Research ReportSurplus Value of Hip Adduction inLeg-Press Exercise in Patients WithPatellofemoral Pain Syndrome:A Randomiz...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSP      atellofemoral pain syndrome           dominantly medial...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSment compared with LP training              Of the 123 patient...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSFigure 1.Flow chart demonstrating the progression of participa...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSA hot pack was applied to the quad-riceps femoris muscle for 1...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPS                                                              ...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSvealed significant interactions for                            ...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSTable 3.Comparison Among Group Changes of Pain, Function, and ...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSwas greater than the measurement         intervention period w...
Surplus Value of Hip Adduction in Leg-Press Exercise in PFPS21 Hodges PW, Richardson CA. The influence          35 Lieber R...
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Surplus value of hip adduction in leg press exercise in patients with patellofemoral pain syndrome


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Surplus value of hip adduction in leg press exercise in patients with patellofemoral pain syndrome

  1. 1. Research ReportSurplus Value of Hip Adduction inLeg-Press Exercise in Patients WithPatellofemoral Pain Syndrome:A Randomized Controlled TrialChen-Yi Song, Yeong-Fwu Lin, Tung-Ching Wei, Da-Hon Lin, Tzu-Yu Yen,Mei-Hwa Jan CY Song, PT, MS, is a PhD student, School and Graduate Institute ofBackground. A common treatment for patients with patellofemoral pain syn- Physical Therapy, College of Med-drome (PFPS) is strength (force-generating capacity) training of the vastus medialis icine, National Taiwan University,oblique muscle (VMO). Hip adduction in conjunction with knee extension is com- Taipei, Taiwan.monly used in clinical practice; however, evidence supporting the efficacy of this YF Lin, MD, PhD, is Orthopedicexercise is lacking. Surgeon, Department of Orthope- dics, West Garden Hospital, Tai-Objective. The objective of this study was to determine the surplus effect of hip pei, Taiwan.adduction on the VMO. TC Wei, PT, MS, is Physical Thera- pist, Yeong-An Clinic, Taipei,Design. This study was a randomized controlled trial. Taiwan. DH Lin, MD, is Orthopedic Sur-Setting. The study was conducted in a kinesiology laboratory. geon, Department of Orthope- dics, En Chu Kong Hospital, Tai-Participants. Eighty-nine patients with PFPS participated. pei, Taiwan. TY Yen, PT, MS, is Physical Thera-Intervention. Participants were randomly assigned to 1 of 3 groups: hip adduc- pist, Yeong-An Clinic.tion combined with leg-press exercise (LPHA group), leg-press exercise only (LP MH Jan, PT, MS, is Associate Pro-group), or no exercise (control group). Training consisted of 3 weekly sessions for 8 fessor, School and Graduate Insti-weeks. tute of Physical Therapy, College of Medicine, National Taiwan Uni-Measurements. Ratings of worst pain as measured with a 100-mm visual analog versity, 3F, No. 17, Xuzhou Rd, Zhongzheng District, Taipei 100,scale (VAS-W), Lysholm scale scores, and measurements of VMO morphology (in- Taiwan, Republic of China. Ad-cluding cross-sectional area [CSA] and volume) were obtained before and after the dress all correspondence to Ms Janintervention. at: [Song CY, Lin YF, Wei TC, et al.Results. Significant improvements in VAS-W ratings, Lysholm scale scores, and Surplus value of hip adduction inVMO CSA and volume were observed after the intervention in both exercise groups, leg-press exercise in patients withbut not in the control group. Significantly greater improvements for VAS-W ratings, patellofemoral pain syndrome: aLysholm scale scores, and VMO volume were apparent in the LP group compared randomized controlled trial. Physwith the control group. There were no differences between the LP and LPHA groups Ther. 2009;89:409 – 418.]for any measures. © 2009 American Physical Therapy AssociationLimitations. Only the VMO was examined by ultrasonography. The resistancelevel for hip adduction and the length of intervention period may have been inade-quate to induce a training effect.Conclusions. Similar changes in pain reduction, functional improvement, andVMO hypertrophy were observed in both exercise groups. Incorporating hip adduc- Post a Rapid Response ortion with leg-press exercise had no impact on outcome in patients with PFPS. find The Bottom Line: www.ptjournal.orgMay 2009 Volume 89 Number 5 Physical Therapy f 409
