504  |  july 2013  |  volume 43  |  number 7  |  journal of orthopaedic & sports physical therapy

[ research report ]

Visual observation of lower extremity movement patterns during various tasks is a common way to assess dynamic function and alignment in the clinical setting.7,19 Functional movements, such as the lunge, step-up, step-down, single-

leg press, bilateral squat, and balance and reach, are frequently used to assess movement quality of the lower extremi-ties.2,5,19,20,22 Authors of previous studies have reported moderate to good interrater reliability for visual assessment of move-

ment quality during a single-limb mini-squat in healthy individuals (κ = 0.92)1 and a lateral step-down in healthy sub-jects (κ = 0.59)25 and in those with patel-lofemoral pain syndrome (κ = 0.67).25 Thus, the interrater reliability of these

observational lower extremity movement-pattern tests should be adequate to sup-port their use in clinical practice.

The forward step-down (FSD) is a functional task requiring stair descent, which involves weight-bearing stress at various knee flexion angles as well as dynamic muscular control. Poor me-chanics during an FSD task could place abnormal stresses on the knee at both the tibiofemoral and patellofemoral joints.18 Accordingly, the FSD task could be per-formed either as a screening tool18 or as an exercise for knee rehabilitation.8,31,32 Loudon et al18 used the FSD task as a screening tool to determine level of func-tion and reported moderate to high in-trarater reliability (intraclass correlation coefficient model 3,1 = 0.94) in individu-als with patellofemoral pain syndrome. However, no studies have investigated the interrater reliability of the FSD task in healthy individuals, which is needed to determine how suitable the test is for clinical practice and screening for risk of injuries.

An exaggerated dynamic knee valgus during weight-bearing tasks can result from many factors, including a lack of muscular strength and flexibility.23,24 Dur-ing weight-bearing tasks requiring knee flexion, the hip abductors and external rotators act eccentrically both to stabi-

TT STUDY DESIGN: Cross-sectional.TT OBJECTIVE: To investigate the interrater reli-

ability of movement-quality ratings for the forward step-down (FSD) test and to compare hip muscle strength and lower extremity joint range of mo-tion and muscle flexibility among asymptomatic women with different levels of movement quality.

TT BACKGROUND: The interrater reliability of the FSD test has not yet been investigated. Ad-ditionally, it is not known whether differences in musculoskeletal measures exist among individuals with different levels of movement quality during the FSD test.

TT METHODS: Two physical therapists assessed movement quality during the FSD test in 26 a symptomatic women (mean SD age, 22.7 0.9 years). Hip muscle strength and lower extrem-ity joint range of motion and muscle flexibility were also assessed. The interrater reliability of the FSD test was estimated by using the kappa coefficient and percent agreement. Differences in musculo-skeletal measures based on movement quality

were assessed by independent t tests.

TT RESULTS: The kappa coefficient and percent agreement for rating the quality of movement on the FSD test were 0.80 (95% confidence interval: 0.57, 1.00) and 85%, respectively. The subjects with moderate movement quality had significantly less strength of the hip abductors, less knee flexion range of motion measured in prone (quadriceps flexibility), and less hip adduction range of motion measured in sidelying (iliotibial band/tensor fascia latae flexibility) compared to those with good movement quality.

TT CONCLUSION: There was good agreement for the rating of movement quality during the FSD test, and there were physical attributes that distinguished those with moderate from those with good quality of movement. J Orthop Sports Phys Ther 2013;43(7):504-510. Epub 11 June 2013. doi:10.2519/jospt.2013.4073

TT KEY WORDS: abductors, hip, knee, reliability, strength

1Applied Kinesiology and Ergonomic Technology Laboratory, Department of Physical Therapy, The Graduate School, Yonsei University, Wonju, Gangwon-do, South Korea. 2Department of Physical Therapy, The Graduate School, Yonsei University, Wonju, Gangwon-do, South Korea. The protocol for this study was approved by the Yonsei University Wonju Campus Human Studies Committee. The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article. Address correspondence to Dr Heon-Seock Cynn, Department of Physical Therapy, Yonsei University, 1 Yonseidae-gil, Wonju-si, Gangwon-do, South Korea. E-mail: cynn@yonsei.ac.kr T Copyright ©2013 Journal of Orthopaedic & Sports Physical Therapy®

KYUNG-MI PARK, PT, MS1 • HEON-SEOCK CYNN, PT, PhD1 • SUNG-DAE CHOUNG, PT, BSc2

Musculoskeletal Predictors of Movement Quality for the Forward Step-down Test

in Asymptomatic Women

43-07 Park.indd 504 6/19/2013 1:09:02 PM

Jour

nal o

f O

rtho

paed

ic &

Spo

rts

Phys

ical

The

rapy

®

Dow

nloa

ded

from

ww

w.jo

spt.o

rg a

t on

Oct

ober

5, 2

013.

For

per

sona

l use

onl

y. N

o ot

her

uses

with

out p

erm

issi

on.

