The Influence of the Q-Angle and Muscle Strength on Idiopathic Anterior Knee Pain in Adolescents

Background and Objectives: Idiopathic anterior knee pain is a common condition in adolescents and is mostly of unknown cause. The aim of this study was to examine the influence of the Q-angle and muscle strength on idiopathic anterior knee pain. Materials and Methods: Seventy-one adolescents (41 females and 30 males) diagnosed with anterior knee pain were included in this prospective study. The extensor strength in the knee joint and the Q-angle were monitored. The healthy extremity was used as a control. The Student's paired sample t-test was applied for testing the difference. Statistical significance was set at 0.05. Results: There was no statistically significant difference in the Q-angle value between the idiopathic AKP and the healthy extremity (p > 0.05) within the entire sample. A statistically significant higher Q-angle of the idiopathic AKP knee (p < 0.05) was obtained in the female subgroup. No statistically significant difference (p > 0.05) was found in the male subgroup. Within the male subgroup, the strength of the extensors within the knee joint of the healthy extremity had statistically significant higher values than the strength of these muscles in the affected extremity (p < 0.05). Conclusion: A greater Q-angle is a risk factor linked to anterior knee pain within the female population. Decreased muscle strength of knee joint extensors is a risk factor linked to anterior knee pain in both sex subgroups.

Lower-Limb Kinematic Change during Pelvis Anterior and Posterior Tilt in Double-Limb Support in Healthy Subjects with Knee Malalignment

This study aimed to investigate lower-limb kinematic changes during pelvic tilting in participants with knee malalignment. To define participants with lower-limb malalignment, the quadriceps angle (Q-angle) was used in this study. The sample population was divided into two groups in accordance with the Q-angle: the experimental group (ABQ) consisted of participants with an abnormal Q-angle greater than the normal range, and the control group (CON) consisted of participants with a normal Q-angle. All participants performed anterior and posterior pelvic tilts in double-limb support. Kinematic change in the lower limb was evaluated using a three-dimensional motion analysis system (Motion Analysis, Santa Rosa, CA, USA). The horizontal plane hip angle in the ABQ was significantly different compared with that in the CON in all positions (p < 0.05), and no significant difference was observed in the other lower-limb kinematic variables (p > 0.05). A significant correlation was identified only between the Q-angle and horizontal plane hip angle in all positions. Based on the results, the Q-angle was strongly related to the thigh, although it may not be related to malalignment with other segments during double-limb support.

Quadriceps muscle volume has no effect on patellofemoral cartilage lesions in patients with end-stage knee osteoarthritis

PURPOSE

The quadriceps muscle has a positive effect on anterior knee pain. However, its effect on the patellofemoral (PF) cartilage in patients with end-stage knee osteoarthritis is unknown. The present study aimed to evaluate whether the quadriceps muscle area had a positive effect on the PF cartilage and whether this muscle had a positive effect on the clinical scores.

MATERIALS AND METHODS

Patients with confirmed cartilage status and clinical scores who underwent total knee arthroplasty (TKA) were included. The PF cartilage status was evaluated during TKA. The thickness and the area of the quadriceps muscle were measured using a knee computed tomography scan obtained before the surgery. The Q-angle, hip-knee-ankle angle, alignment, and Insall-Salvati ratio were measured by radiography.

RESULTS

Altogether, 204 patients were included in the study. Logistic regression was performed including factors associated with PF cartilage lesions. The regression model was found to be statistically significant (Hosmer-Lemeshow test, χ² = 0.493). A smaller hip-knee-ankle (HKA) angle was associated with a higher incidence of PF cartilage lesions (p = 0.033) and only the alignment had an effect on the PF cartilage lesions. PF cartilage lesions did not correlate with the clinical scores. A thicker medial portion of the quadriceps muscle was associated with a significantly higher Knee Society Knee Score (KSKS) (p = 0.028).