  2. 2. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSP atellofemoral pain syndrome dominantly medial patellar pull. Be- with prone-lying or squatting posi- (PFPS) is a common musculo- cause the VMO plays an important tions. These positions, however, are skeletal problem of the knee. role in medial stabilization of the pa- nonfunctional or weight bearing,Patients with PFPS often have ret- tella,11–13 any dysfunction may lead where the tendency of increasingropatellar or peripatellar pain.1 This to reduced medial stabilization of the dynamic Q-angle may exacerbatepain is aggravated by activities that the patella against the counterforce stress on the patellofemoral joint.31increase patellofemoral compressive of lateral pull exerted by the VL and Furthermore, some patients may notforce, such as walking up and down other quadriceps femoris muscle tolerate this position because thestairs, squatting, running, and pro- components.14,15 gradually increasing joint stress maylonged sitting with bent knees.2– 4 aggravate the pain. Leg-press (LP) Numerous rehabilitation protocols exercise, therefore, be used as aPatellofemoral pain syndrome is have been described for treating peo- substitute to train patients in a func-thought to be associated with lateral ple with patellofemoral problems. tional position without aggravatingmalalignment of the patella.5 Pos- Quadriceps femoris muscle strength- symptoms.sible causes of this malalignment ening (increased force-generating ca-include hypotrophy or atrophy of pacity), especially that emphasizing To date, it remains unclear as tothe vastus medialis oblique muscle the VMO, is generally considered to whether the addition of hip adduc-(VMO), changes that are commonly be a conservative treatment.14,16 –19 tion to LP exercise would facilitateseen in patients with PFPS, and an Incorporating hip adduction with VMO hypertrophy and result in a bet-imbalance or delay in the activation knee extension is a popular strategy ter treatment outcome. In additionof the VMO relative to the vastus for strengthening the VMO.14,16 This to the pain and functional scales thatlateralis muscle (VL).5,6 Several ca- intervention takes into consideration typically are used, ultrasonographydaver studies have shown that the the fact that the VMO is connected provides a further quantitative mea-VMO fiber angle was 50 to 57 de- to the adductor magnus and longus sure for assessing muscle morphol-grees off the long axis of the femur muscles.20 Training of the adductor ogy in clinical trials involving pa-in the frontal plane, and the proxi- muscles uses this anatomical link to tients with PFPS. Ultrasonography ismal vastus medialis muscle fiber provide a more-stable proximal at- a noninvasive and low-cost tech-orientation was approximately 15 tachment and transfers physiological nique that is now extensively useddegrees.7–10 Anatomically, the direc- stretch to the VMO, thereby enhanc- for morphological investigations intion of VMO muscle pull was more ing the contraction force.15,21 the field of rehabilitation.32 The mea-horizontal. It also has been demon- surement validity of ultrasound com-strated in a cadaver study that all of Because hip adduction exercise was pared with the magnetic resonancethe quadriceps femoris muscles, ex- found to selectively activate the imaging or computed tomographycept the VMO, can extend the knee VMO,22 numerous studies have ex- gold standards has been reported to(regardless of the force applied) and amined the electrical activity of be acceptable.33,34 Indeed, althoughthat the role of the VMO is to main- the VMO and VL with hip adduc- VMO strength cannot be directlytain medial tracking of the patella tion during various knee extension assessed in vivo, morphologicalduring knee extension.11 An in vivo exercises.15,21,23–29 Findings have changes following exercise