Validity of an artificial intelligence, human pose estimation model for measuring single-leg squat kinematics

1065 Gender differences in lower extremity kinematic patterns that put the anterior cruciate ligament (ACL) at risk have been identified during jump landing and cutting, as well as lower level activities such as walking and jogging. Recent reports have suggested that both hip and knee motions may play significant roles in these at risk movement patterns. PURPOSE: To investigate differences in hip and knee movement patterns between genders during level walking with and without the application of an expected perturbation. METHODS: Twenty subjects (10 males, 10 females) who were regular participants in level I or II (e.g., jumping, cutting, and pivoting sports) sports underwent motion analysis while performing self-paced walking trials. Five trials were undisturbed, and five each with a platform translating either laterally or anteriorly at heel contact. Sagittal, frontal, and transverse plane hip motions as well as sagittal and frontal plane knee motions were measured during stance. A repeated measures MANOVA was used to assess motion, excursion and excursion rates during loading response for each combination of motions (sagittal plane hip and knee motion; transverse and frontal plane hip and frontal plane knee motions). RESULTS: Excursions resulting in knee positioning that places the ACL at risk in the frontal and transverse planes were greater at the hip and knee for females than males (p<0.05) in each walking condition. The rate of these excursions was significantly faster for females than males (p<0.05) suggesting that eccentric muscle demand for these motions was higher among female subjects. There was no difference for hip and knee position at initial contact between genders, and there was no difference in the amount of sagittal plane excursion for the hip and knee between genders. CONCLUSIONS: Females demonstrate kinematic characteristics during both normal and disturbed gait that may potentially contribute to increased ACL strain. Repetition of these potentially harmful movement patterns during provocative athletic maneuvers may lead to ACL injury. Injury prevention programs that implement eccentric muscle training for hip abductors and external rotators may aide in controlling excursion and excursion rates, thus reducing the risk for ACL injury. Supported by NIH Grant R01 HD037985-03.

This study aimed to validate the effectiveness of the Articulation Motion Assessment System (AMAS), a joint kinematic evaluation system, for clinical applications. AMAS enables synchronised measurement using neurophysiological indicators, overcoming laboratory setting limitations. We compared AMAS-based ankle joint kinematic evaluations, particularly the sagittal and frontal plane angles, with two-dimensional (2D) motion analysis to determine the validity and reliability of AMAS. Both AMAS and 2D motion analysis reliably detected significant differences in angles within the sagittal and frontal planes. Correlation analysis revealed a significant moderate-to-strong correlation between the AMAS and the conventional method of 2D motion analysis, proving the measurement validity of the AMAS (ρ = 0.53–0.77 for sagittal plane angles; ρ = 0.46–0.72 for frontal plane angles). The average root mean squared error (RMSE) was significantly lower in AMAS (10.90 ± 2.93° for sagittal plane angles; 13.44 ± 1.09° for frontal plane angles) than in the inertial sensor-based three-dimensional (3D) motion analysis. Reliability analysis revealed high reliability of measurements (intraclass correlation coefficients (ICC) ≥ 0.76). However, the Bland–Altman analysis identified a slightly lower fixed bias, which was observed as a characteristic of each measurement system. The AMAS accurately detects ankle joint angles without being constrained by measurement environment limitations. Synchronised measurements using neurophysiological indicators potentially contribute to understanding ankle joint control mechanisms and developing rehabilitation strategies.

Objective: This study aimed to investigate gender and inter-limb differences in hip muscle strength and lower extremity kinematics among high-level adolescent taekwondo athletes. Material and Methods: Thirty-one (15 male, 16 female; aged between 14-18 years) postpubescent adolescent taekwondo athletes were included in this cross-sectional study. A 2 dimensional movement analysis system was used to analyze lower extremity and trunk kinematics during single-leg squats at 60° and peak knee flexion positions. Hip muscle strength was measured using a handheld dynamometer. Results: Female athletes demonstrated higher knee-to-hip ratio (F1,55=4.345, p=0.042) at peak knee flexion. Male athletes exhibited higher trunk lateral flexion angle both at 60° (F1,55=5.411, p=0.024), and at peak knee flexion (F1,55=12.346, p=0.001) positions. Whereas females demonstrated higher hip frontal plane projection angle (FPPA) both at 60° (F1,55=4.402, p=0.040), and at peak knee flexion (F1,55=4.584, p=0.037) positions. Non-dominant side hip FPPA (F1,55=4.108, p=0.048) was higher for both genders. Gender effects were significant across all parameters of hip muscle strength (p<0.05). No interaction between interlimb and gender was found (p>0.05). Conclusion: The results highlight distinct movement patterns in the frontal and sagittal planes during single-leg squats among female and male adolescent taekwondo athletes. These biomechanical differences should be considered when designing corrective exercise programs and interventions aimed at reducing the incidence of knee injuries in taekwondo athletes, particularly during adolescence.

