Stretching research and practice relies heavily on internal and clinical perceptions of stretching sensation to prescribe intensity due to the lack of equipment required. No research has assessed the relationship between internal and external perceptions of stretch intensity. The purpose of this study was to assess the relationship between participants' stretch sensation and researchers' perception of muscle tension in two passive stretches; supine hip flexion and shoulder extension. Training status and stretching experience were considered with the 18 young adult participants. Joint angles at which participants signaled initial stretch sensation and maximum tolerable stretch for each protocol were recorded by a secondary researcher. The blinded primary researcher recorded joint angles where initial tension and maximum tension were perceived as they executed passive stretching of the participant. While there was evidence of greater hip flexion ROM for women, athletes, participants with stretching experience, as well as with stretching to maximum versus initial point of discomfort, there were no significant differences between the participants and researcher's measurements at initial or maximum endpoints, however correlation and agreement between participant and researcher perceptions were variable. There was an overall large magnitude (eta2 = 0.794), non-significant difference (p = 0.06) with researcher maximum (108.39° ± 17.22) hip flexion measurements higher than participants (98.6° ± 20.08). This mean difference was more apparent with the greater divergence with less trained individuals and stretching experience. Shoulder extension ROM did not reveal any group differences (i.e., sex, trained state, stretch experience). This research demonstrated excellent reliability overall of participant and researcher perceptions for hip flexion and shoulder stretches with lower correlations for sedentary and inexperienced individuals. Results highlight the need for training status and stretching experience to be considered in stretching intensity prescription and scale development.

Mechanical properties of the deep muscle fascia are important in myofascial force transmission and injury; however, its investigation by shear wave elastography (SWE) in the literature is minimal. Regional differences in biarticular muscle stiffness have implications in mechanism of injury. To determine region-specific differences in rectus femoris (RF) fascia and muscle stiffness, 20 healthy participants completed two visits in which RF fascia (FAS) and superficial (SUP) and deep (DEEP) muscle regions were assessed by SWE in three muscle regions (proximal - PROX, medial - MED and distal - DIST) and at three muscle lengths (relaxed - REL, neutral - NEU and passively stretched - PAST). DEEP was consistently stiffer than SUP muscle tissue (all p<0.01) in all conditions and regions, except for REL PROX. Regional differences in SWV in all of FAS, SUP and DEEP were dependent upon local strain. Hip extension increased proximal tissue stiffness above medial and distal regions (all p<0.001) and conditions of hip flexion (p<0.001, p=0.004 and p=0.002, respectively). Similarly, knee flexion increased distal tissue stiffness above conditions of knee extension (all p<0.001). Stretching the muscle by hip extension and knee flexion (PAST) removed differences between the regions in FAS, SUP and DEEP and increased medial SWV above REL and NEU (all p<0.001). These results provide novel insight into regional differences in biarticular muscle and fascial tissue stiffness, implying that local strain increases stiffness in the adjacent region. These findings may have implications in force generation and region-specific mechanisms of injury.

Dual-task effects on spatiotemporal, kinematic, and kinetic parameters and their variability during running.

Immediate effects of ankle-foot orthosis on gait coordination and kinematics in subacute stroke.

Gait asymmetries in children and adolescents with mild leg length discrepancy.

The purpose of this study is to investigate the effect of lower extremity rehabilitation robot training on range of motion (ROM) and balance ability in chronic stroke patients, thereby providing basic data for effective rehabilitation intervention strategies. The subjects were 40 stroke patients who were randomly assigned to an experimental group (n=20) and a control group (n=20). The experimental group performed bridge exercises and gait training using the Angel Robotics walking robot for 20 minutes, while the control group performed bridge exercises and manual resistance exercises provided by a therapist. The intervention was conducted for 4 weeks. To compare the effects before and after the intervention, the ROM of the hip and knee joints was measured using an electronic goniometer, and the Berg Balance Scale (BBS) was assessed. First, regarding the changes in ROM for hip flexion and knee flexion, the experimental group, which combined lower extremity rehabilitation robot training, showed a statistically significant improvement compared to the control group (p&lt;.05). Second, regarding the changes in BBS scores evaluating balance ability, the experimental group also showed a significantly higher improvement than the control group (p&lt;.05). In conclusion, this study confirmed that lower limb rehabilitation robot training is a more effective intervention method than simple muscle strengthening exercises for securing ROM in the lower extremities and enhancing balance in stroke patients. These findings suggest that robot-assisted training can be applied as a useful clinical option to improve lower limb functional recovery and postural control, while also validating the clinical utility of advanced robotic technology in stroke rehabilitation.

