Leonardo Metsavaht

Purpose: The spine and hips are biomechanically interconnected, and disorders affecting both are often categorized under hip-spine syndrome. This study explores the link between pelvic motion impairments and hip functional characteristics, specifically hip strength and flexibility, in low back pain patients with increased contralateral pelvic drop and anterior tilt during gait. The hypothesis was that hip strength and flexibility would correlate with pelvic gait kinematics. Methods: This cross-sectional retrospective study analyzed previously collected data from a clinical motion analysis laboratory biomechanical database. Participants aged 18–65 years with acute or chronic low back pain and the ability to ambulate independently were included. Participants had been previously categorized into distinct gait profiles (P1: Flexed trunk; P2: Lumbar rectification; P3: Pelvic impairment; P4: Trunk extension and rotation; P5: Tight axial control) based on three-dimensional gait kinematics using machine learning algorithms. The current analysis examined intra-profile correlations between pelvic motion during gait (pelvic drop and anteversion) and clinical measures of hip function (hip abductor strength and hip flexor/extensor flexibility). Spearman’s rho was used to assess linear correlations and normalized mutual information was computed to explore non-linear associations. Statistical significance was set at p < 0.05. Results: No statistically significant correlations were found for profiles 3, 4, and 5 ( p > 0.05). Although significant correlations emerged within profiles 1 and 2, as well as when considering profiles 1–5 as a single group ( p < 0.05), these lacked clinical relevance due to low biomechanical plausibility. Conclusion: This study builds on previous literature on biokinetic profiles in low back pain and provides new insights into the associations related to hip–spine kinematics. There was no association between hip strength or flexibility and altered pelvic kinematics during gait in the Pelvic Impairment profile. These findings raise the possibility that the observed pelvic motion impairments may reflect associations other than primary deficits in the hip musculature, such as compensatory or neuromotor strategies, which warrant investigation in longitudinal studies.

Purpose: Patellofemoral pain (PFP) is more prevalent in females and altered lower limb biomechanics have been implicated in its development and persistence. However, it remains unclear whether movement patterns differ between men and women with PFP during functional activities. Many biomechanical studies rely on mixed‐sex cohorts, potentially obscuring sex‐specific movement patterns. Therefore, this study aimed to systematically review biomechanical differences between females and males with PFP during functional tasks. Methods: PubMed/MEDLINE, Embase, Scopus, CINAHL, Cochrane CENTRAL, Cochrane Database of Systematic Reviews and Google Scholar were searched from inception to 10 September 2025. Studies comparing in vivo biomechanical characteristics of females and males with PFP during functional tasks were included, whereas studies using mixed‐sex cohorts without sex‐stratified analysis or focusing exclusively on a single sex were excluded. Extracted data comprised participant demographics, methodological characteristics and kinetic and kinematic outcomes. Methodological quality was assessed using a modified Downs and Black checklist. Random‐effects meta‐analyses were performed using standardized mean differences. Results: Five cross‐sectional studies including 170 individuals with PFP (84 females and 86 males) were analysed. Tasks evaluated included single‐leg squat, step‐down, mini‐squat and single‐leg jumping activities. Meta‐analysis of single‐leg squat data showed greater peak hip adduction in females compared with males (mean difference 4.93°, 95% confidence interval [CI] 2.60–7.25; I ² = 0%). Females also demonstrated greater peak knee abduction (mean difference 5.74°, 95% CI 2.31–9.16; I ² = 66%). No significant differences were observed for contralateral pelvic drop. Qualitative synthesis indicated greater frontal‐plane kinematics in females, whereas males demonstrated greater hip, knee and ankle extension moments during jumping tasks. Several findings were based on single studies. Conclusions: Only a limited number of studies evaluated sex‐specific biomechanics in individuals with PFP. Despite the small number of studies, consistent differences between females and males were observed, suggesting that sex influences movement strategies and should be considered in biomechanical assessment and rehabilitation. Level of Evidence: Level IV.

