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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]

Clinical Scenario: Injuries that affect the groin region are among the most common in football players. To prevent this condition, studies have focused on strengthening the adductors, hip flexors, or abdominal muscles. Recent investigations have used an eccentric-biased exercise (Copenhagen Adduction Exercise [CAE]) that promotes functional and architectural adaptations in the muscle tissue, though its effect on injury risk reduction is unknown. Clinical Question: Can the Copenhagen Adduction Exercise prevent groin injuries in soccer players? Summary of Key Findings: The literature was searched for studies investigating the potential groin injury risk reduction effect of the CAE. (1) Three studies met the inclusion criteria and were used for this appraisal; (2) one study observed a significantly lower injury rate ratio favoring the group that used the CAE program; and (3) 2 studies found similar or higher injury rates in the intervention groups, not supporting the inclusion of the CAE as a preventative tool. Clinical Bottom Line: There is conflicting evidence that usage of the CAE is superior to not performing adductor strengthening exercises in mitigating the risk of sustaining groin injuries. Given the evidence supporting these findings, it is advisable to exercise caution when contemplating the incorporation of the CAE into training regimens aimed at preventing groin injuries. Strength of Recommendation: There is Grade B evidence to suggest that inclusion of the CAE may not be associated with reduced injury rates. [ABSTRACT FROM AUTHOR]

Context: Posterior shoulder tightness evaluated as limited glenohumeral internal rotation and horizontal adduction is a risk factor for throwing-related shoulder and elbow injuries. Given that the throwing motion uses the entire body kinematics, limited lower-limb flexibility might be associated with posterior shoulder tightness. Therefore, we aimed to investigate the relationships between posterior shoulder tightness and lower-limb flexibility in college baseball players. Design: Cross-sectional study. Setting: University laboratory. Participants: Twenty-two college baseball players (20 right-handed and 2 left-handed). Methods: To investigate the relationships between glenohumeral range of motion and lower-limb flexibility using simple linear regression analysis, we measured passive range of motion of glenohumeral internal rotation and horizontal adduction, hip internal/external rotation in the prone/sitting position, ankle dorsiflexion, and quadriceps and hamstrings flexibility from both shoulders and legs. Results: Our analysis indicated that decreases in the lead leg hip external rotation in the prone position were moderately associated with limitations in glenohumeral internal rotation (R2 =.250, β [95% confidence interval, CI] = 0.500 [0.149 to 1.392], P =.018) and horizontal adduction (R2 =.200, β [95% CI] = 0.447 [0.051 to 1.499], P =.019) on the throwing shoulder. Furthermore, there were significant moderate relationships between decreases in glenohumeral internal rotation and limited lead leg quadriceps flexibility (R2 =.189, β [95% CI] = 0.435 [0.019 to 1.137], P =.022), and between decreases in glenohumeral horizontal adduction and limited stance leg ankle dorsiflexion (R2 =.243, β [95% CI] = 0.493 [0.139 to 1.438], P =.010). Conclusion: College baseball players with limited lower-limb flexibilities including the lead leg hip external rotation in the prone position, the lead leg quadriceps flexibility, and the stance leg ankle dorsiflexion showed excessive posterior shoulder tightness. The current results support the hypothesis that lower-limb flexibility is associated with posterior shoulder tightness in college baseball players. [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]

Objectives: The purpose of this study was to compare functional movement screen (FMS) scores and drop vertical jump (DVJ) kinematics between those with and without anterior cruciate ligament reconstruction (ACLR), and to evaluate the association between FMS composite score and DVJ kinematics. Design: Cross-sectional. Participants: Sixty individuals with and without a history of ACLR. Main Outcome Measures: Composite FMS score and the dorsiflexion, knee-flexion, hip-flexion, knee abduction, hip adduction, and trunk-flexion angles during a DVJ. Results: The FMS scores did not differ between groups (P > .05). There were smaller peak and initial contact hip-flexion angles in the ACLR and contralateral limbs compared with controls, and smaller peak dorsiflexion angles in the ACLR compared with contralateral limbs (P < .05). Lower FMS score was associated with a smaller peak dorsiflexion angle, smaller peak knee-flexion angle, and larger peak knee abduction angle in the ACLR limb (ΔR² = .14-.23); a smaller peak dorsiflexion angle and smaller peak knee-flexion angle in the contralateral limb (ΔR² = .17-.19); and a smaller peak dorsiflexion angle, smaller peak knee-flexion angle, and larger peak knee abduction angle in the control limb (ΔR² = .16-.22). Conclusion: The FMS scores did not differ between groups, but were associated with DVJ kinematics and should be a complementary rather than substitute assessment. [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]