Avascular necrosis (AVN) is a progressive bone disorder caused by disruption of blood supply, leading to bone necrosis, structural collapse, and joint dysfunction. Early diagnosis and timely intervention are essential to prevent irreversible disability. We report the case of a 35-year-old Indian male who presented with severe left hip pain significantly affecting daily activities. Magnetic resonance imaging confirmed bilateral AVN, with Grade IV involvement of the left hip and Grade II–III involvement of the right hip. Conservative management failed to provide symptomatic relief, necessitating surgical intervention in the form of total left hip replacement and right hip core decompression. Postoperatively, the patient demonstrated clinical improvement, with pain scores on the Visual Analog Scale reducing from 8/10 to 6/10, hip flexion improving from 90° to 120°, and muscle strength increasing from grade 3/5 to 4/5. AVN is commonly associated with trauma, corticosteroid use, and systemic conditions and progresses from ischemia to joint degeneration if untreated. This case emphasizes the importance of early MRI-based diagnosis and individualized treatment strategies, as advanced AVN often requires surgical management to improve pain, mobility, and overall quality of life.

ABSTRACT This study aims to examine the effects of a four-week intervention using skilled model video instruction and individualized video and implicit verbal feedback on sidestep cutting in youth female soccer players. Forty-eight talented adolescent subjects practiced and received general task instructions. The VIDEO group received skilled model video instruction during practice. The VIDEO+SELF group received video feedback of their own execution alongside skilled model video instruction. The VIDEO+SELF+VB received all components of the VIDEO+SELF group plus implicit verbal feedback. Linear mixed model analysis was performed to analyse lower extremity kinematics and kinetics, and vertical ground reaction force of baseline, immediate post, and one-week retention tests (α≤0.05). Significant effects were found from baseline to retention in the VIDEO+SELF+VB group; hip flexion (p = .025, difference: +2.1°) and abduction angle (p < .001, difference: −5.3°), knee flexion (p = .014, difference: +2.5°) and adduction angle (p < .001, difference: −9.6°), and hip abduction moment (p < .001, difference: −0.96 Nm/kg) at initial contact. These increases in sagittal plane and decreases in frontal plane motion may lower ACL injury risk. On top of skilled model video instruction, the combination of individualized video feedback with implicit verbal feedback led to improvements of movement execution in female soccer players.

BACKGROUND: Physical therapy via telehealth for people with multiple sclerosis (MS) may be a feasible mode of delivery to improve accessibility and continuity of care. However, little evidence exists to guide the selection of tests and measures in telerehabilitation. This study aimed to confirm the reliability and examine the feasibility, safety, and convergent validity of the remote Five Times Sit-to-Stand (rFTSTS) test among people with MS. METHODS: Demographics, disease characteristics, in-person Five Times Sit-to-Stand (FTSTS) and rFTSTS, and hip and knee isometric strength were collected on people with MS (N = 32) at a one-time visit. The rFTSTS and FTSTS were administered concurrently. Inter-rater reliability between rFTSTS and FTSTS was assessed using a 2-way random effect, single measurement intraclass coefficient (ICC). Spearman rank correlations (ρ) were used to determine the association between rFTSTS and knee and hip strength. RESULTS: The rFTSTS and FTSTS had excellent inter-rater reliability (ICC= 1.00, P &lt;. 001), and were easy to administer without adverse events. The rFTSTS exhibited moderate to large associations (P &lt; .05) with the strongest and weakest limb’s hip flexion (strongest: ρ = 0.449; weakest: ρ = 0.474) and extension (strongest: ρ = 0.378; weakest: ρ = 0.362) and the weakest limb’s knee flexion (ρ = 0.552) and extension (ρ = 0.427). CONCLUSIONS: The rFTSTS is feasible, safe, and reliable, and exhibits convergent validity with hip and knee strength. While further validation is needed, the rFTSTS may be a useful measure for telerehabilitation in people with MS with mild to moderate impairment.

