SQUATTING MECHANICS FOLLOWING AN OSTEOCHONDROPLASTY FOR IDIOPATHIC FEMOROACETABULAR IMPINGEMENT

Background: Femoroacetabular impingement (FAI) is primarily due to the repetitive motion of aberrant bone in provocative positions such as hip flexion and internal rotation (IR). The purpose of this study is to evaluate the kinematic changes that occur in the hip during a squat prior to and following an osteochondroplasty for idiopathic FAI. Methods: Subjects were prospectively enrolled when scheduled to undergo hip preservation surgery for primary CAM hip impingement by one of 3 surgeons. Prior to the procedure, subjects were evaluated in the movement science lab while performing a standardized bilateral limb gravity squat. Kinematic data of the trunk, pelvis and lower limbs were analyzed during the descent phase of the squat. Statistical comparison of the operative and non-operative hips was performed prior to and at a minimum of one year following surgery. Results: Twenty-seven hips with a mean age of 16.3 years (12.4 – 19.9 years, 8 males) underwent an osteochondroplasty (8 arthroscopic, 19 surgical hip dislocation) resulting in a decrease in the alpha angle (60.8° versus 46.8°, p<0.001) and a significant improvement in HOOS and UCLA scores. When combining the entire cohort, no statistical difference was seen in side to side nor pre-operative to post-operative kinematic or kinetic data. Asymmetry was seen in the transverse plane hip rotation with 6/27 subjects demonstrating an average reduction of 9.4° in ROM on the affected side and a decrease in both peak IR and external rotation (ER) (average decrease 4.7°). Following osteochondroplasty, asymmetry resolved in 4/6 patients. Also, 16/27 subjects demonstrated asymmetry in rotation at 40° of hip flexion during the squat (11 more ER, 5 more IR) in which 37.5% had resolution of the asymmetry following an osteochondroplasty. Conclusion: Asymmetry in squatting mechanics in patients with FAI is not consistent with all subjects. Those with asymmetry in rotation at 40° of hip flexion during the squat or reduction in overall hip rotation may see a resolution in asymmetry following an osteochondroplasty. Dynamic impingement may present as asymmetry during different positions of hip flexion in a squat.

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Legal Update: North Dakota Supreme Court: Third Edition of Guides is “Most Current”

Guides Newsletter ◽

10.1001/amaguidesnewsletters.1999.janfeb04 ◽

1999 ◽

Vol 4 (1) ◽

pp. 6-7

Author(s):

James J. Mangraviti

Keyword(s):

Internal Rotation ◽

External Rotation ◽

Measurement Techniques ◽

Fourth Edition ◽

Hip Motion ◽

The Difference ◽

The Right ◽

Hip Flexion ◽

Hip Rotation ◽

Hip Extension

Abstract The accurate measurement of hip motion is critical when one rates impairments of this joint, makes an initial diagnosis, assesses progression over time, and evaluates treatment outcome. The hip permits all motions typical of a ball-and-socket joint. The hip sacrifices some motion but gains stability and strength. Figures 52 to 54 in AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, illustrate techniques for measuring hip flexion, loss of extension, abduction, adduction, and external and internal rotation. Figure 53 in the AMA Guides, Fourth Edition, illustrates neutral, abducted, and adducted positions of the hip and proper alignment of the goniometer arms, and Figure 52 illustrates use of a goniometer to measure flexion of the right hip. In terms of impairment rating, hip extension (at least any beyond neutral) is irrelevant, and the AMA Guides contains no figures describing its measurement. Figure 54, Measuring Internal and External Hip Rotation, demonstrates proper positioning and measurement techniques for rotary movements of this joint. The difference between measured and actual hip rotation probably is minimal and is irrelevant for impairment rating. The normal internal rotation varies from 30° to 40°, and the external rotation ranges from 40° to 60°.

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Gender Differences in Kinematic Analysis of the Lower Limbs during the Chasse Step in Table Tennis Athletes

Healthcare ◽

10.3390/healthcare9060703 ◽

2021 ◽

Vol 9 (6) ◽

pp. 703

Author(s):

Xiaoyi Yang ◽

Yuqi He ◽

Shirui Shao ◽

Julien S. Baker ◽

Bíró István ◽

...