trainingstudy12 showed that electrical stimu- been disparate. Selective recruit- can be both observed and quantifiedlation of the VMO resulted in pre- ment of the VMO was reported in 2 via ultrasonography and, thus, mus- studies where VMO activity was cle force and excursion capability higher than VL activity following hip can be determined.35 Available With adduction with knee extension from This Article at a semi-squatting position in subjects The purpose of this study was to who were healthy.21,28 In patients investigate the surplus effect of hip with PFPS, however, incorporation adduction to seated LP exercise on • The Bottom Line clinical of hip adduction has been found to VMO morphology, pain, and func- summary promote a more-balanced VMO/VL tion in patients with PFPS. We hy- • The Bottom Line Podcast ratio29 or increased whole quadri- pothesized that incorporation of • Audio Abstracts Podcast ceps femoris muscle activity.24,25 hip adduction with leg-press train- ing (LPHA) would result in more- This article was published ahead of print on March 19, 2009, at Hodges and Richardson21 and Grel- beneficial effects on VMO hypertro- samer and McConnell30 have advo- phy, pain, and functional improve- cated incorporating hip adduction410 f Physical Therapy Volume 89 Number 5 May 2009
  3. 3. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSment compared with LP training Of the 123 patients initially screened, exercise sessions for 8 weeks. Twoalone. 98 met the study inclusion criteria. assessment sessions were performed Nine of the 98 recruited participants by another physical therapist (blindedMethod declined to participate before ran- to each patient’s grouping) beforeSetting and Participants domization. Therefore, a total of 89 and after the 8-week intervention.A total of 123 patients with a diagno- participants were enrolled in thissis of PFPS were referred to our ki- study. Sample size was calculated Interventionsnesiology laboratory by an orthope- using a predetermined difference be- Simple LP exercise. Leg-press ex-dic surgeon (YFL). The inclusion tween treatment groups of 1.5 cm ercise was performed unilaterallycriteria were: (1) experience of an- for worst pain on a 10-cm VAS. As- starting from 45 degrees of knee flex-terior or retropatellar knee pain after suming a standard deviation of 2 cm, ion to full extension using an EN-performing at least 2 of the following at least 29 participants per treatment Dynamic Track machine.* Exerciseactivities: prolonged sitting, stair group were required to attain 80% within the functional range was con-climbing, squatting, running, kneel- power. sidered safe for patients with PFPS.36ing, hopping and jumping, and deep A blue Thera-Band† was tied to eachknee flexing; (2) insidious onset of Participants were randomly allo- patient’s thigh (without resistance)symptoms unrelated to traumatic ac- cated to 1 of 3 groups: a group that to maintain consistent tactile stimu-cident; (3) presence of pain for more received hip adduction combined lation among groups. Prior to the be-than 1 month; and (4) age of 50 years with leg-press exercise (LPHA), a ginning of exercise training, the uni-and under (to eliminate the possibil- group that received LP exercise only, lateral 1-repetition maximum (RM)ity of osteoarthritis). In addition, par- or a group that received no exercise strength of the lower extremity wasticipants had to exhibit at least 2 (control group). Ten participants determined by Odvar Holten Pyra-of the following positive signs of later dropped out of the study due to mid diagram37 with repetition-to-anterior knee pain during the initial personal factors (not knee pain) or fatigue testing. Patients were unilat-physical examination: (1) patellar work commitment. Seventy-nine par- erally trained at 60% of 1 RM for 5crepitus, (2) pain following isomet- ticipants completed the trial (27 in sets of 10 repetitions. The 1 RM wasric quadriceps femoris muscle con- each exercise group and 25 in the re-measured every 2 weeks, and thetraction against suprapatellar resis- control group, Fig. 1). The demo- exercise intensity was adjusted ac-tance with the knee in slight flexion graphic data for the 3 study groups cordingly. A 60-Hz metronome was(Clarke’s sign), (3) pain following are presented in Table 1. There were used