Background: Femoroacetabular impingement syndrome (FAIS) is a recognized cause of hip pain and functional limitation, particularly in young and physically active individuals. The condition results from abnormal hip morphology leading to mechanical conflict within the joint and is associated with an increased risk of early hip osteoarthritis. Although awareness is rising, key aspects of the disease in athletes remain unclear. Aim: The aim of this study was to review current evidence regarding the epidemiology, risk factors, pathophysiology, clinical presentation, diagnostic strategies and treatment options for FAIS with particular emphasis on athletes. Material and methods: The review of the literature was conducted using available studies concerning FAIS in the PubMed database. Peer-reviewed articles published in English were analyzed, including in the fields of orthopedics, sports medicine and musculoskeletal imaging. Results: FAIS predominantly affects young athletes involved in high-demand sports requiring repetitive hip flexion and rotation. Cam morphology is common in males and appears to develop during skeletal immaturity under repetitive mechanical loading. Diagnosis requires a combination of symptoms, positive clinical tests and imaging-confirmed morphological abnormalities. Nonoperative management can alleviate symptoms in selected patients, however arthroscopic surgery has demonstrated superior outcomes. Return to sport rates after arthroscopic management are generally high, although return to pre-injury performance levels varies. Conclusions: FAIS is a multifactorial condition with significant clinical implications for young and athletic populations. Early recognition, accurate diagnosis with individualized treatment strategies are essential to optimize functional outcomes and delay degenerative joint changes. Further high-quality, sport-specific research is needed to refine prevention strategies and improve long-term outcomes, particularly in athletes.

Fatigue-related changes in running technique may depend on a runner’s preferred style. Understanding these changes can inform targeted training to enhance performance. In previous work, we identified two technique-based clusters of runners: the “neutral pelvis” and the “tilted pelvis” clusters. This follow-up study examined whether fatigue induces cluster-specific technique adaptations. Sixty runners (neutral pelvis, n = 32; tilted pelvis, n = 28) completed a treadmill run to exhaustion at 5% above their individual lactate threshold speed. Stride frequency, duty factor, trunk and lower limb kinematics were compared between clusters at the start, middle, and end of the run using a 2-way repeated measures analysis of variance (ANOVA). All runners reached exhaustion in ∼20 minutes, covering ∼5 km. Runners from the tilted pelvis cluster consistently showed greater trunk-to-pelvis extension, more pelvic anterior tilt and greater hip flexion, and a smaller duty factor compared with the neutral pelvis cluster throughout the run. Fatigue-related adaptations were similar across clusters: reduced stride frequency, increased duty factor, greater trunk flexion during stance, increased plantar flexion, and higher coordination variability (trunk-to-pelvis–hip, hip–knee, knee–ankle) during swing. Although fatigue affected both groups similarly, the underlying technique differences suggest these adaptations may have distinct mechanical or performance consequences. Understanding such cluster-specific responses can help coaches tailor training and fatigue management strategies to individual running styles.

Bracing is a conservative treatment method for hip osteoarthritis (HOA) and has shown favourable effects on pain and functional capacity. However, biomechanical analyses of brace effects remain sparse and are limited to level walking. Stair walking is more demanding than level walking in terms of movement coordination and joint loads. This study, therefore, aimed to investigate the effect of hip bracing on pain perception and biomechanics of the hip, pelvis, and trunk during stair walking in individuals with HOA. Hip, pelvis, and trunk biomechanics and pain during stair ascent and descent were assessed before and after one week of hip bracing in 20 individuals with unilateral mild-to-moderate HOA. Differences between the bracing conditions were analysed with dependent t-tests, and Pearson's correlations were used to analyse the correlation between brace-induced alterations in pain score and biomechanical parameters. Bracing increased movement velocity and reduced stair walking pain by 28%. Furthermore, increased hip extension and reduced hip flexion were found with bracing. Bracing led to a decrease in anterior pelvis tilt, resulting in a more upright pelvis position. Trunk motion was not affected by bracing. During stair ascent, frontal pelvis motion increased, while peak hip adduction and internal rotation decreased with bracing. During stair descent, increased hip extension and external rotation moments were found with bracing, while the pelvis and hip transverse range of motion were reduced. Decreased pelvis rise on the ipsilateral side during stair ascent and increased hip transverse range of motion during stair descent were moderately correlated with a decrease in pain. Bracing can reduce hip pain during stair walking and mitigate some of the effects of HOA on stair walking biomechanics, making it a valuable conservative treatment option for individuals with mild-to-moderate HOA. Limiting hip internal rotation exclusively during periods of high joint loading could be a promising mechanism for reducing pain in individuals with HOA. The observed biomechanical changes are indicative of altered hip abductor muscle activity and increased joint loading. Hence, further analyses are necessary to explore the relationship between hip bracing, muscle activity, joint loading and pain.

