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Context: The hip adductor and abductor muscles play vital roles as stabilizers in the lower-extremity. Their activation during soccer-specific actions is essential, but local muscular fatigue can hinder athletic performance and increase the risk of injury. Design: This study aimed to observe the variations in frontal plane hip strength in female college soccer players before and after a high-workload soccer-specific training session. Furthermore, the study sought to compare the relative changes in hip strength with the internal and external load measures obtained during that session. Methods: Twenty female college soccer players participated in a retrospective observational study. Isometric hip adductor and abductor strength were measured before and after a training session in the college spring season. Measurements were taken with a handheld dynamometer (MicroFET 2) while the players were supine. Global positioning system sensors (Catapult Vector S7), commonly worn by players during training sessions and competitive matches, were used to measure external and internal loads. Statistical analyses were performed using paired samples t test to assess hip adductor and abductor strength changes before and after the training session. Spearman rank was used to identify correlation coefficients between global positioning system data and isometric hip strength. Results: The findings revealed significant decreases in the strength of the right hip adduction (P =.012, −7% relative change), right abduction (P =.009, −7.6% relative change), and left abduction (P =.016, −4.9% relative change) after the training session. Furthermore, relative decreases in hip isometric adduction and abduction strength are related to the distance covered at high speeds. Conclusion: The results of this study highlight that hip isometric adduction and abduction strength tend to decrease after exposure to high workloads during soccer-specific training. [ABSTRACT FROM AUTHOR]

Context: Piriformis syndrome is often associated with muscle spasms and shortening of the piriformis muscle (PM). Physical therapy, including static stretching of the PM, is one of the treatments for this syndrome. However, the effective stretching position ofthe PM is unclear in vivo. This study aimed to determine the effective stretching positions of the PM using ultrasonic shear wave elastography. Design: Observational study. Methods: Twenty-one healthy young men (22.7 [2.41 y) participated in this study. The shear elastic modulus of the PM was measured at 12 stretching positions using shear wave elastography. Three of the 12 positions were tested with maximum internal rotation at 0°, 20°, or 40° hip adduction in 90° hip flexion. Nine of the 12 positions were tested with maximum external rotation at positions combined with 3 hip-flexion angles (70°, 90°, and 110°) and 3 hip-adduction angles (0°, 20°, and 40°). Results.' The shear elastic modulus of the PM was significantly higher in the order of 40°, 20°, and 0° of adduction and higher in external rotation than in internal rotation. The shear elastic modulus of the PM was significantly greater in combined 110° hip flexion and 40° adduction with maximum external rotation than in all other positions. Conclusion.- This study revealed that the position in which the PM was most stretched was maximum external rotation with 110° hip ftexion and 40° hip adduction. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the preliminary effects of movement pattern training (MoveTrain) versus strengthening/flexibility (standard) treatment on hip and pelvic biomechanics in patients with chronic hip-related groin pain. This is a secondary analysis of data collected during a pilot randomized clinical trial. Thirty patients with hip pain, between the ages of 15 and 40 years, were randomized to MoveTrain or standard. Both groups completed 10 treatment sessions over 12 weeks along with a daily home exercise program. Three-dimensional motion analysis was used to collect kinematic and kinetic data of the pelvis and hip during a single-leg squat task at pretreatment and immediately posttreatment. Compared with the standard group, the MoveTrain group demonstrated smaller hip adduction angles (P =.006) and smaller hip external adduction moments (P =.008) at posttreatment. The desired changes to hip joint biomechanics, as found in this study, may require specificity in training that could allow health care professionals to better customize the rehabilitation of patients with hip pain. These findings can also be applied to the design and implementation of future clinical trials to strengthen our understanding of the long-term implications of different rehabilitation techniques for patients with hip pain. [ABSTRACT FROM AUTHOR]

Prior studies have explored the relationship between knee valgus and musculoskeletal variables to formulate injury prevention programs, primarily for females. Nonetheless, there is insufficient evidence pertaining to professional male soccer players. Here, the aim was to test the correlation of lateral trunk inclination, hip adduction, hip internal rotation, ankle dorsiflexion range of motion, and hip isometric strength with knee valgus during the single-leg vertical jump test. Twenty-four professional male soccer players performed a single-leg vertical hop test, hip strength assessments, and an ankle dorsiflexion range of motion test. A motion analysis system was employed for kinematic analysis. Maximal isometric hip strength and ankle dorsiflexion range of motion were tested using a handheld dynamometer and a digital inclinometer, respectively. The correlation of peak knee valgus with peak lateral trunk inclination was.43 during the landing phase (P =.04) and with peak hip internal rotation was −.68 (P <.001). For knee valgus angular displacement, only peak lateral trunk inclination presented a moderate positive correlation (r =.40, P =.05). This study showed that trunk and hip kinematics are associated with knee valgus, which could consequently lead to increased knee overload in male professional soccer players following a unilateral vertical landing test. [ABSTRACT FROM AUTHOR]

The study objective is to test general- and sport-specific adaption during a single training on the Flexibility Trainer. The device is designed to trigger residual muscle tone decreases of the hip-joint muscles by providing (nearly) isokinetic resistance during a full range of motion strength training in adduction/abduction and flexion/extension direction. Static hip flexion and abduction as well as kinematics of double side kicks were analysed on 15 participants before and after training (or rest for controls) to assess general flexibility and sport-specific movement range. Tests were recorded by a Vicon® motion capturing system. Static hip flexion and abduction as well as leg vector spreading angles (VSA) at different nodes of the kick were selected to determine adaptions of active and passive flexibility. Normalised hip joint moments, movement velocities and VSA were calculated to evaluate the training with the device. ANOVAs with 4-repeated measures and Friedman tests were performed to identify time differences and Bonferroni post-hoc test to identify between-subject effects. Significant differences were found for both static flexibility tests (Flexion = 13.65%; Abduction = 9.94%) and the VSA at specific action phases (≤15.15%). Results indicate that short-term adaptions when training with the Flexibility Trainer are exceeding comparable literature showing improved flexibility and sport-specific performance. [ABSTRACT FROM AUTHOR]

Objective: The Posterior Standing Overhead Arm Reach (SOAR) test has been previously reported as a reliable clinical measure of closed chain hip extension motion. The proposed Medial SOAR test expands on that testing approach to provide a similar measure of functional hip adduction motion. This was a preliminary intrarater and interrater reliability and validity study of the Medial SOAR test as a measure of functional hip adduction. Design: Cross-sectional. Setting: University motion analysis laboratory. Participants: Fifty hips were assessed in 25 (22 female) asymptomatic participants (mean age = 23.4 years, SD = 0.8). Main measures: Maximum hip adduction during the Medial SOAR test was measured with a standard goniometer independently by two examiners. The test was also performed using three-dimensional motion capture. The intrarater and interrater reliability of the goniometric measure was determined using intraclass correlation coefficients, and the relationship between measures obtained via goniometry and three-dimensional motion capture was assessed with Pearson correlations and Bland–Altman analysis. Results: Intrarater reliability (ICC2,3) was 0.88 (95% CI = 0.80–0.92) for Examiner 1 and 0.87 (95% CI = 0.79–0.92) for Examiner 2. The standard error of measurement and minimal detectable change were less than 3.0°. Interrater reliability demonstrated an intraclass correlation coefficient = 0.62 (95% CI = 0.28–0.79). Pearson correlations were significant with low-to-moderate associations (r = 0.49, P < 0.001; r = 0.24, P = 0.045). Conclusions: Similar to the previously reported Posterior SOAR test, the Medial SOAR test demonstrated acceptable intrarater and interrater reliability, along with low-to-moderate associations with three-dimensional motion capture. The Medial SOAR test has the potential to provide a reliable and accurate assessment of closed chain hip adduction. [ABSTRACT FROM AUTHOR]

Background: Historically, kinematic measures have been compared across injured and non-injured groups of runners, failing to take into account variability in kinematic patterns that exist independent of injury, and resulting in false positives. Research led by gait patterns and not pre-defined injury status is called for, to better understand running-related injury (RRI) aetiology and within- and between-group variability. Objectives: Synthesise evidence for the existence of distinct kinematic sub-groups across a population of injured and healthy runners and assess between-group variability in kinematics, demographics and injury incidence. Data Sources: Electronic database search: PubMed, Web of Science, Cochrane Central Register of Controlled Trials (Wiley), Embase, OVID, Scopus. Eligibility Criteria: Original, peer-reviewed, research articles, published from database start to August 2022 and limited to English language were searched for quantitative and mixed-methods full-text studies that clustered injured runners according to kinematic variables. Results: Five studies (n = 690) were included in the review. All studies detected the presence of distinct kinematic sub-groups of runners through cluster analysis. Sub-groups were defined by multiple differences in hip, knee and foot kinematics. Sex, step rate and running speed also varied significantly between groups. Random injury dispersal across sub-groups suggests no strong evidence for an association between kinematic sub-groups and injury type or location. Conclusion: Sub-groups containing homogeneous gait patterns exist across healthy and injured populations of runners. It is likely that a single injury may be represented by multiple movement patterns, and therefore kinematics may not predict injury risk. Research to better understand the underlying causes of kinematic variability, and their associations with RRI, is warranted. [ABSTRACT FROM AUTHOR]