Context. Previous studies have reported that the incidence of patellofemoral pain in women is 2.2 times higher than that in men. Lower hip frontal dynamic joint stiffness in women may be related to the magnitude of hip adduction and internal rotation associated with patellofemoral pain. Objective: To identify sex differences in hip frontal dynamic joint stiffness and examine the relationship between hip frontal dynamic joint stiffness and hip adduction and internal rotation during gait. Design: Cross-sectional study. Setting: University campus. Participants: A total of 80 healthy volunteers (40 women and 40 men) participated in this study. Intervention(s): Kinematic and kinetic data during gait were collected using a motion capture system and force plates. Main Outcome Measures: Hip frontal dynamic joint stiffness, hip adduction, and hip internal rotation were calculated during gait. Results: Women demonstrated lower hip frontal dynamic joint stiffness than men during gait (P<.01). They also displayed decreased hip frontal dynamic joint stiffness associated with increased hip adduction (r=-.85, P<.001) and internal rotation (r = -.48, P < .001). Conversely, in men, decreased hip frontal dynamic joint stiffness was associated with increased hip adduction (r=-.74, P<,001) but not internal rotation (r= .17, P= .28). Conclusions: Sex differences between hip frontal dynamic joint stiffness and hip internal rotation during gait may contribute to the increased incidence of patellofemoral pain in women. [ABSTRACT FROM AUTHOR]

Context: Patellofemoral pain (PFP) is a challenging condition, with altered kinematics and muscle activity as 2 common impairments. Single applications of patterned electrical neuromuscular stimulation (PENS) have improved both kinematics and muscle activity in females with PFP; however, the use of PENS in conjunction with a rehabilitation program has not been evaluated. Objective: To determine the effects of a 4-week rehabilitation program with PENS on lower-extremity biomechanics and electromyography (EMG) during a single-leg squat (SLS) and a step-down task (SDT) in individuals with PFP. Study Design: Double-blinded randomized controlled trial. Setting: Laboratory. Patients of Other Participants: Sixteen females with PFP (age 23.3 [4.9] y, mass 66.3 [13.5] kg, height 166.1 [5.9] cm). Intervention: Patients completed a 4-week supervised rehabilitation program with or without PENS. Main Outcome Measures: Curve analyses for lower-extremity kinematics and EMG activity (gluteus maximus, gluteus medius, vastus medialis oblique, vastus lateralis, biceps femoris, and adductor longus) were constructed by plotting group means and 90% confidence intervals throughout 100% of each task, before and after the rehabilitation program. Mean differences (MDs) and SDs were calculated where statistical differences were identified. Results: No differences at baseline in lower-extremity kinematics or EMG were found between groups. Following rehabilitation, the PENS group had significant reduction in hip adduction between 29% and 47% of the SLS (MD = 4.62° [3.85°]) and between 43% and 69% of the SDT (MD = 6.55° [0.77°]). Throughout the entire SDT, there was a decrease in trunk flexion in the PENS group (MD = 10.91° [1.73°]). A significant decrease in gluteus medius activity was seen during both the SLS (MD = 2.77 [3.58]) and SDT (MD = 4.36 [5.38]), and gluteus maximus during the SLS (MD = 1.49 [1.46]). No differences were seen in the Sham group lower-extremity kinematics for either task. Conclusion: Rehabilitation with PENS improved kinematics in both tasks and decreased EMG activity. This suggests that rehabilitation with PENS may improve muscle function during functional tasks. [ABSTRACT FROM AUTHOR]

Context: Excessive knee valgus on landing can cause anterior cruciate ligament injury. Therefore, knee valgus alignment may show characteristic energy absorption patterns during landings with lateral movement that impose greater impact forces on the knee joint compared with landings in other alignments. Objective: To investigate the energy absorption strategy in lower-extremities during side steps in females with knee valgus alignment. Design: Controlled laboratory study. Setting: University research laboratory. Participants: A total of 34 female college students participated in this experiment. Interventions: Participants performed single-leg drop vertical jump and side steps. All participants were divided into valgus (n = 13), neutral (n = 9), and varus (n = 12) groups according to knee position during landing in single-leg drop vertical jumps. Main Outcome Measures: Lower-extremity joint angles, moments, and negative works were calculated during landing in side steps, and 1-way analysis of variance and post hoc tests were used to determine between-group differences. Results: Negative works of hip extensors, knee abductors, and ankle plantar flexors during landing in side steps were significantly smaller in the valgus than in the varus group; however, negative work of the knee extensors was significantly greater in the valgus group than in varus group. Conclusions: The findings of this study indicated that landing with knee valgus induced the characteristic energy absorption strategy in the lower-extremity. Knee extensors contributed more to energy absorption when landing in knee valgus than in knee varus alignment. Learning to land in knee varus alignment might reduce the impact on the knee joint by increasing the energy absorption capacities of hip extensors, knee abductors, and ankle plantar flexors. [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]

