Females with patellofemoral pain have impaired impact absorption during a single-legged drop vertical jump

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.

Anodal tDCS improves the effect of neuromuscular training on the feedforward activity of lower extremity muscles in female taekwondo athletes with dynamic knee valgus

Transcranial direct current stimulation (tDCS) can increase cortical excitability of a targeted brain area. This study aimed to investigate the effect of adding anodal-tDCS (a-tDCS) to neuromuscular training (NMT) on the dynamic knee valgus (DKV) and feedforward activity (FFA) of knee muscles. Thirty-four Taekwondo athletes with DKV, were randomly assigned to either NMT + a-tDCS (N = 17) or NMT + sham tDCS (N = 17). DKV and the knee muscles' FFA at the moment of single and double-leg landing and lateral hopping tasks were evaluated before and after the interventions. DKV and FFA of the knee muscles was improved in all tasks (P < 0.05), however, between-group differences were not significant (P > 0.05). The FFA of the semitendinosus, vastus medialis, gluteus medius, and gastrocnemius muscles in the single-leg landing (P < 0.05), the gluteus medius, gluteus maximus, semitendinosus, biceps femoris, and gastrocnemius muscles in the double-leg landing (P < 0.05), and the gluteus medius, gluteus maximus, and gastrocnemius muscles in the lateral hopping (P < 0.05) tasks were significantly different between the groups. A-tDCS achieved significantly larger improvements in the feedforward activity of lower extremity muscles compared with sham-tDCS. However, between-group comparisons did not show a significant difference in DKV.

Effects of pain exacerbation on postural control in women with patellofemoral pain during single leg squat: a cross-sectional study

BACKGROUND

The center of pressure (COP) excursion parameters are recognized as risk factors for the etiology and development of patellofemoral pain (PFP). The purpose of the present study measures the effect of pain exacerbation on COP excursion, and the correlation between pain intensity and COP excursion in women with PFP during single leg squat (SLS).

METHODS

Sixty patients with PFP participated in this cross-sectional study. The outcome measures were included pain intensity and COP excursion which evaluated in pre and post pain exacerbation during SLS. The COP parameters were evaluated during single leg squat in 60° of knee flexion. A paired t-test and MANOVA was used to compare pain intensity and COP excursion between the two conditions, respectively. Furthermore, A Pearson's correlation matrix was used to examine the relationship between pain intensity with COP excursion.

RESULTS

Statistical analysis showed that pain intensity (t = - 16.655, p < 0.001) and COP excursion (Wilks' Lambda = 0.225, p < 0.001) with medium effect size increased after PFJ loading. In addition, an excellent positive correlation was observed between increased in pain intensity and COP excursion (P < 0.001, r > 0.80).

CONCLUSION

After PFJ loading, women with PFP presented increases in the pain intensity, COP excursions, and sway velocity. In addition, there was an association between the increase in pain intensity and COP excursions. Clinicians aiming to improve postural control of patients with PFP could use kinesio taping as a short-term intervention and balance training to improvements in postural control at medium and long-term. Furthermore, emphasizing psychological factors to reducing kinesiophobia can be useful to restoring proper movement pattern, reducing pain and improving symptoms.

Relationship between exacerbating patellofemoral pain and dynamic knee valgus in females with patellofemoral pain after a patellofemoral joint loading protocol: A cross-sectional

OBJECTIVE

The aim of the present study is to 1) the effect of exacerbating patellofemoral pain (PFP) on dynamic knee valgus (DKV) 2) the relationship between exacerbating PFP and DKV in females with patellofemoral pain.

DESIGN

Cross-sectional study.

METHODS

Sixty women with PFP were recruited from the orthopedic clinics. We evaluated pain intensity and DKV in two conditions without (condition 1) and with (condition 2) PFJ loading during the single-leg squat (SLS) task. The MANOVA test was used to compare pain intensity and DKV angle between the two conditions. Furthermore, the Pearson correlation was used to examine the correlation between pain intensity with DKV angle.