Keyword(s):

Female Athletes ◽

External Rotation ◽

Rotational Velocity ◽

Knee Extension ◽

Lower Limbs ◽

Table Tennis ◽

Male Athletes ◽

Analysis System ◽

Hip Flexion ◽

Hip Internal Rotation

The chasse step is one of the most important footwork maneuvers used in table tennis. The purpose of this study was to investigate the lower limb kinematic differences of table tennis athletes of different genders when using the chasse step. The 3D VICON motion analysis system was used to capture related kinematics data. The main finding of this study was that the step times for male athletes (MA) were shorter in the backward phase (BP) and significantly longer in the forward phase (FP) than for female athletes (FA) during the chasse step. Compared with FA, knee external rotation for MA was larger during the BP. MA showed a smaller knee flexion range of motion (ROM) in the BP and larger knee extension ROM in the FP. Moreover, hip flexion and adduction for MA were significantly greater than for FA. In the FP, the internal rotational velocity of the hip joint was significantly greater. MA showed larger hip internal rotation ROM in the FP but smaller hip external rotation ROM in the BP. The differences between genders can help coaches personalize their training programs and improve the performance of both male and female table tennis athletes.

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IDENTIFICATION OF FACTORS ASSOCIATED WITH DISEASE PROGRESSION IN THE CONTRALATERAL HIP OF PATIENTS WITH SYMPTOMATIC FEMOROACETABULAR IMPINGEMENT

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967121s00145 ◽

2021 ◽

Vol 9 (7_suppl3) ◽

pp. 2325967121S0014

Author(s):

Adam Khan ◽

Craig R. Louer ◽

Wahid Abu-Amer ◽

Gail Pashos ◽

Cecilia Pascual Garrido ◽

...

Keyword(s):

Disease Progression ◽

Femoroacetabular Impingement ◽

External Rotation ◽

Univariate Analysis ◽

Alpha Angle ◽

Hip Osteoarthritis ◽

Symptom Development ◽

Ucla Activity Score ◽

Center Edge ◽

Imaging Characteristics

Introduction: Femoroacetabular Impingement (FAI) is one of the most common causes of hip osteoarthritis. Nevertheless, the factors contributing to symptom development and FAI disease progression are poorly understood. Hypothesis/Purpose: The purpose of this study was to (1) investigate rates of initial and subsequent symptom development in the contralateral hip of patients with FAI, and (2) identify predictors of disease progression (symptom development) in the contralateral hip. Methods: This prospective study included a minimum 5 year follow-up of the contralateral hip in 179 patients undergoing FAI surgery. Symptoms (moderate pain) were monitored over the study course. Univariate analysis compared patient and FAI imaging characteristics of patients developing symptoms to those who remained asymptomatic. Results: 146 patients (146 hips, 81.5%) were included (min 5 year, mean 6.7 years). Thirty-nine (26%) presented with symptoms in the contralateral hip while 34 (23%) developed symptoms. Head-neck offset ratio (HNOR) on AP pelvis radiographs was significantly lower among hips that developed symptoms (0.164 vs. 0.153 p=0.025). Maximum alpha angle (p=0.413), lateral center edge angle (p=0.704), and crossover sign (p=0.115) were not predictive of symptoms. Patients with a UCLA activity score greater than 9 were less likely to develop symptoms (14% vs. 46%, p=0.081), but this was not statistically significant. The total arc of rotation in extension (35.740 vs 45.140, p=0.012) and 900 of flexion (40.00 vs 50.800, p=0.009) as well as external rotation at 900 of flexion (28.940 vs 36.590, p=0.020) were decreased in hips developing symptoms. Internal Rotation in flexion was not significantly decreased in symptomatic patients (11.060 vs 14.20, p=0.113). Conclusions: We identified unique radiographic and physical exam findings that are associated with symptom development in patients with FAI. Specifically, decreased hip rotation arc and decreased HNOR were strongly associated with disease progression and may represent important factors for future risk modeling in FAI patients.

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Identification of Factors Associated with Disease Progression in the Contralateral Hip of Patients with Symptomatic Femoroacetabular Impingement. (139)

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967121s00278 ◽

2021 ◽

Vol 9 (10_suppl5) ◽

pp. 2325967121S0027

Author(s):

Adam Khan ◽

Craig Louer ◽

Wahid Abu-Amer ◽

Gail Pashos ◽

Cecilia Pascual Garrido ◽

...

