Background: Hip abductor muscles play a critical role in stabilizing the pelvis during functional activities. A decline in hip abductor strength is associated with impaired balance and an increased risk of falls, particularly in elderly females who experience physiological changes and age-related muscle loss. Although limb dominance has been proposed to influence lower extremity muscle strength in young adults, no studies have yet examined differences in hip abductor strength between the dominant and non-dominant limbs in elderly females. Furthermore, the relationship between hip abductor strength and self-reported functional ability, as measured by the Korean version of the Lower Extremity Functional Scale (LEFS), has not been investigated in this population. Objects: This study aimed to investigate the correlation between hip abductor strength and the Korean version of the LEFS and to compare hip abductor strength between the dominant and non-dominant limbs in elderly females. Methods: Sixty-seven elderly females were recruited from community centers. Hip abductor strength was measured using a Smart KEMA Pulling Sensor. The relationship between hip abductor strength and LEFS scores was analyzed using Spearman’s correlation coefficient, while a paired t-test was used to identify significant differences in strength between the dominant and non-dominant limbs. Results: Hip abductor strength in both the dominant limb (r = 0.355, p < 0.05) and in the non-dominant limb (r = 0.406, p < 0.05) showed a significant positive correlation with LEFS scores. No significant difference was found in hip abductor strength between the dominant and non-dominant limbs in elderly females (p > 0.05). Conclusion: These findings suggest that hip abductor strength should be considered an important factor influencing lower extremity functional ability, as assessed by the LEFS, in elderly females.

Background: Single-leg squat (SLS) is widely used for assessing lower extremity (LE) function. Although abnormal kinematics and foot pressure distribution (FPD) are key indicators of dysfunction, the relation between specific LE kinematic patterns and FPD during SLS remains under investigated. Objects: This study aimed to investigate the correlations among LE kinematics specifically the dynamic knee valgus angle (DKVA), knee inward distance (KID), hip outward distance (HOD) and FPD (hallux, medial, central, and lateral forefoot [FF]) during SLS. Methods: Thirty healthy participants performed SLS on their dominant leg. LE kinematics were analyzed using two-dimensional video analysis to determine DKVA, KID, and HOD. FPD was recorded using the Zebris FDM and analyzed across four regions (hallux, medial, central, and lateral parts of the FF). Pearson correlation coefficients were used to determine the relationships between LE kinematics and FPD. Results: Pearson correlation analysis revealed that hallux pressure was significant associated with the extent of KID (r = 0.547, p = 0.002). In addition, a moderate positive correlation was found between HOD and FF lateral (r = 0.406, p = 0.026), indicating that lateral pelvis displacement contributes to higher FF lateral loading. However, DKVA, which is conventionally used to assess LE kinematic variables, showed no significant association with FPD. Conclusion: This study identified significant relationship between specific kinematic variables (KID and HOD) and FPD (hallux and FF lateral), however, relationship between DKVA and FPD was not observed. Consequently, it is necessary to separately evaluate joint-specific kinematics, such as KID and HOD, to determine their distinct associations with FPD.

Background: Tensor fasciae latae (TFL) and iliotibial tract (ITB) tightness can pull the pelvis during hip lateral rotation (HLR), increasing pelvic rotation due to muscle tension. Among various tests, the HLR test in the prone position (HLRP) is a clinical evaluation tool for assessing lumbopelvic motion with lower-extremity movement. However, performing the HLRP may result in less compensatory motion and a relatively decreased pelvic rotation angle (PRA) because of a wide base of support. Moreover, there were no studies investigating PRA during an HLR test in the standing position (HLRS). Objects: This study aimed to compare the PRA in the horizontal plane during HLRS and the HLRP between individuals with and without TFL/ITB tightness. Methods: Thirty participants with (n = 15) and without (n = 15) TFL/ITB tightness as assessed by Ober’s test, were recruited. The PRA was measured during active HLRS and HLRP. Two-way mixed analysis of variance was used to identify significant differences in the PRA between groups and within positions. Results: When HLRP and HLRS were performed, the PRA in the horizontal plane occurred at 1.65° ± 0.98° and 7.68° ± 4.69°, respectively, in the TFL/ITB tightness group, and at 1.27° ± 1.07° and 2.37° ± 1.96°, respectively, in the control group. A significant interaction effect was identified between groups and positions on the PRA (p < 0.05). Individuals with TFL/ITB tightness had a significantly greater PRA during HLRS than those in the control group. The PRA during HLRS was significantly greater than that during HLRP in individuals with TFL/ITB tightness. Conclusion: These results suggest that TFL/ITB tightness contributes to increased PRA during HLRS compared with HLRP. Clinically, assessment of the PRA in the standing may provide a functional indicator of compensatory pelvic motion during hip rotation of 45°.