to control the exercise pacecompression of the patella against no significant between-group differ- at 2-second concentric and eccentricthe femoral condyles with the knee ences for any of the demographic contractions from 45 degrees ofin full extension (patellar grind test), variables. None of the participants knee flexion to full extension. There(4) tenderness upon palpation of were engaged in regular sporting were 2-second breaks between rep-the posterior surface of the patella or activities. etitions and 2-minute breaks be-surrounding structures, and (5) pain tween sets. Limbs were alternativelyfollowing resisted knee extension. Randomization trained between exercise sets. All volunteers were enrolled afterParticipants were excluded if they providing written informed consent. LPHA. This exercise was per-had: (1) self-reported clinical evi- The study was performed in a blind formed as per the LP, except that adence of other knee pathology; (2) (nondiscriminatory) manner. A sin- 50-N hip abduction force was ap-patellar tendinitis or knee plica; (3) a gle physical therapist, unaware of plied to the distal one third of thehistory of knee surgery; (4) central the purpose of the study, was re- thigh. This force was achieved byor peripheral neurological patholo- sponsible for randomization and in- tying a blue Thera-Band to an armgy; (5) knee radiographic abnormal- terventions. Stratified allocation was of the EN-Dynamic Track machineities (eg, knee osteoarthritis) or carried out with regard to the num- (Fig. 2). Therefore, this exercise waslower-extremity malalignment (eg, ber of affected sides (unilateral or a combination of LP and 50-N isomet-foot pronation); (6) severe knee pain bilateral) and symptom severity ric hip adduction.(visual analog scale [VAS] score of (Lysholm scale scores 65 or 65). 8); or (7) received nonsteroidal Participants were randomly assignedanti-inflammatory drugs, injections, to the LP group, LPHA group, or con-or physical therapy intervention in trol group in blocks of 9 (chosen * Enraf-Nonius BV, Vareseweg 127, 3047 AT, Rotterdam, the Netherlands.preceding 3 months. through numbered opaque enve- † The Hygenic Corp, 1245 Home Ave, Akron, lopes) and participated in 3 weekly OH 44310-2575.May 2009 Volume 89 Number 5 Physical Therapy f 411
  4. 4. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSFigure 1.Flow chart demonstrating the progression of participants through the trial. LPHA hip adduction with leg-press exercise, LP leg-press exercise.Table 1.Demographic Data for Study Participantsa LPHA Group LP Group Control Group Variable (n 29) (n 30) (n 30) P Sex (male:female) 8:21 8:22 4:26 .337 Age (y) 38.6 10.8 40.2 9.9 43.9 9.8 .129 Height (cm) 162.3 7.2 161.3 8.4 159.7 5.2 .370 Weight (kg) 58.3 9.0 60.1 11.2 57.4 6.9 .505 Body mass index (kg/m2) 22.2 3.2 23.0 3.0 22.5 2.1 .498 Involved side (bilateral:unilateral) 19:10 18:12 18:12 .882 Duration of symptoms (mo) 41.8 36.1 38.3 34.2 27.7 41.0 .056a Data are presented as mean SD. LPHA hip adduction with leg-press exercise, LP leg-press exercise.412 f Physical Therapy Volume 89 Number 5 May 2009
  5. 5. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSA hot pack was applied to the quad-riceps femoris muscle for 15 minutesbefore exercise was commenced. Af-ter exercise completion, participantswere asked to stretch the quadri-ceps, hamstring, iliotibial band, andcalf muscle groups and were given acold pack to apply for 10 minutes.Stretches were maintained for 30seconds and were repeated 3 timesfor each muscle group. All study par-ticipants were asked not participatein any form of sport or exercise dur-ing the intervention period.Control group. Control groupparticipants did not receive any ex-ercise intervention, but were pro-vided with health educational mate-rial regarding patellofemoral pain.They were advised not to perform orreceive any exercise program or in-tervention. Neither tape nor bracewas used. Exercise training was im-plemented after the 8-week controlperiod.Outcome MeasurementsVAS pain assessment. The VAS isa reliable, well-validated, and widelyused tool for assessing knee pain.38 – 41A 100-mm VAS was used to measurethe worst pain (VAS-W) experiencedin the previous week.Functional evaluation. The Lys-holm scale was used to measurefunctional ability. The scale rangesfrom 