Cop

yrig

ht ©

201

3 Jo

urna

l of

Ort

hopa

edic

& S

port

s Ph

ysic

al T

hera

py®

. All

righ

ts r

eser

ved.

mailto:cynn@yonsei.ac.kr

journal of orthopaedic & sports physical therapy | volume 43 | number 7 | july 2013 | 505

lize the pelvis in the frontal plane and to control motion of the femur in the fron-tal and transverse planes.16,24 Weakness of these muscles can lead to excessive hip adduction and hip internal rotation during weight-bearing activities12 and, consequently, to excessive knee valgus alignment.13,24

Other potential factors can also lead to poor lower extremity function during weight-bearing tasks. Limited quadriceps flexibility may limit knee flexion and re-sult in greater ipsilateral hip adduction, whereas limited iliotibial band/tensor fascia latae (ITB/TFL) flexibility may lead to ipsilateral pelvic rotation in the transverse plane, along with hip internal rotation15,21 and tibial external rotation, inducing knee valgus alignment.17 De-creased hamstring and gastrocnemius muscle flexibility may contribute to ab-duction and external rotation of the tib-ia, also facilitating dynamic knee valgus alignment.3,17

The aims of this study were (1) to investigate the interrater reliability of the movement-quality ratings for the FSD test and (2) to compare hip muscle strength and lower extremity joint range of motion and muscle flexibility among asymptomatic women with different levels of movement quality on the FSD test. We hypothesized that (1) interrater reliability of the movement-quality rat-ings for the FSD would be high and (2) women with lower levels of movement quality would have less hip abductor and external rotator muscle strength, greater hip internal rotation range of motion, and decreased flexibility of the ITB/TFL. Women were selected for the study based on a higher incidence of patellofemoral joint pain in this population.4

METHODS

Subjects

Twenty-six asymptomatic female subjects were recruited from the Department of Physical Therapy at

Yonsei University. All subjects had not participated in regular strength training

or in a stretching program for at least 3 months prior to the study. The average SD age, height, and body mass of the subjects were 22.7 0.9 years, 161.5 4.2 cm, and 54.0 3.9 kg, respectively. Subjects were included if they were pain free and had no musculoskeletal or neu-rological injuries in the lower extremities or lumbar spine within the 6 months pri-or to the study. Subjects were excluded if they had undergone surgery for the lower extremities or lumbar spine during the 6 months preceding the study, had any balance impairments secondary to a ves-tibular or neurological disorder, or used medications that could cause dizziness or loss of balance. All subjects read and signed an informed-consent form prior to participation. The protocol for the study was approved by the Yonsei Uni-versity Wonju Campus Human Studies Committee.

The number of subjects in the study was determined by calculating the ef-fect size, based on previously published data25 on the difference in ankle dorsiflex-ion range of motion measured with knee extension between subjects with different levels of movement quality during the lat-eral step-down test. With an effect size of 1.26, power analysis indicated that a total sample size of 18 participants was required to achieve a significance level of .05 and a power of 0.8.

ProceduresTwo examiners participated in data col-lection. One examiner had 2 years of clinical experience in the field of applied kinesiology and musculoskeletal physi-cal therapy. The other examiner had more than 6 years of clinical experience in musculoskeletal physical therapy. Be-fore data collection, the 2 examiners had a 5-hour training session on the methods to be used in the study. For reliability ex-amination of the FSD test, the examin-ers discussed the operational definition and practiced scoring and classifying subjects in 3 categories (good, moderate, and poor), based on movement quality. For musculoskeletal measurements (hip

muscle strength and lower extremity joint range of motion and muscle flexibility), the 2 examiners determined the testing position and methods to detect end range of movement, and standardized all pro-cedures. Following this training session, pilot testing was performed on 5 healthy volunteers and final modifications of the testing procedures were made.

The 2 examiners assessed the move-ment quality of the FSD test simulta-neously on each subject to establish interrater reliability. Following the FSD test, each examiner completed the musculoskeletal measurements of the subjects. The average value of the 2 exam-iners was used for statistical analysis. The data-collection session lasted approxi-mately 40 minutes for each subject. The order of musculoskeletal measurements was randomly determined by drawing a sealed envelope from a box, to account for any potential effects of measurement order. All testing was performed on the dominant limb of each subject, defined as the limb used to kick a ball.10

FSD TestThe FSD test used in this study was a modification of the test used by Piva et al22 (FIGURE). Prior to performing the test, the tibial tuberosity of the tested limb and the vertical front edge of the step, just under the second toe of the tested limb, were marked with a 1-cm red sticker to facilitate visualization. Next, the height of the step was adjusted so that each partici-pant achieved 60° of knee flexion during the test. If the heel of the nontested limb did not contact the floor when the knee of the tested limb was bent to 60°, wood blocks were placed on the step to ensure that the knee of the tested limb reached 60° of flexion when the heel of the non-tested limb touched the floor.