RESULTS

The MANOVA analysis showed that pain intensity (P < 0.000, η2 = 0.623) and DKV angle (P < 0.000, η2 = 0.544) with a medium effect size significantly increased after PFJ loading. Furthermore, an excellent positive correlation was observed between an increase in pain intensity and DKV angle (P < 0.000, r = 0.840).

CONCLUSION

It seems that after the PFJ loading protocol and the subsequent pain exacerbation, the neuromuscular biomechanics of the lower limb are deficits. As a result, the stabilizing muscles activation decreases and increases the lower limb movement in the frontal plane.

Pain and disability were related to Y-balance test but not with proprioception acuity and single-leg triple-hop test in patients with patellofemoral pain: A cross-sectional study

INTRODUCTION

Patellofemoral pain is a common complaint between physically active subjects. Patients with patellofemoral pain present limitations to performing daily activities. Pain could alter proprioceptive acuity and lead to movement impairment. The aim of this study was to investigate the relationship of pain and disability with proprioception acuity and physical performance in patients with patellofemoral pain.

METHODS

Forty-eight patients with patellofemoral pain [age 31.15 (5.91) years; 30 (62.50%) males] were recruited. Data collected included pain intensity, pain duration, disability, joint position sense (JPS) test at 20° and 60° of knee flexion, and physical performance tests (Single-Leg Triple-Hop Test and Y- Balance Test). Spearman's rank correlation coefficient (rs) and 95% confidence intervals (CI) were computed to assess the relationship between the variables.

RESULTS

Pain intensity was correlated with Y-Balance Test posteromedial component (rs = -0.32, 95%CI = -0.55 to -0.03, p = 0.029) and the composite score (rs = -0.35, 95%CI = -0.58, -0.07, p = 0.015). Pain duration was correlated with Y-Balance Test posterolateral component (rs = -0.23, 95% CI = -0.53 to -0.01, p = 0.047). Disability was correlated with Y-Balance Test posteromedial component (rs = 0.41, 95% CI = 0.14 to 0.62, p = 0.004). Pain and disability were not correlated with JPS and the Single-Leg Triple-Hop Test.

CONCLUSION

Pain and disability were related to Y-Balance Test but not to proprioceptive acuity and Single-Leg Triple-Hop Test in patients with patellofemoral pain.

Effectiveness of Interventions Aimed at Changing Movement Patterns in People With Patellofemoral Pain: A Systematic Review With Network Meta-analysis

OBJECTIVE: To summarize the effectiveness of interventions for changing movement during weight-bearing functional tasks in people with patellofemoral pain (PFP). DESIGN: Systematic review with network meta-analysis (NMA). LITERATURE SEARCH: Medline, Embase, CINAHL, SPORTDiscus, and Cochrane Library were searched from inception up to May 2023. STUDY SELECTION CRITERIA: Randomized controlled trials involving people with PFP and nonsurgical, nonpharmacological interventions on task kinematics were included. DATA SYNTHESIS: NMA was conducted for frontal knee movement data, and pairwise meta-analysis was used to pool data when NMA was not possible. Reduced movements were those changes that indicated movements occurring with less amplitude. The GRADE approach was used to grade the certainty of the evidence. RESULTS: Thirty-seven trials were included (n = 1235 participants). Combining knee/hip exercises with internal feedback had the strongest effect on reducing frontal knee movements (standardized mean difference [SMD] from NMA = -2.66; GRADE: moderate evidence). On pairwise comparisons, the same combination of interventions reduced frontal hip movements (SMD = -0.47; GRADE: moderate evidence) and increased sagittal knee movements (SMD = 1.03; GRADE: moderate evidence), with no effects on sagittal hip movements (GRADE: very low evidence), compared to knee/hip exercises alone. There was no effect for single applications of braces on the frontal knee movement (GRADE: very low evidence) and taping on movements of the knee, hip, and ankle (GRADE: very low to low evidence) compared to no intervention. CONCLUSION: Knee/hip exercises combined with internal feedback techniques may change knee and hip movements in people with PFP. The combination of these interventions can reduce frontal knee and hip movements, and can increase sagittal knee movements. J Orthop Sports Phys Ther 2023;53(12):1-13. Epub 14 September 2023. doi:10.2519/jospt.2023.11956.