Objective The aims of this study were to assess the psychological, functional, and physical differences between patients with femoroacetabular impingement (FAI) syndrome and individuals who were asymptomatic (controls) to analyze clinical differences among 4 subtypes of FAI (cam type, cam type with labral tear, pincer type, and pincer type with labral tear), to calculate the correlations among the variables described, and to identify risk factors contributing to the hip function variance. Methods A case–control study was conducted at a hospital rehabilitation unit with a cohort of individuals who were asymptomatic (controls) and a cohort of patients with FAI. Sociodemographic characteristics, pain intensity, psychological health status, hip range of motion (RoM), hip isometric strength, and hip function were assessed. Results A total of 69 controls and 69 patients with FAI were analyzed. Although sociodemographic characteristics were comparable between samples, poorer hip RoM, strength, and psychological health were found for the cases. FAI subtypes showed no significant pain intensity, psychological health, or RoM differences (except for hip adduction), but hip strength differed among FAI subtypes. Multiple significant correlations between psychological health, pain intensity, RoM, strength, and hip function were found. The variance values of the International Hip Outcome Tool, Hip Outcome Score (HOS) for daily living activities, and HOS for sports activities were partially explained (47.6%, 36.0%, and 21.6%, respectively) on the basis of kinesiophobia, hip strength, self-efficacy, and anxiety. Conclusion Patients with FAI showed poorer psychological health, hip RoM, and strength than individuals who were asymptomatic and had similar sociodemographic characteristics. FAI subtype influenced the patients' clinical presentations. Hip strength, kinesiophobia, anxiety, and self-efficacy should be targeted for improving hip function, as they have been demonstrated to be important contributors to hip disability. Impact This study demonstrated that pain catastrophizing, hip strength, and hip adduction differed among FAI subtypes. However, hip function and pain intensity were comparable between FAI subtypes. [ABSTRACT FROM AUTHOR]

Context: Elite golfers have a high incidence of low back pain. Recent reviews have emphasized the need for investigation into how to prevent low back pain in golfers, prompting the current study. Design: Prospective longitudinal cohort study. Methods: Forty-one injury-free golfers were included in this study. At baseline, lower quadrant joint angles and club and ball performance were measured while each golfer performed 10 drives. The golfers were then monitored for 6 months and were allocated into 2 groups depending on whether or not they developed low back pain. The initial, baseline kinematic variables of the low back pain group and the uninjured group were then compared. Results: Over the 6-month monitoring period, 17 (41%) of the golfers developed low back pain. At baseline assessment, the low back pain group had 4° less lead ankle dorsiflexion at setup (P = .01; effect size = 0.82), 6° less lead knee flexion at the top of the backswing (P = .05; effect size = 0.64), 6° less lead ankle dorsiflexion at the top of the backswing (P = .01; effect size = 0.82), 6° more trail hip adduction at the top of the backswing (P = .02; effect size = 0.79), 9° more trail knee flexion at impact (P = .05; effect size = -0.64), and 6° more trail hip adduction at the end of follow through (P < .00; effect size = 1.00). Conclusion: Golfers who developed low back pain during the 6-month monitoring period displayed distinct differences in biomechanics at baseline when all golfers were injury free. These biomechanical differences may be considered a precursor to injury. Three-dimensional motion analysis may indicate whether elite golfers are at risk of developing low back pain. Research is needed to assess whether targeted exercise and sports drills aimed at addressing the biomechanical risk factors identified may prevent low back pain in elite golfers. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the differences in hip adductor and abductor muscle strength in elite male footballers from youth to senior level. Methods: We tested 125 players from the under-13-years (U'13) to senior squads of a Danish male professional football club in this cross-sectional design study. Hip adductor and abductor force (in newtons), torque (in newton meters), normalized torque (in newton meters per body mass), and adduction-to-abduction ratio were measured using handheld dynamometry. Results: Between U'13 and senior level, adductor force increased by 104%, torque by 127%, and normalized torque by 21%. Abductor force increased by 78%, torque by 126%, and normalized torque by 17%. For incremental differences between age groups, significant increases were observed between the ages of U'13 to U'14 (18%–39%) and U'14 to U'15 (19%–33%) for all strength measures (P ≤.021). No incremental difference was observed for adductor-to-abductor ratio. Conclusions: The large increases in hip adductor and abductor strength occurring between the ages of U'13 and U'15 offer insight into the strength capabilities and stress demands in these players, which may relate to injury vulnerability, and facilitate clinicians in selecting best-suited exercise interventions. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to compare three-dimensional kinematic of the trunk, pelvis, hip, and knee during the single-leg squat and hip torque in individuals with and without isolated patellofemoral osteoarthritis (PFOA). Patients and methods: This cross-sectional study evaluated trunk, pelvis, hip, and knee kinematics at 30°, 45°, and 60° knee flexion during the single-leg squat using the Vicon motion capture and analysis system, the Nexus System 2.1.1, and 3D Motion Monitor software. Sixteen individuals (8 males, 8 females; mean age: 49.3±6.2 years; range 40 to 61 years) participated in the study, of which eight were PFOA patients and eight were healthy controls. Isometric hip abductor, extensor, and external rotator torques were evaluated using a handheld dynamometer. Results: The PFOA group exhibited greater hip adduction at 30° (p=0.008), 45° (p=0.005), and 60° (p=0.008) knee flexion in the descending phase of the single-leg squat, as well as at 60° (p=0.009) and 45° (p=0.03) knee flexion in the ascending phase. No significant differences were found between groups for other kinematic variables (p>0.05). The PFOA group exhibited lower isometric hip abductor (p=0.02), extensor (p<0.001), and external rotator (p=0.007) torques. Conclusion: Individuals with PFOA exhibited excessive hip adduction that could increase stress on the lateral patellofemoral joint at 30°, 45°, and 60° knee flexion during the single-leg squat and exhibited weakness of the hip abductors, extensors, and external rotators in comparison to healthy controls. [ABSTRACT FROM AUTHOR]

BACKGROUND: Measurements of hip abduction (ABD) and adduction (ADD) are important in strength and conditioning as well as in clinical practice. However, there is no clear consensus on how ABD and ADD compare in strength in different populations. OBJECTIVE: The aim was to perform a quantitative synthesis of comparisons between the isometric strength of ABD and ADD in different populations. METHODS: ABD and ADD strength data were collected and pooled mean values for ABD:ADD strength ratio were calculated and expressed as standardized mean differences. Forty studies of healthy adults, 5 studies of healthy older adults and 14 studies of adults with various musculoskeletal injuries were included in the analysis. RESULTS: Healthy (non-athletic) males, healthy older adults, and adults with hip and groin pathologies or osteoarthritis tend to have the same ADD and ABD strength; male athletes tend to have a stronger ADD compared with ABD; healthy females and adults with patellofemoral pain tend to have a stronger ABD compared with ADD. CONCLUSIONS: These results can serve as a database to help compare and interpret measurements of ADD and ABD strength ratio in different populations. [ABSTRACT FROM AUTHOR]

Context: It is unclear if lower-extremity joint cooling alters biomechanics during a functional movement. Objective: To investigate the effects of unilateral lower-extremity cryotherapy on movement alterations during a single-leg drop jump. Design: A crossover design. Setting: Laboratory. Patients: Twenty healthy subjects (10 males and 10 females; 23 y, 169 cm, 66 kg). Intervention(s): Subjects completed a single-leg drop jump before and after a 20-minute ankle or knee joint cooling on the right leg, or control (seated without cooling) on 3 separate days. Main outcome measures: Time to peak knee flexion, vertical ground reaction force, lower-extremity joint angular velocity (sagittal plane only), and angle and moment (sagittal and frontal planes) in the involved leg over the entire ground contact (GC; from initial contact to jump-off) during the first landing. Time to peak knee flexion was compared using an analysis of variance; the rest of the outcome measures were analyzed using functional analyses of variance (P < .05). Results: Neither joint cooling condition changed the time to peak knee flexion (F2,95 = 0.73, P = .49). Ankle joint cooling reduced vertical ground reaction force (55 N at 4% of GC), knee joint angular velocity (44°/s during 5%-9% of GC), and knee varus moment (181 N·m during 18%-20% of GC). Knee joint cooling resulted in a reduction in knee joint angular velocity (24°/s during 37%-40% of GC) and hip adduction moment (151 N·m during 46%-48% of GC), and an increase in hip joint angular velocity (16°/s during 49%-53% of GC) and plantarflexion angle (1.5° during 11%-29% of GC). Conclusion: Resuming activity immediately after lower-extremity joint cooling does not seem to predispose an individual to injury during landing because altered mechanics are neither overlapping with the injury time period nor of sufficient magnitude to lead to an injury. [ABSTRACT FROM AUTHOR]