For testing, the subject stood on a 20-cm step, with the foot of the tested limb close to the edge of the step and the nontested limb positioned in front of the step, with the knee straight and the ankle at maximum dorsiflexion. Subjects were asked to keep their trunk straight, hands

43-07 Park.indd 505 6/19/2013 1:09:04 PM

Jour

nal o

f O

rtho

paed

ic &

Spo

rts

Phys

ical

The

rapy

®

Dow

nloa

ded

from

ww

w.jo

spt.o

rg a

t on

Oct

ober

5, 2

013.

For

per

sona

l use

onl

y. N

o ot

her

uses

with

out p

erm

issi

on.

Cop

yrig

ht ©

201

3 Jo

urna

l of

Ort

hopa

edic

& S

port

s Ph

ysic

al T

hera

py®

. All

righ

ts r

eser

ved.

506  |  july 2013  |  volume 43  |  number 7  |  journal of orthopaedic & sports physical therapy

[ research report ]

on their waist, and to bend the knee on the tested side until the heel of the non-tested limb touched the floor. The sub-jects were asked not to apply any weight on the heel of the nontested limb once it reached the floor and to immediately re-extend the knee of the tested limb to re-turn to the starting position. The subjects performed 5 consecutive FSD movements after 3 minutes of familiarization. After the 5 consecutive trials were completed, each examiner rated the performance of the subject across all 5 repetitions of the FSD. Standing 3 m directly in front of and facing the subject, both examiners scored the test simultaneously, based on the following 5 criteria:1. Arm strategy: if the subject used an

arm strategy to recover balance, 1 point was given. Because subjects were instructed to keep their hands on their waist, removing their hands from their waist was interpreted as a strategy to recover balance.

2. Trunk movement: if the subject leaned the trunk to either side, interpreted as recovering balance, 1 point was given.

3. Pelvic plane: if 1 side of the pelvis was rotated in the transverse plane or el-

evated in the frontal plane compared with the other side, 1 point was given.

4. Knee position: if the knee of the tested limb moved medially in the frontal plane and the tibial tuberosity crossed an imaginary vertical line positioned directly over the second toe of the tested foot, 1 point was given. If the knee moved medially and the tibial tu-berosity crossed an imaginary vertical line positioned directly over the me-dial border of the tested foot, 2 points were given.

5. Maintenance of a steady unilateral stance: if the subject had to support body weight on the nontested limb, or the foot of the tested limb moved dur-ing testing, 1 point was given.A total score of 0 or 1 was classified as

good movement quality, a total score of 2 or 3 was classified as moderate movement quality, and a total score of 4 or more was classified as poor movement quality. Each examiner rated the performance of the test individually for each subject. No dis-cussion was allowed between the examin-ers during the performance and scoring of the test. The raters’ scores of the FSD test were used for the calculation of inter-

rater reliability.Immediately after testing, the 2 exam-

iners compared their ratings to determine if they agreed on the good, moderate, or poor classification. Consensus was re-quired to assign each subject to a single category for the analysis comparing musculoskeletal measurements between groups of different movement quality. If consensus was not present between the 2 raters, the subjects were asked to repeat 5 additional FSD movements to finalize the classification. Only 4 of 26 subjects were rated differently between the 2 examiners and needed to repeat the test.

Strength TestingStrength testing of the hip abductors and external rotators was performed with a handheld dynamometer (Lafay-ette Manual Muscle Testing System; La-fayette Instrument Company, Lafayette, IN), as described by Piva et al,22 who re-ported intraclass correlation coefficients of 0.85 and 0.79, respectively, for inter-rater reliability. Muscle strength was re-corded in kilograms and normalized by dividing the raw score by the participant’s body mass. Each trial was performed for 3 seconds, with 1 minute of rest between trials. Each subject was allowed 2 repeti-tions for practice, and the results of the 3 subsequent repetitions were averaged and recorded.Hip Abduction Strength Hip abduction muscle strength was measured in the sidelying position, with the subject ly-ing on the nontested side. The subject’s tested hip was in approximately 30° of abduction and 5° of extension, and the iliac crest of the tested side was manu-ally stabilized by the examiner. The sub-ject performed isometric hip abduction against the resistance of the handheld dynamometer, which was placed just proximal to the lateral malleolus.Hip External Rotation Strength Hip external rotation muscle strength was tested with the subject prone on the table, the tested knee flexed to 90°, and the hip in neutral. The nontested limb was positioned with the hip in the neu-

FIGURE. (A) Start and (B) end positions for the forward step-down test.

43-07 Park.indd 506 6/19/2013 1:09:05 PM

Jour

nal o

f O

rtho

paed

ic &

Spo

rts

Phys

ical

The

rapy

®

Dow

nloa

ded

from

ww

w.jo

spt.o

rg a

t on

Oct

ober

5, 2

013.

For

per

sona

l use

onl

y. N

o ot

her

uses

with

out p

erm

issi

on.

Cop

yrig

ht ©

201

3 Jo

urna

l of

Ort

hopa

edic

& S

port

s Ph

ysic

al T

hera

py®

. All

righ

ts r

eser

ved.

journal of orthopaedic & sports physical therapy | volume 43 | number 7 | july 2013 | 507

tral position and full knee extension. The examiner manually fixed the subject’s pelvis with 1 hand. The subject exerted an isometric action of the hip external rotators against the resistance of the handheld dynamometer, positioned just proximal to the medial malleolus of the tested limb.

