abductor exercises.

METHODS

Thirty-two individuals participated (12 with PFP and 20 without PFP). The average age (± standard deviation) was 29.7 ± 5.9 years for the PFP group and 28.1 ± 6.9 for the control group. Electromyographic (EMG) signals from the gluteus medius (GMED), superior gluteus maximus (SUP-GMAX), and tensor fascia lata (TFL) were obtained using fine-wire electrodes while participants performed 11 different exercises. Normalized EMG activity of each muscle was compared between groups across all exercises.

RESULTS

When averaged across all exercises, persons with PFP exhibited significantly greater EMG activity of TFL (mean = 25.3% MVIC; 95% CI = 19.2, 31.3) compared to those without PFP (mean = 17.6% MVIC; 95% CI = 12.8, 22.4) and significantly lower EMG activity of SUP-GMAX (mean = 16.4% MVIC; 95% CI = 11.0, 22.0) compared to those without PFP (mean = 25.4% MVIC; 95% CI = 21.0, 29.8). Persons with PFP exhibited lower EMG activity of GMED, but only for 3 out of the 11 exercises evaluated (hip abduction, hip hike, step-up).

CONCLUSION

Compared to persons without PFP, those with PFP exhibited activation differences during the performance of exercises used to target the hip abductors. Our results highlight the need for activation training prior to the initiation of strengthening exercises to achieve desired therapeutic effects.

Activation, strength, and resistance: Which variables predict the kinematics of women with and without patellofemoral pain?

INTRODUCTION

Investigating the possible relationship between neuromuscular changes and movement alterations could help to describe the mechanisms underlying patellofemoral pain (PFP).

OBJECTIVE

To investigate whether activation and muscle strength of the trunk and lower limb and muscle resistance of the trunk predict the knee frontal and trunk sagittal kinematics in women with and without PFP.

METHOD

Sixty women (PFP, n = 30; asymptomatic, n = 30) underwent the single-leg squat test to collect electromyographic and kinematic data. Activation of transversus abdominis/internal oblique, gluteus medius (GMed), and vastus medialis oblique (VMO); knee frontal and trunk sagittal angles were analyzed. Participants also underwent maximal isometric tests to determine lateral trunk, hip abductor, and knee extensor torques and performed a lateral trunk resistance test. Multiple regression was used to determine predictive models.

RESULTS

In the PFP group, knee frontal angle (R2 = 0.39, p = 0.001) was predicted by GMed activation (β = 0.23, p = 0.000) and hip abductor torque (β = 0.08, p = 0.022). No variable was able to predict trunk sagittal kinematics in this group. In the asymptomatics, knee frontal angle (R2 = 0.16, p = 0.029) was predicted by hip abductor torque (β = 0.07, p = 0.029), while trunk sagittal angle (R2 = 0.24, p = 0.024) was predicted by VMO activation (β = 0.12, p = 0.016).

CONCLUSION

Kinematics is predicted by the muscles acting in the respective planes, such that hip abductors capacities are related to the knee frontal alignment in both groups, and that of the VMO is related to the trunk sagittal alignment only in asymptomatic women.

Prevention of Secondary Injury after Anterior Cruciate Ligament Reconstruction: Relationship between Pelvic-Drop and Dynamic Knee Valgus

(1) Background: Optimal neuromuscular, Lumbo-Pelvic-Hip Complex, and lower extremity control are associated with decreased risk factors for secondary anterior cruciate ligament (ACL) injury. This study aimed to analyze any asymmetries and malalignments in the Lumbo-Pelvic-Hip Complex and the lower limbs at 6 months after ACL reconstruction (ACLR). (2) Methods: We conducted an exploratory retrospective observational single-center study in patients during the outpatient postoperative rehabilitation program at ICOT (Latina, Italy). From January 2014 to June 2020, 181 patients were recruited, but only 100 patients (86 male 28 ± 0.6 years, 178 ± 0.5 height; 14 female 24 ± 2.0 years, 178 ± 3.0 height) were eligible for the inclusion criteria and studied 6 months after ACL reconstruction surgery. (3) Statistical analysis: Student's t-tests and Pearson's product-moment correlation coefficient were used to determine significant differences between affected and non-affected limbs and variables' association. (4) Results: The study shows a decrease in neuromuscular control of the Lumbo-Pelvic-Hip Complex and dynamic adaptive valgus of the knee at 6 months after ACLR (mean difference between pathological and healthy limb of dynamic adaptive valgus was -10.11 ± 8.19° 95% CI -14.84 to -9.34; mean value was 16.3 ± 6.8° 95% CI 14.04 to 18.55 for healthy limb and 4.2 ± 3.1° 95% CI 3.15 to 5.21 for pathological limb, p < 0.0001). The results also showed a relationship between dynamic adaptive valgus and contralateral pelvic drop (r = 0.78, 95% CI 0.62 to 0.88, magnitude of correlation very large). (5) Conclusions: The analysis showed an associative correlation between decreased postural control of the pelvic girdle and dynamic adaptive valgus of the knee in 38% of patients; this study highlights the usefulness of the Single-Leg Squat Test (SLST) as a clinical/functional assessment to evaluate the rehabilitation process and as a preventive tool to reduce the risk of second ACL injuries during the return to sport.

Adding neuromuscular training to a strengthening program did not produce additional improvement in clinical or kinematic outcomes in women with patellofemoral pain: A blinded randomised controlled trial

BACKGROUND

Patellofemoral pain (PFP) is a knee pain condition with multifactorial aetiology, twice common in women. The recommended conservative treatment is based on strengthening of the core, hip, and knee musculatures. Addition of neuromuscular training to a strengthening protocol might provide further benefits on pain, function, and kinematics in PFP individuals. However, evidence for the effectiveness of this protocol is lacking.

OBJECTIVE

To investigate whether adding neuromuscular training to strengthening program could provide any additional improvements of pain, function, and kinematics in PFP women.

METHODS

71 PFP women were randomly into two groups and submitted to different interventions for 12 weeks. The strengthening group (SG) performed strengthening exercises for the trunk, hip, and knee muscles, while the neuromuscular training group (NMTG) performed the same exercises as SG, plus neuromuscular training from the 4th week onwards. The primary outcomes were pain intensity, function, and 2-D kinematics of the trunk and lower limb. The secondary outcomes were isometric muscle strength and patient satisfaction level. All outcomes were evaluated at 12 weeks, immediately post-treatment.