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.

Is Cam Pincer Deformity a Predisposing Factor for Patellofemoral Pain Syndrome?

Purpose

This study aimed to investigate whether cam and pincer deformities (CPDs) are a risk factor for patellofemoral pain syndrome (PFPS) in women. In addition, it sought to compare the hip joint range of motion and the hip muscle strength of extremities with and without CPDs and PFPS.

Materials and Methods

A total of 82 hips of 41 women with PFPS were included in the study. The mean age of participants was 32.07 ± 7.13 years. The presence of CPDs was detected on digital anterior pelvis radiographs. Pain was evaluated using the visual analog scale, and function using the Kujala scoring system. Maximum isometric muscle strength around the hips was measured using a hand-held dynamometer. Hip joint range of movement angles were measured in all three planes using a universal goniometer.

Results

CPDs were found to predict PFPS in women (p = 0.011, p = 0.048). The rate of CPDs was significantly higher in extremities with PFPS compared to those without PFPS (p = 0.007). The Kujala scores of extremities with cam deformity were significantly lower than those of extremities without pincer deformity (p = 0.043). The internal/external muscle strength ratio was greater, and the abduction/adduction muscle strength ratio was lower in extremities with cam and PFPS than in those without (p = 0.040, p = 0.049). The external rotation and abduction range of movement angles were significantly smaller in extremities with pincer and PFPS compared to those without (p = 0.043, p = 0.035).

Conclusion

CPDs may be a structural predisposing factor in the development of PFPS in women. CPDs assessment when evaluating predisposing factors for PFPS may present an opportunity for the management of PFPS.

Countermovement, Hurdle, and Box Jumps: Data-Driven Exercise Selection

Apart from squat jumps, countermovement jumps (CMJ), and drop jumps, differences among other jump variations are not as well researched, making data-driven exercise selection difficult. To address this gap, this study compared selected concentric and eccentric jump parameters of maximal effort CMJ, hurdle jumps over 50 cm hurdle (HJ), and box jumps onto a 50 cm box (BJ). Twenty recreationally trained men (25.2 ± 3.5 years) performed 3 repetitions of CMJs, HJs, and BJs, each on separate days. The data were collected using force platforms and a linear position transducer. The mean of 3 trials of each jump variation was analyzed using repeated measures ANOVA and Cohen's d. Countermovement depth was significantly greater (p ≤ 0.05) and peak horizontal force significantly lower during CMJ compared to HJ and BJ. However, there were no differences in peak velocity, peak vertical and resultant force, and total impulsion time. Finally, BJ significantly decreased peak impact force by ~51% compared to CMJ and HJ. Therefore, the propulsive parameters of HJ and BJ seem to be similar to CMJ, despite CMJ having a greater countermovement depth. Furthermore, overall training load can be decreased dramatically by using BJ, which reduced peak impact force by approximately half.

Functional tests in women with patellofemoral pain: Which tests make a difference in physical therapy evaluation

BACKGROUND

Patellofemoral pain (PFP) is characterized by anterior knee, which intensifies during functional activities that require the eccentric action of the quadriceps muscle, specially. In ths way, quantitatively measurable functional tests that simulate these activities should be included in the physical therapy evaluation.

OBJECTIVE

To identify which functional tests are most indicated for the evaluation of women with PFD.

METHOD

This study evaluated 100 young women (50 with PFP), during the execution of the following functional performance tests: Triple hop, Vertical Jump, Single leg squat, Step Down, YBalance tests, Lunge test and running. Dynamic valgus was also assessed in the tests. The isometric muscle strength of the following muscle groups: hip abductors, extensors and lateral rotators, knee extensors, evertors, and plantar flexors were evaluated. Functional Perception were evaluated by Anterior Knee Pain Scale and Activities of Daily Living Scale.

RESULTS

PFP group showed lower performance during the Y-Balance, triple hop, vertical jump tests and running. Was observed an increase in dynamic valgus during Triple Hop, Vertical Jump tests and running in PFP group, besides a poorer perception of function. For all lower limb muscle groups, the PFP group showed a reduction in peak isometric force.