Background: Cross-legged sitting posture (CLSP) is common in daily life but may cause asymmetrical loading of the pelvis and spine, potentially leading to postural imbalance and musculoskeletal problems. Although short-term effects of CLSP have been reported, the longterm biomechanical consequences of habitual CLSP remain unclear. Objects: This study compared lumbopelvic alignment and rotational asymmetry between individuals with and without habitual CLSP. Methods: Thirty healthy adults were classified into CLSP (n = 15) and non-CLSP (NCLSP; n = 15) groups based on self-reported sitting habits. Transverse plane pelvic rotation angle (TrPRA) in the supine position and during active straight leg raise (ASLR) was measured using a Smart KEMA motion sensor system, and side-lying lumbopelvic rotation range of motion (SLRR) was assessed with a custom device. Asymmetry index (AI) was calculated for left–right differences. Group comparisons were analyzed using independent t-tests (p < 0.05). Results: Intra-rater reliability of SLRR was very high (intraclass correlation coefficient = 0.958–0.986). No significant group differences were found in TrPRA in the supine position (p > 0.05) or AI of TrPRA during ASLR (p > 0.05). However, the CLSP group demonstrated significantly greater AI in SLRR than the NCLSP group (13.21% ± 6.64% vs. 7.06% ± 4.90%, p = 0.008, Cohen’s d = 1.05). In 10 of the 15 CLSP subjects, the direction of lumbopelvic rotation corresponded to the preferred leg-crossing side. Conclusion: Habitual unilateral CLSP is associated with significantly greater lumbopelvic rotational asymmetry during active side-lying movement, which may contribute to functional imbalance and increased injury risk. Preventive and corrective strategies should include limiting prolonged CLSP, adopting ergonomic seating, and implementing bilateral mobility, rotational control, and core stability exercises. Postural retraining with visual feedback and task-specific practice may further promote symmetrical sitting habits in clinical and occupational environments.

Background: Rotator cuff tears often cause shoulder pain and functional limitations that may require conservative treatment or surgical intervention. Identifying preoperative differences in muscle strength and function can aid in treatment decisions. Objects: This study aimed to compare the preoperative shoulder muscle strength and functional outcomes between patients undergoing arthroscopic rotator cuff repair and those receiving conservative treatment. Methods: A retrospective review was conducted of 315 patients with rotator cuff tears, including 145 who underwent surgery and 170 who received conservative treatment. Shoulder isokinetic muscle strength (external rotator, internal rotators, abductor, and adductors) and functional scores (American Shoulder and Elbow Surgeons [ASES] and Constant-Murley shoulder scores) were measured. The conservative treatment group was assessed during a hospital visit, whereas the surgery group was tested on the morning of the surgery. An independent t-test was used to evaluate the preoperative shoulder strength and functional scores. Results: The conservative treatment group showed lower deficits in external (11.3 ± 23.9) and internal (11.7 ± 15.5) rotators compared to the surgery group (26.3 ± 33.8 and 17.1 ± 26.1, respectively; p = 0.001). Abductor and adductor deficits (18.2 ± 25.3 and 9.8 ± 16.8) were also lower in the conservative treatment group (30.7 ± 31.6 and 21.9 ± 28.4, respectively; p = 0.036 and p = 0.001). The external per internal rotator ratio (50.9 ± 16.8; p = 0.003) and ASES scores were higher (74.5 ± 14.8; p = 0.047) was higher in the conservative treatment group. Conclusion: The conservative treatment group had lower shoulder strength deficits, better muscle balance, and higher ASES scores than the surgery group, indicating superior functional outcomes. These findings suggest that assessing preoperative muscle strength and function might provide valuable insights into treatment planning for patients with rotator cuff tears.

Background: Limitations of shoulder range of motion (ROM), particularly shoulder internal rotation (SIR), are commonly associated with musculoskeletal disorders in both the general population and athletes. The limitation can result in connective tissue lesions such as superior labrum tears and symptoms such as rotator cuff tears and shoulder impingement syndrome. Maintaining the center of rotation of the glenohumeral joint during SIR can be challenging due to the compensatory scapulothoracic movement and anterior displacement of the humeral head. Therefore, observing the path of the instantaneous center of rotation (PICR) using the olecranon as a marker during SIR may provide valuable insights into understanding the dynamics of the shoulder joint. Objects: The aim of the study was to compare the displacement of the olecranon to measure the rotation control of the humeral head during SIR in individuals with and without restricted SIR ROM. Methods: Twenty-four participants with and without restricted SIR ROM participated in this study. The displacement of olecranon was measured during the shoulder internal rotation control test (SIRCT) using a Kinovea (ver. 0.8.15, Kinovea), the 2-dimensional marker tracking analysis system. An independent t-test was used to compare the horizontal and vertical displacement of the olecranon marker between individuals with and without restricted SIR ROM. The statistical significance was set at p < 0.05. Results: Vertical displacement of the olecranon was significantly greater in the restricted SIR group than in the control group (p < 0.05). However, no significant difference was observed in the horizontal displacement of the olecranon (p > 0.05). Conclusion: The findings of this study indicated that individuals with restricted SIR ROM had significantly greater vertical displacement of the olecranon. The results suggest that the limitation of SIR ROM may lead to difficulty in rotation control of the humeral head.

