Frontal Plane Projection Angle Research Articles

Reliability And Validity Of Dynamic Frontal Plane Motion Visual Assessments During A Lateral Step Down

Quantitative assessment of dynamic frontal plane knee motion has been reported to be reliable and valid in a female population. Research investigating the qualitative assessment is limited and small in numbers. PURPOSE: To test the inter- and intra-tester reliability and validity of a qualitative assessment of frontal plane knee motion during a lateral step down. METHODS: Twenty-four men (age=23.7±4.6 years, height=180.7±6.6 cm, weight=86.9±4.8 kg) and thirty women (age = 22.7±4.7 years, height = 168.7±6.9 cm, weight = 66.7±15.4 kg) who self-reported as healthy, active, and free from lower extremity pain/injury participated. Five lateral step-downs were recorded using a video camera and 3D motion capture system on two separate testing dates. Images and knee frontal plane angles were extracted from the video and 3D motion analysis data, respectively, at standing and maximum knee flexion. Two testers observed the videos and images to classify the movement as dynamic valgus (>10°), no change (-10 to 10), or dynamic valgus (<-10°). The classification was based on the estimated change in frontal plane projection angle (FPPA) of the knee from single-legged stance to maximum knee flexion. The FPPA and actual change values were calculated separately. Kappa (κ) values were used to determine reliability and construct validity. RESULTS: A total of 274 videos were analyzed. The intratester reliability was κ=0.724 (women [w]: 0.766, men [m]: 0.642) for tester one and κ=0.626 (w: 0.654, m: 0.581) for tester two. The intertester reliability was κ=0.481 (w: 0.554, m: 0.370) on day one and κ=0.505 (w: 0.473, m: 0.529) on day two. Compared to FPPA, visual assessment resulted in κ=0.602 (w: 0.635, m: 0.475), κ=0.371 (w: 0.497, m: 0.190), κ=0.516 (w: 0.698, m:0.153), κ=0.364 (w: 0.455, m: 0.155) for testers one and two, respectively, on days one and two, respectively. CONCLUSIONS: This study is the first to test reliability and validity in a large sample of men and women. Reliability was fair to substantial and agreement with FPPA was slight to moderate. Results were typically better in women because they rarely demonstrated dynamic varus. Use of visual assessment in the categorization of dynamic frontal plane motion is questionable, especially in a male population.

Comparison of 2-Dimensional Measurement of Knee Frontal Plane Projection Angle in ACL Injured Athletes

Comparison of 2-Dimensional Measurement of Knee Frontal Plane Projection Angle in ACL Injured Athletes

Reliability And Validity Of The Frontal Plane Projection Angle During A Lateral Step-down

Reliability And Validity Of The Frontal Plane Projection Angle During A Lateral Step-down

A preliminary study into the effect of jumping–landing training and strength training on frontal plane projection angle

The presence of increased knee valgus angles during functional tasks has been associated with a range of knee pathologies. A number of different exercise interventions have been undertaken to improve knee alignment during functional tasks. The most successful of these interventions are multi-modal incorporating both strength and jump–landing training. Little research has been undertaken to compare these elements individually to assess if success is due to an individual element or the training as a whole. The study assessed the between group effects of strength training or jump–landing training alone on knee valgus alignment during a number of functional tasks, using a cohort specific treatment superiority design. Thirty asymptomatic female participants undertook a 6 week (minimum 15 sessions) strength or jump–landing programme, the effects of which were examined by assessing for any change in frontal plane projection angle (FPPA) during single leg squat and landing and bilateral drop jump landing. Both training methods had positive effects of FPPA during some but not all of the tasks. Strength training brought about significant changes in FPPA during single leg squat and landing, whilst jump–landing training significantly influenced single leg landing and drop jump landing performance. The changes reported, therefore appear to be related to the nature of the training and the tasks undertaken during that training. The findings indicating that a combined training protocol incorporating both strengthening and jump–landing training may bring about the greatest improvement across a spectrum of tasks for the patient, supporting the previous work on multimodal training.

Does anterior knee pain severity and function relate to the frontal plane projection angle and trunk and hip strength in women with patellofemoral pain?