0 to 100 points (with a score of100 indicating maximal function)and was originally designed to eval-uate symptoms and functions per- Figure 2. Hip adduction with leg-press exercise (a), with a close lateral view of the setup oftaining to knee injury.42 There are resisted hip adduction via Thera-Band (b).8 components to this assessment:stair climbing (10 points), squatting(5 points), pain (25 points), pres- highly with the Kujala anterior knee trasonography (HDI 5000‡) with aence of a limp (5 points), locking pain scale (r .86)45 and has been 5- to 12-MHz broadband linear-array(15 points), instability (25 points), used as a knee function evaluation transducer (38 mm). The ultrasono-swelling (10 points), and the require- tool in patients with patellofemoral graphic measurements included VMOment of support when walking (5 disorders.45,49 –51 cross-sectional area (CSA) on thepoints). The reliability, validity, and patellar-base level and VMO volumerobustness of the Lysholm scale have Measurement of VMO morphol-been well documented.42– 48 The ogy. Vastus medialis oblique mus- ‡ Advanced Technology Laboratories, 22100Lysholm scale was found to correlate cle morphology was assessed by ul- Bothell Everett Hwy, Bothell, WA 98041-3003.May 2009 Volume 89 Number 5 Physical Therapy f 413
  6. 6. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPS SPSS version 11.0.§ Data were sub- jected to an intention-to-treat analy- sis and included all dropouts. De- scriptive statistics (X SD) were used to determine participant char- acteristics. Prior to statistical analy- sis, the Kolmogorov-Smirnov test was performed to assess the normal- ity of continuous data. Normally distributed baseline demographic variables (age, body height, body weight, and body mass index) were compared by 1-way analysis of vari- ance (ANOVA). Non-normally dis- tributed variables (symptom dura- tion) were compared by Kruskal- Wallis test with an alpha of .05. Sex and numbers of afflicted sides (bilat- eral versus unilateral) were com- pared by chi-square test with an alpha of .05. For each outcome vari-Figure 3. able measured, a 2 (preinterventionMeasurement of vastus medialis oblique muscle cross-sectional area on patellar-baselevel. and postintervention) 3 (treat- ment groups: LPHA, LP, and control) 2-way mixed ANOVA was per-under the patellar-base level.52 All CSA was taken from the line pass- formed. When a significant 2-way in-measurements were obtained while ing through the patellar-base level teraction was detected, post hocparticipants were lying on a bed, (Fig. 3). Serial VMO CSAs were ob- analysis was performed using Bonfer-with both legs relaxed (feet were tained every 2 mm until the VMO roni adjustment (P .008).positioned in a frame to prevent leg image on the visual display faded. Torotation) and a thick padded towel control for any potential confound- Resultsplaced underneath the knee to main- ing pressure exerted by the probe All exercise intervention participantstain resting position. holder, gel was applied to the skin except one attended all scheduled such that there was no direct contact exercise sessions. One participant inThe longitudinal length of the patella between the probe and the skin.53 the LP group completed only half of(in millimeters) was determined The image was carefully monitored the intervention and subsequentlyfrom the upper border to the lower by the examiner to ensure that the dropped out of the study due toborder with calipers. The VMO vol- VMO was not being compressed work commitments (Fig. 1). The re-ume under the patellar base was ap- (Fig. 3). maining study participant dropoutsproximated from a series of VMO in both exercise groups completedCSAs using the trapezoidal rule.52 To The intraclass correlation coeffi- the exercise programs but did notobtain a valid calculation of VMO vol- cients for between-day test-retest re- attend postintervention evaluations.ume from the sonographic image, a liability of VMO CSA and volumecustom-made holder was used to fix measurements were .96 and .94, re- Results pertaining to VAS-W, Lysh-the probe.52 The holder was cali- spectively. The actual day-to-day dif- olm scale scores, VMO CSA, andbrated to quantify movement of the ferences (X SD) were 0.02 0.30 VMO volume for the 3 groups beforetransducer by synchronizing with a cm2 