CONCLUSIONS

Quadriceps muscle thickness and area, Q-angle, and patellar height were not associated with PF cartilage lesions, while a smaller HKA angle was associated with PF cartilage lesions. The presence of PF cartilage lesions did not affect the clinical symptoms. However, a thicker medial portion of the quadriceps muscle was associated with a higher KSKS.

Linear influence of distal femur osteotomy on the Q-angle: one degree of varization alters the Q-angle by one degree

PURPOSE

The effect of a distal femur varization osteotomy on patellofemoral biomechanics in genu valgum is unknown. The purpose of this study was to quantify the influence of frontal leg axis correction on the Q-angle with a novel three-dimensional (3-D) measurement method.

METHODS

3-D surface models of ten lower extremities were generated using patient computed tomography (CT) data. The preoperative 3-D Q-angle was measured using a novel defined and validated 3-D measurement method. Biplanar supracondylar osteotomies were simulated with different degrees of varus correction (from 1° to 15°) in one-degree steps beginning from the preoperative valgus deformity, resulting in a total of 150 simulations. Additionally, mechanical leg axis and 3-D Q-angle measurements were performed on 3-D surface models of the postoperative CT scans of the same individuals. Further, pre- and postoperative TT-TG distance was measured.

RESULTS

Mean preoperative Q-angle was 15.8 ± 3.9° (range 10°-21.4°) with a mean preoperative mechanical leg axis of 6.5° ± 2.4 valgus (range 3.8°-11.6° valgus). The Q-angle changed linearly 0.9 ± 0° per 1° of varization. No difference was detected between simulated 3-D Q-angles and effectively corrected postoperative values (n.s.). TT-TG distance changed irregularly and minimally, and with no correlation to the degree of varization.

CONCLUSION

Distal femur varization osteotomy has a linear effect on the Q-angle with a change of 1° per 1° of varization. The difference in TT-TG distance was mainly due to an unintentional rotational component implemented during surgery.

Relationship between movement dysfunctions and sports injuries according to gender of youth soccer player

The purpose of this study is to investigate relationship between movement dysfunctions and sports injuries according to gender of youth soccer player. Thirty-eight middle school soccer players participated in this study and they were divided into male (n=19) and female (n=19) groups. The Functional Movement Screen (FMS) and the Quadriceps-angle (Q-angle) during single-leg squat were analyzed for identifying imbalance and asymmetry of the body, and sports injury questionnaire was examined for 6 months after FMS test. The number of sports injuries did not show significant difference between youth male and female soccer athletes. In FMS results, the scores of overhead squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, and rotary stability and the total scores were no significant differences between gender, but the score for the trunk stability push-up was significantly higher in male group than female group. There was no significant difference of Q-angle values between the left and right legs, but Q-angle value between youth male and female groups significantly showed interaction. Therefore, the present data suggested that FMS and Q-angle during single-leg squat might be indicators to predict and/or prevent sports injury in youth male and female soccer players.

Kinematic alignment more closely restores the groove location and the sulcus angle of the native trochlea than mechanical alignment: implications for prosthetic design

PURPOSE

Kinematic alignment (KA) and mechanical alignment (MA) position the prosthetic trochlea that guides patellar tracking differently. The present study determined whether KA or MA more closely restores the groove location and sulcus angle of the prosthetic trochlea to the native trochlea for three femoral component designs.

METHODS

Ten 3D femur-cartilage models were created by combining computer tomographic (CT) and laser scans of native human cadaveric femurs. Three femoral component designs were positioned using KA and MA. Measurements of the prosthetic and native trochlea were made along the arc length of the native trochlear groove. The alignment technique with the smaller absolute difference between prosthetic and native for the medial-lateral and radial locations of the groove and sulcus angle of the trochlea more closely restored the native trochlea.