The aim of the present study was to determine the relationship between knee pain severity and function with the frontal plane projection angle (FPPA) and trunk and hip peak torque (PT) in women with patellofemoral pain (PFPS). Twenty-two women with PFPS were assessed. Knee pain severity (KPS) was assessed with an 11-point visual analog scale and function with an Anterior Knee Pain Scale. The FPPA was recorded with a digital camera. PT of extensors, abductors, and the lateral rotators of hip and lateral core stability were measured with a handheld dynamometer. FPPA was the only predictor for the KPS. Regarding predictors of function, PT of lateral core stability and the extensor and abductor of the hip explained 41.4% of the function. Increase in FPPA was associated with greater KPS, and the lowest PT of lateral core stability, hip abductors, and extensors was associated with lower function in women with PFPS.

Foot and ankle mobility and the frontal plane projection angle in asymptomatic controls

The frontal plane projection angle (FPPA) is a measure of the degree of dynamic knee valgus during functional tasks such as the single leg squat. An increased FPPA is associated with patellofemoral pain and is indicative of knee valgus during other tasks such as running. Therefore, it is important to determine factors that can contribute to FPPA in order to develop treatment strategies for people with (or at risk of) PFJ pain.

Reliability of Hop Distance and Frontal-Plane Dynamic Knee Valgus Angle during Single-leg Horizontal Hop Test

Context: Single-leg hop for distance (SHD) performance and twodimensional (2-D) video assessment of frontal-plane knee valgus, during the single-leg landings, have been reported to identify the risk of knee injuries such as patellofemoral pain syndrome and/ or anterior cruciate ligament tears. There are limited studies investigating the reliability and measurement error in single-leg hop for distance test and the 2-D video analysis of knee valgus angle on landing from this maximal forward hop. Objective: To evaluate the reliability and measurement error of hop distance and 2-D video assessment of lower limb frontal-plane dynamic knee valgus on landing during the SHD task. Design: Repeated measures reliability study. Participants: 12 recreationally active university students (8 men and 4 women 34.2 ± 3.1 y, height 170.8 ± 6.5 cm; mass 82.1 ± 15.9 kg). Main outcome measurement: Within and between-days reliability and measurement error values of hop performance and 2-D frontalplane projection angle (FPPA) during SHD test. Methods: For hop and 2-D tests: participants performed maximal SHD with standard 2-D digital video recording of the landing for assessment of FPPA. Results: For hop test distance: the within-day ICCs showed good to excellent reliability (0.89-0.93), and between-days ICCs were good, (0.85- 0.90). Standard error of measurement for SHD value ranged from 6.52- 9.83 cm. FPPA on landing: the within-day ICCs showed good reliability (0.87 to 0.90), and between-days ICCs were good, (0.81-0.88). Standard error of measurement for 2-D values ranged from 1.33-1.61°. Conclusions: Hop distance and 2-D FPPA on landing during SHD were shown to be a reliable measure of lower extremity performance and dynamic knee valgus. Using the measurement error values existing along with previously published normative data, clinicians can now make informed decisions about individual performance and variations in performance/injury risk following interventions.

Foot and ankle mobility on the frontal plane projection angle in asymptomatic controls: Implications for patellofemoral pain

Introduction: The frontal plane projection angle (FPPA) is a measure of the degree of dynamic knee valgus during functional tasks such as the single leg squat. An increased FPPA is associated with, and is a risk factor for patellofemoral pain (PFP). Therefore, it is important to determine factors that can contribute to FPPA in order to develop treatment strategies for people with (or at risk of) PFP. Foot and ankle mobility can influence tibial rotations and hence, may be associated with FPPA.

Observational Ratings of Frontal Plane Knee Position Are Related to the Frontal Plane Projection Angle but Not the Knee Abduction Angle During a Step-down Task

Laboratory study, cross-sectional. To determine if the magnitude of frontal plane knee angle, as determined with a 3-D motion-capture system (knee abduction angle [KAA]) or digital video (frontal plane projection angle [FPPA]), varies among groups of individuals with different frontal plane knee position, as determined by observational ratings. Performing functional tasks with the knee positioned medial to the foot may increase the risk for knee injury. The KAA and FPPA are commonly used in research settings to determine injury risk. However, observational ratings of frontal plane knee position are easier to perform in the clinical setting. It is not clear whether observational ratings of knee position can be used as a surrogate for the KAA or FPPA. Eighty-one female collegiate athletes performed a lateral step-down task. Participants were rated as good, fair, or poor based on observation of their knee position relative to the foot in the frontal plane and assigned to observational rating groups. Movement was concurrently recorded with a 3-D motion-capture system and a digital video camera to calculate KAA and FPPA, respectively. Knee abduction angle did not differ among participants assigned to the different observational rating groups (P = .265). In contrast, FPPA values differed between groups (P<.001), with the highest values in the poor group and the lowest values in the good group. Observational ratings of frontal plane knee position relative to the foot are an appropriate clinical substitute for FPPA but not KAA. Therefore, observational ratings of medial knee position may be more suitable as a clinical screening tool when FPPA is the measure of interest.