RESULTS

At 12 weeks, there was no evidence of between-group differences for any outcome, but both interventions provided clinically significant improvements for pain intensity (SG: mean difference -3.9, 95% confidence interval [CI] -5.0, -2.9; NMTG: mean difference -3.1, 95% CI -4.1, -2.0) and function (SG: mean difference 15.3, 95% CI 11.5, 19.2; NMTG: mean difference 16.9, 95% CI 13.2, 20.7).

CONCLUSION

Neuromuscular training did not produce any additional benefits for pain, function, or kinematics at 12 weeks of treatment.

Trunk Biomechanics in Individuals with Knee Disorders: A Systematic Review with Evidence Gap Map and Meta-analysis

BACKGROUND

The trunk is the foundation for transfer and dissipation of forces throughout the lower extremity kinetic chain. Individuals with knee disorders may employ trunk biomechanical adaptations to accommodate forces at the knee or compensate for muscle weakness. This systematic review aimed to synthesize the literature comparing trunk biomechanics between individuals with knee disorders and injury-free controls.

METHODS

Five databases were searched from inception to January 2022. Observational studies comparing trunk kinematics or kinetics during weight-bearing tasks (e.g., stair negotiation, walking, running, landings) between individuals with knee disorders and controls were included. Meta-analyses for each knee disorder were performed. Outcome-level certainty was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE), and evidence gap maps were created.

RESULTS

A total of 81 studies investigating trunk biomechanics across six different knee disorders were included (i.e., knee osteoarthritis [OA], total knee arthroplasty [TKA], patellofemoral pain [PFP], patellar tendinopathy [PT], anterior cruciate ligament deficiency [ACLD], and anterior cruciate ligament reconstruction [ACLR]). Individuals with knee OA presented greater trunk flexion during squatting (SMD 0.88, 95% CI 0.58-1.18) and stepping tasks (SMD 0.56, 95% CI 0.13-.99); ipsilateral and contralateral trunk lean during walking (SMD 1.36; 95% CI 0.60-2.11) and sit-to-stand (SMD 1.49; 95% CI 0.90-2.08), respectively. Greater trunk flexion during landing tasks in individuals with PFP (SMD 0.56; 95% CI 0.01-1.12) or ACLR (SMD 0.48; 95% CI 0.21-.75) and greater ipsilateral trunk lean during single-leg squat in individuals with PFP (SMD 1.01; 95% CI 0.33-1.70) were also identified. No alterations in trunk kinematics of individuals with TKA were identified. Evidence gap maps outlined the lack of investigations for individuals with PT or ACLD, as well as for trunk kinetics across knee disorders.

CONCLUSION

Individuals with knee OA, PFP, or ACLR present with altered trunk kinematics in the sagittal and frontal planes. The findings of this review support the assessment of trunk biomechanics in these individuals in order to identify possible targets for rehabilitation and avoidance strategies.

TRIAL REGISTRATION

PROSPERO registration number: CRD42019129257.

Moderate reliability of the lateral step down test amongst experienced and novice physical therapists

BACKGROUND/INTRODUCTION

The lateral step-down test is used to appraise movement quality in patients with patellofemoral pain (PFP), however, it is unclear if reliability of the test is affected by physical therapist experience.

OBJECTIVE

Determine if there is a difference in reliability between 'experienced' and 'novice' physical therapists appraising movement quality of patients with PFP during the lateral step-down test.

METHODS

Three 'experienced' and 3 'novice' physical therapists analyzed movement quality of 22 participants [mean age (SD) 28.25 (6.5) years] with PFP. Physical therapists viewed two-dimensional videos of participants performing the lateral step-down test and appraised the quality with a score (0-1 = 'good'; 2-3 = 'fair', and 4-5 = 'poor') at baseline and 1 week. Inter- and intra-rater reliability were calculated with kappa and percent agreement. Differences between the groups were assessed with the chi-square test with an a priori alpha level of < 0.05.

RESULTS

Inter- and intra-rater reliability ranged from fair to moderate (ĸ = 0.40-0.65). There was no difference in reliability between 'experienced' and 'novice' physical therapists at baseline (p = .13) or 1 week post testing (p = .94).

CONCLUSIONS

There was no difference in reliability between 'experienced' and 'novice' physical therapists using categories to appraise movement quality during the lateral step-down test for patients with chronic PFP.

The association and reliability of the frontal plane projection angle during the lateral step down test on knee function in patients with patellofemoral pain

BACKGROUND

The lateral step-down test is used by physical therapists (PT) to identify movement faults in patients with patellofemoral pain (PFP). The FPPA is a measure of knee valgus and PTs have access to open source video analysis software and high quality smart phones and video cameras to implement 2D video analysis into practice. The purpose of our study was to determine the reliability of PTs measuring the frontal plane projection angle (FPPA) during the lateral step-down test, and to determine if the FPPA was associated with pain, self-reported knee function and fear of movement.

METHODS

Twenty-two subjects (mean age[SD] = 27.8 [6.6] years, females n = 14, males n = 8) with PFP were analyzed by six PTs using 2D video analysis software. The FPPA was measured during the lateral step down test. Numeric Pain Rating Scale (NPRS), Anterior Knee Pain Scale (AKPS) and the Tampa Scale of Kinesiophobia (TSK) were collected. Intraclass correlation (ICC) was used to assess for PT measurement reliability. Correlations between outcomes were calculated using Spearman correlation coefficient and standard error of measurement (SEM) and minimal detectable change (MDC) were reported.

RESULTS

Reliability amongst PTs measuring the FPPA was good (ICC [95 %CI] = 0.85 [0.72-0.93]; SEM = 3.33°, MDC = 9.20°). There were no significant correlations (p > 0.05) between FPPA and NPRS(ρ = -0.046), AKPS(ρ = 0.066), or TSK(ρ = -0.204).

CONCLUSIONS

Although reliability measuring FPPA was good, the large SEM and MDC associated with this measurement may limit its clinical utility in those with PFP.