Range-of-Motion TestingHip external and internal rotation, ad-duction, flexion, as well as knee flexion range of motion were measured with a fluid-filled inclinometer (MIE Medi-cal Research Ltd, Leeds, UK).29 Ankle dorsiflexion range of motion was mea-sured with a universal goniometer in 1° increments. Intraclass correlation coef-ficients for interrater reliability of these range-of-motion measurements have been reported to be higher than 0.82.22,26 For this study, 1 examiner performed the measurements while the other examiner read and recorded the values. The incli-nometer was first zeroed on a fixed verti-cal reference prior to the measurements. Two practice repetitions were performed to ensure that the subject was relaxed and comfortable. Data are the average of 3 measurements, taken with 5 seconds between trials.Hip External Rotation Hip external ro-tation was measured with the subject in a prone position. The knee of the tested limb was flexed to 90°, and the nontested hip was abducted about 30°, so that the hip motion on the tested side would not be obstructed. The starting position for measuring hip rotation was determined by positioning the tested tibia perpen-dicular to the support surface. The in-clinometer was positioned on the distal third of the fibula. The examiner manu-ally fixed the subject’s pelvis at neutral with 1 hand, then moved the tested limb through passive hip external rotation. End range of motion was defined as the point at which the lower shank could no longer be moved without pelvic rotation.Hip Internal Rotation Hip internal ro-tation was determined in the same way as the measurement of hip external rota-

tion, except that the tested hip was inter-nally rotated.Knee Flexion in Prone (Quadriceps Flex-ibility) The examiner manually fixed the subject’s pelvis in neutral with 1 hand to avoid anterior tilting of the pelvis or extension of the lumbar spine. The incli-nometer was placed over the distal half of the anterior border of the tibia. The knee on the tested side was then pas-sively flexed to end range of motion. The measurement was taken when the lum-bar spine or pelvis first began to move or when the end range of motion was achieved. The opposite limb remained flat on the table.Hip Adduction in the Sidelying Posi-tion (ITB/TFL Flexibility) Hip adduc-tion was examined using the Ober test.16 The subject was positioned lying on the side, with the tested limb in the superior position and the knee flexed at 90°. The nontested limb was slightly flexed at the hip and knee to maintain stability on the table. The examiner manually fixed the subject’s pelvis in neutral with 1 hand and grasped just below the knee of the tested side with the other hand. The inclinom-eter was placed over the distal portion of the tested thigh. The examiner moved the tested thigh first in flexion, then through abduction combined with extension, un-til the hip was positioned in midrange hip abduction with neutral flexion/extension. From this position, the thigh was allowed to drop toward the table until the thigh stopped, at which point the inclinometer value was recorded.Hip Flexion in the Supine Position (Ham-string Flexibility) The subject was placed in the supine position with the knee of the tested limb in full extension. The nontested limb remained flat on the table to avoid posterior pelvic tilt. The exam-iner lifted the tested limb in hip flexion, while maintaining the knee in full exten-sion. The inclinometer was placed on the distal half of the anterior border of the tibia. The measurement was taken when no further motion occurred or when the examiner noted any change in the posi-tion of the pelvis.

Ankle Dorsiflexion With the Knee Ex-tended (Gastrocnemius Flexibility) The subject was positioned in the prone posi-tion, feet over the edge of the table. The foot of the tested ankle was maintained in subtalar joint neutral, with the examiner palpating the medial and lateral aspects of the head of the talus. Dorsiflexion was measured as the angle formed by the line from the head of the fibula to the tip of the lateral malleolus and the lateral mid-line of the foot, using the border of the rearfoot/calcaneus.

Statistical AnalysisKappa coefficients and percent agree-ment between examiners were used as estimates of interrater reliability for the rating of the quality of movement on the FSD test. Kappa values of 0.20 or less were considered poor, 0.21 to 0.40 fair, 0.41 to 0.60 moderate, and greater than 0.60 good.30 All of the continuous vari-ables were found to approximate a nor-mal distribution (Kolmogorov-Smirnov Z test, P>.05). Independent t tests were used to identify differences in demo-graphic variables (age, height, and body mass), as well as in the musculoskeletal measurements between subjects with good and moderate movement quality on the FSD test. The alpha level was set at .05. All statistical analyses were per-formed using PASW Statistics 18 (SPSS Inc, Chicago, IL).

RESULTS

The examiners rated the move-ment quality on the FSD test as good for 11 subjects, moderate for 14

subjects, and poor for 1 subject. The kap-pa coefficient (95% confidence interval) and percent agreement for the interrater reliability of rating the quality of move-ment for the FSD test were 0.80 (0.57, 1.00) and 85%, respectively. The results of the independent t tests (excluding the subject with the poor rating) assess-ing the differences in demographics and musculoskeletal measurements between the good and moderate groups are sum-

43-07 Park.indd 507 6/19/2013 1:09:07 PM

Jour

nal o

f O

rtho

paed

ic &

Spo

rts

Phys

ical

The

rapy

®

Dow

nloa

ded

from

ww

w.jo

spt.o

rg a

t on

Oct

ober

5, 2

013.