and 0.06 0.68 cm3, respec- and after the 8-week interventionscaled hub, which was turned in a tively. The standard errors of mea- period are shown in Table 2. Therefull circle to mobilize the transducer surement were 0.29 and 0.52, were no significant baseline differ-by 1 mm from the proximal patellar respectively. ences among the groups. The 2-waybase toward the distal patellar apex ANOVA for repeated measures re-along a line perpendicular to the Data Analysishorizontal representing the upper Data obtained from the most symp- § SPSS Inc, 233 S Wacker Dr, Chicago, ILborder of the patella. The first VMO tomatic knee were analyzed using 60606.414 f Physical Therapy Volume 89 Number 5 May 2009
  7. 7. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSvealed significant interactions for .715 .714 .962 .838 P Data are presented as mean SD. VAS-W worst pain as measured by the 100-mm visual analog scale, CSA cross-sectional area, CI confidence interval. Asterisk denotes significant difference betweenVAS-W, Lysholm scale scores, VMO Comparison Between Preintervention and Postintervention Changes of Pain, Function, and Vastus Medialis Oblique Muscle (VMO) Morphology for the Hip Adduction ( 1.16 to 0.80) ( 2.93 to 4.27) ( 0.38 to 0.36) ( 0.45 to 0.55)CSA, and VMO volume. Post hoc Difference (95% CI)analyses indicated that VAS-W, Lysh- 0.18 0.01 Mean 0.67 0.05olm scale scores, VMO CSA, and Control Group (n 30)VMO volume significantly increasedfollowing intervention in the LP and intervention interventionLPHA groups (P .008), but not the 4.81 2.55 75.7 10.9 3.38 1.52 2.82 1.91 Post-control group (Tab. 2). Furthermore,values pertaining to the VAS-W andLysholm scale were significantly bet-ter in both exercise groups com- 4.99 2.18 3.39 1.47 2.76 2.01 75.1 9.3pared with the control group after Pre-intervention (P .008) (Tab. 3). Thevalues for VMO volume were signif-icantly higher in the LP group com- .005* .005* .005* .005*pared with the control group after Pintervention (P .008), whereas the ( 3.56 to 1.61)between-group difference in VMO (7.13 to 14.33) (0.34 to 1.08) (0.57 to 1.56) Difference (95% CI)CSA did not reach the level of ad- 2.58 Mean 10.73 0.71 1.06justed significance (P .012). The LP Group (n 30)values for VMO CSA and VMO vol-ume were not different between the With Leg-Press Exercise (LPHA) Group, the Leg-Press Exercise (LP) Group, and the Control Groupa intervention interventionLPHA group and the control group 2.26 2.20 86.5 10.4 4.46 1.90 4.45 2.52after intervention (P .046 and Post-P .02, respectively). No differenceswere detected between the LP andLPHA groups (Tab. 3). 4.85 2.49 75.7 12.8 3.75 1.59 3.38 2.37 Pre-The pretest-posttest effect size in theLPHA group ranged from 0.48 to0.77 for VMO morphology and 0.76 .005* .005* .004* .005*to 1.10 for VAS-W and Lysholm scale Pscores, and the corresponding valuesfor the LP group were 0.71 to 0.75 ( 3.17 to 1.19) (7.27 to 14.59) (0.22 to 0.92) (0.58 to 1.59) Differenceand 0.89 to 0.95, respectively. When (95% CI) 2.18 Mean 10.93 0.57 1.08comparing the effect between the LPHA Group (n 29)LPHA and control groups, effect sizevalues were 0.78 for VAS-W, 1.12 forthe Lysholm scale scores, and 0.56 to intervention intervention preintervention and postintervention values (P .008). 2.62 2.51 4.24 1.43 4.12 1.830.77 for VMO CSA and VMO volume. 85.7 8.5 Post-These effect sizes were consistentlysmaller than those associated withthe LP group and control group com- 4.80 2.26 74.8 12.1 3.67 1.45 3.04 2.18parison, where effect size values Pre-were 0.92 for VAS-W and 0.75 to0.77 for VMO CSA and VMO volume.An exception was Lysholm scale VMO volume (cm3)scores (effect size 1.01). However, VMO CSA (cm2)there was no significant difference in Variable Lysholm scaleimprovement for any variable be- Table 2.tween the LP and LPHA groups. VAS-W aMay 2009 Volume 89 Number 5 Physical Therapy f 415