Introduction: Rocker-soled shoes have mechanical advantages by redistributing load to the forefoot and reducing local overload, and are widely used for foot and ankle pathologies and in sports models. By creating a plantar volume proximal to the metatarsal heads, the rocker establishes a fulcrum during support and can modify biomechanics. Compared with conventional shoes, the rocker shifts the point of rotation, redistributes pressure, and can alter the kinematic demands on the hip, knee, and ankle. Although some studies show changes in gait parameters with rocker shoes, the findings are heterogeneous, and there remains a lack of evidence from standardized three-dimensional (3D) analysis protocols in healthy individuals. The objective of this study was to compare 3D kinematic gait parameters in healthy individuals walking in conventional versus rocker shoes, with the hypothesis that rocker shoes would reduce peak knee flexion and ankle eversion/inversion amplitudes. Methods: Cross-sectional study with 20 healthy volunteers (12 men), with clinical alignment of the hindfoot between 0° and 10°. Patients with rigid deformities, prior foot surgery/fractures, rheumatic diseases, and other secondary causes of metatarsalgia were excluded. The following were compared: conventional shoes (flat, flexible sole; 13 mm; 6 mm drop; Ever Way® Marvin) and rocker shoes (rigid sole; 30 mm; apex at 60% of the length; radius 15.5 cm; Hoka® Gaviota 5). The 3D kinematics were collected by a Vicon system with eight cameras. The walk was performed on a treadmill for three minutes at 5.5 km/h. Results: Age 27.9 ± 4.8 years. Conventional shoes showed higher peak knee flexion during support, higher peak and longer ankle eversion times, and lower peak ankle inversion (p < 0.05). Conclusion: The rocker sole modifies gait kinematics in healthy individuals, reducing peak knee flexion and peak ankle eversion time, and increasing peak inversion time, compared to conventional shoes.

Purpose: To investigate the influence of peak contralateral pelvic drop and ipsilateral femoral adduction during running on traditional radiographic parameters of femoral head coverage. Methods: This cross‐sectional retrospective study included 19 patients (38 hips), 9 males and 10 females, with a mean age of 40 ± 10 years, all presenting with symptomatic unilateral femoroacetabular impingement. Participants underwent a three‐dimensional running analysis and anteroposterior pelvic radiographs. Using specialised software, the femur and pelvis were rotated in the coronal plane based on the peak angles of contralateral pelvic drop and femoral adduction obtained from the biokinetic running analysis. After prior validation, traditional femoral head coverage parameters were assessed on both standard and adjusted radiographs, and the variation of each radiographic measurement was obtained. Results: The mean contralateral pelvic drop and ipsilateral femoral adduction were 4.6° ± 3.8° and 5.3° ± 2.6°, respectively. Comparing adjusted with standard radiographs, the lateral centre‐edge angle significantly decreased by 4.8° ± 4.1° ( p < 0.001), while the femoro‐epiphyseal acetabular roof index, acetabular index, sharp angle and extrusion index significantly increased by 10.1° ± 5.9°, 5.4% ± 4.4%, 5.2° ± 4.5° and 4.7° ± 4.0° ( p < 0.001), respectively. After image adjustment, the percentage of hips classified as dysplastic increased based on the lateral centre‐edge angle (0%–18%), acetabular index (11%–45%), extrusion index (5%–21%) and sharp angle (45%–76%). The femoro‐epiphyseal acetabular roof index classified five hips (13%) as unstable. Linear regression demonstrated that each degree of pelvic drop resulted in a decrease of 0.92° of the lateral centre‐edge angle and increases of 0.94°–1.13° in the other radiographic measurements. Conclusion: This study demonstrated that femoral head coverage significantly decreases due to contralateral pelvic drop during running. This results in an increased number of dysplastic findings on adjusted radiographs. Patients with significant contralateral pelvic drop and ipsilateral femoral adduction during running may be at risk for functional dysplasia. Level of Evidence: Level III, retrospective cross‐sectional.

Background: There is a lack of consensus regarding the optimal identification of motion-based subgroups (biokinetic profiles) of patients with patellofemoral pain (PFP) to guide effective management strategies. Purpose: To investigate different biokinetic profiles among patients with PFP during a step-down task and compare their clinical and physical characteristics. Study Design: Descriptive laboratory study. Methods: A total of 49 patients with PFP had their 3-dimensional kinematics assessed during a step-down task using an optoelectronic system. The variables analyzed were trunk and lower limb joint angles. Self-organizing maps and K-means clustering techniques were used to identify distinct biokinetic profiles. Clinical characteristics compared among profiles were hip/knee isometric strength and passive range of motion, descriptive characteristics, and patient-reported outcome measures. Results: Four biokinetic profiles were identified for the step-down task in patients with PFP. Profile 1 (Balanced Alignment Profile) exhibited a trunk-hip-knee aligned movement pattern, with increased knee flexion ( P < .05). This profile presented the highest International Knee Documentation Committee (IKDC) Subjective Form and the lowest visual analog scale (VAS)-Pain scores ( P < .05). Profile 2 (Trunk-hip-knee Compensation Profile) and Profile 3 (Pelvic-Hip Interactor Profile) exhibited increased dynamic knee valgus during the step-down task. However, Profile 2 presented limited trunk ( P < .05) and knee flexion, while Profile 3 presented increased anterior pelvic tilt ( P < .05) and trunk flexion. Profile 2 had excessive passive hip internal rotation ( P < .05) and a majority of women ( P < .05), while Profile 3 exhibited increased isometric hip and knee strength ( P < .05) and lower levels of pain. Profile 4 (Protective Movement Profile) exhibited a possibly protective adaptation, showing decreased hip, knee, and pelvis peak angles and decreased ipsilateral trunk tilt ( P < .05), as well as the lowest IKDC scores and the highest VAS-Pain scores ( P < .05). Conclusion: This study identified 4 clinically relevant biokinetic profiles of patients with PFP based on their kinematics during a step-down task. The principal clinical value of this study is the development of a functional classification for patients with PFP. Each profile exhibits characteristics that may provide valuable insights for clinicians to implement targeted interventions and improve patient care. Acknowledging the variability in movement profiles and their implications in PFP underscores the importance of moving beyond one-size-fits-all treatment strategies. Clinical Relevance: This study uncovers previously unknown movement-based biokinetic profiles in patellofemoral pain and identifies several modifiable clinical characteristics associated with each profile, which could be addressed through targeted interventions.