Background Differences in sagittal plane lower limb kinematics have been identified in people with chronic ankle instability (CAI) during sporting activites; however, studies have not considered frontal plane kinematics or assessment of kinematics during functional tasks. Objective To determine if frontal plane kinematics differ in people with and without CAI during single leg squat and step down tasks. Design Case-control study. Setting Research laboratory. Participants Eighteen individuals with CAI (22.5 ± 2 years) and 18 individuals with no previous ankle injury (23.5 ± 4 years) were recruited. Participants with CAI had at least one previous ankle sprain and a minimum of one of the following: repeated sprains on the same ankle, “giving away” of the ankle in the last 6 months, or feelings of ankle instability during sports or daily activities. Interventions Digital cameras recorded movement while participants performed a single leg squat to 60 degrees and stepped off a 17 cm high step. Each task was repeated 3 times. Participants had markers on the following landmarks: anterior superior iliac spines, midshaft of the femur approximately two thirds proximal to the knee, tibial tuberosity, and centre of the malleoli. Digital images were imported into custom-built software and markers were used to calculate knee and pelvis angles. Main outcome measurements Fontal plane knee and pelvis angles and amount of frontal plane movement during the tasks. Results Knee and pelvic angles and amount of movement in the frontal plane did not differ between people with CAI and controls during single leg squat or step down tasks (p > 0.05). Conclusions Frontal plane knee and pelvic kinematics are unaffected in CAI participants during functional tasks. Further research using motion analysis and increased task complexity should be used to confirm this finding and determine the need to address frontal plane knee and pelvis control in CAI management.

Hatfield, GL, Charlton, JM, Cochrane, CK, Hammond, CA, Napier, C, Takacs, J, Krowchuk, NM, and Hunt, MA. The biomechanical demands on the hip during progressive stepping tasks. J Strength Cond Res 31(12): 3444-3453, 2017-Functional hip strengthening exercises are important components of lower extremity (LE) rehabilitation and include single-leg squats (SLS), step-downs (SD), and step-ups (SU). The biomechanical demand of these tasks is unclear. This repeated-measures study determined hip biomechanical demands in a healthy population. Twenty individuals (10 men, 26.6 ± 5.1 years, 22.1 ± 2.3 kg·m) participated. Three-dimensional motion, ground reaction force data, and surface electromyograms (EMG) were recorded during 4 randomly ordered tasks. Outcomes included frontal and sagittal plane hip moment impulses and muscle activity for each task. Repeated measures analysis of variance models (alpha = 0.05) determined between-task differences. Step-down and SLS were most biomechanically demanding, with significantly higher hip flexion and adduction moment impulses, and gluteus medius (GM) and quadriceps activity compared with half step-down (HSD) and SU. No significant difference was found between SD and SLS, indicating minimal difference in demand between the 2 tasks, likely due to kinematic similarities in performance; there were no significant differences in knee or hip sagittal plane angle excursion, or peak pelvic obliquity angle between the 2 tasks. Step-up was least demanding, with the lowest hip flexion and adduction moment impulses and GM, quadriceps, and hamstrings activity. Step-up was least demanding on the hip and would be a good starting task for hip strengthening protocols. Step-down and SLS were most demanding, requiring higher hip moments and muscle activity. These results provide evidence, which may be used in planning of progressive rehabilitation programs for patients with LE pathologies.