Context: Examining the coordinated coupling of muscle recruitment patterns may provide insight into movement variability in sport-related tasks. Objective: The purpose of this study was to examine the relationship between coupled gluteus maximus and medius recruitment patterns and hip-adduction variability during single-limb step-downs. Design: Cross-sectional. Setting: Biomechanics laboratory. Participants: Forty healthy adults, including 26 women and 14 men, mean age 23.8 (1.6) years, mean body mass index 24.2 (3.1) kg/m2, participated. Interventions: Lower-extremity kinematics were acquired during 20 single-limb step-downs from a 19-cm step height. Electromyography (EMG) signals were captured with surface electrodes. Isometric hip-extension strength was obtained. Main Outcome Measures: Hip-adduction variability, measured as the SD of peak hip adduction across 20 repetitions of the step-down task, was measured. The mean amplitudes of gluteus maximus and gluteus medius EMG recruitment were examined. Determinism and entropy of the coupled EMG signals were computed with cross-recurrence quantification analyses. Results: Hip-adduction variability correlated inversely with determinism (r = −.453, P =.018) and positively with entropy (r =.409, P =.034) in coupled gluteus maximus/medius recruitment patterns but not with hip-extensor strength nor with magnitudes of mean gluteus maximus or medius recruitment (r = −.003,.081, and.035; P =.990,.688, and.864, respectively). Conclusion: Hip-adduction variability during single-limb step-downs correlated more strongly with measures of coupled gluteus maximus and medius recruitment patterns than with hip-extensor strength or magnitudes of muscle recruitment. Examining coupled recruitment patterns may provide an alternative understanding of the extent to which hip neuromuscular control modulates lower-extremity kinematics beyond examining muscle strength or EMG recruitment magnitudes. [ABSTRACT FROM AUTHOR]

Context: Joint mobilizations have been studied extensively in the literature for the glenohumeral joint and talocrural joint (ankle). Consequently, joint mobilizations have been established as an effective means of improving range of motion (ROM) within these joints. However, there is a lack of extant research to suggest these effects may apply within another critical joint in the body, the hip. Objective: To examine the immediate effects of hip joint mobilizations on hip ROM and functional outcomes. Secondarily, this study sought to examine the efficacy of a novel hip mobilization protocol. Design: A prospective exploratory study. Setting: Two research labs. Patients or Other Participants: The study included 19 active male (n = 8) and female (n = 11) college students (20.56 [1.5] y, 171.70 [8.6] cm, 72.23 [12.9] kg). Interventions: Bilateral hip mobilizations were administered with the use of a mobilization belt. Each participant received hip joint mobilization treatments once during 3 weekly sessions followed immediately by preintervention and postintervention testing/measurements. Testing for each participant occurred once per week, at the same time of day, for 3 consecutive weeks. Hip ROM was the first week, followed by modified Star Excursion Balance Test the second week and agility T test during the third week. Main Outcomes Measures: Pretest and posttest measurements included hip ROM for hip flexion, extension, abduction, adduction, internal and external rotation, as well as scores on the modified Star Excursion Balance Test (anterior, posterolateral, and posteromedial directions) and agility T test. Results: A significant effect for time was found for hip adduction, internal and external rotation ROM, as well as the posterolateral and posteromedial directions of the modified Star Excursion Balance Test. A separate main effect for both limbs was found for adduction and internal rotation ROM. Conclusion: Isolated immediate changes in ROM and functional outcomes were evident. Further evaluation is needed. [ABSTRACT FROM AUTHOR]

Background: and Purpose: Hereditary spastic paraplegias (HSP) are a group of clinically diverse genetic disorders that share the neurologic symptom of difficulty in walking due to progressive serious muscle weakness and spasticity in the legs. This study describes a physiotherapy program for improving the functional ability of a child diagnosed with complicated HSP and reports the treatment results. Methods: A 10‐year‐old boy with complicated HSP received a physiotherapy intervention that included strengthening of the leg muscles and treadmill training for 1 h per session, three to four times a week for 6 weeks. Outcome measures included sit‐to‐stand, 10‐m walk, 1‐min walk tests, and gross motor function measures (dimensions D and E). Results: After the intervention, the sit‐to‐stand, 1‐min walk, and 10‐m walk test scores improved by 6.75 times, 2.57 m, and 0.05 m/s, respectively. Furthermore, the gross motor function measure dimensions D and E scores improved by 8% (46%–54%) and 5% (22%–27%), respectively. The gains in each parameter were maintained at the 3‐ and 6‐month and 1‐year follow‐ups. Conclusion: These results suggest that structured physiotherapy programs can benefit the functional rehabilitation of children with complicated HSP. [ABSTRACT FROM AUTHOR]

Reference anthropometric and physical performance qualities can improve understanding of sporting needs and streamline preparation and rehabilitation programs. However, these data and their relationships with competitive success are absent in rodeo athletes. We hypothesized that riding performance would be most correlated with hip adductor, neck, and grip strength, whereas jump, reactive strength index (RSI), and change of direction abilities would best predict bull-fighting performance. Forty-three amateur (n = 9), professional (n = 23), or internationally ranked (n = 11) male rodeo athletes (bareback = 9, bull riders = 16, saddle bronc = 7, bullfighters = 11) (26.8 ± 5.6 years) volunteered for this study. Anthropometrics included body mass, height, and body fat percentage. Performance measures included isometric hip adduction and abduction, neck flexion and extension, handgrip strength, squat and countermovement jump heights, eccentric utilization ratio, reactive strength index, change of direction, bike sprints, and several pneumatic power measures. Bullfighters were taller and heavier than bull riders (effect size [ES] = 0.84-0.87, p = 0.008-0.017). Bull riders were leaner than bullfighters (ES = 0.74, p = 0.012). Fighters had greater RSI than riders (ES = 0.73-1.47, p < 0.001-0.030). Competitive level of rodeo riders (n = 32) correlated with age, rodeo experience (ρ = 0.37-0.43, p = 0.013-0.049), bent-leg abduction (ρ = 0.43, p = 0.014), straight-leg hip adduction and abduction (ρ = 0.49-0.56, p < 0.001-0.005), neck flexion force (ρ = 0.43, p = 0.016), and rotational power (ρ = 0.50, p = 0.004). The competitive level of the fighters correlated with age (ρ = 0.64, p = 0.036) and time trial performance (ρ = -0.76, p = 0.006). This is the first study providing normative and correlational strength and power performance data in a rodeo population. These data highlight the need for more event-specific physical preparation. Riders should focus their physical preparation on hip and neck strength and rotational power. Bullfighters should prioritize stiffness and anaerobic power. [ABSTRACT FROM AUTHOR]

The purpose was to evaluate the intra- and inter-session reliability of hip isometric strength assessment using a frame-stabilized dynamometer (FSD) and to compare the results in the hip adduction (ADD) and abduction (ABD) strength assessment using handheld dynamometer (HHD). Twenty participants (24.2 [2.6] years, 69.3 [10.0] kg) underwent testing on an FSD (ADD and ABD short and long-lever, internal [IR] and external rotation [ER] tests) and using an HHD (ADD and ABD long-lever tests). Analysis revealed excellent (ICC2.k > 0.90) relative intra-set and inter-set reliability for two visits and good reliability for test-retest results (ICC2.1 0.79–0.90), regardless of the test. Among the tests, SEM and MDC were the highest for the IR and ER results. In comparison with HHD, long-lever ADD strength was higher and long-lever ABD strength was lower when measured using FSD. Although both measurements have been shown to be highly reliable, the discrepancy between the devices exists. [ABSTRACT FROM AUTHOR]

Introduction: Poliomyelitis has been considered a statutory notifiable infectious disease in Hong Kong since 1948. Approximately 15% to 80% of patients suffer from post-polio syndrome (PPS) with an increased risk of falling and chronic pain. Most of them relied on the use of knee lock-type orthoses as aids. This study aimed to evaluate the effect of using a custom-fit knee robotic orthosis on their gait performance. Materials and Methods: A case series report was used for this study on a group of individuals suffering from chronic PPS who used orthoses and had a history of falling. A knee robotic orthosis was custom-fit for eight sessions of walking practice. Assessments included laboratory gait analysis, functional measures, and subjective ratings of exertional level. Pain responses were recorded to evaluate the effect of using the knee robotic orthosis on participants' gait performance. Results: Five participants completed the study in using the knee robotic orthosis. All achieved reduction in shoulder tilting and trunk swaying movement on walking at the anterior-posterior and the medial-lateral direction. A total of 80% of the study participants achieved reduction in trunk rotation movement, lower-limb circumduction, and hip hiking movement on the affected side on walking. All study participants were able to demonstrate improvement in their gait symmetry after using the knee robotic orthosis as reflected by the symmetric index improvement of kinematics. The rate of perceived exertion and the visual analog scale of pain in all study participants were reported lower when they used the knee robotic orthosis. However, the 10-m walking time achieved was longer. Conclusions: The knee robotic orthosis had a positive effect on remediating the abnormal kinematics of PPS patients using conventional lock-knee orthosis after eight sessions of training practice. Reduction in the limping gait pattern and improvement in gait symmetry was achieved in using a knee robotic orthosis for walking. The chronic pain response and the physical exertional level on walking were also reduced. However, the walking speed achieved was slower. Clinical Relevance: The application of the knee robotic orthosis for walking assist is new to most of the PPS patients. The positive outcomes achieved merit further research for future clinical practice. [ABSTRACT FROM AUTHOR]