For

per

sona

l use

onl

y. N

o ot

her

uses

with

out p

erm

issi

on.

Cop

yrig

ht ©

201

3 Jo

urna

l of

Ort

hopa

edic

& S

port

s Ph

ysic

al T

hera

py®

. All

righ

ts r

eser

ved.

508  |  july 2013  |  volume 43  |  number 7  |  journal of orthopaedic & sports physical therapy

[ research report ]marized in TABLE 1. Significantly less hip abductor strength, knee flexion range of motion in the prone position, and hip ad-duction range of motion in the sidelying position were found in the subjects with moderate movement quality compared to those with good movement quality. The frequency of movement deviations for each group, as rated by raters 1 and 2, is summarized in TABLE 2.

DISCUSSION

The purposes of this study were to investigate the interrater reliabil-ity of assessing movement quality

of the lower extremity during the FSD test and to compare the musculoskeletal characteristics between asymptomatic women with different levels of movement quality. The primary findings were that the kappa coefficient and percent agree-ment of the FSD test were high, and that the subjects with moderate movement quality had significantly less hip abduc-tor strength and quadriceps and ITB/TFL flexibility compared to those with good movement quality.

The interrater reliability of the clas-sification system for rating movement quality during the FSD test in our inves-tigation (κ = 0.80; agreement, 85%) was similar to that previously reported by Piva et al22 (κ = 0.67; agreement, 80%), who used the same classification system during a lateral step-down test in patients with patellofemoral pain syndrome. In contrast, previous studies reported bet-ter interrater reliability for movement quality assessed during functional tasks. Ageberg et al1 reported high interrater reliability (κ>0.90; agreement, 96%) for the visual assessment of mediolateral knee motion during a single-limb mini-squat. Similarly, Ekegren et al11 reported high intrarater reliability (κ = 0.75-0.85; agreement, 88%-90%) for visual ratings of dynamic knee valgus during a drop jump performed by healthy participants. These differences in interrater reliability can be partially explained by the classi-fication criteria. These authors1,11 used a

classification system solely based on the frontal plane position of the knee relative to the foot. In contrast, the classification system used in this study is more com-prehensive and requires the simultaneous evaluation of arm strategy, trunk, pelvis, knee alignment, and balance. This great-er number of scoring criteria might have increased the probability of disagreement between raters.

In this study, the examiners rated the movement quality on the FSD test as good for 11 subjects and moderate for 14 subjects. In addition, 1 subject (3.8%) was considered to have poor movement quality during the FSD. Chmielewski et al5 reported that 11.5% of uninjured sub-

jects who performed a lateral step-down task had a poor movement rating. It is possible that the greater the number of deviations during the FSD, the greater the potential risk of limited performance and injury.

Previous studies have established an association between hip abductor weakness and altered movement pat-tern during dynamic activities.6,9,14,26,28 Our findings are consistent with these studies, as we found that subjects with a moderate movement quality during the FSD showed relatively lower hip ab-duction strength than those with good movement quality. Hip abduction mus-culature provides pelvis and stance limb

TABLE 1Subject Characteristics for Groups   

Based on Quality of Movement*

Abbreviation: ROM, range of motion.*Values are mean SD.†Significantly different between good and moderate groups (P

journal of orthopaedic & sports physical therapy | volume 43 | number 7 | july 2013 | 509

stability by eccentric control during weight-bearing activities.12,16 Weakness of the hip abductors can lead to excessive femoral adduction, a contralateral pelvic drop, or both during weight-bearing ac-tivities.24 This, in turn, can alter hip and knee joint mechanics.24 The 2 movement alterations more likely to occur as a result of weaker hip abductors are changes in trunk alignment and pelvic plane motion, which were the most frequent movement deviations noted in our sample (TABLE 2). Leaning the trunk laterally over the stance leg shifts the center of mass over the hip joint center, thereby reducing the internal abduction moment demand on the weak muscles.21 In addition, elevat-ing the contralateral pelvis is a common compensation strategy for reducing the demand on the hip abductors, as it moves the ground reaction force vector closer to the hip joint center.23

In this study, strength of the hip ex-ternal rotators was not reduced in those with moderate quality of movement, suggesting that the trunk lean and pelvic rotation exhibited in the moderate group during the FSD test were not caused by weak hip external rotators.

Our findings showed that there was no significant difference in hip external and internal rotation range of motion between the groups with good and mod-erate quality of movement. Rabin and Kozol25 investigated hip external and internal rotation range of motion during the lateral step-down test in healthy fe-males and reported no significant differ-ence between groups with different levels of movement quality. In contrast to our findings, Sigward et al27 demonstrated decreased hip external rotation range of motion among subjects with greater me-dial displacement of the knee during the drop-land task. The difference between our findings and those of Sigward et al27 may be due to differences in the function-al task used in the 2 studies (drop landing versus FSD).