PurposeThis study aims to evaluate the clinical outcomes of patients who underwent endoscopic transcapsular iliopsoas tenotomy for painful snapping hip syndrome at minimum of ten years follow‐up.MethodsThis is a monocentric retrospective study on a consecutive series of patients undergoing endoscopic transcapsular iliopsoas tenotomy procedure for painful snapping hip syndrome between January 2012 and June 2015. Included patients were clinically evaluated at a minimum of ten years of follow‐up. Perioperative, early or late complications and adverse events were recorded. Modified Harris Hip Score (mHHS) and Hip Disability and Osteoarthritis Outcome Score (HOOS) were calculated preoperatively, at 1 year, and after 10 years postoperatively. Hip flexion strength was assessed preoperatively and at 1 month, 6 months, 1 year and after 10 years postoperatively.ResultsTwenty patients were included in the study. No patient was lost to follow‐up at a minimum of 10 years. Mean follow‐up was 10.6 years. No perioperative complications were reported. No serious or minor adverse events were recorded. None of the patients required revision hip arthroscopy or was scheduled for total hip arthroplasty at the last follow‐up. Three patients (15%) exhibited hip flexion weakness on clinical examination and in these patients MRI revealed iliopsoas muscle atrophy. Three patients (15%) reported persistent snapping during hip flexion‐extension. No sensory deficits were observed. Both mHHS and HOOS were significantly improved (p < 0.001) at the last follow‐up.ConclusionsEndoscopic transcapsular iliopsoas tenotomy is a safe and effective procedure for snapping hip syndrome at long‐term follow‐up.Level of EvidenceLevel IV.

The pericapsular nerve group (PENG) block has proven to be an effective strategy for postoperative pain management in total hip arthroplasty (THA). However, its implementation requires specialized equipment and expertise, which limits its reproducibility. The objective of this study was to describe the technique of direct visualization-guided PENG block (PENG-DV) and assess its outcomes for postoperative pain control. A retrospective cohort study was conducted in patients who underwent THA through a direct anterior approach (DAA) and received the PENG-DV block as part of a standardized multimodal analgesia protocol. Demographic variables, pain score on the visual analogue scale (VAS), opioid consumption, muscle strength, and ambulation within the first 24h were evaluated. Of the 128 patients identified, 112 were included in the analysis. The cohort was predominantly female (60.7%), with a mean age of 63 years. The median postoperative VAS score was 2 and 3 at 12 and 24h respectively, increasing to 5 during physical therapy. By postoperative day one, 83.9% of patients ambulated, and most achieved muscle strength ≥ 3 for both hip flexion and knee extension. A total of 54.5% of patients required opioid rescue, with a mean morphine equivalent consumption of 10mg within the first 24h. PENG-DV for THA via DAA appears to be a promising strategy for effective pain control in the immediate postoperative period, as part of a multimodal analgesic approach designed to reduce opioid consumption and promote early mobilization.