Strength, Flexibility and Postural Control of the Trunk and Lower Body in Participants with and without Patellofemoral Pain

Patellofemoral pain (PFP) is a frequent knee condition. The aim of this study was to investigate strength, flexibility and postural control in people with and without PFP. Fifty-five participants between 14 and 54 years of age (PFP = 18, control group = 37) were included. Strength and flexibility for all trunk, hip, knee and ankle muscle groups were measured along with postural control outcomes. Analyses were conducted based on the “affected” and “non-affected” leg within-group and between-groups. Between-groups analysis demonstrated a statistically lower strength of trunk muscles (range: 35.8–29.3%, p < 0.001), knee extensors (20.8%, p = 0.005) and knee flexors (17.4%, p = 0.020) in PFP participants. Within-group analysis proved an 8.7% (p = 0.018) greater hip internal rotation strength and ankle extension flexibility (p = 0.032) of the “affected side” in PFP participants. This was, to our knowledge, the first study to investigate the strength of all trunk muscle groups. The results indicate that participants with PFP exhibit impaired strength of trunk muscle groups, along with knee muscle deficits, which may present a rehabilitation target. Clinicians should consider implementing trunk strengthening exercises into PFP programs along with knee-targeting exercise programs.

Trunk muscle endurance in individuals with and without patellofemoral pain: Sex differences and correlations with performance tests

OBJECTIVES

To compare trunk muscle endurance among females and males with and without patellofemoral pain (PFP), and to investigate the correlations between trunk muscle endurance and performance of the single leg hop test (SLHT) and forward step-down test (FSDT).

DESIGN

Cross-sectional.

SETTING

Laboratory-based study.

PARTICIPANTS

110 females and 38 males with PFP, 61 females and 31males without PFP.

MAIN OUTCOME MEASURES

Anterior and lateral trunk muscle endurance were assessed with the prone and bilateral side-bridge tests, respectively. Performance during the SLHT and FSDT was also assessed.

RESULTS

Lower anterior and lateral trunk muscle endurance were identified in females (p < .001; d = -0.74 to -0.86), but not in males (p ≥ .806; d = -0.04 to 0.05) with PFP as compared to sex-matched controls. Moderate to large, positive correlations between anterior and lateral trunk muscle endurance with performance in the SLHT and FSDT were identified in females (r = .27 to .50; p < .004) and males (r = 0.27 to 0.59; p < .031) with PFP and females without PFP (r = 0.26 to 0.40; p < .044).

CONCLUSION

Our findings highlight that assessing trunk muscle endurance is advised in females with PFP. Trunk muscle endurance of individuals with PFP may have a role in the performance of hopping and stepping down tasks.

Factors associated with low back pain in air force fighter pilots: a cross-sectional study

INTRODUCTION

Low back pain in military pilots is a frequent condition which constantly leads to absences from work, decreased concentration and performance during flight, as well as changes in work functions.

METHODS

This is a cross-sectional analytical study including 28 fighter pilots who underwent an evaluation comprising muscle strength and fatigue resistance, trunk mobility and application of questionnaires to identify associated clinical factors.

RESULTS

It was observed that 68% of the pilots reported low back pain with an average pain intensity of 3.7 at numerical pain scale in the last week. No significant differences were observed regarding the range of motion and trunk muscle strength when pilots with low back pain were compared with asymptomatic pilots. However, lateral right trunk muscle (mean difference=16, 95% CI 0.6 to 33.0]) and lateral left trunk muscle (mean difference=22, 95% CI 1 to 44) fatigue sooner in pilots with low back pain when the two groups were compared (p=0.04 for both).

CONCLUSION

There was a high rate of low back pain complaints among fighter pilots. There was also a significant reduction in fatigue resistance of the lateral trunk muscles in symptomatic pilots when compared with asymptomatic pilots. These factors must be considered in the physical training of this population.

Effect of static knee joint flexion on vastus medialis obliquus fiber angle in patellofemoral pain syndrome: An ultrasonographic study

INTRODUCTION

In patients with patellofemoral pain syndrome, the vastus medialis obliquus muscle fiber angle measured by ultrasound at knee extension was found to be different from that in healthy individuals. An important feature of patellofemoral pain syndrome is the increase in pain severity during activities that require knee flexion.

OBJECTIVE

To investigate whether there was an ultrasonographic change in the vastus medialis obliquus fiber angle by flexing the knee joint in patients with patellofemoral pain syndrome compared to healthy pain-free individuals.

DESIGN

A cross-sectional clinical study.

SETTING

An outpatient clinic of a tertiary care hospital.

PARTICIPANTS

Forty-seven patients with patellofemoral pain syndrome (median age of 40 years) and 43 healthy volunteers (median age of 39 years) were included in the study.

INTERVENTIONS

No intervention.

MAIN OUTCOME MEASURES

Vastus medialis obliquus fiber angle measured by ultrasonography at three different positions of knee joint including extension, 30° of flexion, and 45° of flexion.

RESULTS

There was no significant change in the vastus medialis obliquus fiber angle with knee flexion in both groups (p > .05 for each group). However, the median vastus medialis obliquus fiber angle values in the group with patellofemoral pain syndrome were significantly lower at all knee joint angles than those in the comparison group (p < .05 at all knee joint angles).

CONCLUSIONS

Although the vastus medialis obliquus fiber angle does not change with static knee flexion, the lower angle of the vastus medialis obliquus fiber in those with patellofemoral pain syndrome implicitly suggests that vastus medialis obliquus dysfunction may exist.

Effects of a Targeted Exercise Program on Inter-Leg Asymmetries in Patients with Patellofemoral Pain

Patellofemoral pain (PFP) is often associated with impaired muscle strength, flexibility, and stability. It has been suggested that inter-leg asymmetries have an important role in increasing the risk of musculoskeletal injuries, including PFP. Thus, the aim of this study was to identify significant asymmetries and determine the effects of a symmetry targeted exercise program in patients with PFP. Eighteen patients aged 13 to 54 years (24.17 ± 12.52 years) with PFP participated in this study. Strength, flexibility and stability outcomes of the trunk, hip, knee and ankle muscles were assessed. A single-group pretest–posttest design was used to assess changes in inter-leg and agonist–antagonist asymmetries resulting from the 8-week period of the supervised exercise program. Results indicated a significant improvement in inter-leg symmetry regarding bilateral stance in a semi-squat position (p = 0.020, d = 0.61, df = 17) and ankle plantarflexion (p = 0.003, d = 0.32, df = 17) and ankle dorsiflexion strength (p < 0.001, d = 0.46, df = 17). In addition, the ratio of ankle dorsiflexion/plantarflexion (p = 0.036, d = 1.14, df = 17) and hip extension/flexion (p = 0.031, d = 0.94, df = 16) changed significantly during the intervention period. To our knowledge, this was the first study to evaluate inter-leg asymmetries resulting from a period of a supervised exercise program. The results indicate that an exercise program focusing on individual asymmetries may influence specific deficits and contribute to better rehabilitation outcomes.