Context: A limiting factor for reducing anterior cruciate ligament injury risk is ensuring that the movement adaptions made during the prevention program transfer to sport-specific activity. Virtual reality provides a mechanism to assess transferability, and neuroimaging provides a means to assay the neural processes allowing for such skill transfer. Objective: To determine the neural mechanisms for injury risk–reducing biomechanics transfer to sport after anterior cruciate ligament injury prevention training. Design: Cohort study. Setting: Research laboratory. Participants: Four healthy high school soccer athletes. Interventions: Participants completed augmented neuromuscular training utilizing real-time visual feedback. An unloaded knee extension task and a loaded leg press task were completed with neuroimaging before and after training. A virtual reality soccer-specific landing task was also competed following training to assess transfer of movement mechanics. Main Outcome Measures: Landing mechanics during the virtual reality soccer task and blood oxygen level–dependent signal change during neuroimaging. Results: Increased motor planning, sensory and visual region activity during unloaded knee extension and decreased motor cortex activity during loaded leg press were highly correlated with improvements in landing mechanics (decreased hip adduction and knee rotation). Conclusion: Changes in brain activity may underlie adaptation and transfer of injury risk–reducing movement mechanics to sport activity. Clinicians may be able to target these specific brain processes with adjunctive therapy to facilitate intervention improvements transferring to sport. [ABSTRACT FROM AUTHOR]

Clinical Scenario: Shoulder range of motion (ROM) in throwing athletes relies on a balance of mobility and stability to maintain proper function and health that, if disrupted, can lead to shoulder injury. There have been several studies that address the relationship between ROM deficits and overhead injuries; however, it may be unclear to clinicians which interventions are most effective for increasing ROM in the glenohumeral joints of overhead athletes. Clinical Question: In overhead athletes who have deficient shoulder ROM, is instrument-assisted soft tissue mobilization (IASTM) more effective at acutely increasing ROM over the course of a patient’s treatment when compared with self-stretching? Summary of Key Findings: A thorough literature review yielded 3 studies relevant to the clinical question, and all 3 studies were included. Two articles found a significant increase in acute ROM when compared with a self-stretch measure. All 3 articles showed increases in internal rotation and horizontal adduction, and 1 study reported an increase in total arc of shoulder ROM. Clinical Bottom Line: There is moderate evidence to support the use of IASTM to acutely increase ROM in the glenohumeral joint of overhead athletes. Clinicians should be aware of the variability with recommended treatment times; however, positive results have been seen with treatments lasting 5 to 6 minutes per treatment region. There is no consensus for treatment intensity, and certain IASTM tools require certification. Strength of Recommendation: Grade B evidence exists that IASTM is more effective at increasing shoulder ROM (ie, internal rotation, horizontal adduction, external rotation, total arc of motion) in overhead athletes than self-stretching measures. [ABSTRACT FROM AUTHOR]

