Is Hip Abduction Strength Asymmetry Present in Female Runners in the Early Stages of Patellofemoral Pain Syndrome?

Comparing kinematic asymmetry and lateral step-down test scores in healthy, chronic ankle instability, and patellofemoral pain syndrome female basketball players: a cross-sectional study

We aimed to understand whether ankle dorsiflexion range of motion (ROM) and dynamic knee valgus (DKV) kinematic inter-limb asymmetries would be associated with the Lateral Step-Down Test (LSD) in basketball players with chronic ankle instability (CAI), patellofemoral pain (PFP) and healthy controls (HC). An observational cross-sectional study with a between-subject design was employed. Female basketball athletes with CAI (n = 20), PFP (n = 20) and HC (n = 20) were recruited. Ankle dorsiflexion-ROM, DKV angle during a single-limb squat, and LSD quality were measured bilaterally. The Asymmetry index (ASI) was calculated to identify between-limb percentage imbalances. The correlation matrix between the tasks was calculated. Ankle dorsiflexion-ROM was less in the CAI and PFP than in the HC group regardless of limb (p < 0.001). DKV angle was greater in the CAI and PFP than in the HC group bilaterally (p < 0.001). LSDs were similar between the PFP and CAI groups (p = 0.698) but worse than the HC group (p = 0.001). The ASI showed asymmetry across all tasks (p < 0.001), with the greatest asymmetry for the DKV angle. The correlation matrix between tasks on both limbs was significant (p < 0.05). Our findings suggest significant asymmetries in ankle dorsiflexion-ROM and frontal plane knee control are present in female basketball athletes with CAI and PFP, and thus, highlights need to evaluate and reduce limb asymmetries in these populations.

The effect of three types of exercises programs on the patella location in athletes with patellofemoral pain

BACKGROUND

The aim of this study was to compare the effect of exercises focusing on the proximal and distal joints to knee and knee local exercises on the Patellar location in athletes with patellofemoral pain (PFP).

METHODS

A randomized controlled, single-blinded trial was conducted. Thirty-five athletes with PFP were randomly divided into three groups; proximal (12), distal (11) and local (12). Q Angle was measured with goniometer, tilt and congruence angle were measured with digital radiology before and after the exercise programs. The exercises were performed three sessions of 70 min per week, for 8 weeks. Data were analyzed by mixed analysis of variance, post hoc test and dependent t-test.

RESULTS

In the pre-intervention, no significant difference was observed between the groups (P > 0.05). But in the post-intervention, Q angle, tilt angle, congruence angle and knee pain in the proximal group were significantly less than the distal and local groups (P < 0.01); while there were no significant differences between the distal and local groups (P > 0.05). Also, in the proximal group, there were significant differences between pre-intervention and post intervention in Q angle, tilt angle and congruence angle (P = 0.001), but no significant differences were observed in the distal and local groups (P > 0.05). Knee pain in all three groups showed significant differences between pre-intervention and post-intervention (P < 0.01).

CONCLUSIONS

The findings of the present study indicated further improvement in patellar location and knee pain in the proximal group. Accordingly, proximal group exercises can improve the pain and performance of athletes with PFP by patellar relocation to the normal position.

Do Injury-Resistant Runners Have Distinct Differences in Clinical Measures Compared with Recently Injured Runners?

INTRODUCTION

Although lower extremity muscle strength, joint motion, and functional foot alignment are commonly used, time-efficient clinical measures that have been proposed as risk factors for running-related injuries, it is unclear if these factors can distinguish injury resistance in runners.

PURPOSE

This study compares clinical measures, with consideration of sex, between recently injured runners (3 months to 1 yr prior), those with a high level of injury resistance who have been uninjured for at least 2 yr, and never-injured runners.

METHODS

Averaged bilateral values and between-limb symmetry angles of lower limb isometric muscle strength, joint motion, navicular drop, and foot posture index (FPI) were assessed in a cohort of recreational runners, and their injury history was recorded. Differences in clinical measures between injury groupings were examined, with consideration of sex.

RESULTS

Of the 223 runners tested, 116 had been recently injured, 61 had been injured >2 yr ago and were deemed to have acquired reinjury resistance, and 46 were never injured. Plantarflexion was greater in both recently injured (P = 0.001) and acquired reinjury resistance runners (P = 0.001) compared with never-injured runners. Recently injured runners displayed higher hip abduction strength compared with never-injured runners (P = 0.019, η2 = 0.038, small effect size). There were no statistically significant differences in the remaining measures between the injury groupings. With the exception of FPI, there was no interaction between sex and injury grouping for any of the measures.

CONCLUSION

Commonly used clinical measures of strength, joint motion, and functional foot alignment were not superior in injury-resistant runners compared with recently injured runners, questioning their relevance in identifying future injury resistance of runners.