Reliability of Using a Handheld Tablet and Application to Measure Lower-Extremity Alignment Angles.

Landing kinematics have been identified as a risk factor for knee injury. Detecting atypical kinematics in clinical settings is important for identifying individuals at risk for these injuries. To determine the reliability of a handheld tablet and application (app) for measuring lower-extremity kinematics during drop vertical-jump landings. Measurement reliability. Laboratory. 23 healthy young adults with no lower-extremity injuries and no contraindications for jumping and landing. Subjects performed 6 drop vertical jumps that were captured with an iPad2 and analyzed with a KinesioCapture app by 2 novice and 2 experienced raters. Three trials each were captured in the frontal and sagittal planes. Frontal-plane projection angles, knee flexion, and hip flexion at initial contact and maximum knee flexion were measured. ICC and SEM were calculated to determine intertrial and interrater reliability. One-way ANOVAs were used to examine differences between the measured angles of the raters. Average intertrial reliability ranged from .71 to .98 for novice raters and .77 to .99 for experienced raters. SEMs were 2.3-4.3° for novice raters and 1.6-3.9° for experienced raters. Interrater ICC2,1 was.39-.98 for the novice raters and .69-.93 for the experienced raters. SEMs were smallest with the experiences raters, all less than 1.5°. A handheld tablet and app is promising for evaluating landing kinematics and identifying individuals at risk for knee injury in a clinical setting. Intertrial reliability is good to excellent when using average trial measures. Interrater reliability is fair to excellent depending on experience level. Multiple trials should be assessed by a single rater when assessing lower-extremity mechanics with a handheld tablet and app, and results may vary with experience level or training.

The Effect of Hip Abductor Muscle Fatigue on Frontal Plane Knee Projection Angle During Step Landing

Context:A number of acute and overuse knee pathologies share a mechanism involving a poor dynamic alignment of the limb creating increased stress in the tissues. Inappropriate execution of a correct strategy during landing has been suggested to involve insufficient activity of the hip abductor and external rotator muscles. Limited data describing the relationships between hip-abductor muscle fatigue and hip/knee joint mechanics exists.Objective:To investigate the effect of fatigue of the hip abductor muscles on knee valgus angle.Design:Repeated measures.Participants:30 asymptomatic subjects: 15 female (age 20.4 ± 1.4, range 18–26 years; height 1.66 m, range 1.60–1.76 m; weight 63.9 kg, range 58–68 kg) and 15 male subjects (age 22 ± 3.2, range 18–28 years; height 1.84 m, range 1.65–1.90 m; weight 82.1 kg, range 69–93 kg).Main outcome Measures:Knee valgus (frontal plane projection) angle was assessed during a step landing task before and following a fatiguing protocol of the hip abductor muscles involving repeated 10 s maximal isometric contractions of the hip abductor muscles, until strength was recorded as 50% of preintervention score.Results:Males showed no significant change in knee valgus angle at initial ground contact (p = .9 ES 0.1) or in maximum knee valgus (p = .64 ES 0.5) following the fatiguing. Females showed a significant increase in maximum knee valgus angle following the fatiguing (p = .0018 ES 1.0), though the knee valgus angle at initial contact was not changed (p = .12 ES 0.67). They also demonstrated a significant increase in the change in knee valgus angle between initial contact and maximum following the fatiguing (p = .0004 ES 0.88).Conclusion:Females appear more susceptible to the effects of hip muscle fatigue, leading to a detrimental change in landing kinematics which may then predispose them to knee injury.

Relationship between hip and core strength and frontal plane alignment during a single leg squat

ObjectiveThe purpose of this study was to examine the relationship between frontal plane kinematics of the single leg squat and strength of the trunk and hip in females. ParticipantsForty healthy females participated in this study. MethodsAn isometric “make” test using a dynamometer was used to assess peak force normalized to body weight for hip abduction, hip extension, hip external rotation, and a sidelying plank test. Two-dimensional software was used to analyze the frontal plane projection angle (FPPA) and pelvic angle during a single leg squat to 60°. ResultsAll 4 strength factors were significantly correlated with the FPPA, ranging from r = 0.396 to r = 0.466. During multiple regression analysis, hip abduction strength was the greatest predictor of the variation in FPPA at r2 = 0.22, p = 0.002. Thus, hip abduction strength accounted for 22% of the variation in the FPPA during the single leg squat. The only strength factor demonstrating a significant correlation with the pelvic angle was hip extension strength (r = 0.550, p < 0.001). ConclusionClinicians should consider the role of the hip abductors, hip external rotators, hip extensors and core musculature on the impact on the FPPA during a single squat, with focus on the hip abductors.