Background Hip adduction and abduction muscle function plays an important role for risk of groin pain in athletes. Maximal isometric strength can be obtained clinically using a handheld dynamometer. However, in very strong athletes this is challenging, as external fixation of the dynamometer is needed for reliable measures. An alternative to unilateral testing, is the long-lever hip adduction squeeze test and a novel bilateral hip abduction press test. While promising intra-tester reliability has been found for maximal strength during the long-lever hip adduction squeeze test, inter-tester reliability may be more challenging during both maximal and explosive strength measurements. Hypothesis/purpose The aim of the present study was to assess intra- and inter-tester reliability of maximal, and explosive strength during the long lever hip adduction squeeze test and the long lever hip abduction press test in healthy adults using a hand-held dynamometer. Study design Intra- and interrater reliability study. Methods Forty-nine healthy subjects were included for intra- (n=20) and inter-tester reliability (n=29). Subjects performed the hip adduction long lever squeeze test and the bilateral hip abduction press test in a randomized order. Maximal isometric strength and early (0-100 ms) and late (0-200 ms) phase rate of force development (explosive muscle strength) was obtained using a hand-held dynamometer. Relative reliability for all tests was assessed using ICC2,1 two-way mixed model with absolute agreement, thereby taking bias between testers into account. Results Maximal isometric strength showed good intra- and inter-tester reliability for adduction (ICC: 0.93-0.97) and abduction (ICC: 0.88-0.92). For 0-200 ms rate of force development, both the squeeze and press test showed good intra-tester reliability (ICC: 0.85-0.87), whereas inter-tester reliability was good for hip adduction squeeze (ICC: 0.75) and moderate for hip abduction press (ICC: 0.71). For 0-100 ms rate of force development, the hip abduction press test showed good intra-tester reliability (ICC: 0.78). Remaining tests for intra- and inter-tester reliability showed moderate reliability (ICC: 0.50-0.71). Conclusion Assessment of maximal isometric strength in hip adduction squeeze and abduction press test showed good intra- and inter-tester reliability, whereas only 0-200 ms rate of force development demonstrated good intra-tester reliability of both tests. Therefore, rate of force development should preferably be conducted by the same tester, while the long lever squeeze and press test can reliably be used within- and between testers to measure maximal isometric strength. Level of Evidence 3 [ABSTRACT FROM AUTHOR]

Background: Return-to-play (RTP) assessment after anterior cruciate ligament reconstruction (ACLR) rarely includes hip strength. Hypothesis: It was hypothesized that (1) patients after ACLR will have weaker hip abduction (AB) and adduction (AD) strength compared with the contralateral limb, with larger deficits in women, (2) there will be a correlation between hip and thigh strength ratios and patient-reported outcomes (PROs), and (3) hip AB and AD strength will improve over time. Study Design: Descriptive laboratory study. Methods: Included were 140 patients (74 male, 66 female; mean age, 24.16 ± 10.82 years) who underwent RTP assessment at 6.1 ± 1.6 months after ACLR; 86 patients underwent a second assessment at 8.2 ± 2.2 months. Hip AB/AD and knee extension/flexion isometric strength were measured and normalized to body mass, and PRO scores were collected. Strength ratios (hip vs thigh), limb differences (injured vs uninjured), sex-based differences, and relationships between strength ratios and PROs were determined. Results: Hip AB strength was weaker on the ACLR limb (ACLR vs contralateral: 1.85 ± 0.49 vs 1.89 ± 0.48 N·m/kg; P <.001) and hip AD torque was stronger (ACLR vs contralateral: 1.80 ± 0.51 vs 1.76 ± 0.52 N·m/kg; P =.004), with no sex-by-limb interaction found. Lower hip-to-thigh strength ratios of the ACLR limb were correlated with higher PRO scores (r = −0.17 to −0.25). Over time, hip AB strength increased in the ACLR limb more than in the contralateral limb (P =.01); however, the ACLR limb remained weaker in hip AB at visit 2 (ACLR vs contralateral: 1.88 ± 0.46 vs 1.91 ± 0.45 N·m/kg; P =.04). In both limbs, hip AD strength was greater at visit 2 than visit 1 (ACLR: 1.82 ± 0.48 vs 1.70 ± 0.48 N·m/kg; contralateral: 1.76 ± 0.47 vs 1.67 ± 0.47 N·m/kg; P <.01 for both). Conclusion: The ACLR limb had weaker hip AB and stronger AD compared with the contralateral limb at initial assessment. Hip muscle strength recovery was not influenced by sex. Hip strength and symmetry improved over the course of rehabilitation. Although strength differences across limbs were minor, the clinical importance of these differences is still unknown. Clinical Relevance: The evidence provided highlights the need to integrate hip strength into RTP assessments to identify hip strength deficits that may increase reinjury or lead to poor long-term outcomes. [ABSTRACT FROM AUTHOR]

The superficial hip adductor muscles are situated in close proximity to each other. Therefore, relative movement between the overlying skin and the muscle belly could lead to a shift in the position of surface electromyography (EMG) electrodes and contamination of EMG signals with activity from neighboring muscles. The aim of this study was to explore whether hip movements or isometric contraction could lead to relative movement between the overlying skin and 3 adductor muscles: adductor magnus, adductor longus, and adductor gracilis. The authors also sought to investigate isometric torque--EMG relationships for the 3 adductor muscles. Ultrasound measurement showed that EMG electrodes maintained a position which was at least 5 mm within the muscle boundary across a range of hip flexion--extension angles and across different contraction levels. The authors also observed a linear relationship between torque and EMG amplitude. This is the first study to use ultrasound to track the relative motion between skin and muscle and provides new insight into electrode positioning. The findings provide confidence that ultrasound-based positioning of EMG electrodes can be used to derivemeaningful information on output from the adductor muscles and constitute a step toward recognized guidelines for surface EMG measurement of the adductors. [ABSTRACT FROM AUTHOR]

Clinical Scenario: Ice hockey and soccer are both dynamic sports that involve continuous, unpredictable play. These athletes consistently demonstrate higher rates of groin strains compared with other contact sports. Measuring the hip adductor/ abductor ratio has the potential to expose at-risk players, reduce injury rales, and preserve groin health in players with chronic strains. Focused Clinical Question: What is the clinical utility of measuring the hip adductor/abductor ratio for preseason and in-season ice hockey and soccer players? Summary o f Key Findings: Three studies, all of which were prospective cohort designs, were included. One study involved assessing preseason strength and flexibility as a risk factor for adductor strains in professional ice hockey players. Another study performed with the same professional hockey team used preseason hip adductor/abductor strength ratios to screen for those players who would benefit from a strengthening intervention aimed at reducing the incidence of adductor strains. The final study, which was performed in elite Ul7 soccer players, assessed the effectiveness of monthly in-season strength monitoring as a guide to trigger in-season interventions to decrease injury incidence. Clinical Bottom Line: Measuring the hip adductor/abductor strength ratio in hockey and soccer players can be a beneficial preseason and in-season tool to predict future groin strain risk and screen for athletes who might benefit from a strengthening intervention. Strength o f Recommendation: Level 3 evidence exists to support monitoring the hip adductor/abductor strength ratio to assess and reduce the risk of adductor strains in ice hockey and soccer players. [ABSTRACT FROM AUTHOR]

Context: Compared to shoulder and elbow functions, the hip functional characteristics of baseball pitchers have not been fully investigated. Therefore, little is known about the relationship between hip function and pitching performance. Objective: The purpose of this study was to evaluate the characteristics of hip flexibility and strength, focusing on their influences on the ball velocity in baseball pitchers. Design: Descriptive laboratory study. Setting: Laboratory and university baseball facility. Participants: Twenty-three college baseball pitchers. Interventions: Passive hip range of motion (ROM) and isometric hip muscle strength were bilaterally measured. The pitchers threw 20 fastballs at an official pitching distance. Main Outcome Measures: Bilateral hip ROM and strength in flexion, extension, abduction, adduction, and external and internal rotation; the maximal ball velocity. Results: The pivot side showed smaller hip external rotation ROM (P< .01), larger hip internal rotation ROM (P = .03), and greater hip adduction strength (P = .03) than the stride side. The hip extension ROM on the stride side had a negative correlation with the maximal ball velocity (r = -.58, P < .01). The maximal ball velocity (135.3 [4.1] km/h) positively correlated with the hip extension (r=.59, P< .01), flexion (r= .57, P<.01), abduction (r=.55, P< .01), and adduction (r=.55, Pc.Ol) strength on the pivot leg, and the hip flexion (r=.53, P=.01), abduction (r=.67, P<.01), and adduction (r=.46, P= .03) strength on the stride leg. Conclusions: These findings suggest that baseball pitchers do not have marked side-to-side differences in hip flexibility and strength, and that an important fitness factor for increasing ball velocity is not the hip flexibility but the hip muscle strength of both legs. [ABSTRACT FROM AUTHOR]

The HumanTrak captures human movement through markerless motion tracking and can be a crucial tool in military physical screening. Reliability was examined in eighteen healthy participants who completed shoulder and hip ROM, and dynamic tasks in three body armour conditions. Generally, for all conditions, good to excellent reliability was observed in shoulder abduction and flexion, hip abduction and adduction, and dynamic squats knee and hip flexion (ICC ≥ 0.75 excluding outliers). Shoulder adduction and hip flexion demonstrated moderate to excellent reliability (ICC ≥ 0.50). Shoulder and hip extension and the drop jump were unreliable (ICC: 0.10–0.94, 0.15–0.89, and 0.30–0.82, respectively) due to the large distribution of ICC scores. Tasks with ROM values ≥ 100° involving movement towards or perpendicular to the HumanTrak camera tended to have greater reliability than movements moving away from the camera and out of the perpendicular plane regardless if body armour was worn. Practitioner summary: The HumanTrak analyses ROM in a time-efficient manner in a military setting. This study established that shoulder abduction and adduction (no body armour) and shoulder, hip, and knee flexion were the most reliable measurement for all conditions. Further work is required for movements across different planes. Abbreviations: ROM: range of motion; NBA: no body armour; BA: unloaded body armour; BA9: body armour with 9 kg; RGB: red, green, blue; ICC: intra-class correlation; SEM: standard error of measurement; MDC: minimal detectable change: MSE: mean square error; r: pearson correlations; N: sample size [ABSTRACT FROM AUTHOR]