CONCLUSION

The YBalance, triple hop, vertical jump tests, and running should be included in the physical therapy evaluation, in addition to aspects of lower limb muscle strength.

Relationship between kinesiophobia, isometric hip and knee torques to pelvic, hip and knee motion during the single-leg drop jump in women with patellofemoral pain: A cross-sectional study

BACKGROUND

Individuals with patellofemoral pain (PFP) have kinesiophobia and hip and knee strength deficits. These factors may be related to kinematic alterations of pelvic, hip and knee during a more demanding functional activity, such as jumping landing. The aim was to investigate the relationships between kinesiophobia and hip/knee torque to pelvic/hip/knee kinematics during the single-leg drop vertical jump in women with PFP.

METHOD

Thirty women with PFP were assessed with Tampa Scale for Kinesiophobia; isokinetic dynamometry of the hip extensor, hip abductor, and knee extensor; and three-dimensional motion analysis system during the single-leg drop vertical jump. A Pearson correlation matrix was used to investigate relationship among variables.

RESULTS

Fair correlations were found between increased kinesiophobia and increased peak hip internal rotation angle (r = 0.43; p = 0.018) as well as between greater peak knee extensor torque and greater peak knee flexion (r = 0.41; p = 0.022). Moderate to good correlation was found between increased peak hip abductor torque and increased peak contralateral pelvic drop (r = 0.52; p = 0.003). No other significant correlations were found between variables.

CONCLUSIONS

Kinesiophobia is associated with hip kinematics, but not with knee kinematics, during the single-leg vertical drop jump in women with PFP. The greater hip abductor torque is associated with greater contralateral pelvic drop. The positive relationship between knee extensor torque and knee flexion indicates that rehabilitation programs involving quadriceps muscle strengthening may assist women with PFP in control knee flexion and improve load absorption during jumping landing.

Effects of Patellofemoral Pain Syndrome on Changes in Dynamic Postural Stability during Landing in Adult Women

Background

This study investigated the effects of lower limb movements on dynamic postural stability (DPS) during drop landing in adult women with patellofemoral pain syndrome (PFPS).

Methods

Thirty-eight adult women were recruited and divided into two groups, the PFPS group and the control group. The study participants performed a single-leg drop landing from a 30 cm box, and their lower limb movements and DPS were measured. Differences between groups were examined using independent sample t-tests. In addition, stepwise multiple linear regression was used to examine the kinematic parameters that contribute to the DPS.

Results

The PFPS group had significantly lower hip flexion, internal rotation, knee flexion, ankle external rotation, pelvic oblique, tilt, rotation, and higher hip abduction, knee valgus, and ankle plantarflexion. In terms of DPS, the PFPS group had a significantly higher anteroposterior and a lower mediolateral than that of the control group. In the control group, regression analysis revealed a controlled anteroposterior using knee flexion, while the PFPS group controlled mediolateral through ankle plantarflexion.

Conclusions

Patients with PFPS experienced more shock on their knee joint during landing than patients in the control group with greater anteroposterior instability and lower mediolateral instability.

Association between landing biomechanics, knee pain, and kinesiophobia in athletes following anterior cruciate ligament reconstruction: A cross-sectional study

INTRODUCTION

Kinesiophobia is a fear of physical movement and activity and is known to impact return to sports and second injury after anterior cruciate ligament reconstruction.

OBJECTIVE

To determine the association among landing biomechanics, knee pain, and kinesiophobia in athletes following anterior cruciate ligament reconstruction.

DESIGN

A cross-sectional study SETTING: Clinical center of sports medicine PARTICIPANTS: This study included 31 athletes who participated in sports after primary, unilateral anterior cruciate ligament reconstruction (age, median [interquartile range]: 20.0 [7.0] years; body mass index: 22.2 [2.6] kg/m² ; time from anterior cruciate ligament reconstruction: 24.0 [23.0] months).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Kinesiophobia was measured using the Tampa Scale for Kinesiophobia-11. Knee function included joint laxity, strength, and single-leg hop distance. Knee pain intensity during sports activities was measured using a numerical rating scale. Vertical ground reaction force was measured, and electromyography data for the vastus medialis and semitendinosus muscles during single-leg jump landing were collected. Univariate correlation analysis and multiple regression analysis were performed to identify the associations between the Tampa Scale for Kinesiophobia-11 score and outcome measures.