RESULTS

For three femoral component designs, KA more closely restored to native the mean medial-lateral location (p = 0.0033 to < 0.0001) and mean radial location (p = 0.0150 to < 0.0001) than MA. For two femoral component designs, KA more closely restored to native the mean sulcus angle (p = 0.0326 to 0.0006) than MA. However, the differences in the mean sulcus angles between KA and MA were less than 2° for all three designs.

CONCLUSION

KA more closely restored the native trochlea, which explains why the reported risk of patellofemoral complications for KA is not higher than MA according to five randomized clinical trials. Small design modifications of the medial-lateral and radial locations and sulcus angle are strategies for restoring the native trochlea. Such modifications might further reduce the risk of patellofemoral complications.

LEVEL OF EVIDENCE

II.

Ultrasonographic assessment of articular cartilage of the femoral condyle in patients with an increased Q-angle

Introduction

The patella is a sesamoid for the quadriceps, which increases its power during knee extension and thus transfers considerable forces. The etiology of patellofemoral pain is multifactorial. In the absence of injury, the commonly accepted hypothesis is associated with increased compression of articulating surfaces.

Aim

The aim of the study was to perform an ultrasound evaluation of the thickness of articular cartilage covering the medial and lateral femoral condyle in patients with an increased Q-angle.

Materials and methods

The study included 26 women aged between 35 and 45 years. A total of 13 patients with Q >15° were included in the study group, and 13 patients with Q ≤15° were included in the control group. A goniometer was used for Q-angle measurement. The thickness of articular cartilage covering the medial and lateral femoral condyle of the femoral bone was measured using a HONDA HS-2200 ultrasound with a linear HLS-584M transducer. The Shapiro–Wilk test was used for the assessment of data distribution normality; the distribution was normal. The differences in the measured parameters were assessed with the ANOVA test for independent samples. The Bonferroni test was used for a multiple comparison.

Results

The statistical analysis showed statistically significantly reduced thickness of articular cartilage on the lateral femoral condyle (p = 0.00) in the Q >15° group. No statistically significant differences were demonstrated for the thickness of articular cartilage on the medial femoral condyle (p = 0.47).

Conclusions

The thickness of the articular cartilage on the lateral femoral condyle is lower than that of the medial femoral condyle in women aged between 35 and 45 years with the Q-angle >15°.

Q-vector measurements: physical examination versus magnetic resonance imaging measurements and their relationship with tibial tubercle-trochlear groove distance

PURPOSE

An increased lateral quadriceps vector has been associated with lateral patellar dislocation. Surgical correction of this increased vector through tibial tubercle medialization is often recommended when the quadriceps vector is "excessive". This can be evaluated by physical examination measurements of Q-angle and/or tubercle sulcus angle (TSA), as well as the magnetic resonance imaging (MRI) measurement of tibial tubercle-trochlear groove (TT-TG) distance. This study examined the relationship between three objective measurements of lateral quadriceps vector (TT-TG, Q-angle, TSA). A secondary goal was to relate lateral patellar tilt to these measurements.

METHODS

Consecutive patients undergoing patellofemoral stabilization surgery from 9/2010 to 6/2011 were included. The Q-angle and TSA were measured on intra-operative physical examination. The TT-TG and patellar tilt were measured on MRI. TSA, Q-angle, and patellar tilt were compared to TT-TG using Pearson correlation coefficient.

RESULTS

The study cohort included 49 patients, ages 12-37 (mean 23.2); 62% female. The Pearson correlation coefficients showed (+) significance (p < 0.01) between the TT-TG and both TSA and Q-angle. Tilt and TT-TG were (+) non-significantly correlated. Despite positive correlations of each measurement with TT-TG, there is not uniform intra-patient correlation. In other words, if TT-TG is elevated for a patient, it does not guarantee that all other measurements, including tilt, are elevated in that individual patient.

CONCLUSION

The TT-TG distance has significant positive correlation with the measurements of TSA and Q-angle in patients undergoing surgery for patellofemoral instability. The clinical relevance is that the variability within individual patients demonstrates the need for considering both TSA and TT-TG before and during surgical intervention to avoid overcorrection with a medial tibial tubercle osteotomy.