Previous research established that male powerlifters have less range of motion (ROM) in several movements about the shoulder and hip compared with sedentary male subjects. It is unclear if these differences in ROM are related to strength, training type, and years of training experience or if individuals with less ROM have a better propensity to gain strength. The purpose of this study was to compare strength and ROM in male powerlifters and recreationally strength-trained male subjects and to determine if ROM would be an effective predictor of strength in these groups. Twelve powerlifters and 12 recreationally strength-trained control subjects completed 1 repetition maximum (1RM) squat and bench press testing. In a subsequent session, active ROM was measured, and velocity data were collected during submaximal squat repetitions. There was no significant difference (p > 0.05) between the groups for age, height, body mass, training experience, and training frequency. Powerlifters had significantly greater (p ≤ 0.05) training duration and absolute squat and bench press 1RM. Powerlifters had significantly less shoulder extension and horizontal abduction, and hip flexion, extension, and adduction than recreationally strength-trained men. Significant negative relationships were found between 2-lift Wilks score (body mass relative strength) and shoulder extension and horizontal abduction, as well as hip flexion and extension. In powerlifters, significant negative relationships were found between competition Wilks score, shoulder extension, and hip flexion. Because these relationships correspond to the bottom position of the squat and bench press, it may be best to ensure that shoulder extension and hip flexion remain sufficient to achieve competition depth. [ABSTRACT FROM AUTHOR]

Background Significant effort has gone into the identification and quantification of the underlying mechanisms of primary ACL injury. Secondary ACL injury is observed in approximately 1/4 to 1/3 of athletes who return to sport following ACL reconstruction. However, little has been done to evaluate the mechanisms and playing circumstances surrounding these repeat injuries. Hypothesis/Purpose The purpose of this study was to characterize the mechanisms of non-contact secondary ACL injuries using video analysis. It was hypothesized that in video recordings of secondary ACL injury, athletes would exhibit greater frontal plane hip and knee angles, but not greater hip and knee flexion, at 66 ms following initial contact (IC) as compared to at IC and 33ms following IC. Study Design Cross-Sectional Study Methods Twenty-six video recordings of competitive athletes experiencing secondary ACL ruptures via noncontact mechanisms were analyzed for lower extremity joint kinematics, playing situation, and player attention. Kinematics were assessed at IC as well as 33 ms (1 broadcast frame) and 66 ms (2 broadcast frames) following IC. Results Knee flexion and knee frontal plane angles were greater at 66 ms than IC (p ≤ 0.03). Hip, trunk, and ankle frontal plane angles were not greater at 66 ms than IC (p ≥ 0.22). Injuries were distributed between attacking play (n=14) and defending (n=8). Player attention was most commonly focused on the ball (n=12) or an opponent (n=7). A single-leg landing accounted for just over half of the injuries (54%), while a cutting motion accounted for the remainder of the injuries (46%). Conclusion Secondary ACL injury was most likely to occur during landing or a sidestep cut with player attention external to their own body. Knee valgus collapse combined with limited hip motion was identified in the majority of secondary injuries. Level of Evidence Level IIIb [ABSTRACT FROM AUTHOR]

Background: Running-related injuries are prevalent among distance runners. Changing step rate is a commonly used running retraining strategy in the management and prevention of running-related injuries. Objective: The aims of this review were to synthesise the evidence relating to the effects of changing running step rate on injury, performance and biomechanics. Design: Systematic review and meta-analysis. Data Sources: MEDLINE, EMBASE, CINAHL, and SPORTDiscus. Results: Thirty-seven studies were included that related to injury (n = 2), performance (n = 5), and biomechanics (n = 36). Regarding injury, very limited evidence indicated that increasing running step rate is associated with improvements in pain (4 weeks: standard mean difference (SMD), 95% CI 2.68, 1.52 to 3.83; 12 weeks: 3.62, 2.24 to 4.99) and function (4 weeks: 2.31, 3.39 to 1.24); 12 weeks: 3.42, 4.75 to 2.09) in recreational runners with patellofemoral pain. Regarding performance, very limited evidence indicated that increasing step rate increases perceived exertion (− 0.49, − 0.91 to − 0.07) and awkwardness (− 0.72, − 1.38 to − 0.06) and effort (− 0.69, − 1.34, − 0.03); and very limited evidence that an increase in preferred step rate is associated with increased metabolic energy consumption (− 0.84, − 1.57 to − 0.11). Regarding biomechanics, increasing running step rate was associated with strong evidence of reduced peak knee flexion angle (0.66, 0.40 to 0.92); moderate evidence of reduced step length (0.93, 0.49 to 1.37), peak hip adduction (0.40, 0.11 to 0.69), and peak knee extensor moment (0.50, 0.18 to 0.81); moderate evidence of reduced foot strike angle (0.62, 034 to 0.90); limited evidence of reduced braking impulse (0.64, 0.29 to 1.00), peak hip flexion (0.42, 0.10 to 0.75), and peak patellofemoral joint stress (0.56, 0.07 to 1.05); and limited evidence of reduced negative hip (0.55, 0.20 to 0.91) and knee work (0.84, 0.48 to 1.20). Decreasing running step rate was associated with moderate evidence of increased step length (− 0.76, − 1.31 to − 0.21); limited evidence of increased contact time (− 0.95, − 1.49 to − 0.40), braking impulse (− 0.73, − 1.08 to − 0.37), and negative knee work (− 0.88, − 1.25 to − 0.52); and limited evidence of reduced negative ankle work (0.38, 0.03 to 0.73) and negative hip work (0.49, 0.07 to 0.91). Conclusion: In general, increasing running step rate results in a reduction (or no change), and reducing step rate results in an increase (or no change), to kinetic, kinematic, and loading rate variables at the ankle, knee and hip. At present there is insufficient evidence to conclusively determine the effects of altering running step rate on injury and performance. As most studies included in this review investigated the immediate effects of changing running step rate, the longer-term effects remain largely unknown. Prospero Registration: CRD42020167657. [ABSTRACT FROM AUTHOR]

This study investigated the effect of a handball-specific fatigue protocol on hip and knee kinematics. Twenty female handball athletes performed three trials of the single-leg landing (SLL), sidestep cutting manoeuvre (SCM), and drop vertical jump (DVJ) before and after the fatigue protocol. Knee and hip angle waveforms were compared using statistical parametric mapping (p < 0.05). During the SLL, the fatigue increased hip adduction (4–7% cycle) and knee abduction (4–9% and 25–27%). For the SCM, hip flexion was reduced under fatigue during 14–29% and 44–68% of the cycle. Similarly, the knee flexion decreased between 7–36% and 53–73%. Besides, during the fatigue state, the athletes reduced the hip abduction between 0–11% of the cycle and increased the knee abduction between 20–23%. During the DVJ task, when fatigued, the hip flexion decreased between 19–44% of the cycle and the knee flexion between 1–16% and 18–77%. The fatigue protocol altered the lower limb kinematics, decreasing knee and hip flexions during the SCM and DVJ and increasing the knee valgus during both single-leg landing tasks. [ABSTRACT FROM AUTHOR]

Background: Postoperative biomechanics after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) are an outcome of interest, but correlation with patient-reported outcomes (PROs) remains unclear. Purpose/Hypothesis: The purpose of this study was to assess the correlation between changes in hip biomechanics in FAIS patients after hip arthroscopy and changes in PRO scores. We hypothesized that gait analysis would demonstrate significant correlations between pre- and postoperative changes in biomechanics and changes in PRO scores. Study Design: Descriptive laboratory study. Methods: FAIS patients without dysplasia or arthritis who underwent primary hip arthroscopy for labral repair and femoroplasty underwent preoperative and 1-year postoperative 3-dimensional motion tracking and biomechanical testing during normal gait. Joint kinematics calculated included flexion/extension (sagittal plane), abduction/adduction (frontal plane), and internal/external rotation (transverse plane). Peak hip angles and moments were compared between baseline and 1-year postoperative measures. At baseline, 1-year, and 2-year postoperatively, patients completed the following PRO surveys: 12-Item Short Form Health Survey (SF-12), modified Harris Hip Score (mHHS), and Hip disability and Osteoarthritis Outcome Score (HOOS). Joint kinematics that significantly improved 1 year after surgery were assessed for correlations with PRO scores. Results: A total of 10 patients (12 hips) were enrolled prospectively. PROs significantly improved at 1 and 2 years postoperatively compared with baseline values for HOOS, mHHS, and SF-12 Physical Component Score, with all patients achieving the minimal clinically important difference (MCID) on the HOOS Sport/Recreation and Quality of Life subscales. From preoperatively to 1-year postoperatively, significant improvements were seen in peak hip abduction angle (from −2.3° ± 1.8° to −4.6° ± 1.8°; P =.0058) and peak hip extension moment (from −1.03 ± 0.19 to −0.85 ± 0.20 N·m/kg; P =.014); however, there were no significant correlations between these changes and the pre- to postoperative changes on any PRO scores. Conclusion: Gait analysis of FAIS patients after hip arthroscopy demonstrated small, albeit significant, changes in postoperative hip kinetics and kinematics; however, these changes did not correlate with the large, clinically significant improvements in PROs at 1 year after surgery. Clinical Relevance: The results of this study suggest that the degree of improvement in short-term PROs after hip arthroscopy for FAIS may not be related to small changes in biomechanics postoperatively. [ABSTRACT FROM AUTHOR]