The subjects with moderate move-ment quality had relatively lower quad-riceps flexibility compared to those with

good movement quality. As the knee only needed to be flexed to 60° during the FSD test, it is not clear how reduced flexibility could be associated with poor quality of movement. Our data also indicated that individuals with moderate movement quality had less ITB/TFL flexibility. De-creased muscle flexibility of the ITB/TFL may lead to ipsilateral rotation of the pel-vis in the transverse plane, internal rota-tion of the hip,15,21 and external rotation of the tibia, thus facilitating dynamic knee valgus alignment.17 Finally, our study found no difference in hamstring and gastrocnemius flexibility between sub-jects with good and moderate quality of movement on the FSD, suggesting that hamstring and gastrocnemius flexibility may not be responsible for the movement deviation observed in a symptomatic women exhibiting moderate quality of movement during the FSD test.

Our study has some limitations. First, the findings are limited to asymptomatic women, which limits the generalizability of the results to other populations, in-cluding asymptomatic males or patients with a knee disorder. Second, because the subjects of this study were recruited from the Department of Physical Therapy, we cannot rule out subject bias, as these individuals could have had knowledge of good and bad movement patterns. However, we provided consistent verbal instruction to each subject to reduce this bias. Third, because the functional move-ment test was performed first and the musculoskeletal measurements second, the potential for examiner bias during the musculoskeletal measurements can-not be excluded. Fourth, we examined reliability using a categorical distribution (good, moderate, and poor) and not each movement deviation, which could have affected reliability ratings. Although the frequency distribution was similar be-tween raters, it does not guarantee that for each trial the raters observed the same movement deviation. Fifth, a cause-and-effect relationship between movement pattern and noted strength and flexibil-ity differences between groups cannot be

assumed, given the cross-sectional de-sign of the study. Finally, the validity of using movement quality on the FSD test to predict those at greater risk of injuries is unknown.

CONCLUSION

Assessment of movement quality on the FSD test had good interrater reliability. Asymptomatic women

with moderate movement quality during the FSD test exhibited less hip abduction strength and decreased quadriceps and ITB/TFL flexibility compared to those with good movement quality. t

KEY POINTSFINDINGS: Assessment of movement qual-ity on the FSD test had good interrater reliability. Asymptomatic women with moderate movement quality during the FSD test exhibited less hip abduction strength and decreased quadriceps and ITB/TFL flexibility compared to those with good movement quality.IMPLICATIONS: Clinicians should consider assessment of hip abductor strength and flexibility of the quadriceps and ITB/TFL when individuals demonstrate poor quality of movement on the FSD test.CAUTION: The results of this study are limited to asymptomatic women.

REFERENCES

1. Ageberg E, Bennell KL, Hunt MA, Simic M, Roos EM, Creaby MW. Validity and inter-rater reli-ability of medio-lateral knee motion observed during a single-limb mini squat. BMC Mus-culoskelet Disord. 2010;11:265. http://dx.doi.org/10.1186/1471-2474-11-265

2. Austin AB, Souza RB, Meyer JL, Powers CM. Identification of abnormal hip motion associ-ated with acetabular labral pathology. J Orthop Sports Phys Ther. 2008;38:558-565. http://dx.doi.org/10.2519/jospt.2008.2790

3. Bell DR, Padua DA, Clark MA. Muscle strength and flexibility characteristics of people display-ing excessive medial knee displacement. Arch Phys Med Rehabil. 2008;89:1323-1328. http://dx.doi.org/10.1016/j.apmr.2007.11.048

4. Chinkulprasert C, Vachalathiti R, Powers CM. Patellofemoral joint forces and stress during

43-07 Park.indd 509 6/19/2013 1:09:10 PM

Jour

nal o

f O

rtho

paed

ic &

Spo

rts

Phys

ical

The

rapy

®

Dow

nloa

ded

from

ww

w.jo

spt.o

rg a

t on

Oct

ober

5, 2

013.

For

per

sona

l use

onl

y. N

o ot

her

uses

with

out p

erm

issi

on.

Cop

yrig

ht ©

201

3 Jo

urna

l of

Ort

hopa

edic

& S

port

s Ph

ysic

al T

hera

py®

. All

righ

ts r

eser

ved.

http://dx.doi.org/10.1186/1471-2474-11-265http://dx.doi.org/10.1186/1471-2474-11-265http://dx.doi.org/10.2519/jospt.2008.2790http://dx.doi.org/10.2519/jospt.2008.2790http://dx.doi.org/10.1016/j.apmr.2007.11.048http://dx.doi.org/10.1016/j.apmr.2007.11.048

510  |  july 2013  |  volume 43  |  number 7  |  journal of orthopaedic & sports physical therapy

[ research report ]