Background: Single-leg squat (SLS)s are commonly used as assessment tool and closed kinetic exercises are useful for assessing performance of the lower extremities. Pronated feet are associated with foot pressure distribution (FPD) during daily activities. Objects: To compare the FPD during SLSs between groups with pronated and normal feet. Methods: This cross-sectional study included 30 participants (15 each in the pronated foot and control groups) are recruited in this study. The foot posture index was used to distinguish between the pronated foot and control groups. The Zebris FDM (Zebris Medical GmbH) stance analysis system was used to measure the FPD on the dominant side during a SLS, which was divided into three phases. A two-way mixed-model ANOVA was used to identify significant differences in FPD between and within the two groups. Results: In the hallux, the results of the two-way mixed-model ANOVAs revealed a significant difference between the group and across different phases (p < 0.05). The hallux, and central forefoot were significantly different between the group (p < 0.05). Moreover, significant differences across different phases were observed in the hallux, medial forefoot, central forefoot, lateral forefoot, and rearfoot (p < 0.05). The post hoc t-tests were conducted for the hallux and forefoot central regions. In participants with pronated foot, the mean pressure was significantly greater in hallux and significantly lower, in the central forefoot during the descent and holding phases. Conclusion: SLSs are widely used as screening tests and exercises. These findings suggest that individuals with pronated feet should be cautious to avoid excessive pressure on the hallux during the descent-to-hold phase of a SLS.

Background: Delivery workers repeatedly get in and out of trucks and walk or run to deliver packages during work. Iliotibial band syndrome (ITBS) is a well-known non-traumatic overuse injury of the lateral side of the knee caused by frequent knee flexion and extension. Hip muscle strength is among the factors that prevent lower extremity injuries. Although many studies have examined the relationship between ITBS and hip muscle strengths, there was no study comparing hip muscle strength and ratio between delivery workers with and without ITBS. Objects: This study aimed to compare hip muscle strength and hip internal/external rotator and adductor/abductor strength ratios between delivery workers with and without ITBS. Methods: Fourteen delivery workers with ITBS matched inclusion criteria in the present study among 20 participants. Because total sample size was required 28 subjects by G*power program (ver. 3.1.9.4; University of Trier), 14 delivery workers without ITBS were recruited. Hip muscle strengths were measured in a side-lying position using a Smart KEMA pulling sensor (KOREATECH Co. Ltd.). An independent t-test was used to compare hip muscle strengths and hip internal/external rotator and hip adductor/abductor strength ratios between delivery workers with and without ITBS. Results: The adductor/abductor strength ratio was significantly greater in delivery workers without ITBS than in those with ITBS (p < 0.05). The strengths of the hip abductor, hip adductor, hip internal rotator, hip external rotator, and the ratio of internal/external rotator strengths were not significantly different between the delivery workers with and without ITBS (p > 0.05). Conclusion: This study’s findings showed that delivery workers with ITBS had significantly lesser adductor/abductor strength ratio, while the strengths of the hip abductor and adductor muscles did not differ significantly. These results suggest that adductor/abductor strength ratio should be considered when evaluating and treating ITBS in delivery workers.

Background: Pronated foot posture (PFP) contributes to excessive dynamic knee valgus (DKV). Although foot orthoses such as medial arch support (MAS) are widely and easily used in clinical practice and sports, few studies have investigated the effect of MAS on the improvement of DKV during stair descent in individuals with a PFP. Moreover, no studies reported the degree of improvement in DKV according to the severity of PFP when MAS was applied. Objects: This study aimed to examine the immediate effect of MAS on DKV during stair descent and determine the correlation between navicular drop distance and changes in DKV when MAS is applied. Methods: Twenty individuals with a PFP (15 males and five females) participated in this study. The navicular drop test was used to measure PFP severity. The frontal plane projection angle (FPPA) was calculated under two conditions, with and without MAS application, using 2-dimensional video analysis. Results: During stair descent, the FPPA with MAS (173.1° ± 4.7°) was significantly greater than that without MAS (164.8° ± 5.8°) (p < 0.05). There was also a significant correlation between the navicular drop distance and improvement in the FPPA when MAS was applied (r = 0.453, p = 0.045). Conclusion: MAS application can affect the decrease in DKV during stair descent. In addition, MAS application should be considered to improve the knee alignment for individuals with greater navicular drop distance.