Noncontact Knee Ligament Injury Prevention Screening in Netball: A Clinical Commentary with Clinical Practice Suggestions for Community-Level Players

Netball is a predominantly female team court-sport which is played worldwide. Netball is becoming more popular in the United States following its countrywide introduction to schools and community centers. A unique characteristic of netball is the footwork rule which restricts players to a one-step landing after catching the ball. Most netball landings are single-leg landings resulting in high vertical ground reaction forces and high skeletal tissue forces. Thus, high-risk landing events that have the biomechanical potential for injury occur frequently. Noncontact knee ligament injuries are common following a knee abduction collapse when landing. Because the consequences of noncontact knee ligament injury are profound, strategies are needed to mitigate the burden of such injury for players, teams, and society. The purpose of this clinical commentary is to demonstrate how theoretical principles, different types of research, and different levels of evidence underpin a rational clinical reasoning process for developing noncontact knee ligament injury prevention screening procedures in netball. The theoretical principles that are discussed in this commentary include injury control, the sequence of prevention, principles of screening in injury prevention, the multifactorial model of injury etiology, complex systems theory, and systems science. The different types of research that are reviewed include descriptive and analytic-observational studies. The different levels of evidence that are discussed include prospective studies, cross-sectional studies, and clinicians' own kinesiological modelling. Subsequently, an integrated approach to the evidence-informed development of noncontact knee ligament injury prevention screening procedures is presented. Clinical practice suggestions include a selection of evidence-informed screening tests that are quickly and easily implemented with netball players in local communities. The need for repeated screening at strategic timepoints across a season/year is explained. Sports physical therapists will find this commentary useful as an example for how to undertake clinical reasoning processes that justify the content of screening procedures contributing to noncontact knee ligament injury prevention in community-level netball.

LEVEL OF EVIDENCE

5.

Joint position sense in individuals with anterior knee pain

BACKGROUND

Anterior knee pain (AKP) commonly affects both physically active and sedentary individuals and the aetiology is unknown. Altered joint position sense (JPS) impacts accurate motor action and knee joint stability. It is unclear whether people with AKP have altered JPS.

OBJECTIVE

The aim of our study was to investigate JPS in the knees of individuals with AKP.

METHOD

A descriptive cross-sectional study measured JPS in 25 participants with unilateral or bilateral AKP. JPS was measured using active JPS testing during single leg squat (SLS) and active knee extension (AKE) in sitting. Target angles (TA) were self-determined based on each participant's capabilities. The absolute error (AE) was the main outcome measure. Impaired JPS was classified as an AE equal to or greater than five degrees.

RESULTS

There were no significant differences in JPS when comparing the affected and unaffected knees in participants with AKP (p > 0.05). However, a subgroup of participants with altered knee JPS was identified. There was a tendency towards greater knee flexion in the TAs of knees without AKP.

CONCLUSION

Our results showed that JPS is not significantly more impaired in knees with AKP compared with knees without AKP in a group of individuals with AKP. A subgroup with altered JPS in knees with and without AKP was identified. This finding could be because of compensatory gait patterns and the precision of the Vicon 3D motion analysis system.

CLINICAL IMPLICATIONS

Joint position sense should be assessed bilaterally in individuals with AKP.

A New Clustering Method for Knee Movement Impairments using Partitioning Around Medoids Model

Background:

The movement system impairment (MSI) model is a clinical model that can be used for the classification, diagnosis, and treatment of knee impairments. By using the partitioning around medoids (PAM) clustering method, patients can be easily clustered in homogeneous groups through the determination of the most discriminative variables. The present study aimed to reduce the number of clinical examination variables, determine the important variables, and simplify the MSI model using the PAM clustering method.

Methods:

The present cross-sectional study was performed in Shiraz, Iran, during February-December 2018. A total of 209 patients with knee pain were recruited. Patients’ knee, femoral and tibial movement impairments, and the perceived pain level were examined in quiet standing, sitting, walking, partial squatting, single-leg stance (both sides), sit-to-stand transfer, and stair ambulation. The tests were repeated after correction for impairments. Both the pain pattern and the types of impairment were subsequently used in the PAM clustering analysis.

Results:

PAM clustering analysis categorized the patients in two main clusters (valgus and non-valgus) based on the presence or absence of valgus impairment. Secondary analysis of the valgus cluster identified two sub-clusters based on the presence of hypomobility. Analysis of the non-valgus cluster showed four sub-clusters with different characteristics. PAM clustering organized important variables in each analysis and showed that only 23 out of the 41 variables were essential in the sub-clustering of patients with knee pain.

Conclusion:

A new direct knee examination method is introduced for the organization of important discriminative tests, which requires fewer clinical examination variables.

Dynamic Knee Valgus in Single-Leg Movement Tasks. Potentially Modifiable Factors and Exercise Training Options. A Literature Review

Dynamic knee valgus (DKV) as an incorrect movement pattern is recognized as a risk factor for lower limb injuries. Therefore, it is important to find the reasons behind this movement to select effective preventive procedures. There is a limited number of publications focusing on specific tasks, separating the double-leg from the single-leg tasks. Test patterns commonly used for DKV assessment, such as single-leg squat (SLS) or single leg landings (SLL), may show different results. The current review presents the modifiable factors of knee valgus in squat and landing single-leg tests in healthy people, as well as exercise training options. The authors used the available literature from PubMed, Scopus, PEDro and clinicaltrials.gov databases, and reviewed physiotherapy journals and books. For the purpose of the review, studies were searched for using 2D or 3D motion analysis methods only in the SLL and SLS tasks among healthy active people. Strengthening and activating gluteal muscles, improving trunk lateral flexion strength, increasing ROM dorsiflexion ankle and midfoot mobility should be taken into account when planning training programs aimed at reducing DKV occurring in SLS. In addition, knee valgus during SLL may occur due to decreased hip abductors, extensors, external rotators strength and higher midfoot mobility. Evidence from several studies supports the addition of biofeedback training exercises to reduce the angles of DKV.

Validity and reliability of 2-dimensional trunk, hip, and knee frontal plane kinematics during single-leg squat, drop jump, and single-leg hop in females with patellofemoral pain

OBJECTIVES

To investigate validity and between-session reliability of frontal plane trunk, hip, and knee kinematics during three functional tasks in females with patellofemoral pain (PFP).

DESIGN

Observational.

SETTING

Research Laboratory.

PARTICIPANTS

20 females with PFP (22.7 ± 3.2 years, 69.9 ± 9.2 kg, 167.7 ± 9.6 cm).