Keyword(s):

Disease Progression ◽

Femoroacetabular Impingement ◽

External Rotation ◽

Alpha Angle ◽

Hip Osteoarthritis ◽

Symptom Development ◽

Ucla Activity Score ◽

Center Edge ◽

Imaging Characteristics

Objectives: Femoroacetabular Impingement (FAI) is one of the most common causes of hip osteoarthritis. Nevertheless, the factors contributing to symptom development and FAI disease progression are poorly understood. The purpose of this study was to (1) investigate rates of symptom development in the contralateral hip of patients with FAI at mid-term follow-up, and (2) identify predictors of disease progression (symptom development) in the contralateral hip. Methods: This prospective study included 179 patients undergoing ipsilateral FAI surgery with no history of previous contralateral hip surgery. In the current study, the contralateral hip was assessed at minimum 5 year follow-up. Symptoms (defined as moderate pain) and the need for surgery were monitored over the study course. Statistical analysis compared patient and FAI imaging characteristics of patients developing symptoms to those who remained asymptomatic. Results: A total of 146 hips (81.5%) were included at a mean 6.7 years of follow-up. Thirty-nine (26.7%) presented with symptoms in the contralateral hip, while an additional 35 (23.9%) developed symptoms during the follow-up period. Twenty-Six (17.8%) progressed to surgery for their contralateral hip. Head-neck offset ratio (HNOR) on AP pelvis radiographs was significantly lower among hips that developed symptoms (0.16 vs. 0.15 p=0.03). Maximum alpha angle (p=0.41), lateral center edge angle (p=0.70), and crossover sign (p=0.12) were not predictive of symptoms. Patients with a UCLA activity score greater than 9 were less likely to develop symptoms (14% vs. 46%, p=0.081), but this was not statistically significant. The total arc of rotation in 90° of flexion (40.0° vs 50.8°, p=0.01) as well as external rotation at 900 of flexion (28.9° vs 36.6°, p=0.02) were decreased in hips developing symptoms. Internal rotation in flexion was not significantly decreased in symptomatic patients (11.1° vs 14.2°, p=0.11). Kaplan Meier survival analysis demonstrated 53% and 45% of patients remaining asymptomatic at 5 and 8 year time points (Figure). Conclusions: At a mean follow-up of 6.7 years, significant symptoms in the contralateral hip of patients with FAI are present in 50.7% of patients, while 49.3% remain asymptomatic or minimally symptomatic. We identified unique radiographic and physical exam findings that are associated with symptom development in patients with FAI. Specifically, decreased hip rotation arc and decreased HNOR were strongly associated with disease progression and may represent important factors for future risk modeling in FAI patients.

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Assessment of Functional End Ranges of Lower Limb Joints in Positions Commonly Used for ADLs in India

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2021/v33i35a31873 ◽

2021 ◽

pp. 64-71

Author(s):

Niketa Patel ◽

Lavina Rajesh Khatri ◽

Lata Parmar

Keyword(s):

External Rotation ◽

Plantar Flexion ◽

Cultural Practice ◽

Lower Limbs ◽

Rural And Urban ◽

Ankle Joints ◽

Hip Abduction ◽

Hip Flexion ◽

Age Range ◽

Ankle Plantar Flexion

Background: In many countries of Asian continent, floor sitting is preferred instead of chair supported sitting. Indian population differs noticeably in its cultural practice and daily tasks which involves squatting and cross-legged sitting on the ground. Aim: The purpose of the study was to assess the functional end-ranges of the hip, knee and ankle joints in healthy Indian subjects in positions commonly used for ADLs in India which includes squatting and cross-legged sitting. Methods: 66 healthy subjects were recruited from rural and urban populations with age range 30-50 years. Joint ROM of the lower extremities was measured using Universal Goniometer. All the subjects were asked to acquire squat and cross legged positions which were graded. Results: Our results finding showed that the subjects in cross leg sitting grade 2 (independent CLS) had hip flexion ranges ≥1150, hip abduction ≥ 410, hip external rotation ≥ 420, ankle plantar flexion ≥ 460, p<0.005. For squatting, grade 2 (independent squat) had hip flexion ranges ≥ 1130,p>0.005, Knee flexion ≥1200, p>0.005 and ankle dorsiflexion ≥150, p<0.005. Conclusion: From the results, it is suggested that squatting and cross-leg sitting multiple times a day can prevent the early closer of end ranges of the lower limbs.

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EFFECT OF STATIC ANATOMIC ALIGNMENT ON DYNAMIC LIMB VALGUS DURING SIDE-STEP CUTTING IN UNINJURED ADOLESCENT ATHLETES

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00028 ◽

2019 ◽

Vol 7 (3_suppl) ◽

pp. 2325967119S0002

Author(s):

Nicole Mueske ◽

Daniel T. Feifer ◽

Curtis VandenBerg ◽

J. Lee Pace ◽

Mia J. Katzel ◽

...