MORE INFORMATIONWWW.JOSPT.ORG@

forward step-up, lateral step-up, and forward step-down exercises. J Orthop Sports Phys Ther. 2011;41:241-248. http://dx.doi.org/10.2519/jospt.2011.3408

5. Chmielewski TL, Hodges MJ, Horodyski M, Bish-op MD, Conrad BP, Tillman SM. Investigation of clinician agreement in evaluating movement quality during unilateral lower extremity func-tional tasks: a comparison of 2 rating methods. J Orthop Sports Phys Ther. 2007;37:122-129. http://dx.doi.org/10.2519/jospt.2007.2457

6. Cichanowski HR, Schmitt JS, Johnson RJ, Niemuth PE. Hip strength in collegiate female athletes with patellofemoral pain. Med Sci Sports Exerc. 2007;39:1227-1232. http://dx.doi.org/10.1249/mss.0b013e3180601109

7. Costigan PA, Deluzio KJ, Wyss UP. Knee and hip kinetics during normal stair climbing. Gait Pos-ture. 2002;16:31-37. http://dx.doi.org/10.1016/S0966-6362(01)00201-6

8. Crossley K, Bennell K, Green S, Cowan S, McConnell J. Physical therapy for patello-femoral pain: a randomized, double-blinded, placebo-controlled trial. Am J Sports Med. 2002;30:857-865.

9. Dierks TA, Manal KT, Hamill J, Davis IS. Proximal and distal influences on hip and knee kinemat-ics in runners with patellofemoral pain during a prolonged run. J Orthop Sports Phys Ther. 2008;38:448-456. http://dx.doi.org/10.2519/jospt.2008.2490

10. Edwards L, Dixon J, Kent JR, Hodgson D, Whittaker VJ. Effect of shoe heel height on vastus medialis and vastus lateralis elec-tromyographic activity during sit to stand. J Orthop Surg Res. 2008;3:2. http://dx.doi.org/10.1186/1749-799X-3-2

11. Ekegren CL, Miller WC, Celebrini RG, Eng JJ, MacIntyre DL. Reliability and validity of observational risk screening in evaluating dy-namic knee valgus. J Orthop Sports Phys Ther. 2009;39:665-674. http://dx.doi.org/10.2519/jospt.2009.3004

12. Fulkerson JP. Disorders of the Patellofemoral Joint. 3rd ed. Baltimore, MD: Williams & Wilkins; 1997.

13. Hewett TE, Myer GD, Ford KR, et al. Bio-mechanical measures of neuromuscular control and valgus loading of the knee pre-

dict anterior cruciate ligament injury risk in female athletes: a prospective study. Am J Sports Med. 2005;33:492-501. http://dx.doi.org/10.1177/0363546504269591

14. Ireland ML, Willson JD, Ballantyne BT, Davis IM. Hip strength in females with and without patellofemoral pain. J Orthop Sports Phys Ther. 2003;33:671-676.

15. Jull GA, Janda V. Muscle and motor control in low back pain: assessment and management. In: Twomey LT, Taylor JR, eds. Physical Therapy of the Low Back. New York, NY: Churchill Living-stone; 1987:253-278.

16. Kendall FP, Provance P, McCreary EK. Muscles: Testing and Function. 4th ed. Baltimore, MD: Williams & Wilkins; 1993.

17. Kwak SD, Ahmad CS, Gardner TR, et al. Ham-strings and iliotibial band forces affect knee kinematics and contact pattern. J Orthop Res. 2000;18:101-108. http://dx.doi.org/10.1002/jor.1100180115

18. Loudon JK, Wiesner D, Goist-Foley HL, Asjes C, Loudon KL. Intrarater reliability of func-tional performance tests for subjects with patellofemoral pain syndrome. J Athl Train. 2002;37:256-261.

19. Lowry CD, Cleland JA, Dyke K. Management of patients with patellofemoral pain syndrome using a multimodal approach: a case series. J Orthop Sports Phys Ther. 2008;38:691-702. http://dx.doi.org/10.2519/jospt.2008.2690

20. Mascal CL, Landel R, Powers C. Management of patellofemoral pain targeting hip, pelvis, and trunk muscle function: 2 case reports. J Orthop Sports Phys Ther. 2003;33:647-660.

21. Page P, Frank CC, Lardner R. Assessment and Treatment of Muscle Imbalance: The Janda Ap-proach. Champaign, IL: Human Kinetics; 2010.

22. Piva SR, Fitzgerald K, Irrgang JJ, et al. Reli-ability of measures of impairments associated with patellofemoral pain syndrome. BMC Musculoskelet Disord. 2006;7:33. http://dx.doi.org/10.1186/1471-2474-7-33

23. Powers CM. The influence of abnormal hip mechanics on knee injury: a biomechani-cal perspective. J Orthop Sports Phys Ther. 2010;40:42-51. http://dx.doi.org/10.2519/jospt.2010.3337

24. Powers CM. The influence of altered lower-

extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports Phys Ther. 2003;33:639-646.