LEVEL OF EVIDENCE

Diagnostic study, Level III.

Investigation of the Relationship Between Flatfoot and Patellar Subluxation in Adolescents

Patellar subluxation is common in adolescents, and a variety of factors are related to this condition, with valgus of the knee joint an important factor. The results of many studies suggest that flatfoot can cause an abnormality of the lower limb power line. Structural abnormalities of the foot caused by the high stresses exerted by body weight can lead to structural deformity of the knee and can also cause knee valgus. Screening for foot problems can help determine the risk of patellar subluxation, and early intervention can lessen the incidence of this condition. The purpose of the present study was to investigate the effects of flatfoot on the structure and function of the knees and, especially, the risk of patellar subluxation. A total of 72 participants were recruited for this cross-sectional study. The mean age at examination was 15.4 ± 4.0 (range 9 to 22) years. The measured parameters were heel valgus angle, arch index, and quadriceps angle (Q-angle). Overall, the mean values of the heel valgus angle, arch index, and Q-angle were 5.9° ± 2.4° (range 1° to 11°), 0.33 ± 0.07 (range 0.23 to 0.46), and 19.1° ± 3.5° (range 9° to 26°), respectively. The Q-angle was directly associated with the heel valgus angle (r = 0.818, p < .001) and arch index (r = 0.655, p < .001). We found that flatfoot can affect the morphology of the knee joint and increase the risk of patellar subluxation.

Lower extremity rotational deformities and patellofemoral alignment parameters in patients with anterior knee pain

PURPOSE

Anterior knee pain is a common musculoskeletal condition amongst young adult population. Lower extremity structural factors, such as increased femoral anteversion and lateral tibial torsion, may contribute to patellofemoral malalignment and anterior knee pain. The aim of this study was to evaluate the lower extremity structural factors and related patellofemoral alignment parameters that play a role in the aetiology of anterior knee pain.

METHODS

This study involved three groups: patients with unilateral symptomatic knees (n = 35), asymptomatic contralateral knees in the same patients and a control group (n = 40). All subjects were physically examined, and Q-angles were measured. The lower extremities of all subjects were imaged by a very low-dose CT scan, and the symptomatic knees of patients were compared with their asymptomatic contralateral knees and with the healthy knees of controls regarding femoral anteversion, tibial torsion, sulcus angle, patellar tilt angle and lateral patellar displacement.

RESULTS

Regarding the Q-angle, femoral anteversion and lateral tibial torsion, no significant differences were found between the symptomatic and asymptomatic knees, whereas significant differences were found between the symptomatic knees and controls. The symptomatic group demonstrated significantly greater sulcus angle only in 30° of knee flexion than did the controls.

CONCLUSION

Patients with unilateral anterior knee pain may have similar morphology at their contralateral asymptomatic lower extremity, and different morphology compared with healthy controls. Lower extremity rotational deformities may increase the risk of anterior knee pain; however, these deformities alone are not sufficient to cause knee pain, and may be predisposing factor rather than a direct aetiology.

LEVEL OF EVIDENCE

Diagnostic study, Level III.

Correlation of the tibial tuberosity-trochlear groove distance with the Q-angle

PURPOSE

The Q-angle has been used for years to quantify lateralization of the patella. The tibial tuberosity-trochlea groove distance (TT-TG distance) was introduced to analyse patellar tracking. Does a significant correlation exist between these two parameters? Do other significant interrelations exist between the Q-angle/TT-TG distance, torsion of the femur and tibia, the frontal axis, overall leg length, gender, former patellar dislocation, BMI?

METHODS

One hundred knees in 55 patients with patellofemoral symptoms were included in a prospective study. All patients underwent clinical examination, including measurement of the Q-angle. A torsional CT was obtained from all patients.