Keyword(s):

Lower Extremity ◽

Internal Rotation ◽

Knee Flexion ◽

External Rotation ◽

Acl Injury ◽

Adolescent Athletes ◽

Knee Abduction ◽

Hip Flexion ◽

Hip Internal Rotation ◽

Hip Rotation

BACKGROUND Dynamic limb valgus, combining hip adduction and internal rotation with knee abduction posture and moments, has been implicated in ACL injury. However, the contribution of static lower extremity alignment to dynamic limb valgus is unknown. This study assessed the relationships among lower extremity static alignment and dynamic kinematics and kinetics during side-step cutting in uninjured adolescent athletes. METHODS This prospective study included 88 limbs from 44 uninjured athletes aged 8-15 years (mean 12.3, SD 2.3; 19 (44%) female) who were evaluated during an anticipated 45° side-step cut. 3D lower extremity kinematics and kinetics from a custom 6 degree of freedom model were assessed while standing and during the loading phase of the cut from initial contact to peak knee flexion; 2-3 trials per limb were averaged for analysis. Femoral anteversion was measured for each limb with the participant lying prone. Relationships among static and dynamic measures were investigated using correlation and multiple linear regression. RESULTS In terms of static alignment, more static hip internal rotation and more static knee external rotation (tibia external relative to femur) were associated with more internal hip rotation and external knee rotation dynamically during cutting (r=0.34, p=0.001) (Table 1). Static hip adduction was also related to more external hip rotation and less hip flexion dynamically (p=0.24, p=0.02). More static knee abduction, external hip rotation and hip adduction were associated with higher average knee abduction angles during cutting (r=0.25, p=0.02). However, only static external knee rotation was associated with higher dynamic knee abduction moments (r=0.48, p<0.0001) (Figure 1). During cutting, positive associations were observed between hip flexion, knee flexion, and hip internal rotation (r=0.24, p=0.03). Knee adduction angles were related to more hip flexion, internal hip rotation, and knee external rotation (r=0.25, p=0.02). Additionally, lower peak knee flexion was associated with higher peak ground reaction force and more external knee rotation (r=0.24, p=0.02). Both simple correlation and multiple regression analysis indicated that higher knee abduction moments were related dynamically to higher knee abduction angles, greater knee external rotation, higher hip abduction angles, and greater hip internal rotation (R2=0.72, p<0.001). After considering dynamic metrics, no static measure remained significantly related to knee abduction moments. CONCLUSION/SIGNIFICANCE Static knee rotation was the only anatomic alignment measure associated with knee abduction moments during side-step cutting in uninjured adolescent athletes. Knee abduction moments were influenced more by dynamic posture than static alignment. As knee abduction moments have been implicated in ACL injury, this study supports the notion of dynamic limb valgus, specifically increased knee abduction and hip internal rotation, relating to ACL injury. Motion analysis can be used to identify these risky biomechanical patterns, and neuromuscular training can be used to correct them. Since knee abduction moments are primarily determined by dynamic posture, neuromuscular training can be used to reduce these moments and ACL injury risk. [Figure: see text][Table: see text]

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The role of lumbar lordosis and pelvic sagittal balance in femoroacetabular impingement

The Bone & Joint Journal ◽

10.1302/0301-620x.100b10.bjj-2018-0060.r1 ◽

2018 ◽

Vol 100-B (10) ◽

pp. 1275-1279 ◽

Cited By ~ 13

Author(s):

R. R. Fader ◽

M. A. Tao ◽

M. A. Gaudiani ◽

R. Turk ◽

B. U. Nwachukwu ◽

...