The aims of this study were to clarify the relationship between the combined forward flexion capacity of the lumbar spine and hip joint, referred to as TrunkAflex, and Lumbar Stiffness Disability Index (LSDI) scores in patients following lumbar spine surgery, and to assess whether TrunkAflex better reflects disabilities with activities of daily living (ADL) than the number of fused segments or lumbar spine flexion alone. This prospective, cross-sectional, multicenter study included 147 patients who underwent lumbar spine surgery and completed LSDI questionnaires. Lateral radiographs were obtained in the maximum seated flexion position. Radiographic parameters included pelvic incidence (PI)-corrected lumbar lordosis in flexion (PI-LLflex), representing lumbar spine flexion ability, pelvic femoral angle in flexion (PFAflex), representing hip joint flexion ability, and TrunkAflex, defined as the angle between the axis of the L1 vertebral body and the proximal femoral shaft, mathematically expressed as the sum of PI-LLflex and PFAflex. Correlation analyses were used to determine the relationships between LSDI and these parameters. Subgroup analyses were performed to compare the lumbar fusion (upper instrumented vertebra [UIV] at L1 or below) and thoracolumbar fusion (UIV at T12 or above) groups. The LSDI score was significantly correlated with the number of fused segments (r = 0.328, p < 0.01), and PI-LLflex showed a significant correlation with LSDI (r = -0.354, p < 0.01). However, TrunkAflex demonstrated the strongest correlation with LSDI (r = -0.491, p < 0.01). Subgroup analysis revealed that PI-LLflex was more influential in the lumbar fusion group, while PFAflex was more impactful in the thoracolumbar fusion group. Nevertheless, TrunkAflex consistently showed the strongest correlation with LSDI across all groups. Notably, TrunkAflex was minimally influenced by PI, making it a practical and consistent parameter for trunk forward flexion assessment. This study demonstrated that the combined forward flexion ability of the lumbar spine and hip joint, represented by TrunkAflex, is a stronger predictor of LSDI scores than the number of fused segments or lumbar spine flexion alone, irrespective of the fusion range. Preoperative assessment of hip joint function is particularly important when planning long-segment fusion, and adjusting surgical strategies to preserve appropriate TrunkAflex may contribute to better postoperative ADL outcomes.

Subtrochanteric femoral fractures (SFF) are challenging to manage due to their complex anatomy and high complication rates. Various surgical techniques, including locking compression plate fixation (LCPF) and intramedullary nailing (IMN), have been used, but there is no consensus on the optimal treatment method. To compare perioperative outcomes, radiological parameters, and functional recovery between LCPF and IMN in patients with SFF. A comprehensive search was conducted on PubMed, Scopus, Cochrane Library, and Google Scholar from inception through March 2025. 5 studies comprising 341 patients (185 LCPF and 156 IMN) met the inclusion criteria. Primary outcomes included intraoperative blood loss, operative time, hip flexion, varus malalignment, time to full weight-bearing, hospital stay, malunion, nonunion, postoperative complications, and Harris Hip Score (HHS). IMN showed significantly lower blood loss (MD: 147.53 mL; p < 0.001), shorter hospital stay (MD: 4.73 days; p < 0.001), and better HHS (MD: -4.49 points; p = 0.02) compared with LCPF. LCPF was associated with shorter operative time (MD: 11.93 minutes; p = 0.03). No significant differences were observed in hip flexion, varus malalignment, nonunion, or overall complication rates. Both LCPF and IMN provide acceptable outcomes in the management of SFF. However, IMN offers significant advantages in reducing intraoperative blood loss, shortening hospital stay, and enhancing early functional recovery. These findings suggest that IMN may be the preferable option, particularly in patients at higher risk for perioperative morbidity. Further large-scale, prospective randomised studies are warranted to validate these conclusions and establish definitive treatment guidelines.