MAIN OUTCOME MEASURES

Trunk, hip, and knee frontal plane peak angles during the single leg squat (SLS), drop vertical jump (DVJ), and single leg hop (SLH) kinematics were evaluated using 2-dimensional (2D) and 3-dimensional (3D) motion capture. Participants returned to the lab one week later and competed a second 2D analysis of the functional tasks. Concurrent validity was assessed by evaluating relationship between 2D and 3D frontal plane kinematics with Pearson correlations. Between-session reliability was assessed by evaluating 2D kinematics with intraclass correlation coefficients by a single assessor.

RESULTS

Moderate to strong correlations (r = 0.55-0.76, p < .05) were found for frontal plane hip kinematics during all three tasks and the trunk during the SLH. Frontal plane kinematics demonstrated good to excellent test-retest reliability for each of the three tasks, (ICC _(2,1) = 0.70-0.90).

CONCLUSION

2D hip joint angles during the three functional tasks were the only valid frontal plane angles. Trunk, hip, and knee 2D frontal plane kinematics ranged between good-excellent reliability.

Estimación de par basada en electromiografía de superficie: potencial herramienta para la rehabilitación de rodilla

Introducción. Múltiples estudios de procesamiento de señales han reportado la aplicación de las señales de electromiografía de superficie (sEMG) en robótica y en procesos de rehabilitación motora.Objetivo. Realizar una revisión de la literatura sobre el uso de señales de sEMG como alternativa para la estimación del par de rodilla con el fin de medir objetivamente el progreso de los pacientes en las diferentes etapas de rehabilitación de lesiones de rodilla.Materiales y métodos. Se realizó una revisión de la literatura publicada entre 1986 y 2018, sin límites geográficos, en las bases de datos Engineering Village, IEEE Xplore, ScienceDirect, Web of Science, Scopus y PubMed mediante la combinación de 8 términos de búsqueda.Resultados. Al finalizar la búsqueda inicial se obtuvieron 355 registros. Luego de realizar la remoción de duplicados esta cifra descendió a 308, los cuales fueron analizados para determinar si cumplían con los criterios de inclusión. Finalmente se incluyeron 18 estudios que describen de forma comparativa cómo estimar el par a partir de señales de sEMG.Conclusiones. El uso de señales de sEMG para calcular el par en una articulación es una herramienta alternativa que permite al terapeuta acceder a parámetros cuantitativos y, de esta forma, valorar el progreso de los pacientes durante el proceso de rehabilitación de rodilla.

Core muscles thickness is not associated with knee frontal plane projection angle during single-leg squat in healthy people

BACKGROUND

Core muscles play an important role in lower limb stability and alignment, with their weakness being associated with poor alignment and, consequently, with injuries. Despite muscle structure being critical to muscle strength production, we did not find studies associating the morphology of the core muscles and lower limb alignment during functional tasks.

RESEARCH QUESTION

Is there association between thickness of core muscles (external oblique - EO, internal oblique - IO, transversus abdominis - TrA and gluteus medius - GMed) and lower limb alignment during the single-leg squat in healthy subjects?

METHODS

Forty-six healthy participants (27 male and 19 female) performed the following evaluations: (i) measurements of muscle thickness of the EO, IO, TrA and GMed using ultrasound and (ii) measurements of lower limb alignment using the knee frontal plane projection angle (FPPA) during the single-leg squat. A Spearman rank correlation coefficient (r_s) was performed between the thickness of selected core muscles (OE, OI, TrA and GMed) and the knee FPPA. In addition, a partial correlation (r) was performed, using sex, physical activity level and body mass index as control variables.

RESULTS

We did not observe significant correlations between the knee FPPA and the thickness of the EO (r_s = 0.194; p = 0.197), IO (r_s = 0.182; p = 0.225), TrA (r_s = 0.073; p = 0.627) and GMed (r_s = -0.092; p = 0.542). When controlling for sex, physical activity level and body mass index, similar results were observed [EO (r = 0.157; p = 0.316), IO (r = 0.261; p = 0.092), TrA (r = 0.030; p = 0.850) and GMed (r = -0.144; p = 0.356)] SIGNIFICANCE: Our results demonstrated that core muscles' thickness is not associated with lower limb alignment during the single-leg squat in healthy people.

Risk Factors for Lower-Extremity Injuries Among Contemporary Dance Students

OBJECTIVE

To determine whether student characteristics, lower-extremity kinematics, and strength are risk factors for sustaining lower-extremity injuries in preprofessional contemporary dancers.

DESIGN

Prospective cohort study.

SETTING

Codarts University of the Arts.

PATIENTS

Forty-five first-year students of Bachelor Dance and Bachelor Dance Teacher.

ASSESSMENT OF RISK FACTORS

At the beginning of the academic year, the injury history (only lower-extremity) and student characteristics (age, sex, educational program) were assessed using a questionnaire. Besides, lower-extremity kinematics [single-leg squat (SLS)], strength (countermovement jump) and height and weight (body mass index) were measured during a physical performance test.

MAIN OUTCOME MEASURES

Substantial lower-extremity injuries during the academic year were defined as any problems leading to moderate or severe reductions in training volume or in performance, or complete inability to participate in dance at least once during follow-up as measured with the Oslo Sports Trauma Research Center (OSTRC) Questionnaire on Health Problems. Injuries were recorded on a monthly basis using a questionnaire. Analyses on leg-level were performed using generalized estimating equations to test the associations between substantial lower-extremity injuries and potential risk factors.

RESULTS

The 1-year incidence of lower-extremity injuries was 82.2%. Of these, 51.4% was a substantial lower-extremity injury. Multivariate analyses identified that ankle dorsiflexion during the SLS (OR 1.25; 95% confidence interval, 1.03-1.52) was a risk factor for a substantial lower-extremity injury.

CONCLUSIONS

The findings indicate that contemporary dance students are at high risk for lower-extremity injuries. Therefore, the identified risk factor (ankle dorsiflexion) should be considered for prevention purposes.

Lower Trunk Muscle Thickness Is Associated With Pain in Women With Patellofemoral Pain

OBJECTIVES

To compare trunk muscle thickness of women with and without patellofemoral pain (PFP) and to assess the association of trunk muscle thickness with self-reported pain of women with PFP.

METHODS

Forty-four women were recruited and divided into 2 groups: a PFP group (n = 22) and a pain-free group (n = 22). The thickness of the following trunk muscles was obtained by B-mode ultrasound imaging: transversus abdominis, obliquus internus (OI), obliquus externus (OE), rectus abdominis, and multifidus. Self-reported pain was measured on a visual analog scale.