AB1165-HPR Relationship between Anterior Knee Pain Severity, Functional Capacity, Frontal Plane Projection Angle, Trunk and Hip Strength in Patellofemoral Pain

BackgroundPatellofemoral Pain Syndrome (PFPS) is characterized by anterior knee pain most commonly on the patella lateral facet. Although the increased Frontal Plane Projection Angle (FPPA), core deficit and hip strength...

The effect of videotape augmented feedback on drop jump landing strategy: Implications for anterior cruciate ligament and patellofemoral joint injury prevention

BackgroundModification of high-risk movement strategies such as dynamic knee valgus is key to the reduction of anterior cruciate ligament (ACL) and patellofemoral joint (PFJ) injuries. Augmented feedback, which includes video and verbal feedback, could offer a quick, simple and effective alternative to training programs for altering high-risk movement patterns. It is not clear whether feedback can reduce dynamic knee valgus measured using frontal plane projection angle (FPPA). MethodsVertical ground reaction force (vGRF), two-dimensional FPPA of the knee, contact time and jump height of 20 recreationally active university students were measured during a drop jump task pre- and post- an augmented feedback intervention. A control group of eight recreationally active university students were also studied at baseline and repeat test. ResultsThere was a significant reduction in vGRF (p=0.033), FPPA (p<0.001) and jump height (p<0.001) and an increase in contact time (p<0.001) post feedback in the intervention group. No changes were evident in the control group. ConclusionAugmented feedback leads to significant decreases in vGRF, FPPA and contact time which may help to reduce ACL and PFJ injury risk. However, these changes may result in decreased performance. Clinical relevanceAugmented feedback reduces dynamic knee valgus, as measured via FPPA, and forces experienced during the drop jump task and therefore could be used as a tool for helping decrease ACL and PFJ injury risk prior to, or as part of, the implementation of injury prevention training programs.

THE RELATIONSHIP BETWEEN 2D KNEE VALGUS ANGLE DURING SINGLE LEG SQUAT (SLS), SINGLE LEG LANDING (SLL), AND FORWARD RUNNING

BackgroundTwo-dimensional (2D) analysis of knee valgus during common athletic screening tasks such as SLS has been purported to identify individuals who may be at a high-risk of ACL injury. There...

Knee valgus angle during single leg squat and landing in patellofemoral pain patients and controls

BackgroundPatellofemoral pain (PFP) is a commonly presenting disorder of the lower limb, frequently effecting young physically active individuals particularly females. The condition has been associated with poor control of limb alignment while undertaking unilateral limb loading tasks. This poor alignment of the limb is believed to alter loading stress within the patellofemoral joint. This study aims to investigate the degree of knee valgus, assessed as 2D frontal plane projection angle (FPPA) during single leg squatting (SLS) and hop landing (SLL) tasks in patients with PFP and compare their performance to controls and the uninjured limb. MethodTwelve female subjects with unilateral PFP formed the patient group and thirty asymptomatic females formed the control group. They had their 2D frontal plane projection angle (FPPA) assessed during single leg squatting (SLS) and hop landing (SLL) tasks. ResultsIn the asymptomatic control group the mean FPPA for SLS was 8.4±5.1° and SLL had a mean FPPA of 13.5±5.7°. In the PFP group the mean FPPA for SLS was 16.8±5.4° and SLL had a mean FPPA of 21.7+/−3.6°, these differences were significant (p<0.01) for both tasks. ConclusionPatients with PFP have a greater degree of knee valgus on unilateral limb loading task than either their contralateral asymptomatic limb or an asymptomatic control group. If not corrected this may lead to further PFJ stress and ongoing morbidity.