Context: Gluteal-muscle strength has been identified as an important component of injury prevention and rehabilitation in several common knee injuries. However, many conventionally prescribed gluteal-strengthening exercises are not performed during dynamic weight-bearing activities, which is when most injuries occur. Objectives: To compare lower-limb muscle-activation patterns between conventional gluteal-strengthening exercises and off-axis elliptical exercises with motorized foot-plate perturbations designed to activate gluteal muscles during dynamic exercise. Evidence Acquisition: Twelve healthy volunteers (26.1 ± 4.7 y) participated in the study. They performed 3 conventional exercises (single-leg squat, forward lunge, and clamshell) and 3 elliptical exercises (regular, while resisting an adduction force, and while resisting an internal-rotation torque). Gluteus medius (GMed) and maximus (GMax), quadriceps, hamstrings, and gastrocnemius muscle activations during each exercise were recorded using surface electromyography (EMG) and normalized to maximal voluntary isometric contraction (MVIC). Evidence Synthesis: Normalized GMed EMG was the highest during the adduction-resistance elliptical exercise (22.4% ± 14.8% MVIC), significantly greater than forward lunge (8.2% ± 3.8% MVIC) and regular elliptical (6.4% ± 2.5% MVIC) and similar to clamshell (19.1% ± 8.8% MVIC) and single-leg squat (18.4% ± 7.9% MVIC). Normalized GMax EMG during adduction-resistance (11.1% ± 7.6% MVIC) and internal-rotation-resistance elliptical (7.4% ± 3.8% MVIC) was significantly greater than regular elliptical (4.4% ± 2.4% MVIC) and was similar to conventional exercises. The single-leg squat required more muscle activation from the quadriceps and gastrocnemius than the elliptical exercises. Conclusions: Off-axis elliptical exercise while resisting an adduction force or internal-rotation torque activates gluteal muscles dynamically while avoiding excessive quadriceps activation during a functional weight-bearing activity compared with conventional gluteal-strengthening exercises. [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]

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]

Context: Ice hockey athletes frequently injure the hip complex via a noncontact mechanism. The authors investigated patterns of strength and range of motion (ROM) to establish major differences compared with soccer athletes. Soccer athletes were compared with ice hockey athletes due to similarities between the 2 sports with regard to the intermittent nature and high number of lower-limb injuries. Objective: To compare the differences in ROM and strength of the hip for both the dominant (Dom) and nondominant (Ndom) limbs in ice hockey and soccer athletes. Design: Case-control study. Setting: Bilateral ROM in hip flexion in sitting (FS) and lying (FL), extension, abduction, adduction, and internal rotation (IR) and external rotation (ER) were measured using a goniometer and assessed for strength using a handheld dynamometer on both the Dom and Ndom limbs. Participants: 24 male, active, uninjured NCAA Division III ice hockey (16) and soccer (8) athletes. Main Outcome Measures: ROM and strength for hip FS, FL, extension, abduction, adduction, IR, and ER. A mixed-model ANOVA was used to investigate interactions and main effects. Results: Ice hockey athletes exhibited greater hip-adduction ROM than soccer athletes in the Dom leg (both P = .002) and when both limbs were combined (P= .010). Ice hockey athletes had less ROM inER (P - .042) than soccer athletes. Ice hockey athletes displayed less strength in adduction in their Ndom leg than in their Dom leg (P - .02), along with less adduction than soccer players in their Ndom leg (P = .40). Ice hockey athletes displayed less strength in hip adduction (P = .030), FS (P - .023) and FL (P = .030) than soccer athletes. Conclusions: The findings suggest that ice hockey athletes may present an at-risk profile for noncontact hip injuries in comparison with soccer athletes with regard to strength and ROM of the hip. [ABSTRACT FROM AUTHOR]

Context: Ankle immobilization is often used after ankle injury. Objective: To determine the influence of 1 week's unilateral ankle immobilization on plantar-flexor strength, balance, and walking gait in asymptomatic volunteers. Design: Repeated-measures laboratory study. Setting: University laboratory. Participants: 6 physically active male participants with no recent history of lower-limb injury. Interventions: Participants completed a 1-wk period of ankle immobilization achieved through wearing a below-knee ankle cast. Before the cast was applied, as well as immediately, 24 h, and 48 h after cast removal, their plantar-flexor strength was assessed isokinetically, and they completed a single-leg balance task as a measure of proprioceptive function. An analysis of their walking gait was also completed Main Outcome Measures: Peak plantar-flexor torque and balance were used to determine any effect on muscle strength and proprioception after cast removal. Ranges of motion (3D) of the ankle, knee, and hip, as well as walking speed, were used to assess any influence on walking gait. Results: After cast removal, plantar-flexor strength was reduced for the majority of participants (P = .063, CI = -33.98 to 1.31) and balance performance was reduced in the immobilized limb (P < .05, CI = 0.84-5.16). Both strength and balance were not significantly different from baseline levels by 48 h. Walking speed was not significantly different immediately after cast removal but increased progressively above baseline walking speed over the following 48 h. Joint ranges of motion were not significantly different at any time point. Conclusions: The reduction in strength and balance after such a short period of immobilization suggested compromised central and peripheral neural mechanisms. This suggestion appeared consistent with the delayed increase in walking speed that could occur as a result of the excitability of the neural pathways increasing toward baseline levels. [ABSTRACT FROM AUTHOR]