RESULTS

The 44 participants were 18 to 35 years old. Women with PFP had lower thickness of the OI and OE than pain-free women, with moderate or large effect sizes ranging from -0.78 to -0.98, which was negatively related to self-reported pain correlations (r = -0.53 to -0.40). The contraction ratios of the OI and OE were also lower in women with PFP than in pain-free women (P < .05). No differences between groups were found for the transversus abdominis, multifidus, and rectus abdominis, with also no correlation with self-reported pain.

CONCLUSIONS

Lower thickness of the OI and OE is present in women with PFP, which is related to self-reported pain. These findings might help in understanding the alterations in trunk biomechanics of individuals with PFP and the mechanisms by which interventions targeting trunk muscle strength are beneficial to individuals with PFP.

Added Value of Gluteus Medius and Quadratus Lumborum Dry Needling in Improving Knee Pain and Function in Female Athletes With Patellofemoral Pain Syndrome: A Randomized Clinical Trial

OBJECTIVE

To compare the effects of exercise therapy alone and exercise therapy plus gluteus medius (GM) and quadratus lumbarum (QL) dry needling on pain and function in female athletes with patellofemoral pain (PFP).

DESIGN

Single-blind randomized controlled trial with follow-up.

SETTING

Physiotherapy clinic.

PARTICIPANTS

Convenience sample of female athletes with PFP (N=40), who were randomly assigned to the exercise therapy (Ex group) or exercise-therapy+dry needling (Ex+DN group) group.

INTERVENTIONS

The Ex group received exercise therapy for 4 weeks, and the Ex+DN group received exercise therapy in combination with dry needling directed at GM and QL trigger points for 4 weeks.

MAIN OUTCOME MEASURES

In all participants, pain intensity, function (Kujala score, modified star excursion balance test, step-down test), and QL and GM pressure pain threshold (PPT) were recorded at baseline and at 4 and 6 weeks after the start of treatment. Analysis of variance (2 groups×3 times) was used to compare within- and between-group differences.

RESULTS

The group versus time interaction effect was significant for all variables (P<.05). Both groups showed significant improvements in pain, function, and PPT at weeks 4 and 6 compared to baseline (P<.05). Between-groups comparisons showed significantly greater improvements in pain, function, and PPT in the Ex+DN group (P<.05).

CONCLUSIONS

Targeting intervention to treat trigger points in the GM and QL muscles combined with exercise therapy had superior beneficial effects compared to exercise alone in managing PFP. Therefore, adding GM and QL muscle dry needling to exercise therapy may be advisable to enhance the effects of PFP rehabilitation.

Factors affecting knee abduction during weight-bearing activities in individuals with anterior cruciate ligament reconstruction

OBJECTIVE

To investigate if muscle strength and muscle activation patterns are associated with increased knee abduction during two functional tasks, commonly used in rehabilitation for individuals with anterior cruciate ligament reconstruction (ACLR).

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PARTICIPANTS

24 women and 29 men approximately 7 months after ACLR.

MAIN OUTCOME MEASURES

Isometric peak torque of the trunk and lower extremity muscles were determined during maximal voluntary contractions. Trunk and lower extremity average muscle activation amplitude and peak knee abduction were evaluated during the single-leg squat (SLS) and the single-leg hop for distance (SLHD) for the injured side. Separate backward regressions were performed for men and women.

RESULTS

In women, lower knee flexion and extension strength were associated with greater peak knee abduction during the SLS (B = 4.63-18.26, p ≤ 0.036); lower knee flexion strength and iliocostalis activation on the non-injured side were associated with greater peak knee abduction during the SLHD (B = 0.60-20.48, p ≤ 0.043). No associations between muscle function and peak knee abduction were found in men.

CONCLUSIONS

Muscle function may contribute differently to knee abduction in men and women after ACLR. This should be considered when designing rehabilitation programs to reduce knee abduction in these patients.

Kinematic and kinetic differences between military patients with patellar tendinopathy and asymptomatic controls during single leg squats

BACKGROUND

Knee valgus alignment has been associated with lower-limb musculoskeletal injury. This case-control study aims to: assess biomechanical differences between patients with patellar tendinopathy and healthy controls.

METHODS

43 military participants (21 cases, 22 controls) were recorded using 3D-motion capture performing progressively demanding, small knee bend, single leg and single leg decline squats. Planned a priori analysis of peak: hip adduction, knee flexion, pelvic tilt, pelvic obliquity and trunk flexion was conducted using MANOVA. Kinematic and kinetic data were graphed with bootstrapped t-tests and 95% CI's normalised to the squat cycle. ANOVA and correlations in SPSS were used for exploratory analysis.

FINDINGS

On their symptomatic side cases squatted to less depth (-6.62°, p < 0.05) than controls with exploratory curve analysis revealing a pattern of increased knee valgus collapse throughout the squatting movement (p < 0.05). Greater patella tendon force was generated by: the eccentric than concentric phase of squatting (+30-43%, ES 0.52-1.32, p < 0.01), declined (plantarflexed) compared to horizontal surface (+36-51%, ES 1.19-1.68, p < 0.01) and deeper knee flexion angles (F ≥ 658.3, p < 0.01) with no difference between groups (F ≤ 1.380, p > 0.05). Cases experienced more pain on testing on decline board (ES = 0.69, p < 0.01). For symptomatic limbs pain (r_s = 0.458-0.641, p ≤ 0.05), but not VISA-P (Victoria Institute of Sport Assessment) (r_s = 0.053-0.090, p > 0.05), correlated with extensor knee moment.

INTERPRETATION

Knee valgus alignment is a plausible risk factor for patellar tendinopathy. Conclusions relating to causation are limited by the cross-sectional study design. Increasing squat depth, use of a declined surface and isolating the eccentric phase enable progression of loading prescription guided by pain.

Trunk postural control during unstable sitting differs between patients with patellofemoral pain syndrome and healthy people: A cross-sectional study

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a common orthopedic problem with a high prevalence among young women. Patients with PFPS have altered trunk muscle activity, impaired postural control and greater displacement of the center of pressure (COP) while standing. Training in unstable sitting, by putting more emphasis on trunk sensory receptors, may improve trunk proprioception by minimizing the role of the lower extremities. The aim of this study was to compare trunk postural control in healthy persons and in patients with PFPS.