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.

Biomechanics Differ for Individuals With Similar Self-Reported Characteristics of Patellofemoral Pain During a High-Demand Multiplanar Movement Task

CONTEXT

Patellofemoral pain (PFP) is often categorized by researchers and clinicians using subjective self-reported PFP characteristics; however, this practice might mask important differences in movement biomechanics between PFP patients.

OBJECTIVE

To determine whether biomechanical differences exist during a high-demand multiplanar movement task for PFP patients with similar self-reported PFP characteristics but different quadriceps activation levels.

DESIGN

Cross-sectional design.

SETTING

Biomechanics laboratory.

PARTICIPANTS

A total of 15 quadriceps deficient and 15 quadriceps functional (QF) PFP patients with similar self-reported PFP characteristics.

INTERVENTION

In total, 5 trials of a high-demand multiplanar land, cut, and jump movement task were performed.

MAIN OUTCOME MEASURES

Biomechanics were compared at each percentile of the ground contact phase of the movement task (α = .05) between the quadriceps deficient and QF groups. Biomechanical variables included (1) whole-body center of mass, trunk, hip, knee, and ankle kinematics; (2) hip, knee, and ankle kinetics; and (3) ground reaction forces.

RESULTS

The QF patients exhibited increased ground reaction force, joint torque, and movement, relative to the quadriceps deficient patients. The QF patients exhibited: (1) up to 90, 60, and 35 N more vertical, posterior, and medial ground reaction force at various times of the ground contact phase; (2) up to 4° more knee flexion during ground contact and up to 4° more plantarflexion and hip extension during the latter parts of ground contact; and (3) up to 26, 21, and 48 N·m more plantarflexion, knee extension, and hip extension torque, respectively, at various times of ground contact.

CONCLUSIONS

PFP patients with similar self-reported PFP characteristics exhibit different movement biomechanics, and these differences depend upon quadriceps activation levels. These differences are important because movement biomechanics affect injury risk and athletic performance. In addition, these biomechanical differences indicate that different therapeutic interventions may be needed for PFP patients with similar self-reported PFP characteristics.

Additional effects of core stability exercises on pain and function of patients with patellofemoral pain: A randomized controlled trial

Background/purpose:

Recently, there is more emphasis on the role of core muscles in pathogenesis and rehabilitation of patellofemoral pain (PFP). We aimed to investigate whether increased core muscle strength and endurance improve clinical outcomes.

Methods:

In a randomized controlled trial, 60 patients (M/F: 25/35, age = 32.28 (5.9) years) with PFP were randomly allocated into two groups of routine exercise (control) and combined core plus routine exercise (intervention). Home exercise was scheduled at least 5 times/week for 12 weeks. We assessed the outcomes of pain (Visual analogue scale) and function (Anterior knee pain score) before and immediately after interventions.

Results:

Significant improvements were reported in both groups (P < 0.001). There were significant between-group differences in both outcomes in favor of the intervention (Pain: 12.4, CI 95%: 7.1–17.8, P < 0.001; Function: 6.4, CI 95%: 2.2–10.5, P = 0.003).

Conclusion:

Outcome improvements were significantly greater in intervention group. Inclusion of core stability exercises may lead to additional benefits.

Trunk endurance, posterior chain flexibility, and previous history of musculoskeletal pain predict overuse low back and lower extremity injury: a prospective cohort study of 545 Navy Cadets

OBJECTIVE

To investigate predictors of low back and lower extremity musculoskeletal injury in a cohort of Naval cadets.

DESIGN

Prospective Cohort Study METHODS: 545 Naval cadets (Males, n = 394, 72%) were followed-up over eight months. Nine variables were investigated as predictors: history of musculoskeletal symptoms in the last 12 months, ankle dorsiflexion range of motion, sit and reach test, isometric hip abduction and external rotation strength, alignment during the single leg squat test, single leg hop test for distance, prone plank and side plank tests. All injuries that required medical attention were registered. Predictive associations were examined using univariable and multivariable logistic regression analyses.

RESULTS

The incidence of all injuries was 7%. Cadets who failed the 60-second plank test (OR = 3.3; 95% CI, 1.2-8.8, P = 0.04), had ≤18 cm in the sit and reach test (OR = 4.0; 95% CI, 1.4-11.2, P = 0.01), or reported pain in the last 12 months in two or more body regions (OR = 2.7; 95% CI, 1.02-7.3, P = 0.04), had greater odds of sustaining an overuse injury. No predictors were identified for acute injuries.

CONCLUSION

Decreased trunk endurance on the prone plank test, reduced posterior chain flexibility on the sit and reach test, and a history of pain reported in two or more sites in the last 12 months were predictors of overuse injuries in Naval cadets. Assessment and intervention of these modifiable risk factors may be clinically relevant in injury screening and prevention.