Keyword(s):

Lumbar Spine ◽

Femoroacetabular Impingement ◽

Lumbar Lordosis ◽

Pelvic Tilt ◽

Alpha Angle ◽

Dynamic Imaging ◽

Anterior Pelvic Tilt ◽

Hip Flexion ◽

Male Subjects

Aims The purpose of this study was to evaluate spinopelvic mechanics from standing and sitting positions in subjects with and without femoroacetabular impingement (FAI). We hypothesize that FAI patients will experience less flexion at the lumbar spine and more flexion at the hip whilst changing from standing to sitting positions than subjects without FAI. This increase in hip flexion may contribute to symptomatology in FAI. Patients and Methods Male subjects were prospectively enrolled to the study (n = 20). Mean age was 31 years old (22 to 41). All underwent clinical examination, plain radiographs, and dynamic imaging using EOS. Subjects were categorized into three groups: non-FAI (no radiographic or clinical FAI or pain), asymptomatic FAI (radiographic and clinical FAI but no pain), and symptomatic FAI (patients with both pain and radiographic FAI). FAI was defined as internal rotation less than 15° and alpha angle greater than 60°. Subjects underwent standing and sitting radiographs in order to measure spine and femoroacetabular flexion. Results Compared with non-FAI controls, symptomatic patients with FAI had less flexion at the spine (mean 22°, sd 12°, vs mean 35°, sd 8°; p = 0.04) and more at the hip (mean 72°, sd 6°, vs mean 62°, sd 8°; p = 0.047). Subjects with asymptomatic FAI had more spine flexion and similar hip flexion when compared to symptomatic FAI patients. Both FAI groups also sat with more anterior pelvic tilt than control patients. There were no differences in standing alignment among groups. Conclusion Symptomatic patients with FAI require more flexion at the hip to achieve sitting position due to their inability to compensate through the lumbar spine. With limited spine flexion, FAI patients sit with more anterior pelvic tilt, which may lead to impingement between the acetabulum and proximal femur. Differences in spinopelvic mechanics between FAI and non-FAI patients may contribute to the progression of FAI symptoms. Cite this article: Bone Joint J 2018;100-B:1275–9.

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Less hip range of motion is associated with a greater alpha angle in people with longstanding hip and groin pain

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-021-06733-2 ◽

2021 ◽

Author(s):

August Estberger ◽

Anders Pålsson ◽

Ioannis Kostogiannis ◽

Eva Ageberg

Keyword(s):

Range Of Motion ◽

Internal Rotation ◽

Sensitivity And Specificity ◽

Groin Pain ◽

External Rotation ◽

Alpha Angle ◽

Good Sensitivity ◽

Level Of Evidence ◽

Hip Range Of Motion ◽

Hip Flexion

Abstract Purpose A higher alpha angle has been proposed to correlate with lower hip range of motion, but the association in people with longstanding hip and groin pain is currently unclear. The aims were to: (1) assess the association between range of motion and alpha angle in patients with longstanding hip and groin pain; (2) examine if a cut-off value in range of motion variables could identify patients with an alpha angle above or below 60°. Methods Seventy-two participants were consecutively recruited from an orthopaedic department after referral for hip- and groin-related pain. Passive hip range of motion was measured in flexion, internal rotation with 90° hip flexion, internal rotation in neutral hip position, external rotation with 90° hip flexion, and abduction. The alpha angle was calculated from a frog-leg lateral radiograph. Linear regression examined the association between range of motion and alpha angle, and an ROC-curve analysis was performed to identify the sensitivity and specificity of range of motion cut-offs. Results Lower range of motion in internal rotation in flexion, external rotation, and abduction were associated with higher alpha angle. Internal rotation of 27° or less displayed good sensitivity (81%) and specificity (85%) to detect an alpha angle above 60°, while a cut-off of 41° in external rotation and 27° in abduction showed a sensitivity of 72% and specificity of 50% and 60%, respectively. Conclusion Less internal rotation in flexion, external rotation, and abduction are associated with a greater alpha angle in a cohort of people with longstanding hip and groin pain. A cut-off of 27° in internal rotation has good sensitivity and specificity to identify people with an alpha angle above or below 60° and have the potential to be used in the clinical setting to identify patients that require further imaging, or that are unlikely to have cam morphology. Level of evidence II.

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The Bipolar Hip: Combined Acetabular and Femoral Pathomorphology Determine Hip Motion

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00421 ◽

2019 ◽

Vol 7 (7_suppl5) ◽

pp. 2325967119S0042

Author(s):

Jessica Shin ◽

Temitope F. Adeyemi ◽

Taylor Hobson ◽

Christopher L. Peters ◽

Travis G. Maak

Keyword(s):