RESULTS

There was no correlation between peak vertical ground reaction force and Tampa Scale for Kinesiophobia-11 score (Spearman's r = -0.172, P = 0.355). On multiple regression analyses, lower preparatory vastus medialis activity during landing (beta coefficient = -0.513, P < 0.001) and knee pain intensity (beta coefficient= 0.569, P < 0.001) were significantly associated with greater Tampa Scale for Kinesiophobia-11 scores.

CONCLUSIONS

In athletes who have participated in sports following anterior cruciate ligament reconstruction, lower preparatory vastus medialis activity during landing and knee pain intensity are associated with greater kinesiophobia. These findings indicate that interventions to address the landing muscle activity pattern and pain control should be performed to decrease kinesiophobia after anterior cruciate ligament reconstruction. This article is protected by copyright. All rights reserved.

Central vs. Peripheral Vision during a Singe-Leg Drop Jump: Implications of Dynamics and Patellofemoral Joint Stress

Landing on a single-leg without receiving direct visual information (e.g., not looking at the ground) may increase the risk of injury. We examined whether visual focus contributed to the changing lower-extremity dynamics and patellofemoral joint stress during a single-leg drop jump task. Twenty healthy volunteers visited the laboratory for three separate sessions. During each session, participants randomly performed either of two types of a single-leg drop jump task from a 30 cm high wooden box. Subsequently, participants looked at the landing spot (central vision condition) or kept their heads up (peripheral vision condition) when performing the task. Sagittal and frontal plane lower-extremity joint angles and joint moments (in the ankle, knee, and hip), including the vertical ground reaction force, and patellofemoral joint stress during the first landing phase (from initial contact to peak knee flexion) were compared. Greater ankle inversion and hip adduction were observed when landing with the peripheral vision condition. However, the magnitudes were negligeable (Cohen’s d effect size <0.35). No statistical difference was observed in other comparisons. Landing on a single-leg from a 30 cm height without receiving full visual attention (peripheral vision condition) does not increase the risk of lower-extremity traumatic and overuse injuries.

Relationship between lower limb EMG activity and knee frontal plane projection angle during a single-legged drop jump

OBJECTIVES

To assess a relationship between lower limb muscle activity and the frontal plane knee kinematics during a single-legged drop jump.

DESIGN

Correlation study; SETTING: Functional Anatomy Laboratory.

PARTICIPANTS

35 healthy collegiate male athletes.

MAIN OUTCOME MEASURES

Muscle activity (%MVIC) of gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius and lateral gastrocnemius; peak knee frontal plane projection angle; and Pearson's correlation coefficients between muscle activity and peak knee frontal plane projection angle. All outcomes were assessed for both dominant and non-dominant limbs.

RESULTS

Significant correlations (r = 0.46-0.60, P < 0.05) were found between the muscle activities of the gluteus maximus, gluteus medius, biceps femoris, and semitendinosus, when compared to the knee frontal plane projection angle.

CONCLUSION

Gluteal muscles and hamstring muscles are associated with the peak knee frontal plane projection angle during a single-legged drop jump test. Thus, gluteal and hamstring muscle activities should be considered when developing rehabilitation or injury prevention programs.

Review of musculoskeletal modelling in a clinical setting: Current use in rehabilitation design, surgical decision making and healthcare interventions

BACKGROUND

Musculoskeletal modelling is a common means by which to non-invasively analyse movement. Such models have largely been used to observe function in both healthy and patient populations. However, utility in a clinical environment is largely unknown. The aim of this review was to explore existing uses of musculoskeletal models as a clinical intervention, or decision-making, tool.

METHODS

A literature search was performed using PubMed and Scopus to find articles published since 2010 and relating to musculoskeletal modelling and joint and muscle forces.