Background: The uncemented collum femoris-preserving (CFP) stem offers preservation of the femoral neck and a more conservative soft tissue resection, which may facilitate a more normal walking pattern. We used gait analysis to evaluate if patients operated with a CFP stem showed more favourable hip kinematics and kinetics when compared with a group of patients operated with a conventional uncemented stem. Methods: 44 patients randomised to receive either a CFP or a Corail stem were studied and were operated using a direct lateral incision. Gait analysis was performed 2 years after the operation with a 12-camera motion capture system and 2 force plates. Hip kinematics and kinetics were analysed and 66 subjects served as controls. Results: None of the variables: speed, stride, cadence and stance showed any statistical significant difference between the 2 study groups. Neither did the hip kinematics and kinetics. Compared to controls, patients operated with the CFP stem showed an increased stance (62.5% vs. 61.1%, p < 0.006) and decreased hip abduction (-2.1° vs. -6.5°). Patients operated with the Corail stem showed decreased speed (1.18 vs. 1.23 m/second), and stride length (1.26 vs. 1.33 m), decreased hip extension (-7.5° vs. -12.8°) and range of hip flexion/extension (38° vs. 40.9°), as well as their hip adduction that was increased (6.3° vs. 4°), whereas their hip abduction was reduced (-2.8° vs. -6.5°), (p < 0.004) compared to the controls. Conclusions: Use of a CFP stem did not significantly influence any of the gait parameters studied when compared to a standard stem, but still both stems studied were associated with gait deviations when compared to controls. Whether these differences could be attributed to the stem used, the underlying hip disease, or both is still unknown. [ABSTRACT FROM AUTHOR]

Background Adductor strains are the most common non-contact musculoskeletal injury sustained in ice hockey. Systematic reviews have determined higher level of play and lower hip adduction to abduction strength ratios to be associated with an increased risk of adductor strain across multiple sports. Limited research exists regarding hip adduction and abduction strength profiles across various levels of ice hockey players. Purpose To compare isometric hip adduction and abduction strength profiles among bantam, high school, tier one juniors, and NCAA Division I collegiate ice hockey players. A secondary purpose was to identify whether differences in strength profiles between dominant and non-dominant limbs exist. Study Design Cross-sectional cohort study. Methods A questionnaire of demographic data, hockey, and injury specific information was completed by all subjects. The mean of three reps of maximal hip isometric adduction and abduction strengths were quantified using a handheld dynamometer with external belt-fixation. Ratios of hip adduction-to-abduction strength were calculated and normalized for body weight. Results A total of 87 uninjured skaters were included in this study with a mean age of 17 years. Mean hip adductor-to-abductor ratios for Bantam hockey players were 121% followed by collegiate (115%), Juniors (111%), and high school (109%) hockey players. No statistically significant differences were found between peak hip adduction and abduction isometric strength and playing level. In addition, there was no difference between unilateral hip strength ratios and shooting hand or leg dominance. While 34.5% of subjects reported a history of adductor injury, no significant differences existed regarding strength ratios during bilateral comparison or when compared to their team norms. Three subjects were found to have unilateral ratios of less than 80%, while two subjects demonstrated bilateral ratios of less than 80%. Conclusions Symmetry is illustrated between dominant and non-dominant legs in ice hockey players with and without a history of adductor injury. Results align well with previously established cross-sectional data from Australian football, with ratios of 103% in high school players, 107% in semi-professional players, and 113% in collegiate players. Level of Evidence Level 3 [ABSTRACT FROM AUTHOR]

Proximal fibula osteotomy (PFO) is a relatively new surgery to treat medial compartment knee osteoarthritis (KOA), which can improve varum deformity and relieve knee joint pain. However, the gait alterations in KOA patients after PFO are still poorly understood. The purpose of this study was to evaluate the gait patterns change in patients of medial compartment KOA after PFO. Gait data were collected for 9 females with unilateral medial compartment KOA before and at 6 months after PFO and also for 9 healthy age-matched females. Paired t -test was used to determine the effect of PFO within the KOA group, and independent t -test were performed to compare between KOA and control groups for spatiotemporal, kinematic, and kinetic variables. The results showed that patients with KOA had significantly increased knee peak flexion angle, knee sagittal range of motion, and peak external hip adduction moment but decreased knee frontal range of motion in the affected limb after PFO. The gait symmetry was improved postoperatively confirmed by single support and swing phases, knee peak flexion angle and sagittal range of motion, peak external hip and knee adduction moments, and peak anterior and peak posterior ground reaction forces. These findings provided evidence of a biomechanical benefit and gait improvement following PFO to treat medial compartment KOA. [ABSTRACT FROM AUTHOR]

Purpose: To determine the most relevant pelvis and femur morphological characteristics for differentiating runners with high versus low hip adduction during running. Methods: Fifteen female and 14 male runners underwent instrumented kinematics analysis of overground running and computed tomography scanning of pelvis and femur. The peak hip adduction angle during the stance phase of running was identified for each participant. Using the cohort average of the peak hip adduction angle as the classifying threshold, participants were categorized into high or low hip adduction groups. To determine the most relevant morphologic features for discriminating high and low hip adduction runners, a feature selection-based support vector machine classification analysis was performed. Results: Of the 15 morphology variables examined, femoral head anteversion and femur length were shown to be the best discriminant variables for group classification. Together, these variables achieved a prediction accuracy of 0.93, sensitivity of 1.0, and specificity of 0.88. Conclusions: Our results highlight the importance of femur morphology in contributing to increased hip adduction during running. [ABSTRACT FROM AUTHOR]

This study examined lower extremity joint kinematics in individuals with chronic ankle instability (CAI) and controls during unanticipated and anticipated single-leg drop landings onto a laterally inclined platform. Physically active adults with CAI 15 (n = 15) and controls (n = 15) performed an unanticipated and anticipated 30 cm single-leg drop landing onto a 20° laterally inclined platform. Three-dimensional ankle, knee and hip-joint kinematics were recorded 200 ms pre- to 200 post-landing and analysed with a 2 (group) × 2 (landing condition) SPM ANOVA (p < 0.05). Results revealed individuals with CAI displayed significantly greater ankle internal rotation post-landing across both landing conditions. Anticipated landings elicited significantly greater pre-landing ankle inversion and external rotation, knee abduction and hip adduction. Additionally, significantly less ankle inversion, knee and hip flexion, and knee adduction and hip abduction were present during post-landing of the anticipated landing. Greater ankle internal rotation during landing may contribute to the ankle 'giving way' in individuals with CAI. However, preparatory and reactive proximal-joint kinematics were similar in both groups during landing. This highlights the possible role of the knee and hip joints in assisting with ankle-joint stability during anticipated inversion perturbations. [ABSTRACT FROM AUTHOR]

Purpose: Due to the paucity of information regarding the lower limb biomechanics in running at slow speed, as well as the concentration of most previous studies on a single movement plane, this study aimed to investigate lower limb joint kinetics with increasing running speed. Methods: Twenty-eight runners were asked to stay on the treadmill at a bent velocity which was incrementally increased to 2.5 m/s, 3.5 m/s, and 4.5 m/s speeds. The three-dimensional joint moment and sagittal mechanical muscle power of the lower limb were calculated during the stance phase of running. Repeated measures analysis of variance (ANOVA) with Bonferroni post hoc test was used to examine the variables during running at various speeds. Results: The results showed that at the hip joint in the frontal plane, an adduction moment developed in the middle of the stance phase, and the highest peak adduction moment was obvious at the highest speed condition (4.5 m/s). Also, the time elapsed to peak in the highest speed condition was less than the others. In the transverse plane, although the 3.5 m/s-speed condition experienced the maximum external rotation peak moment, the 4.5 m/s-condition speed reached the internal status earlier than the two other speeds. In the sagittal plane, the highest speed condition showed the highest extension and flexion moments. Conclusion: Increasing running speed in runners leads to more kinetic output and mechanical power gradient. [ABSTRACT FROM AUTHOR]

BACKGROUND: Few studies have reported the contribution of correction of leg length discrepancy (LLD) on the kinematic and kinetic characteristics of the pelvis and hip joints among those who must stand while working using shoe insoles and a three-dimensional (3D) motion analysis system. OBJECTIVE: To investigate dynamic pelvic and hip joint angles and hip moments using a 3D motion analysis system with and without insoles in standing workers with LLD. METHODS: Kinematic and kinetic data of 31 participants with LLD were collected using a motion analysis system and force platforms. Participants were asked to walk wearing standard shoes or shoes with LLD-corrected insoles. Repeated-measures analysis of variance (ANOVA) was used to compare the kinematic and kinetic data of the hip joints and pelvic orientation according to leg side and corrective interventions for LLD. RESULTS: There were significant differences in maximal ROM of hip adduction and abduction with vs. without LLD insoles in the longer and shorter legs (p < 0.05). There were significant differences in maximal elevation (p = 0.004) and total coronal motion (p = 0.006) of the pelvic segment with and without insole corrections in the longer leg during gait. CONCLUSIONS: LLD correction using a customized insole is a recommended therapeutic intervention to improve the musculoskeletal imbalances of hip and pelvic segments in workers with LLD. [ABSTRACT FROM AUTHOR]