METHODS

Twenty-one women diagnosed with PFPS and 21 healthy women volunteered to participate in this cross-sectional study. The participants were asked to maintain trunk postural balance on an unstable sitting device, and COP indices of trunk postural control were compared between groups.

RESULTS

All COP indices (e.g., mean anterior-posterior and lateral COP displacement, mean COP velocity and mean area of COP displacement) were significantly increased in participants with PFPS in comparison to healthy controls (P < 0.001). The effect sizes of all the indices were greater than 0.80.

CONCLUSIONS

Trunk postural control is impaired in patients with PFPS, and this finding has clinical implications for rehabilitation in patients with PFPS. Adding seated postural control training to conventional physical therapy management in patients with PFPS may have beneficial effects by emphasizing trunk proprioception while minimizing the role of the lower extremities.

Correlation between Dorsiflexion Ankle Range of Motion and Patellofemoral Pain Syndrome

Abstract The change in lower extremity movement pattern has been previously associated with severe knee disorders, including anterior cruciate ligament rupture, patellar tendinopathy, iliotibial band syndrome, and patellofemoral pain (PFP). The aim of this study was to verify the clinical reliability of ankle dorsiflexion range of motion (ADROM) measurement with weight bearing (WB) using an app on the smartphone (iHand) and to verify if there is correlation between the limitation of the ADROM and the PFP. A total of 67 women, mean age 34.3 ± 2.4, height 182 ± 3.6, weight 73.7 ± 4.2, were allocated to the control group (n = 23) and the PFP group (n = 23). Two examiners evaluated the active ADROM (lunge test) in both ankles at two times to test inter-examiner and intra-examiner reliability. It was observed in the PFP group that the mean ADROM was 17.7 ± 2.5 and the control group was 35.3 ± 6.2 (right) and 17.1 ± 2.9 and 32.9 ± 5, 4 (left). It is concluded that the use of the smartphone app proved to be reliable for clinical application in the evaluation of ADROM with WB and that there is a relation between the low DFT of DFT with the presence of patellofemoral pain.Keywords: Data Accuracy. Ankle. Patellofemoral Pain Syndrome.Resumo A alteração no padrão de movimento da extremidade inferior tem sido previamente associada com severas desordens do joelho, incluindo a ruptura do ligamento cruzado anterior, tendinopatia patelar, síndrome da banda iliotibial e dor patelofemoral - DPF. O objetivo do estudo foi verificar a confiabilidade clínica da mensuração da dorsiflexão de tornozelo - DFT com descarga de peso - WB utilizando um app no smartphone (iHand) e verificar se há correlação entre a limitação da DFT com a DPF. Participaram 67 mulheres, idade média 34,3±2,4, altura 182±3,6, peso 73,7±4,2, alocadas em grupo controle (n=23) e grupo DFP (n=23). Dois examinadores avaliaram a DFT ativa (lunge test) em ambos os tornozelos em dois momentos para se testar a confiabilidade inter-examinador e intra-examinador. O coeficiente de correlação intraclasse - CCI foi utilizado para a análise da confiabilidade das medidas. Observou-se alta confiabilidade (0,9965 [p<0,0001]) e (0,9949 [p<0,0001]) para tornozelo direito e esquerdo respectivamente. Observou-se no grupo DFP que a ADM média de DFT foi de 17,7±2,5 e grupo controle de 35,3±6,2 (direito) e 17,1±2,9 e 32,9±5,4 (esquerdo). Conclui-se que a utilização do app de smartphone se mostrou confiável para aplicação clínica na avaliação da DFT com WB e que há relação entre a baixa ADM de DFT com a presença de dor patelofemoral.Palavras-chave: Acurácia dos Dados. Tornozelo. Síndrome da Dor Patelofemoral

Modifiable Factors Associated with Knee Abduction During Weight-Bearing Activities: A Systematic Review and Meta-Analysis

BACKGROUND

Increased knee abduction angle during activity is suggested to be a risk factor for sustaining an anterior cruciate ligament (ACL) injury or developing patellofemoral pain syndrome (PFPS). Knowledge of the modifiable mechanisms that are associated with increased knee abduction will aid in the appropriate design of preventive and rehabilitative strategies for these injuries.

OBJECTIVE

Our objective was to systematically review modifiable mechanisms contributing to increased knee abduction in healthy people and in individuals with an ACL injury or PFPS.

METHODS

We performed a systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched the databases MEDLINE, CINAHL, and Embase until September 2015. Inclusion criteria were studies in healthy individuals and/or those with ACL injury or PFPS reporting (1) muscle strength, muscle activation, proprioception, and/or range of motion (ROM) and (2) knee abduction angle assessed with either motion analysis or visual observation during weight-bearing activity.

RESULTS

In total, 33 articles were included. Reduced trunk strength, reduced gluteus maximus amplitude, decreased ankle ROM, and increased hip external rotation ROM were moderately associated with increased knee abduction angle (r -0.34 or higher, standardized difference in means (SDM) greater than -0.39, p < 0.05, articles n = 3, total sample size n = 101-114) in healthy individuals. Decreased strength of hip abductors, external rotators, and extensors and knee flexors were at most weakly associated with increased knee abduction angle (r ≤ 0.21, p = 0.013-0.426, articles n = 2-9, total sample size n = 80-311). Too few articles included patients with knee injury to be included in any meta-analysis.

CONCLUSION

The associations identified in this review indicate that investigation of strengthening of the trunk muscles, and improvement of gluteus maximus activation and ankle ROM to change knee kinematics is merited. Studies on modifiable factors associated with increased knee abduction angle in people with knee injury are needed.

Association of Hip and Trunk Strength With Three-Dimensional Trunk, Hip, and Knee Kinematics During a Single-Leg Drop Vertical Jump

Martinez, AF, Lessi, GC, Carvalho, C, and Serrao, FV. Association of hip and trunk strength with three-dimensional trunk, hip, and knee kinematics during a single-leg drop vertical jump. J Strength Cond Res 32(7): 1902-1908, 2018-Kinematic changes have been correlated with different lower-limb injuries. Movement is influenced by multiple factors and strength is one of the contributors that can influence it. Thus, the aim of this study was to evaluate the correlation among trunk and hip isometric strength with trunk and lower-limb kinematics during a single-leg drop vertical jump. Twenty-three healthy recreational female athletes aged between 18 and 35 years underwent isometric evaluation of hip abductor, hip extensor, and lateral trunk muscle strength and 3-dimensional trunk and lower-limb kinematics during a single-leg drop vertical jump. Pearson's correlation coefficients (r) were calculated to establish the association among hip and trunk strength and trunk, hip, and knee kinematics. As result, no significant correlations were found between the peak and movement excursion values of kinematic and hip and trunk isometric strength data. The lack of correlation between isometric strength and kinematics in healthy female athletes indicates that intervention programs should not be focused solely on strength exercises to influence the movement pattern during single-landing activities.