RESULTS

The correlation coefficient was 0.33/0.34 (left/right leg), showing that the TT-TG distance tends to rise in direct ratio to a rising Q-angle. Thus, a significant correlation was found (p = 0.017). Femoral and tibial torsion had a positive effect on the TT-TG distance, but showed no significant correlation. Leg length had a significant effect on the TT-TG distance (p = 0.04). The frontal axis had a nonsignificant influence on the Q-angle or TT-TG distance. On average, the Q-angle in women was 2.38° greater than it was in men, but the difference was not significant.

CONCLUSION

A significant correlation was noted between the Q-angle and the TT-TG distance. Both depend on various parameters and must be assessed for the analysis of patellofemoral maltracking. The Q-angle did not differ significantly between men and women; thus, the conclusion is that no different ranges need not be used.

LEVEL OF EVIDENCE

Diagnostic study, Level III.

A new diagnostic parameter for patellofemoral pain

PURPOSE

Q-angle measurement procedure have not been well standardised. There is a lack of consensus about subject position and knee flexion angle while measuring the Q-angle. Morover Q-angle value which obtained in a single position is a static value and gives an information about the subject's current position. The aim of this study is to obtain a more significant parameter which includes different postures (supine, standing, sitting) and different knee flexion angles instead of a single Q-angle in a fixed position. At the same time this parameter must be functional and dynamic,not a static value like Q-angle. We named this parameter as ΔQ.

METHODS

Our study was applied on case and control groups. All subjects in both groups were male. Case group was consisted of 14 subjects who had patellofemoral pain. Control group was consisted of 14 subjects who had normal knees and normal lower extremities with no reported knee problems. We obtained 3 different Q-angle values and 3 different ΔQ values for each subject in both groups. Pearson correlation analysis was used for investigation of continuous variables in normal distribution, Spearman correlation analysis was used in abnormal distribution. t test was used in the comparison of values. Logistic regression analysis(forward conditional mod) was used for detecting of determinants of pain.

RESULTS

ΔQ1s of both groups were found as the only statistical significant predictive value for patellofemoral pain.

CONCLUSION

There is not an agreement about a standardised q-angle measurement procedure in the literature. Moreover, present procedures provide information about a single and fixed position. In this situation Q-angles which obtained in these fixed positions are static values. We think that we can overcome these problems with this new value. ΔQ contains multiple q-angles and gives information about all. Also it is a dynamic value for being oriented to position change. Therefore, ΔQ is an useful indicator for evaluating patellofemoral pain.

The effects of squatting with visual feedback on the muscle activation of the vastus medialis oblique and the vastus lateralis in young adults with an increased quadriceps angle

[Purpose] The purpose of this study was to identify the effects of performing squat exercises with visual feedback on the activation of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles in young adults with an increased quadriceps angle (Q-angle). [Subjects] This study used a motion analysis program (Dartfish, Switzerland) to select 20 young adults with an increased Q-angle, who were then divided into a squat group that received visual feedback (VSG, n=10) and a squat group that received no visual feedback (SG, n=10). [Methods] The intensity of exercises was increased every two weeks over a six-week exercise period in both groups. A visual marker was attached to the patella of the subjects in the VSG, and they then performed squat exercises with a maximum of 90° of knee flexion within a route marked on a mirror. The SG performed squat exercises with a maximum 90° of knee flexion without attaching a visual feedback device. [Results] Analysis of the muscle activation due to 90° squat exercises indicated that both groups had statistically significant increases in activation of the VL. The VSG exhibited statistically significant increases in activation of the VMO. [Conclusion] This study confirmed that squat exercises with visual feedback are effective in activation of the VMO and VL muscles. The findings are meaningful in terms of preventing the occurrence of patellofemoral pain.