The Microsoft Kinect is becoming a widely used tool for inexpensive, portable measurement of human motion, with the potential to support clinical assessments of performance and function. In this study, the relative osteokinematic Cardan joint angles of the hip and knee were calculated using the Kinect 2.0 skeletal tracker. The pelvis segments of the default skeletal model were reoriented and 3-dimensional joint angles were compared with a marker-based system during a drop vertical jump and a hip abduction motion. Good agreement between the Kinect and marker-based system were found for knee (correlation coefficient = 0.96, cycle RMS error = 11°, peak flexion difference = 3°) and hip (correlation coefficient = 0.97, cycle RMS = 12°, peak flexion difference = 12°) flexion during the landing phase of the drop vertical jump and for hip abduction/adduction (correlation coefficient = 0.99, cycle RMS error = 7°, peak flexion difference = 8°) during isolated hip motion. Nonsagittal hip and knee angles did not correlate well for the drop vertical jump. When limited to activities in the optimal capture volume and with simple modifications to the skeletal model, the Kinect 2.0 skeletal tracker can provide limited 3-dimensional kinematic information of the lower limbs that may be useful for functional movement assessment. [ABSTRACT FROM AUTHOR]

BACKGROUND: Dynamic knee valgus (DKV) is a known risk factor for acute and chronic knee injuries and is more frequently diagnosed in females. A real-time single-leg squat test (SLST) could screen for DKV to prevent injuries. OBJECTIVE: To compare the differences in lower extremity strength and range of motion (ROM) in female soccer athletes with and without DKV during an SLST. METHODS: Eighteen subjects with DKV (DKV group) and 18 subjects without DKV (control group) during a single-leg squat were included. Hip strength (flexion, extension, abduction, adduction, internal rotation, and external rotation) was measured with a hand-held dynamometer. Hip ROM (internal and external rotation), and ankle ROM (dorsiflexion with the knee flexed and extended) were measured. Independent t-test was used to compare the averages of the groups. RESULTS: There were significant differences in hip abduction to adduction strength ratio (DKV: 1.48 ± 0.3, control: 1.22 ± 0.26, p < 0.01) and ankle dorsiflexion with knee flexed (DKV: 17.22 ± 6.82, control: 21.22 ± 4.55, p < 0.05) and extended (DKV: 10.14 ± 4.23, control: 14.75 ± 3.40, p < 0.001) between the groups. CONCLUSION: The hip abduction to adduction strength ratio and gastrocnemius and soleus flexibility may be associated factors in dynamic knee valgus and therefore should be assessed and treated, if indicated, as a possible preventive measure in female athletes with this variation. [ABSTRACT FROM AUTHOR]

Introduction: Traditional swaddling, which implies restrictive immobilisation of the infant's lower limbs with the hips in forced extension and adduction, has been shown to be a risk factor for Developmental Dysplasia of Hip (DDH). Methods: We reviewed the literature regarding the correlation between DDH and post-natal positioning by swaddling and baby-wearing, to draw awareness of healthcare professionals towards an important risk factor for DDH that has often been overlooked. Results: There is overwhelming evidence in the literature, by both experimental and clinical studies, that proves the close association between improper post-natal positioning of the baby's hips in extension-adduction and an increased incidence of DDH. On the other hand, "hip safe" swaddling which allows unrestricted flexion-abduction movements of the infants' hips, and the use of baby-wearing devices which keep the lower limbs in an attitude of hip flexion-abduction and knee flexion, is optimal for hip development. Populations which practice these "hip-safe" techniques of infant immobilisation have a lower incidence of DDH as compared to those which practice restrictive immobilisation. Furthermore, populations which have adopted "hip-safe" positioning have demonstrated a significant decrease in the incidence of DDH. Understanding this association is vital, since this is a modifiable risk factor, rectification of which can decrease the incidence of DDH. Conclusion: Policy makers and governments must design educational campaigns tailored to their respective populations to increase awareness regarding the benefits of "hip-safe" techniques of infant positioning, since this simple intervention has the potential of decreasing the incidence of DDH. [ABSTRACT FROM AUTHOR]

Purpose: To examine the influence of hip abductor strength, neuromuscular activation, and pelvis and femur morphology in contributing to sex differences in hip adduction during running. In addition, we sought to determine the best predictors of hip adduction during running for both men and women. Methods: Fifteen female runners and 14 male runners underwent strength testing, instrumented overground running (e.g., kinematics and muscle activation), and computed tomography scanning of pelvis and femur. Morphologic measurements included bilateral hip width to femur length ratio, acetabulum abduction, acetabulum anteversion, femoral anteversion, and femoral neck-shaft angles. Sex differences for all variables were examined using independent t tests. Linear regression was used to assess the ability of each independent variable of interest to predict peak hip adduction during the late swing and stance phase of running. Results: Compared with men, women exhibited significantly greater peak hip adduction during both late swing (8.5° ± 2.6° vs 6.2° ± 2.8°, P = 0.04) and stance phases of running (13.4° ± 4.2° vs 10.0° ± 3.2°, P = 0.02). In addition, women exhibited significantly lower hip abductor strength (1.8 ± 0.3 vs 2.0 ± 0.3 N⋅m⋅kg-1, P = 0.04), greater femoral neck-shaft angles (134.1° ± 5.0° vs 129.9° ± 4.1°, P = 0.01), and greater hip width to femur length ratios than men (0.44 ± 0.02 vs 0.42 ± 0.03, P = 0.03). Femoral anteversion was the only significant predictor of peak hip adduction during late swing (r = 0.36, P = 0.05) and stance (r = 0.41, P = 0.03). Conclusions: Our findings highlight the contribution of femur morphology as opposed to hip abductor strength and activation in contributing to hip adduction during running. [ABSTRACT FROM AUTHOR]

Although obesity has been linked to several differences in walking mechanics, few studies have examined movement mechanics of overweight and obese (OW/OB) children performing higher impact activities, such as running. Purpose: The purpose of this study is to determine differences in running mechanics between healthy weight (HW) children and children classified as OW/OB. Methods: Forty-two children (17 OW/OB, 25 HW) ran overground while kinematic and kinetic data were recorded using a motion capture system and force plate. Kinematic variables of interest included stance time, step length, and frontal and sagittal plane joint angles and excursions at the hip, knee, and ankle. Kinetic variables of interest included ground reaction forces and hip, knee, and ankle moments in the sagittal and frontal planes. Results: The OW/OB group spent more time in stance, took shorter steps, displayed less hip flexion during the first half of stance, had greater ankle inversion at foot strike, had greater knee abduction throughout stance, and had smaller knee flexion, knee adduction, and hip adduction excursions. In comparing unscaled ground reaction forces, the OW/OB group displayed greater peak vertical force, vertical impact peaks, and vertical loading rates. The OW/OB group also displayed greater unscaled plantar and dorsiflexion moments, knee flexion and extension moments, ankle inversion moments, and knee and hip abduction moments. Conclusion: These data suggest that increased body weight in children is associated with changes in running mechanics. Higher joint moments and ground reaction forces may indicate increased injury risk or the development of joint degeneration among overweight/obese children. [ABSTRACT FROM AUTHOR]

Background: The optimal treatment for complete avulsions of the proximal adductor longus (AL) is still debatable, and different operative and nonoperative treatment options have been suggested. Purpose: To report surgical techniques and functional outcomes of a series of athletes who were treated operatively for proximal AL tears. Study Design: Case series; Level of evidence, 4. Methods: A retrospective evaluation of patients who underwent surgical repair of complete proximal AL tear with concomitant distal fascial release with or without lesions of the neighboring soft tissue structures was performed. This included preinjury Tegner score, age, number of tendons involved, time interval from injury to surgery, and postoperative complications. Self-reported outcomes were defined based on the ability to regain sports activities (excellent, good, moderate, fair, or poor). Between-group comparisons were performed to identify factors associated with improved outcomes. The Mann-Whitney nonparametric test was used for comparing continuous variables, and the Fisher exact test was used for comparing nominal variables. Results: A total of 40 male athletes were included in the evaluation, with an average follow-up of 11 months (range, 6 months-8 years). Self-reported outcome was excellent in 23 (57.5%), good in 13 (32.5%), and moderate in 4 (10%) patients. Comparisons between patients with excellent versus good/moderate outcomes revealed nonsignificant differences regarding age at injury and preinjury Tegner score. Athletes with excellent outcomes received surgery sooner after the injury compared with athletes with good/moderate outcomes (2.4 ± 1.8 vs 11.4 ± 11.0 weeks, respectively; P <.01). Conclusion: Surgical repair for complete proximal AL tears with a concomitant distal fascial release resulted in outcomes rated as good or excellent in 90% of the cases. This treatment should be considered particularly in high-level athletes with a clear tendon retraction and within the first month after the injury. Further research is nevertheless needed to compare these outcomes with other treatment alternatives to better define criteria advocating surgery. [ABSTRACT FROM AUTHOR]