Purpose The following study aimed to investigate the existence of different gait profiles in patients with low back pain (LBP) and assess their clinical characteristics. Methods This is a cross-sectional retrospective study that included individuals with chronic or acute LBP. Three-dimensional gait kinematics were assessed, including mean angles, range of motion (ROM), and coordination of the trunk and pelvis across three planes. An artificial intelligence algorithm was leveraged to identify distinct gait profiles using principal component analysis, self-organizing maps, and K-means clustering techniques. Clinical characteristics, such as demographics, hip and trunk passive ROM, and hip strength, were compared across profiles using the Kruskal-Wallis test with Bonferroni adjustment at a 5% significance level. Results 111 patients were analyzed (mean age 44.6; 56% females). Five distinct gait profiles were identified. Profile 1 (Flexed Trunk) was mainly characterized by an increased lateral trunk ROM and flexed trunk (4.1^o; 5.2^o; p < 0.05). Profile 2 (Lumbar Rectification), by trunk flexion and posterior pelvic tilt (3.4^o; 7.2^o; p < 0.05). Profile 3 (Pelvic Impairment Profile), by excessive pelvic ROM and maximum angle in the coronal plane (2.9^o and 11.1^o; p < 0.05) and pelvic anterior tilt (12.2^o; p < 0.05). Profile 4 (Trunk Extension and Excessive Rotation), by trunk extension, and excessive trunk axial ROM (-3.0^o; 7.1^o; p < 0.05). Profile 5 (Tight Axial Control), by a prominent pelvis-trunk in-phase component in the coronal and axial planes with pelvic predominance (20.2%; 45.6%; p < 0.001). Profiles 1 and 2 predominantly consisted of males with higher body mass (> 77.3%; >76.8 kg; p < 0.001), while profiles 3 and 4, females with lower body mass (> 86.2%; p < 0.001). Profile 4 displayed increased hip passive ROM, and profiles 1 and 5 decreased (p < 0.05). No significant differences were found in age, hip strength, and passive trunk ROM between profiles (p > 0.05). Conclusion Each of the five profiles identified reveals distinct kinematic and physical characteristics, providing meaningful insights into clinical implications, associated pathologies, anatomical structures at risk, and management.

Background: Running biomechanics can influence injury risk, but whether the combined effect of different biomechanical factors can be identified by individual running profiles remains unclear. Here, we identified distinct biomechanical profiles among healthy runners, examined lower limb mechanical load characteristics, and evaluated potential implications for injury risk. Hypothesis: Multiple factors would serve as a common denominator allowing identification of specific patterns. Study Design: Cross-sectional. Level of Evidence: Level 2. Methods: Step cadence, stance time, vertical oscillation, duty factor, vertical stiffness, peak ground reaction force (GRF), and anteroposterior, lateral, and vertical smoothness were determined from 3-dimensional kinematic data from 79 healthy runners using a treadmill at 2.92 m/s. Principal component analysis, self-organizing maps, and K-means clustering techniques delineated distinct biomechanical running profiles. Mutual information analysis, Kruskal-Wallis, and Pearson’s Chi-squared tests were conducted. Results: Five biomechanical profiles (P1-P5) demonstrated different running mechanical characteristics: P1 exhibited low cumulative and peak mechanical load due to a combination of high duty factor, low step cadence, and longer stance time; P2 showed characteristics associated with the lowest peak mechanical load due to reduced peak GRF and greater smoothness; P3 and P5 showed contrasting running patterns, but maintained moderate smoothness and peak GRF; and P4 exhibited the highest peak mechanical load, driven by high GRF, low duty factor, and high vertical oscillation. Conclusion: The 5 profiles appear to be associated with different lower limb load patterns, highlighting previously unrecognized connections between biomechanical variables during running. Some variables contribute to increased peak and cumulative load, whereas others help reduce it, underscoring the complex interplay of biomechanical factors in running. Clinical Relevance: Identifying distinct running profiles can help clinicians better understand individual variations in mechanical load and injury risk, thus informing targeted interventions, such as personalized training adjustments or rehabilitation programs, to prevent injuries and enhance performance in runners.