FINDINGS

4662 abstracts were found, of which 39 relevant articles were reviewed. Journal articles were categorised into 5 distinct groups: non-surgical treatment, orthoses assessment, surgical decision making, surgical intervention assessment and rehabilitation regime assessment. All reviewed articles were authored by collaborations between clinicians and engineers/modellers. Current uses included insight into the development of osteoarthritis, identifying candidates for hamstring lengthening surgery, and the assessment of exercise programmes to reduce joint damage.

INTERPRETATION

There is little evidence showing the use of musculoskeletal modelling as a tool for patient care, despite the ability to assess long-term joint loading and muscle overuse during functional activities, as well as clinical decision making to avoid unfavourable treatment outcomes. Continued collaboration between model developers should aim to create clinically-friendly models which can be used with minimal input and experience by healthcare professionals to determine surgical necessity and suitability for rehabilitation regimes, and in the assessment of orthotic devices.

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.

Physical Therapist Management of Anterior Knee Pain

PURPOSE OF REVIEW

Anterior knee pain is a common musculoskeletal complaint among people of all ages and activity levels. Non-operative approaches with an emphasis on physical therapy management are the recommended initial course of care. The purpose of this review is to describe the current evidence for physical therapist management of anterior knee pain with consideration of biomechanical and psychosocial factors.

RECENT FINDINGS

The latest research suggests anterior knee pain is a combination of biomechanical, neuromuscular, behavioral, and psychological factors. Education strategies to improve the patient's understanding of the condition and manage pain are supported by research. Strong evidence continues to support the primary role of exercise therapy and load progression to achieve long-term improvements in pain and function. Preliminary studies suggest blood flow restriction therapy and movement retraining may be useful adjunct techniques but require further well-designed studies. Anterior knee pain includes multiple conditions with patellofemoral pain being the most common. An insidious onset is typical and often attributed to changes in activity and underlying neuromuscular impairments. A thorough clinical history and physical examination aim to identify the patient's pain beliefs and behaviors, movement faults, and muscle performance that will guide treatment recommendations. Successful physical therapist management involves a combination of individualized patient education, pain management, and load control and progression, with an emphasis on exercise therapy.

Effects of whole body vibration with exercise therapy versus exercise therapy alone on flexibility, vertical jump height, agility and pain in athletes with patellofemoral pain: a randomized clinical trial

Background

Patellofemoral pain (PFP) is the most prevalent orthopedic problem in active young adults. Due to its multifactorial etiology, a variety of therapeutic measures have been adopted to treat PFP, including exercise therapy, electrotherapy, and manual therapy. It has also been suggested that whole body vibration (WBV) can improve neuromuscular function in persons with knee problems. The aim of the present study was to evaluate the effects of adding WBV to routine exercise programs on flexibility, vertical jump height, agility and pain in athletes with PFP.

Methods

Twenty-four male athletes with PFP were randomized into two groups of WBV + exercise (n = 12) or exercise only (n = 12). Participants received their interventions during 4 consecutive weeks (12 sessions). Pain intensity, flexibility and agility were assessed respectively as score on a numerical rating scale, the sit-and-reach test, and a modified T-test, and vertical jump height was measured to the nearest centimeter. The tests were done before and after the interventions, and the results were compared between the two groups. Independent t-tests and paired t-tests were used for between- and within-group comparisons, respectively.

Results

After the interventions, all variables for vertical jump height, flexibility, agility and pain intensity improved significantly in both groups (p < 0.05). The flexibility test showed significantly greater improvement in the WBV + exercise group (p<0.001), whereas for vertical jump height, agility and pain intensity, there were no statistically significant differences between groups (p>0.05).

Conclusions

The present findings showed that exercise therapy with and without WBV can significantly decrease pain and increase agility, vertical jump height and flexibility in athletes with PFP. Adding WBV to routine exercise therapy, however, can augment the effects of the latter on flexibility.

Trial registration

IRCT, IRCT20090831002391N39. Registered 7 February 2018, https://en.irct.ir/search/result?query=IRCT20090831002391N39.