Objective To analyze the in vivo three-dimensional kinematics of the proximal carpal row by magnetic resonance imaging (MRI) and to delineate the characteristics of the adaptive kinematics of the proximal carpal row in different movement patterns. Methods We studied the in vivo three-dimensional kinematics of the proximal carpal row with a markerless bone registration technique. Magnetic resonance images of 12 healthy volunteers' wrist were acquired during motion patterns of dart throwing motion (DTM), extension-flexion motion (EFM), and radioulnar deviation (RUD). A total of 15 different wrist positions were performed and recorded from each volunteer. Image data were entered into the software designated for carpal kinematics measurement. The respective motions of the scaphoid and triquetrum relative to the lunate in cross-sectional, sagittal and coronal planes were analyzed. Results In DTM, rotation of the scaphoid relative to the lunate was 0 ° in the cross-sectional plane, 23° in the sagittal plane, and 0° in the coronal plane. In cross-sectional and coronal planes, the range of rotation was not statistically significant (t=-0.039, P=0.970; t=0.163, P=0.873), whereas rotation in the sagittal plane was significant (t=-4.521, P=0.001). In EFM, rotation of the scaphoid relative to the lunate was 2 ° in the cross-sectional plane, 48° in the sagittal plane and 15 °in the coronal plane. In the cross-sectional plane, the movement was not significant (t=0.312, P=0.761), whereas rotation in the sagittal and coronal planes showed statistically significant differences (t=-9.206, P=0.000; t=5.697, P=0.000). In RUD, rotation of the scaphoid relative to the lunate was 7° in the cross-sectional plane, 15° in the sagittal plane and 6° in the coronal plane. Data in the cross-sectional and coronal planes were not significant (t=-1.402, P=0.188; t=-1.410, P=0.186), whereas rotation in the sagittal plane showed statistically significant difference (t=3.180, P=0.009). In DTM, rotation of the triquetrum relative to the lunate was 8° in the cross-sectional plane, 8° in the sagittal plane and 8 ° in the coronal plane. Data in the cross-sectional plane were not significant (t= 2.128, P=0.057), whereas rotation in the sagittal and coronal planes showed statistically significant difference (t=-4.439, P=0.001; t=-3.078, P=0.011). In EFM, rotation of the triquetrum relative to the lunate was 2 ° in the cross-sectional plane, 15° in the sagittal plane and 3 ° in the coronal plane. Data in cross-sectional and coronal planes were not significant (t=0.487, P=0.636; t=-1.455, P=0.174), whereas rotation in the sagittal plane showed significant difference (t=-3.547, P=0.005). In RUD, rotation of the triquetrum relative to the lunate was 4 ° in cross-sectional plane, 4° in the sagittal plane and 7° in the coronal plane. Data in the cross-sectional and sagittal planes were not significant (t=1.006, P=0.336; t=1.015, P=0.332), whereas rotation in the coronal plane showed significant differences (t=-2.236, P=0.047). Conclusion In different movement patterns, the proximal carpal row adapts accordingly. The adaptive motion in the sagittal plane is the most significant, yet the intercarpal motion of proximal carpal row in the cross-sectional and coronal planes are synchronous. Adaptive range of motion between the scaphoid and lunate is much more than that between the lunate and triquetrum. Adaptive range of motion in the EFM is greater than that in the DTM and RUD. The adaptive motion of the proximal carpal row maintains the overall harmonious motion of the wrist. Key words: Carpal bones; Magnetic resonance imaging; Imaging,three-dimensional; Kinematics

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.

Frontal and transverse plane hip kinematics and gluteus maximus recruitment correlate with frontal plane knee kinematics during single-leg squat tests in women

Investigation the effect of Graston Technique on strength and postural stabilization in individuals with asymptomatic dynamic knee valgus

Objective To improve the visualization of anteromedial and posterolateral bundles of anterior cruciate ligament (ACL) and investigate the optimal MRI plane for the bundles at a 3.0 T MR scanner.Methods MR images of 149 knee joints were reviewed retrospectively.Display rates of AMB,PLB and their different parts (the top portion,the middle portion and the low portion) on MR different planes including axial,sagittal and coronal planes were analyzed and their differences were compared with the x2 section method.Results There was no statistical difference in the display rates of two bundles of ACL between axial plane ( 115/149,77.2％ ) and coronal plane (103/149,69.1％ ) (x2 =2.4606,P ＞0.0125 ).Statistical differences were found between axial and sagittal plane,coronal plane and sagittal plane (21/149,14.1％ ) ( x2 =119.5138,92.8695 respectively,P ＜0.0125 ).There was a statistical difference for the top portion of ACL between axial plane ( 104/149,69.8％ ) and coronal plane,sagittal (0/149,0)and coronal planes ( 7/149,4.7％ ) ( x2 =135.081,159.7526 respectively,P ＜ 0.0125 ),between sagittal and coronal planes (x2 =7.1684,P ＜ 0.0125 ).For the middle portion of ACL,there was no statistical difference between axial plane ( 108/149,72.5％ ) and coronal plane (94/149,63.1％ ) (x2 =3.0120,P ＞ 0.0125 ),while statistical differences were found between axial and sagittal plane,coronal planes and sagittal plane ( 10/149,6.7％ ) ( x2 =134.7454,104.2173 respectively,P ＜ 0.0125 ).For the low portion of ACL,there was no statistical difference between axial plane ( 103/149,69.1％ ) and coronal plane (101/149,73.8％ ) (x2 =0.8065,P ＞0.0125),while statistical differences were detected between axial and sagittal plane,coronal planes and sagittal plane ( 18/149,12.1％ ) ( x2 =100.5300,115.9132,P ＜ 0.0125 ). The different parts of ACL displayed low intensity on different MR planes and normal morphology.Conclusions ACL can be displayed on conventional MR planes at a 3.0 T MR scanner to some extent.Axial and coronal planes might be the optimal MRI planes for ACL and its two bundles. Key words: Magnetic resonance imaging; Anterior cruciate ligament; Knee joint