Context: Hip-adductor strains are among the most common lower-extremity injuries sustained in athletics. Treatment of these injuries involves a variety of exercises used to target the hip adductors. Objective: To identify the varying activation levels of the adductor longus during common hip-adductor exercises. Design: Descriptive study. Setting: Laboratory. Participants: 24 physically active, college-age students. Intervention: None. Main Measurement Outcomes: Peak and average electromyographic (EMG) activity of the adductor longus muscle during the following 6 hip-adductor rehabilitation exercises: side-lying hip adduction, ball squeezes, rotational squats, sumo squats, standing hip adduction on a Swiss ball, and side lunges. Results: The side-lying hip-adduction exercise produced more peak and average activation than any other exercise (P < .001). Ball squeezes produced more peak and average activation than rotational squats, sumo squats, and standing adduction on a Swiss ball (P < .001). Ball squeezes had more average activation than side lunges (P = .001). All other variables for peak activation during the exercises were not statistically significant (P > .08). These results allowed the authors to provide an overall ranking system (highest to lowest muscle activation): side-lying hip adduction, ball squeezes, side lunges, standing adduction on a Swiss ball, rotational squats, and sumo squats. Conclusion: The study provides a ranking system on the activation levels of the adductor longus muscle for 6 common hip-adductor rehabilitation exercises, with the side-lying hip-adduction and ball-squeeze exercises displaying the highest overall activation. [ABSTRACT FROM AUTHOR]

Context: Decreased flexibility in muscles and joints of lower extremities is commonly observed in runners. Understanding the effect of decreased flexibility on knee walking kinematics in runners is important because, over time, altered gait patterns can make runners vulnerable to overuse injuries or degenerative pathologies. Objectives: To compare hamstring and iliotibial-band (ITB) flexibility and knee kinematics in runners and nonrunners. Design: A descriptive, comparative laboratory study. Setting: Hamstring and ITB flexibility were measured with the active knee-extension test and the modified Ober test, respectively, in both groups of participants. Three-dimensional (3D) walking kinematic data were then recorded at the knee using a motion-tracking system. Participants: 18 runners and 16 nonrunners. Main Outcome Measures: Knee-extension angle (hamstring flexibility) and hip-adduction angle (ITB flexibility). Knee kinematic parameters of interest included knee angle at initial contact, peak knee angles, and knee-angle range in all planes of movement. Results: The runners had a significantly less flexible ITB than the nonrunners (hip adduction [-] and adduction [+] angles, 3.1° ± 5.6° vs -6.4° ± 4.5°; P < .001). The runners demonstrated a greater mean tibial external-rotation angle at initial contact (7.3° ± 5.8° vs 2.0° ± 4.0°; P = .01) and a smaller mean peak tibial internal-rotation angle (-1.6° ± 3.0° vs -4.2° ± 3.2°; P = .04) than the nonrunners. Conclusion: This study provides new insight into the relationship between muscle flexibility and 3D knee kinematics in runners. This supports the premise that there is an association between muscle flexibility and transverse-plane knee kinematics in this population. [ABSTRACT FROM AUTHOR]

Context: Previous studies investigated the relationship between ultrasound-derived anatomical muscle thickness (MTH) and individual muscle cross-sectional area (CSA) and muscle volume in several limb and trunk muscles; however, the adductor muscle that contributes to hip adduction and pelvic stabilization, as well as balance ability, has not been studied. Objective: To examine the relationship between MTH of the lower, middle, and upper thigh measured by B-mode ultrasound and the muscle CSA and volume of adductor muscle obtained by magnetic resonance imaging (MRI) to confirm the possibility of predicting adductor muscle CSA/volume using ultrasound-derived MTH. Setting: University research laboratory. Subjects: 10 men and 10 women (20-41 y old) volunteered to participate in this study. Main Outcome Measures: A series of continuous muscle CSAs along the thigh were measured by MRI scans (1.5-T scanner, GE Signa). In each slice, the anatomical CSA of the adductors was analyzed, and the muscle volume was calculated by multiplying muscle CSA by slice thickness. Thigh MTH was measured by B-mode ultrasound (Aloka SSD-500) at 5 sites (anterior 30%, 50%, and 70% and posterior 50% and 70% of thigh length). Results: A strong correlation was observed between anterior 30% MTH and 30% adductor CSA in men (r = .845, P < .002) and women (r = .952, P < .001) and in both groups combined (r = .922, P < .001). Anterior 30% MTH was also strongly correlated to adductor muscle volume when combined with thigh length (n = 20, r = .949, P < .001). However, there were moderate or nonsignificant correlations between anterior and posterior 50% and 70% MTH and adductor muscle CSA/volume. Conclusions: The results suggest that MTH in the upper portion of anterior thigh best reflects adductor muscle CSA or muscle volume, while the lower portions of the anterior and posterior sites are least likely to predict adductor muscle size. [ABSTRACT FROM AUTHOR]