The role of core stability in the development of non-contact acute lower extremity injuries in an athletic population: A prospective study

OBJECTIVES

Stability of the core is associated with lower extremity functioning. Consequently, impaired core stability might play a role in developing non-contact acute lower extremity sports injuries. The objective was to investigate components of core stability as potential risk factors for acute lower extremity injuries.

DESIGN

A cohort study was set up with a follow-up and injury registration period of 1.5 years.

PARTICIPANTS

142 male and female physical education students were included.

MAIN OUTCOME MEASURES

Measures of isometric hip and core muscular strength, endurance, proprioception and neuromuscular control of the core, and postural control were taken at the start of the study. Sports-related injury occurrence was registered during follow-up.

RESULTS

27 (19%) injuries of interest occurred during follow-up. After multivariate model building, a significant predictive effect was found for side-to-side hip abduction strength asymmetry (p = .007). The hazard of developing an acute lower extremity injury increased with 6.2% with a 1 unit increase in side-to-side strength imbalance, regardless of gender.

CONCLUSION

Hip abduction strength imbalance was determined as a risk factor for the development of non-contact, acute lower extremity injuries. Normalizing hip strength imbalances might be beneficial for injury prevention. However, further research is needed to support this claim.

Do hip muscle weakness and dynamic knee valgus matter for the clinical evaluation and decision-making process in patients with patellofemoral pain?

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Hip muscle weakness in PFP patients may be consequence and not the cause of pain.

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Pain and disability may not be associated with kinematics after treatment.

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Hip muscle weakness may have no causal relationship with dynamic knee valgus.

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The mechanical factors that may impair the management of PFP are likely to be overestimated.

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PFP patients should be treated on a biopsychosocial approach.

Background

Patellofemoral pain is a very common musculoskeletal condition. In the last years, evidence regarding this disease increased exponentially. Although widely investigated, this problem still frustrates patients and clinicians for having an unfavorable prognosis. Some gaps still exist in the understanding and managing of patellofemoral pain. Numerous cross-sectional association studies show an association between gluteus muscular strength and dynamic knee valgus in patients with patellofemoral pain. In spite of this biological plausibility, many evidences challenge the direct relationship between these factors. Recent studies have concluded that women with patellofemoral pain show muscular weakness of the hip based on the cross-sectional studies, however prospective studies indicate that hip weakness cannot be considered a risk for development of patellofemoral pain. In addition, some clinical trials have demonstrated that strength training of the gluteal muscles promotes significant improvement in symptoms but not alter the kinematics of the patients with patellofemoral pain. These findings cast doubt on whether the cause of this condition is really being treated, whether all individuals suffering from patellofemoral pain present dynamic knee valgus or if this is a disturbance present in only a subgroup of patients and whether the strengthening of the hip musculature is an option to consider for prevention of patellofemoral pain.

Conclusion

Certainly, more studies should be conducted to clarify the influence of mechanical patterns on this condition, but with the existing evidence so far, the importance given to these issues in the evaluation and clinical decision on treatment of these patients seems questionable. Therefore, this masterclass explores the understanding about patellofemoral pain, highlighting mainly the importance of muscular strength and dynamic knee valgus, as well as other possible factors that must be consider during the evaluation and the decision making in these patients.

Walking mechanics for patellofemoral pain subjects with similar self-reported pain levels can differ based upon neuromuscular activation

Patellofemoral pain (PFP) is often studied on subjects who are classified using only self-reported data. Neuromuscular activation influences movement mechanics for PFP subjects, but is not likely to be self-reported. We compared lower-extremity mechanics, during a common movement (walking), between two subdivisions of a group of PFP subjects that were similar, based on common self-report tools, but different, based on a common objective measure of quadriceps activation. Our intent was to highlight the importance of objectively considering neuromuscular activation when researching PFP movement mechanics. Thirty similar PFP research subjects (based on four common self-report tools) were divided into two subdivisions, based on different quadriceps central activation ratios (CAR): a quadriceps deficit (QD; CAR <0.95) group and a no quadriceps deficit (NQD; CAR ≥0.95) group. All subjects in both groups performed five walking trials, while common mechanical characteristics were measured: 3D ground reaction force, and 3D joint kinematics and kinetics. Functional statistics were used to compare mechanical characteristics between the groups across the entire stance phase of gait (α=0.05). Numerous differences were found between the two groups for ground reaction force, and joint kinematics and kinetics. For example, the NQD group exhibited 5% greater vertical ground reaction force at peak impact, and 5% less vertical ground reaction force during the unloading portion of stance, relative to the QD group. The results indicate that when researching movement mechanics associated with PFP, it is important to consider objectively-measured neuromuscular activation characteristics that are not likely to be self-reported by PFP subjects.