Context: Athletic pelvic and groin injuries are a common yet challenging problem. Pelvic belts have been successfully used to reduce pain and improve function but are not a practical solution for athletes. Therefore, there is scope to explore the use of a more dynamic intervention developed to aid in the management of this type of injury. Objectives: To undertake a preliminary investigation into the effectiveness of a dynamic elastomeric fabric orthosis (DEFO) in supporting the management of athletic pelvic and groin injury. Design: A case series with an AB design. Daily assessments were undertaken over 15 days; the onset of intervention was randomized with a minimum baseline period of 6 d. Follow-up assessment was undertaken after 1 mo. Settings: Community and university. Participants: 8 athletes presenting with pelvic or groin injury confirmed through clinical screening. Intervention: A bespoke DEFO. Main Outcome Measures: Force produced on bilateral resisted hip adduction and self-scored pain (using a numerical rating scale of 0-10) at rest and during an active straight-leg raise and a broad jump. Results: In 7 cases a significant improvement was observed on at least 1 measure (2-SD method, celeration line, and/or the point of nonoverlapping data). The remaining case showed minimal symptoms during testing. [ABSTRACT FROM AUTHOR]

Purpose: Training in martial arts is commonly performed by repeating a technical action continuously for a given number of times. This study aimed to investigate if the repetition of the task alters the proper technical execution, limiting the training efficacy for the technical evaluation during competition. This aim was pursued analyzing lower-limb kinematics and muscle activation during repeated roundhouse kicks. Methods: Six junior karate practitioners performed continuously 20 repetitions of the kick. Hip and knee kinematics and sEMG of vastus lateralis, biceps (BF), and rectus femoris were recorded. For each repetition, hip abduction-adduction and flexion-extension and knee flexion-extension peak angular displacements and velocities, agonist and antagonist muscle activation were computed. Moreover, to monitor for the presence of myoelectric fatigue, if any, the median frequency of the sEMG was computed. All variables were normalized with respect to their individual maximum observed during the sequence of kicks. Linear regressions were fitted to each normalized parameter to test its relationship with the repetition number. Results: Linear-regression analysis showed that, during the sequence, the athletes modified their technique: Knee flexion, BF median frequency, hip abduction, knee-extension angular velocity, and BF antagonist activation significantly decreased. Conversely, hip flexion increased significantly. Conclusions: Since karate combat competitions require proper technical execution, training protocols combining severe fatigue and technical actions should be carefully proposed because of technique adaptations. Moreover, trainers and karate masters should consider including specific strength exercises for the BF and more generally for knee flexors. [ABSTRACT FROM AUTHOR]

Context: Hip- and knee-joint kinematics during drop landings are relevant to lower-extremity injury mechanisms. In clinical research the "gold standard" for joint kinematic assessment is 3-dimensional (3D) motion analysis. However, 2-dimensional (2D) kinematic analysis is an objective and feasible alternative. Objective: To quantify the relationship between 2D and 3D hip and knee kinematics in single-leg drop landings and test for a set of 3D hip and knee kinematics that best predicts 2D kinematic measures during single-leg drop landings Design: Descriptive, comparative laboratory study. Participants: 31 healthy college-age women (65.5 kg [SD 12.3], 168.1 cm [SD 6.7]). Methods: Participants performed five 40-cm single-leg landings during motion capture at 240 Hz. Multiple regressions were used to predict relationships for knee and hip between 2D frontal-plane projection angles (FPPA) and 3D measurements. Results: 2D knee FPPA had a strong relationship with 3D frontal-plane knee kinematics at initial contact (IC) (r² = .72), which was only minimally improved with the addition of knee sagittal-plane and hip transverse-plane positions at IC (r² = .77). In contrast, 2D knee FPPA had a low relationship with 3D knee-abduction excursion (r² = .06). The addition of knee sagittal-plane and hip transverse-plane motions did not improve this relationship (r² = .14). 2D hip FPPA had a moderate relationship with 3D frontal-plane hip position at IC (r² = .52), which was strengthened with the addition of hip sagittal-plane position (r² = .60). In addition, hip 2D FPPA into adduction excursion had a strong association with 3D hip-adduction excursion (r² = .70). Conclusion: 2D kinematics can predict 3D frontal-plane hip and knee position at IC during a single-leg landing but predict 3D frontal-plane knee excursion with far less accuracy. [ABSTRACT FROM AUTHOR]

Secomb, JL, Dascombe, BJ, and Nimphius, S. Importance of joint angle-specific hip strength for skating performance in semiprofessional ice hockey athletes. J Strength Cond Res 35(9): 2599-2603, 2021--Ice hockey athletes with faster sprint acceleration and change-of-direction (COD) skating performance possess a competitive advantage. However, it is unknown whether joint anglespecific hip strength, in combination with measures known to relate to skating performance (e.g., countermovement jump [CMJ]), better explains skating performance. The purpose of this research was to determine whether hip strength in joint angles specific to skating positions and CMJ performance explains sprint skating acceleration and COD performance. Thirteen semiprofessional male hockey (26.76 6.7 years; 88.4 618.1 kg; 181.9 6 5.4 cm) athletes were assessed for CMJ performance, hip abduction and adduction strength, 10-m sprint skating acceleration, and COD (505) performance. Linear multiple regressions to predict skating acceleration and COD performance were calculated with variables chosen based on functional justification and magnitude of correlation. Hip abductor relative peak force (rPF) at 25° of hip abduction and CMJ rPF explained 46.0% (adjusted) of variance in sprint acceleration performance (F[2,12] 5 6.18, p 5 0.02). Countermovement jump peak eccentric velocity, adductor rPF at 50° of hip abduction, and difference in abductor rPF between 50° and 25° of hip abduction explained 85.0% (adjusted) of the variance in 505 time (F[3,12] 5 22.8, p, 0.001). Hip strength at joint angles functionally relevant to skating (e.g., at 25° and 50°), in combination with relevant CMJ variables, explained large and very large amounts of variance in sprint skating acceleration andCODperformance in this cohort. The inclusion of joint angle-specific hip strength profiling to a physical performance testing battery may provide practitioners with more specific knowledge on the strength of the hip through abduction range of motion, which may affect skating performance. [ABSTRACT FROM AUTHOR]

To examine the kinematics of athletes with good and poor lumbopelvic stability (LPS) based on clinical rating criteria of single leg squat (SLS) and dip test (DT) The aim was to establish if good and poor LPS categorization is supported by differences in kinematic variables. Sixty-two recreational athletes had their LPS categorized using clinical rating criteria for SLS and DT as good, poor or neither good nor poor. Kinematic measures were examined in those with good (N = 8) or poor (N = 14) LPS and results compared to the rating criteria. Multiple clinical rating criteria for good and poor LPS groups were distinguished by kinematic measures. Smoothness of motion for both SLS and DT distinguished good and poor LPS. Minimal (good) or discernible movement (poor) out of the starting plane was confirmed with kinematic measures. For SLS these movements were: weight-bearing hip adduction, non-weightbearing hip abduction, pelvic rotation, and trunk sideflexion, and for DT: weightbearing hip adduction, non-weightbearing hip abduction and pelvic obliquity. Additionally, hip dissociation (SLS) distinguished good and poor LPS. Athletes with good and poor LPS have different kinematic measures in single leg squat and dip test. Multiple clinical rating criteria of LPS that distinguish good and poor stability were confirmed by kinematic measures. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the current study was 1) to evaluate sex differences in peak hip adduction during the late swing and stance phases of running and 2) to determine whether peak hip adduction during late swing is predictive of peak hip adduction during stance. Methods: A total of 15 female and 16 male heel strike runners ran over ground at a speed of 4m⋅s-1. Hip joint kinematics during running were quantified using a 3D motion capture system. Sex differences in peak hip adduction during the late swing and stance phases were compared using independent-samples t-tests. Linear regression analysis was used to determine the relationship between late swing and stance phase hip adduction. Results: Compared with males, females exhibited significantly greater peak hip adduction during both the late swing (8.5° ± 2.6° vs 6.1° ± 2.8°, P = 0.019) and the stance phases of running (13.3° ± 4.2° vs 9.6° ± 3.4°, P = 0.011). Furthermore, late swing peak hip adduction was predictive of subsequent stance phase peak hip adduction (r = 0.63, P < 0.001). Conclusion: Sex differences in hip adduction during stance are influenced in part by late swing phase hip adduction. Further studies are needed to identify potential causes of excessive hip adduction during the late swing phase of running. [ABSTRACT FROM AUTHOR]

Purpose: To investigate differences in lower extremity joint angles between a forward (FSD) and lateral (LSD) step-down task at different heights (4 and 6 inches). Methods: Eighteen healthy adults performed four variations of the step-down task while hip, knee, and ankle kinematics were measured. A two-way repeated measures analysis of variance was performed. Results: There was a significant interaction and main effect for step direction and height for knee external rotation and ankle dorsiflexion angle (P <.05). Participants exhibited greater hip adduction, knee flexion, knee adduction, and ankle dorsiflexion during performance of the FSD than the LSD at the 4- and 6-inch height. For each step direction, participants demonstrated greater hip flexion, hip adduction, knee flexion, knee adduction, and ankle dorsiflexion during performance of the task at the 6-inch height. Conclusions: The FSD requires greater movement of the lower extremity than the LSD and increasing step height increases the biomechanical demands of the lower extremity. [Athletic Training & Sports Health Care. 2021;13(4):e212–e220.] [ABSTRACT FROM AUTHOR]