The anterior hip muscles, especially the iliocapsularis, reflected head of rectus femoris and gluteus minimus, attach to hip capsulo-ligamentous complex directly, and may contribute to anterior hip stability by increasing the tension of the capsulo-ligamentous complex by muscle contraction. However, it has not been verified whether the contraction of these muscles actually increases the tension of the capsulo-ligamentous complex invivo. The objectives of our study were to clarify (1) whether deep hip muscle contractions increase the tension of the hip capsulo-ligamentous complex, and (2) which muscles most affect the changes in the tension of the capsulo-ligamentous complex. Twenty-eight healthy young individuals (22.8 ± 1.6 years) participated. The tasks included isometric hip flexion, abduction, adduction, and knee extension contraction and rest in a supine position. The shear elastic moduli (G) of the capsulo-ligamentous complex, iliocapsularis, rectus femoris, and gluteus minimus were measured using shear wave elastography. Higher G values correspond to increased muscle activity and tension of the capsulo-ligamentous complex. The G of the capsulo-ligamentous complex showed higher in hip abduction contraction than in the resting position (p = 0.008). The results of the multiple regression analysis showed that only the amount of change in G of the iliocapsularis was a significant variable, even when adjusted for maximum torque (R2 = 0.412, β = 0.513, p = 0.009). The tension of the hip capsulo-ligamentous complex increased with isometric hip abduction, implying tension transfer between the muscle and the capsulo-ligamentous complex. Furthermore, the iliocapsularis has been suggested to play an important role in the transmission of tension.

Hip flexor tightness is common in ice hockey players because of postural demands. It remains unknown whether hip tightness plays a role in the occurrence of low back pain (LBP). It was hypothesized that ice hockey players with hip flexor tightness would be at increased risk of developing LBP. Cohort study; Level of evidence, 2. Preseason hip flexor tightness was measured annually for 4 seasons in a boy's high school team, a college men's team, and a college women's team providing a total of 289 player-seasons. A digital level was placed on the anterior thigh during the Thomas test. "Tight" was defined as a Thomas test >5° above horizontal with the remaining players defined as normal. Game and practice injuries with associated time loss and diagnosis were recorded. LBP was defined as an injury in the lumbar region requiring the player to miss ≥1 game or >2 practices. Prevalence and incidence of LBP were compared between players with tight versus normal hip flexor flexibility, and relative risks were computed. Additionally, hip flexion abduction and adduction strength was assessed with a handheld dynamometer. Incidence and prevalence of LBP was compared between weak, average, and strong players within each team. There were 33 cases of LBP resulting in 97 missed games and 377 missed practices. The incidence of LBP was 1.02/1000 athlete-exposures (95% CI 0.72-1.43). Of 172 players with hip flexor tightness, 27 (15.7%) developed LBP compared with 6 of 117 (5.1%) with normal flexibility (P = .006). LBP incidence was higher for players with tight (1.42; 95% CI, 0.98-2.06) versus normal (0.55; 95% CI, 0.21-0.98) hip flexor flexibility (relative risk, 3.17; 95% CI, 1.31-7.67; P = .007). Players with hip flexor tightness missed 85 games and 318 practices because of LBP compared with 12 games and 59 practices for players with normal hip flexor flexibility (P < .001). LBP incidence was not different between teams (P = .91). Incidence of LBP was not different between players weak, average, or strong in hip flexion (P = .53), abduction (P = .48) or adduction (P = .35). Hip flexor tightness was associated with increased risk of LBP. Hip flexor stretching and postural training is indicated for players with hip flexor tightness.

Lower-extremity kinematics during unanticipated side-cutting including before initial ground contact.

Inverse kinematic alignment (iKA), which preserves the natural knee oblique joint line in total knee arthroplasty, has been shown to produce lower-limb kinematics similar to healthy controls during gait. However, its ability to maintain this advantage during more demanding activities remains unclear. This study evaluated lower-limb kinematics and muscle activation patterns during squatting in individuals who underwent iKA, adjusted mechanical alignment (aMA), and healthy controls. Kinematics were analyzed using a 3D Vicon system, while muscle activation patterns were recorded using electromyography. The iKA group (80.36° [27.43°]) exhibited knee range of motion comparable to healthy controls (95.25° [23.33°]), while the aMA group (67.39° [28.52°]) showed a significant difference (P = .004). Additionally, the aMA group showed reduced hip flexion compared with controls during squatting (P < .001). Although both iKA and aMA groups displayed differences in hip extension and ankle dorsiflexion compared with controls, no differences in muscle activation patterns were observed. These findings suggest that the iKA and aMA groups can squat without altering muscle activity patterns. However, iKA demonstrates biomechanical outcomes that resemble those of healthy controls in certain aspects. Persistent strength deficits in both surgical groups highlight the need for targeted rehabilitation to restore strength.