BackgroundStudies have shown that on the coronal plane, whether the direction of the distal locking screw is parallel to the tangent line of the tibiotalar joint can be used to determine whether there is varus or valgus deformity after the treatment of distal tibial fractures with intramedullary nail (IMN) fixation. However, there has been no statistical analysis of the included angle on the coronal plane, and there have been no reports on whether there is a relationship between the direction of the distal locking screw on the sagittal plane or the included angle of the tangent line of the tibiotalar joint and the postoperative alignment of distal tibial fractures treated with IMN fixation.ObjectiveOur aim was to evaluate the relationship between the angles formed by the distal locking screw and the tibiotalar joint tangent (ADTTs) on the sagittal and coronal planes and postoperative alignment in the treatment of distal tibial fractures with IMN fixation.MethodsWe performed a retrospective analysis of 100 patients with distal tibial fractures treated with IMN fixation using the suprapatellar approach. On the coronal and sagittal planes, the ADTTs were arranged from small to large and divided into 4 groups, namely, groups A, B, C and D. One-way ANOVA was used to compare the lateral distal tibial angle (LDTA) and anterior distal tibial angle (ADTA) among all groups, and the chi-square test was used to compare the incidence of postoperative tibial misalignment among all groups. Univariate analysis was performed using chi-square tests to identify factors that might be associated with dislocation, including fibular open reduction and internal fixation (ORIF), limited open reduction, ADTT, IMN diameter, injury mechanism, open vs. closed fracture, comminution, and fibular fracture level. Then, the statistically significant variables in the univariate analysis were included in a multivariate logistic regression equation to evaluate the independent factors related to misalignment.ResultsOn the coronal plane, the ADTTs of groups A, B, C and D were < 0°, 0°-1.3°, 1.3°-2.7° and > 2.7°, respectively. The mean LDTAs of groups B and C (0°-1.3° and 1.3°-2.7°), group A (< 0°) and group D (> 2.7°) were 89.5 ± 1.6°, 92.0 ± 3.2° and 85.8 ± 3.5°, respectively (P < 0.01). Deformity greater than 5° were more likely in groups A and D than groups B and C [14 of 50 (28%) vs. 1 of 50 (2%), P < 0.001]. On the sagittal plane, the ADTTs of groups A, B, C and D were < 8.9°, 8.9°-10.4°, 10.4°-11.7° and > 11.8°, respectively. The average ADTAs of groups B and C (8.9°-10.4° and 10.4°-11.7°), group A (< 8.9°) and group D (> 11.8°) were 80.4 ± 1.3°, 83.1 ± 3.7° and 77.9 ± 2.5°, respectively (P < 0.01). Deformity greater than 5° was more likely in groups A and D than groups B and C [13 of 50 (26%) vs. 0 of 50 (0%), P < 0.001]. An ADTT of 0°-2.7° on the coronal plane and 8.9°-11.7° on the sagittal plane (OR: 0.08, P = 0.02) and limited open reduction (OR: 0.21, P < 0.01) were independent factors that reduced the likelihood of misalignment.ConclusionThe alignment of distal tibial fractures after surgery is sensitive to the ADTT and use of limited open reduction. Controlling the ADTT between 0° and 2.7° on the coronal plane and between 8.9° and 11.7° on the sagittal plane is helpful to reduce the occurrence of misalignment after the treatment of distal tibial fractures by IMN fixation.