Single leg squat ratings by clinicians are reliable and predict excessive hip internal rotation moment

BACKGROUND

Single leg squats are commonly used subjective assessments of general biomechanical function, injury risk, as a predictor for recovery and as an outcome measure of rehabilitation. While 3D motion capture is a useful tool for elite sports performance and research it is impractical for routine clinical use.

RESEARCH QUESTION

This cross-sectional study aims to: assess reliability and validity of clinicians' subjective ratings of single leg squats compared to 3D motion capture, and to identify whether performance predicts joint moments.

METHODS

22 healthy military volunteers were simultaneously recorded on video and 3D motion capture performing single leg squats. Videos were reviewed twice by 5 physiotherapists rating performance on a 0-5 scale assessing squat depth, hip adduction, pelvic obliquity, pelvic tilt and trunk flexion summated into a composite score.

RESULTS

Hip adduction and trunk flexion exhibited moderate to substantial inter- and intra-rater reliability (range κ = 0.408-0.699) other individual criteria were mostly fair (κ ≤ 0.4). Composite scores for inter-rater reliability were ICC_(1,1) = 0.419 and ICC_(1,κ) = 0.783 and intra-rater reliability were ICC_(1,1) = 0.672 and κ(w) = 0.526. Validity against 3D kinematics was poor with only 6/75 individually rated criteria reaching κ > 0.40. Correlation was found between composite scores and hip internal rotation moment (r_s = 0.571, p = 0.009).

SIGNIFICANCE

Repeated use of single leg squats by a single practitioner is supported. Comparisons between clinicians are unreliable but improved by average measures from multiple raters. Heterogeneous reliability across scoring components suggests a qualitative description of the criteria scored is less ambiguous than using composite scores in a clinical setting. Composite scores may be more useful for analysis at a population level. Poor validity against kinematic data suggests clinicians use additional information upon which they find agreement such as estimating kinetics. Correlation between hip internal rotation moment and subjective ratings may be such an example of clinicians trying to identify excessive abnormal loading.

Identification of Directed Interactions in Kinematic Data during Running

The knowledge of motion dynamics during running activity is crucial to enhance the development of rehabilitation techniques and injury prevention programs. Recent studies investigated the interaction between joints, using several analysis techniques, as cross-correlation, sensitivity analysis, among others. However, the direction of the joints pairing is still not understood. This paper proposes a study of the influence direction pattern in healthy runners by using kinematic data together with partial directed coherence, a frequency approach of Granger causality. The analysis was divided into three anatomical planes, sagittal, frontal, and transverse, and using data from ankle, knee, hip, and trunk segments. Results indicate a predominance of proximal to distal influence during running, reflecting a centralized anatomic source of movements. These findings highlight the necessity of managing proximal joints movements, in addition to motor control and core (trunk and hip) strengthening training to lumbar spine, knee, and ankle injuries prevention and rehabilitation.

Single leg squat performance in physically and non-physically active individuals: a cross-sectional study

BACKGROUND

Single-leg squat (SLS) is a functional test visually rated by clinicians for assessing lower limb function as a preventive injury strategy. SLS clinical rating is a qualitative evaluation and it does not count objective outcomes as kinematics data and surface electromyography (sEMG) assessment. Based on the SLS rating, the aims of this study were (i) to determine the clinical rating agreement among six raters and (ii) to assess kinematic and sEMG predictors of good SLS performance in physically and non-physically active individuals.

METHODS

Seventy-two healthy adults, divided in physically active and non-physically active groups, performed three SLSs on their dominant leg. Clinical ratings, kinematic data and sEMG were acquired. By using a validated clinical scale, six expert clinicians rated each SLS watching a video at three different time points. Intra and inter-rater agreement of clinical ratings were undertaken and a binary logistic regression analysis was used to determine kinematic and sEMG as predictors of SLS performance.

RESULTS

The weighted kappa coefficient for intra-rater reliability within each rater ranged between moderate and almost perfect agreement (0.55-0.85) whereas the weighted kappa coefficient for inter-rater reliability among raters was fair (0.34, time point 0; 0.31, time point 1; 0.30, time point 2). SLS analyses of physically active compared to non-physically active group showed a statistically significant difference in knee flexion and hip flexion (p = 0.041 and p = 0.023 respectively) and no difference in clinical ratings (p = 0.081). Greater knee flexion can predict the good SLS performance taking into account the belonging group (p = 0.019).

CONCLUSIONS

Physically active individuals seemed to be at less risk to perform a non-good SLS and they had greater knee and hip flexions kinematics than non-physically active individuals. Knee flexion can predict the SLS performance quality therefore a greater knee flexion might also be considered a protective element from injuries.

TRIAL REGISTRATION

ClinicalTrials.gov identifier (trial has been registred retrospectively: NCT03203083. Date registration: June 21, 2017.

Hip abductor, trunk extensor and ankle plantar flexor endurance in females with and without patellofemoral pain

BACKGROUND

Previous studies have reported strength deficit in hip abduction, extension and external rotation in females with patellofemoral pain (PFP) when compared with healthy control; however, there is conflicting evidence for a decrease in hip muscle endurance. Therefore, it seems important to evaluate hip muscle endurance in females with PFP. Moreover, trunk extensor and ankle plantar flexor endurance have not yet been evaluate in females with PFP.

OBJECTIVE

To compare hip abductor, trunk extensor and ankle plantar flexor endurance between females with and without PFP.

METHODS

Twenty females with PFP (mean age, 21.1 years) and 76 healthy females (mean age, 20.5 years) were recruited. Subject performed three endurance clinical tests: (1) The hip abductor isometric endurance test, (2) The Sorensen test and (3) The heel rise test. Group differences were assessed using an independent t tests, or Mann-Whitney U tests for non-normally distributed data.

RESULTS

Subjects with PFP exhibited significantly lower hip abductor, trunk extensor and ankle plantar flexor endurance than healthy controls. On average, subjects with PFP had deficits of 16% in hip abduction, 14% in trunk extension and 26% in ankle plantar flexion.

CONCLUSION

Females with PFP exhibited diminished hip abductor, trunk extensor and ankle plantar flexor endurance compared to healthy controls.