Impaired Knee Muscle Capacity Is Correlated With Impaired Sagittal Kinematics During Jump Landing in Women With Patellofemoral Pain

Nunes, GS, Barton, CJ, and Serrão, FV. Impaired knee muscle capacity is correlated with impaired sagittal kinematics during jump landing in women with patellofemoral pain. J Strength Cond Res XX(X): 000-000, 2020-Knee and hip muscle capacity is impaired in women with patellofemoral pain (PFP), but little is known about the rate of force development (RFD) at the knee. Impaired muscle capacity may contribute to reduced sagittal plane movement at the knee and hip during jump landing in women with PFP. This study aimed to (a) compare knee extensor muscle capacity (including RFD), and hip abductor and extensor muscle capacity between women with and without PFP; and (b) evaluate the relationship between hip/knee muscle capacity and sagittal kinematics during single-legged drop jump landing in women with PFP. Fifty-two physically active women (26 with PFP and 26 controls) participated. Rate of force development (in %/ms), isometric, concentric, and eccentric torque (in N·m·kg × 100) were evaluated using isokinetic dynamometry, and knee and hip kinematics were evaluated using three-dimensional motion capture. Compared with the control group (CG), the PFP group (PFPG) presented lower isometric (12%, PFPG = 217.2 ± 46.0; CG = 246.5 ± 38.8; p = 0.02), concentric (21%, PFPG = 133.0 ± 42.6; CG = 169.2 ± 28.8; p < 0.01), and eccentric (17%, PFPG = 172.9 ± 56.7; CG = 208.4 ± 59.4; p = 0.03) knee extension torque; lower RFD until 30% (30%, PFPG = 0.57 ± 0.27; CG = 0.83 ± 0.37; p < 0.01) and 60% (31%, PFPG = 0.47 ± 0.24; CG = 0.67 ± 0.33; p = 0.01) of maximal isometric torque; and lower concentric hip abduction (13%, PFPG = 94.7 ± 19.1; CG = 108.4 ± 17.5; p = 0.01) and extension (17%, PFPG = 134.4 ± 34.3; CG = 162.6 ± 38.0; p < 0.01) torque. Significant correlations between reduced RFD for knee extension and reduced sagittal plane knee/hip range of motion during landing were identified (r = 0.39-0.49). In conclusion, women with PFP have impaired knee extensor isometric and dynamic strength, and RFD. Impaired knee extensor RFD is associated with a stiffer landing strategy (reduced movement).

A proximal progressive resistance training program targeting strength and power is feasible in people with patellofemoral pain

OBJECTIVES

To evaluate the feasibility of a 12-week progressive resistance training program for people with patellofemoral pain (PFP) targeting proximal muscle strength and power; and resulting clinical and muscle capacity outcomes.

DESIGN

Feasibility study.

SETTING

Clinical environment.

PARTICIPANTS

Mixed-sex sample of people with PFP.

MAIN OUTCOME MEASURES

Feasibility outcomes included eligibility, recruitment rate, intervention adherence, and drop-outs. Secondary outcomes included perceived recovery, physical function (AKPS and KOOS-PF), worst pain (VAS-cm), kinesiophobia (Tampa), physical activity (IPAQ), and hip strength (isometric and 10 repetition maximum) and power.

RESULTS

Eleven people, from 36 who responded to advertisements, commenced the program. One participant withdrew. Ten participants who completed the program reported improvement (3 completely recovered; 6 marked; and 1 moderate). Higher AKPS (effect size [ES] = 1.81), improved KOOS-PF (ES = 1.37), and reduced pain (ES = 3.36) occurred alongside increased hip abduction and extension dynamic strength (ES = 2.22 and 1.92, respectively) and power (ES = 0.78 and 0.77, respectively). Isometric strength improved for hip abduction (ES = 0.99), but not hip extension.

CONCLUSION

A 12-week progressive resistance training program targeting proximal muscle strength and power is feasible and associated with moderate-large improvements in pain, function, and hip muscle capacity in people with PFP. Further research evaluating the efficacy of progressive resistance training is warranted.