Background: Movement variability may affect injury assessment and may change as athletes mature. Hypothesis/Purpose: We hypothesized that pre-teen athletes would exhibit greater variability than teenage athletes when performing drop jump, heel touch, and single leg hop motions. Methods: 55 uninjured pediatric athletes were divided into pre-teen (age 7-12 years; n=29; 11 female) and teenage (age 13-15 years; n=26; 13 female) groups of similar size. All participants performed 2-3 repetitions per side of three sports related tasks: drop jump (41 cm), heel touch (single-leg squat from 15 cm or 23 cm step, depending on whether subject height &lt;155 cm), and single leg hop for distance. 3D kinematics were recorded using motion capture during the loading phase of each task. To assess intra-individual variability, we examined the standard deviation (SD) and range (maximum-minimum) of key metrics among the multiple repetitions of each task performed by each participant. Variability was compared between age groups using 2-sided t-tests. Results: In the drop jump and heel touch, the younger group was more variable than the older group (Figure 1.1 left). The median within-subject SD of repeat measurements varied from 1-6° in the sagittal plane, 1-3° in the frontal plane, and 1-4° in the transverse plane over both groups (Table 1.2), while the within-subject range of measurements varied from 2-11° in the sagittal, 2-5° in the frontal, and 2-7° in the transverse planes (Table 1.3). Representing a worst-case scenario, the 95th percentile for range of measurements was &gt;15° for many sagittal plane variables and &gt;10° for many frontal and transverse plane variables in the younger group. In the singl- leg hop, the older group was much more variable than the younger group in the sagittal plane, particularly at the trunk, pelvis, and ankle (Figure 1.1 right). The younger group was still more variable than the older group at the trunk and pelvis in the transverse plane. Median within-subject variability ranged from 2-9° for SD and 3-17° for range of repeat measurements. Conclusion: There was substantial within-subject variability in performing sports related tasks for pediatric athletes of all ages. Variability was generally lower for older athletes, but was particularly high in the older group for sagittal plane trunk and pelvis motion during single-leg hop landing, which may reflect the need to adjust for less constrained positioning of a larger proximal mass. The high variability in performing sports tasks suggests that multiple trials should be analyzed for a more complete and representative evaluation. [Figure: see text][Table: see text][Table: see text]

The position of the anterior cruciate ligament (ACL) is one of the anatomical factors that lead to its injury. We evaluated 66 patients divided in two groups: 33 patients in the examined group with a diagnosed ACL lesion, and 33 patients in the control group with diagnosed patellofemoral pain. The patients were matched by age, sex, type of lesion (whether it was profession related) and whether the lesion was left or right sided. Measurements were carried out by radiography and MRI. The following positions of angles were measured: the angle of ACL in sagittal and frontal plane, the angle of the inner side of lateral condyle in frontal and horizontal plane and the angle between the course of ACL and the inner side of lateral condyle. In our study there is a significant difference (P < 0.05) in the degree of the ACL angles in the frontal plane between the examined group (74.5 degrees) and the control group (70.6 degrees). Also, there was a significant difference (P < 0.05) in the degree of the ACL angle in the sagittal plane between the examined group (48 degrees ) and the control (50.4 degrees). The angle between the inner side of the lateral condyle of the femur and the ACL of the examined group (32.9 degrees) differs significantly (P < 0.01) from the same angle of the control group (40.6 degrees ). According to the results of our study it appears that the increment of the ACL angle in the frontal plane, the decrement of the ACL angle in the sagittal plane and the decrement of the angle between the ACL and the inner side of the lateral condyle in the frontal plane are associated with the rupture of the ACL.

Bone cutting errors can cause malalignment of unicompartmental knee arthroplasties (UKA). Although the extent of tibial malalignment due to horizontal cutting errors has been well reported, there is a lack of studies evaluating malalignment as a consequence of keel cutting errors, particularly in the Oxford UKA. The purpose of this study was to examine keel cutting errors during Oxford UKA placement using a navigation system and to clarify whether two different tibial keel cutting techniques would have different error rates. The alignment of the tibial cut surface after a horizontal osteotomy and the surface of the tibial trial component was measured with a navigation system. Cutting error was defined as the angular difference between these measurements. The following two techniques were used: the standard "pushing" technique in 83 patients (group P) and a modified "dolphin" technique in 41 patients (group D). In all 123 patients studied, the mean absolute keel cutting error was 1.7° and 1.4° in the coronal and sagittal planes, respectively. In group P, there were 22 outlier patients (27%) in the coronal plane and 13 (16%) in the sagittal plane. Group D had three outlier patients (8%) in the coronal plane and none (0%) in the sagittal plane. Significant differences were observed in the outlier ratio of these techniques in both the sagittal (P=0.014) and coronal (P=0.008) planes. Our study demonstrated overall keel cutting errors of 1.7° in the coronal plane and 1.4° in the sagittal plane. The "dolphin" technique was found to significantly reduce keel cutting errors on the tibial side. This technique will be useful for accurate component positioning and therefore improve the longevity of Oxford UKAs. Retrospective comparative study, Level III.

Evaluation of dynamic spinal alignment changes and compensation using three-dimensional gait motion analysis for dropped head syndrome