Logistic Regression ◽

Femoral Head ◽

Internal Rotation ◽

External Rotation ◽

Alpha Angle ◽

Acetabular Version ◽

Femoral Version ◽

Hip Flexion ◽

Hip Internal Rotation ◽

Head Neck

Objectives: Prior studies have suggested femoral version may outweigh the effect of cam impingement on hip internal rotation; however, the effects of acetabular morphology were considered. This study investigates the influences of acetabular and femoral morphology on hip range of motion (ROM) in patients with femoroacetabular impingement syndrome (FAIS). Methods: With IRB approval, a retrospective chart review and radiographic analysis was performed of patients presenting with hip pain to the clinic of a single surgeon. Patients were included in the study if their hip pain was thought to be intra-articular in origin, had full physical exam documentation (including bilateral hip evaluations and measurements of passive hip ROM), Tönnis grade ≤ 1, and had full imaging including: AP pelvis, 45⁰ Dunn lateral, and false profile radiographs and a CT scan with 3-D reconstructions of the affected hip. Patients were excluded if they had prior hip surgery, prior hip trauma or other underlying hip pathology. Femoral head/neck angle, femoral version, size and clock-face location of the maximum femoral alpha angle, mid-coronal center edge angle (CEA), mid-sagittal CEA, acetabular version at the 1, 2 and 3 o’clock positions and the McKibbin index were measured on CT scan. Univariable and multivariable logistic regression analyses were performed to determine which measurements correlated with hip ROM. Results: 200 hips from 200 patients were included in the final analysis. Mean age was 31.9 ±10 years, 145 (72%) patients were female, and mean BMI of the cohort was 25.2 ± 5. Univariable logistic regression analysis found femoral head/neck angle, mid-sagittal CEA, acetabular version at 1 and 2 o’clock, and McKibbin Index all significantly correlated with hip flexion (all q’s > 0.05 after adjusting for false discovery rate). Femoral head-neck angle, femoral version, and McKibbin index all significantly correlated with external rotation. Femoral neck version, mid-sagittal CEA, acetabular version at all three clock positions, McKibbin index, max femoral alpha angle, and alpha position all significantly correlated with internal rotation. In the multivariate logistic regression analysis mid-sagittal CEA was the only measurement correlating with flexion, femoral head/neck angle and McKibbin index were the only significant variables correlating with external rotation, and McKibbin index and maximum femoral alpha angle were the only variables correlating with internal rotation. The results of the logistic regressions are summarized in Figure 1. Conclusion: Our univariate data supported previous data that suggested femoral version significantly correlated with hip internal rotation. However, multivariate analysis including acetabular version demonstrated that combined acetabular and femoral version significantly correlated with internal and external rotation while femoral version in isolation did not. In contrast to prior studies, an increased cam deformity, as defined by max femoral alpha angle, remained a significant contributor to reduced internal rotation but did not affect hip flexion. Rather, the increased mid-sagittal CEA remained the sole significant contributor to reduced hip flexion in the multivariable analysis. These data suggest that hip ROM is affected in a bipolar fashion and careful multiplanar evaluation of the femoral and acetabular pathomorpohlogy should be conducted prior to attempting to increase hip ROM with corrective osteoplasty or osteotomy. [Figure: see text]

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Isometric Hip-Rotator Torque Production at Varying Degrees of Hip Flexion

Journal of Sport Rehabilitation ◽

10.1123/jsr.19.1.12 ◽

2010 ◽

Vol 19 (1) ◽

pp. 12-20 ◽

Cited By ~ 8

Author(s):

Sam Johnson ◽

Mark Hoffman

Keyword(s):

Sports Medicine ◽

Outcome Measure ◽

External Rotation ◽

Knee Injuries ◽

Main Outcome Measure ◽

Medicine Research ◽

Type Design ◽

Change Function ◽

Hip Flexion ◽

Hip Rotation

Context:Hip torque production is associated with certain knee injuries. The hip rotators change function depending on hip angle.Objective:To compare hip-rotator torque production between 3 angles of hip flexion, limbs, and sexes.Design:Descriptive.Setting:University sports medicine research laboratory.Participants:15 men and 15 women, 19-39 y.Intervention:Three 6-s maximal isometric contractions of the hip external and internal rotators at 10°, 40°, and 90° of hip flexion on both legs.Main Outcome Measure:Average torque normalized to body mass.Results:Internal-rotation torque was greatest at 90° of hip flexion, followed by 40° of hip flexion and finally 10° of hip flexion. External-rotation torque was not different based on hip flexion. The nondominant leg’s external rotators were stronger than the dominant leg’s, but the reverse was true for internal rotators. Finally, the men had more overall rotator torque.Conclusions:Hip-rotation torque production varies between flexion angle, leg, and sex. Clinicians treating lower extremity problems need to be aware of these differences.

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