Effects of a functional foot orthosis on the knee angle in the sagittal plane of college students in their 20s with flatfoot

[Purpose] The purpose of this study was to examine the effects of a functional foot orthosis on the knee angle in the sagittal plane of college students in their 20s who had flatfoot. [Subjects and Methods] The subjects of this study were 20 college students diagnosed as having flatfoot. The variations of their knee angle (Q-angle) in the sagittal plane during the stance phase were measured using the VICON Motion System (Vicon, Hansung, Korea) before and while wearing a foot orthosis. The experimental data were analyzed using SPSS 12.0 for Windows. [Results] The Q-angle in the test group during the stance phase showed statistically significant declines on the right and left sides while wearing the foot orthosis during the gait-phases of loading response and midstance. During initial contact, terminal stance, and preswing, the Q-angle also decreased on the right and left sides after wearing the foot orthosis, but the changes were not statistically significant. [Conclusion] The college students with flatfoot exhibited declines in the Q-angle in the sagittal plane while wearing a foot orthosis. In this regard, the application of active gait training using orthotic shoes for long hours is likely to help individuals with flatfoot to achieve normal gait.

Does pelvic width influence patellar tracking? A radiological comparison between sexes

INTRODUCTION

Pelvic width has been believed to affect patellar tracking by influencing the quadriceps angle (Q-angle). Anatomically, the upper arm of the Q-angle does not closely match the orientation of the quadriceps femoris. The pelvis is often considered wider and the Q-angle larger in female than in male individuals. The purpose of this retrospective study was to investigate the accuracy of such an assumption by using a radiologic comparison, which might be more objective.

MATERIALS AND METHODS

One hundred consecutive adult patients (50 men and 50 women) aged 18-30 years with unilateral injury to the lower extremity were studied. Full-length standing X-rays of these patients was used to analyze the relationship between the pelvis and the uninjured lower extremity and compare it between the sexes. The pelvic width was defined as the distance between the centers of the bilateral femoral heads.

RESULTS

The pelvic width did not differ statistically between male and female (P=0.74). The femur length and sum of the lengths of the femur and tibia differed between the sexes (both P<0.001). Normalization of the pelvic width to the femur length or sum of the lengths of the femur and tibia resulted in a significant difference between male and female (P<0.001). The angle formed by the femoral and tibial mechanical axes correlated strongly with the angle formed by the femoral anatomic and tibial mechanical axes (Pearson correlation coefficient=0.89).

DISCUSSION

Pelvic width does not differ with respect to gender. The pelvis may appear relatively wider in women due to the difference in body height. However, this difference may not increase Q-angle. Patellar mal-tracking may stem from other, more critical predisposing factors.

LEVEL OF EVIDENCE

Level IV. Anatomic study.

Dynamic medial patellofemoral ligament reconstruction in recurrent patellar instability: A surgical technique

The medial patellofemoral ligament (MPFL) is the primary stabilizer of the patellofemoral joint; its reconstruction has been recommended in adults over the past decade after recurrent patellar instability. However, there has been no standardized technique for reconstruction, therefore, ideal graft and technique for reconstruction are yet undetermined. However, dynamic MPFL reconstruction studies claim to be superior to other procedures as it is more anatomical. This preliminary study aims at assessing the outcomes of MPFL reconstruction in a dynamic pattern using hamstring graft. We performed this procedure in four consecutive patients with chronic patellar instability following trauma. MPFL reconstruction was done with hamstring tendons detached distally and secured to patellar periosteum after being passed through a bony tunnel in the patella without an implant and using the medial collateral ligament as a pulley. In all 4 knees, the MPFL reconstruction was isolated and was not associated with any other realignment procedures. No recurrent episodes of dislocation or subluxation were reported at 24 months followup.