Comparison of 2-Dimensional Measurement Techniques for Predicting Knee Angle and Moment During a Drop Vertical Jump

To determine the association of 2-dimensional (2D) video-based techniques and 3-dimensional (3D) motion analysis to assess potential knee injury risk factors during jump landing. Observational study. Research laboratory. Thirty-six female athletes in cutting and pivoting sports. : Athletes performed a drop vertical jump during which movement was recorded with a motion analysis system and a digital video camera positioned in the frontal plane. The 2D variables were the frontal plane projection angle (FPPA), the angle formed between thigh and leg, and the knee-to-ankle separation ratio, the distance between knee joints divided by the distance between ankles. The 3D variables were knee abduction angle and external abduction moment. All variables were assessed at peak knee flexion. Linear regression assessed the relationship between the 2D and 3D variables. In addition, intraclass correlation coefficients (ICC) determined rater reliability for the 2D variables and compared the 2D measurements made from digital video with the same measurements from the motion analysis. : The knee-to-ankle separation ratio accounted for a higher variance of 3D knee abduction angle (r = 0.350) and knee abduction moment (r = 0.394) when compared with the FPPA (r = 0.145, 0.254). The digital video measures had favorable rater reliability (ICC, 0.89-0.94) and were comparable with the motion analysis system (ICC, ≥ 0.92). When compared with the FPPA, the knee-to-ankle separation ratio had better association with previously cited knee injury risk factors in female athletes. The 2D measures have adequate consistency and validity to merit further clinical consideration in jump landing assessments.

Reliability of 2-Dimensional Video Assessment of Frontal-Plane Dynamic Knee Valgus During Common Athletic Screening Tasks

Two-dimensional (2D) video analysis of frontal-plane dynamic knee valgus during common athletic screening tasks has been purported to identify individuals who may be at high risk of suffering knee injuries such as anterior cruciate ligament tear or patellofemoral pain syndrome. Although the validity of 2D video analysis has been studied, the associated reliability and measurement error have not. To assess the reliability and associated measurement error of a 2D video analysis of lower limb dynamic valgus. Reliability study. 20 recreationally active university students (10 women age 21.5 ± 2.3 y, height 170.1 ± 6.1 cm, weight 66.2 ± 10.2 kg, and 10 men age 22.6 ± 3.1 y, height 177.9 ± 6.0 cm, weight 75.8 ± 7.9 kg). Within-day and between-days reliability and measurement-error values of 2D frontal-plane projection angle (FPPA) during common screening tasks. Participants performed single-leg squat and drop jump and single-leg landings from a standard 28-cm step with standard 2D digital video camera assessment. Women demonstrated significantly higher FPPA in all tests except the left single-leg squat. Within-day ICCs showed good reliability and ranged from .59 to .88, and between-days ICCs were good to excellent, ranging from .72 to .91. Standard error of measurement and smallest detectable difference values ranged from 2.72° to 3.01° and 7.54° to 8.93°, respectively. 2D FPPA has previously been shown to be valid and has now also been shown to be a reliable measure of lower extremity dynamic knee valgus. Using the measurement error values presented along with previously published normative data, clinicians can now make informed judgments about individual performance and changes in performance resulting from interventions.

Normative values of dynamic knee valgus during single leg squat in basketball and volleyball athletes

BackgroundVolleyball and basketball are among the sports with a higher incidence of knee injuries. The inability to maintain a proper alignment of the lower limbs during functional activities could create...

Comparison of 2D and 3D kinematic changes during a single leg step down following neuromuscular training

Objectives Evaluate the effects of a weight-bearing neuromuscular training program on 2D and 3D lower extremity kinematics during a single leg step down. Design Pre-test, post-test quasi experimental. Setting Laboratory. Participants Sixty nine healthy females performed a single leg step down. The 20 females with the most medial knee orientation during this task participated in this study (20.0 yr (1.6 yr), 167.9 cm (6.0 cm), 63.2 kg (8.3 kg)). Main Outcome Measures 2D knee frontal plane projection angle (FPPA) and 3D lower extremity joint (hip and knee) and segment (pelvis and femur) angles during a single leg step down before and after training were compared using paired t-tests. Pearson correlation coefficients were used to measure the association of 2D and 3D kinematic changes following training. Results Knee FPPA decreased 4.6° after training ( P < 0.001). Hip flexion ( P < 0.001) and hip adduction ( P = 0.04) increased after training. However, no other 3D joint kinematic changes were observed. Segment angle changes included decreased femoral internal rotation ( P = 0.008) and adduction ( P = 0.08) and increased anterior pelvic tilt ( P < 0.001) and contralateral pelvic drop ( P = 0.02). The association between changes in 2D and 3D joint kinematics ranged from 0.12 to 0.34. Conclusions Exercises intended to improve altered lower extremity kinematics may reduce medial knee 2D FPPA values during a single leg step down. However, this 2D change may not be linked with any specific change in 3D joint kinematics.