Context: Posterior shoulder tightness has been associated with altered shoulder range of motion (ROM) and several pathologic entities in baseball players. This tightness is hypothesized to be the result of the cumulative stress placed on the posterior shoulder during the deceleration phase of the throwing motion. The role of the posterior shoulder static restraints is to absorb this load while the glenohumeral (GH) external rotators eccentrically decelerate the arm after ball release and therefore also help dissipate this force. As such, the authors hypothesized that if the GH external rotators are weak, an excessive amount of this deceleration force is placed on the static restraints, which may lead to subsequent tightness. Objective: To compare the relationship between GH external-rotation strength and posterior shoulder tightness as measured by GH horizontal-adduction and internal-rotation ROM. Design: Descriptive study. Setting: Laboratory. Participants: 45 professional baseball players. Main Outcome Measures: GH external-rotation strength and GH horizontal-adduction and internal-rotation ROM. Results: GH external-rotation strength showed no relationship with either GH horizontal-adduction ROM (r2 = .02, P = .40) or GH internal-rotation ROM (r2 = .002, P = .77). Conclusion: There is little to no relationship between GH external-rotation strength and posterior shoulder tightness in professional baseball players. The posterior static restraints of the shoulder may absorb a large majority of the deceleration forces during the throwing motion. Although strengthening of the posterior shoulder dynamic restraints should not be overlooked, routine stretching of the static restraints may be more beneficial for decreasing posterior shoulder tightness and the subsequent risks associated with this tightness, although future research is warranted. [ABSTRACT FROM AUTHOR]

Context: Recently, attention in sports has been given to eccentric hip-muscle function, both in preventing musculoskeletal injuries and improving performance. Objective: To determine the key isokinetic variables of eccentric hip torque that predict the functional performance of women in the single-leg triple long jump (TLJ) and the timed 6-m single-leg hop (TH). Design: Within-subject correlational study. Setting: Musculoskeletal laboratory. Participants: 32 healthy women age 18-25 y. Intervention: The participants performed 2 sets of 5 eccentric hip-abductor/adductor and lateral/medial-rotator isokinetic contractions (30°/s) and 3 attempts in the TLJ and TH. Main Outcome Measurements: The independent variables were the eccentric hip-abductor and -adductor and medial- and lateral-rotator isokinetic peak torque, normalized according to body mass (Nm/kg). The dependent variables were the longest distance achieved in the TLJ normalized according to body height and the shortest time spent during the execution of the TH. Results: The forward-stepwise-regression analysis showed that the combination of the eccentric hip lateral-rotator and -abductor isokinetic peak torque provided the most efficient estimate of both functional tests, explaining 65% of the TLJ variance (P < .001) and 55% of the TH variance (P < .001). Conclusions: Higher values for eccentric hip lateral-rotator and hip-abductor torques reflected better performance. Thus, the eccentric action of these muscles should be considered in the development of physical training programs that aim to increase functional performance. [ABSTRACT FROM AUTHOR]

Throwing injuries. Objective: To study the effects of posterior capsule tightness on humeral head position in late cocking simulation. Design: Eight fresh frozen shoulders were placed in position of "late cocking," 90 degrees abduction, and 10 degrees adduction and maximal external rotation. 3D measurements of humeral head relationship to the glenoid were taken with an infrared motion sensor, both before and after suture plication of the posterior capsule. Plications of 20% posterior/inferior capsule and 20% entire posterior capsule were performed, followed by plications of 40% of the posterior/inferior capsule and 40% entire posterior capsule. Setting: Cadaver Lab. Intervention: Posterior capsular placation. Main Outcome Measures: Humeral head position. Results: 40%, but not 20%, posterior/inferior and posterior plications demonstrated a trend to increased posterior-superior humeral head translation relative to controls. Conclusion: Surgically created posterior capsular tightness of the glenohumeral joint demonstrated a nonsignificant trend to increased posterior/superior humeral head translation in the late cocking position of throwing. [ABSTRACT FROM AUTHOR]