Effect of Weight-bearing Therapeutic Exercise on the Q-angle and Muscle Activity Onset Times of Elite Athletes with Patellofemoral Pain Syndrome: A Randomized Controlled Trial

[Purpose] The purpose of this study was to determine the effect of a weight-bearing therapeutic exercise program for elite athletes diagnosed as having patellofemoral pain syndrome (PFPS). [Subjects] The subjects were 34 elite athletes from the Seoul T Center. They were randomly allocated to three groups: an elastic band exercise group (EBG), a sling exercise group (SEG), or a control group (CG). [Methods] Therapeutic exercises were performed 3 times a week for 8 weeks. The visual analogue scale (VAS) hamstring length, and static and dynamic Q angles were used to test the exercise effect of the exercises, as well as the onset time of electromyographic activity of vastus medialis oblique (VMO) and vastus lateralis (VL). [Results] Decrease of the dynamic Q-angle in EBG was significant and significantly greater than that in CG. The decrease in VAS in SEG was significant and significantly greater than that in CG. There were significant differences in the VL and VMO activity onset times in SEG between pre- and post-test, and their differences between pre- and post-test were also significantly different. [Conclusion] Weight-bearing therapeutic exercise is hoped that clinicians will use this information for better implementation of effective exercise methods for elite athletes with PFPS.

No association between q-angle and foot posture with running-related injuries: a 10 week prospective follow-up study

BACKGROUND/PURPOSE

There is a paucity of knowledge on the association between different foot posture quantified by Foot Posture Index (FPI) and Quadriceps angle (Q-angle) with development of running-related injuries. Earlier studies investigating these associations did not include an objective measure of the amount of running performed. Therefore, the purpose of this study was to investigate if kilometers to running-related injury (RRI) differ among novice runners with different foot postures and Q-angles when running in a neutral running shoe.

METHODS

A 10 week study was conducted including healthy, novice runners. At baseline foot posture was evaluated using the foot posture index (FPI) and the Q-angle was measured. Based on the FPI and Q-angle, right and left feet / knees of the runners were categorized into exposure groups. All participants received a Global Positioning System watch to allow them to quantify running volume and were instructed to run a minimum of two times per week in a conventional, neutral running shoe. The outcome was RRI.

RESULTS

Fifty nine novice runners of mixed gender were included. Of these, 13 sustained a running-related injury. No significant difference in cumulative relative risk between persons with pronated feet and neutral feet was found after 125 km of running (Cumulative relative risk = 1.65 [0.65; 4.17], p = 0.29). Similarly, no difference was found between low and neutral Q-angle (Cumulative relative risk = 1.25 [0.49; 3.23], p = 0.63).

CONCLUSION

Static foot posture as quantified by FPI and knee alignment as quantified by Q-angle do not seem to affect the risk of injury among novice runners taking up a running regimen wearing a conventional neutral running shoe. These results should be interpreted with caution due to a small sample size.

LEVEL OF EVIDENCE

2a.

Effects of Foot Position during Squatting on the Quadriceps Femoris: An Electromyographic Study

Weightlifters have commonly believed that changing joint position can alter specific muscle activation. The magnitude of force produced by a muscle is highly dependent upon the length of the muscle. The purpose of this study was to determine the effect of foot positioning on muscle activation of the superficial quadriceps as measured by surface electromyography (sEMG) during a functional squatting movement in healthy adults. Twenty physically active asymptomatic adults (7 females and 13 males) were included in the study while four different foot positions (Neutral, Internally Rotated, Externally Rotated, and Staggered) were assessed. Three quadriceps muscles (Rectus Femoris (RF), Vastus Medialis Oblique (VMO), and Vastus Lateralis Oblique(VLO) were measured. Raw EMG was transformed using a root mean square algorithm. Six one-way repeated measure ANOVAs were conducted to examine the peak and average RMS amplitude for each muscle across each condition, with an alpha level of 0.05 set a priori. Across all foot positions only the Staggered foot position reached statistical significance when compared to all other foot positions for each muscle group. Results suggest that altering the foot position during a partial weight squat has little to no effect on the EMG amplitudes of the quadriceps. However, more research is needed to examine the concentric and eccentric phases of the squatting motion separately with the addition of full weight bearing squats.