25. Rabin A, Kozol Z. Measures of range of motion and strength among healthy women with differ-ing quality of lower extremity movement during the lateral step-down test. J Orthop Sports Phys Ther. 2010;40:792-800. http://dx.doi.org/10.2519/jospt.2010.3424

26. Robinson RL, Nee RJ. Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome. J Or-thop Sports Phys Ther. 2007;37:232-238. http://dx.doi.org/10.2519/jospt.2007.2439

27. Sigward SM, Ota S, Powers CM. Predictors of frontal plane knee excursion during a drop land in young female soccer players. J Orthop Sports Phys Ther. 2008;38:661-667. http://dx.doi.org/10.2519/jospt.2008.2695

28. Souza RB, Powers CM. Differences in hip kine-matics, muscle strength, and muscle activation between subjects with and without patellofemo-ral pain. J Orthop Sports Phys Ther. 2009;39:12-19. http://dx.doi.org/10.2519/jospt.2009.2885

29. Van Dillen LR, Bloom NJ, Gombatto SP, Susco TM. Hip rotation range of motion in people with and without low back pain who participate in rotation-related sports. Phys Ther Sport. 2008;9:72-81. http://dx.doi.org/10.1016/j.ptsp.2008.01.002

30. Viera AJ, Garrett JM. Understanding interob-server agreement: the kappa statistic. Fam Med. 2005;37:360-363.

31. Witvrouw E, Danneels L, Van Tiggelen D, Wil-lems TM, Cambier D. Open versus closed kinetic chain exercises in patellofemoral pain: a 5-year prospective randomized study. Am J Sports Med. 2004;32:1122-1130. http://dx.doi.org/10.1177/0363546503262187

32. Witvrouw E, Lysens R, Bellemans J, Peers K, Vanderstraeten G. Open versus closed kinetic chain exercises for patellofemoral pain. A pro-spective, randomized study. Am J Sports Med. 2000;28:687-694.

NOTIFY JOSPT of Changes in AddressPlease remember to let JOSPT know about changes in your mailing address. The US Postal Service typically will not forward second-class periodical mail. Journals are destroyed, and the USPS charges JOSPT for sending them to the wrong address. You may change your address online at www.jospt.org. Visit “INFORMATION FOR READERS”, click “Change of Address”, and select and complete the online form. We appreciate your assistance in keeping JOSPT’s mailing list up to date.

43-07 Park.indd 510 6/19/2013 1:09:11 PM

Jour

nal o

f O

rtho

paed

ic &

Spo

rts

Phys

ical

The

rapy

®

Dow

nloa

ded

from

ww

w.jo

spt.o

rg a

t on

Oct

ober

5, 2

013.

For

per

sona

l use

onl

y. N

o ot

her

uses

with

out p

erm

issi

on.

Cop

yrig

ht ©

201

3 Jo

urna

l of

Ort

hopa

edic

& S

port

s Ph

ysic

al T

hera

py®

. All

righ

ts r

eser

ved.

www.jospt.orghttp://dx.doi.org/10.2519/jospt.2011.3408http://dx.doi.org/10.2519/jospt.2011.3408http://dx.doi.org/10.2519/jospt.2007.2457http://dx.doi.org/10.1249/mss.0b013e3180601109http://dx.doi.org/10.1249/mss.0b013e3180601109http://dx.doi.org/10.1016/S0966-6362(01)00201-6http://dx.doi.org/10.1016/S0966-6362(01)00201-6http://dx.doi.org/10.2519/jospt.2008.2490http://dx.doi.org/10.2519/jospt.2008.2490http://dx.doi.org/10.1186/1749-799X-3-2http://dx.doi.org/10.1186/1749-799X-3-2http://dx.doi.org/10.2519/jospt.2009.3004http://dx.doi.org/10.2519/jospt.2009.3004http://dx.doi.org/10.1177/0363546504269591http://dx.doi.org/10.1177/0363546504269591http://dx.doi.org/10.1002/jor.1100180115http://dx.doi.org/10.1002/jor.1100180115http://dx.doi.org/10.2519/jospt.2008.2690http://dx.doi.org/10.1186/1471-2474-7-33http://dx.doi.org/10.1186/1471-2474-7-33http://dx.doi.org/10.2519/jospt.2010.3337http://dx.doi.org/10.2519/jospt.2010.3337http://dx.doi.org/10.2519/jospt.2010.3424http://dx.doi.org/10.2519/jospt.2010.3424http://dx.doi.org/10.2519/jospt.2007.2439http://dx.doi.org/10.2519/jospt.2007.2439http://dx.doi.org/10.2519/jospt.2008.2695http://dx.doi.org/10.2519/jospt.2008.2695http://dx.doi.org/10.2519/jospt.2009.2885http://dx.doi.org/10.1016/j.ptsp.2008.01.002http://dx.doi.org/10.1016/j.ptsp.2008.01.002http://dx.doi.org/10.1177/0363546503262187http://dx.doi.org/10.1177/0363546503262187

504JOSPTjul13505JOSPTjul13506JOSPTjul13507JOSPTjul13508JOSPTjul13509JOSPTjul13510JOSPTjul13