  8. 8. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSTable 3.Comparison Among Group Changes of Pain, Function, and Vastus Medialis Oblique Muscle (VMO) Morphology for the HipAdduction With Leg-Press Exercise (LPHA) Group, the Leg-Press Exercise (LP) Group, and the Control Groupa LPHA Group vs Control Group LP Group vs Control Group LPHA Group vs LP Group Mean Difference Mean Difference Mean Difference Variable (95% CI) P (95% CI) P (95% CI) P VAS-W 2.19 ( 3.44 to 0.93) .001* 2.54 ( 3.79 to 1.30) .005* 0.35 ( 0.90 to 1.61) .577 Lysholm scale 9.99 (4.81 to 15.17) .005* 10.73 (5.60 to 15.87) .005* 0.74 ( 5.92 to 4.44) .776 VMO CSA (cm2) 0.86 (0.02 to 1.70) .046 1.09 (0.25 to 1.92) .012 0.23 ( 1.07 to 0.62) .598 VMO volume (cm3) 1.30 (0.21 to 2.40) .020 1.63 (0.55 to 2.71) .004* 0.33 ( 1.42 to 0.77) .556a CSA cross-sectional area, CI confidence interval. Asterisk denotes significant difference among groups (P .008).Discussion intervention improved by approxi- stair climbing and squatting. OurStrengthening of the knee extensor mately 11 points. This finding is sim- findings of decreased pain and in-via hip adduction is a very common ilar to those of a previous study in creased functional capacity agreetherapeutic approach for treating which Lysholm scale scores in- with previous research demonstrat-people with patellofemoral pain.14,16 creased from 67.6 6.4 points to ing that patients with PFPS were ableThe effects of 8-week LP and LPHA 81.1 9.4 points after 6 weeks of iso- to perform significantly more step-exercise interventions on pain re- kinetic training.49 Unlike the VAS, ups, step-downs, and squats beforeduction, functional improvement, the minimal change in the Lysholm pain onset after quadriceps femorisand VMO hypertrophy were compa- scale scores representing a clinically muscle training.59 The relationshiprable, indicating that there is no ad- relevant improvement in functional between quadriceps femoris muscleditive beneficial effect of incorporat- status is yet to be determined. Out of strength and locomotor function ining hip adduction with LP exercise. 100 points, a score of 95 to 100 in- patients with PFPS has been docu-This finding may be attributed to the dicates excellent function, a score of mented previously by Powers andfact that during simple LP exercise, 84 to 94 indicates good function, a Perry.60 Leg-press exercise training,the hip adductor magnus and longus score of 65 to 83 indicates fair func- especially in the eccentric contrac-muscles are simultaneously activated tion, and a score of 65 indicates tion mode, is better suited for indi-to stabilize hip movement.54 poor function.42 Overall, the patients viduals with PFPS who demonstrate in our study exhibited significant weaker eccentric than concentricThis is the first study, to our knowl- functional improvement from a level quadriceps femoris muscle strength.61edge, that investigated the clinical of fair to good following LP or LPHA Given the improvements in 1 RMeffects of adding hip adduction to training. Functional improvements (from 90 30 kg to 145 50 kg inLP exercise for the management of in our study were significantly corre- the LPHA group and from 89 33 kgPFPS. Limited knowledge might be lated with reductions in VAS-W (r to 138 51 kg in the LP group), it isgained if change of the training po- .451, P .005). This finding is com- not surprising that both exercisesition would result in different out- parable to that from a previous re- groups exhibited significant im-comes. However, the effects of exer- port (r .424, P .009).49 It must provements in the stair-climbing andcise training on pain reduction in the be borne in mind that the results squatting scores on the Lysholmcurrent study can be considered clin- of intention-to-treat may even be scale (r .347, P .05).ically significant based on a previous that a VAS change of 1.5 mm Folland and Williams62 concludedin patients with PFPS is the minimal Because the Lysholm scale is not a that the primary morphological ad-difference to be considered clinically PFPS-specific scale, we made a fur- aptation after resistance exercise isimportant.38 These findings are in ac- ther subanalysis of the stair-climbing related to an increase in the CSA ofcordance with the results of previ- and squatting items. Initially, 93% the whole muscle and individualous studies regarding pain reduction and 82% of the exercise intervention muscle fibers (caused by an increasewhere various quadriceps femoris participants had difficulty perform- in myofibril size and number). Aftermuscle retraining exercise protocols ing the stair-climbing and squatting both LPHA and LP exercise interven-were used.49,55–59 Functional perfor- tasks, respectively. After exercise in- tion in our study, VMO hypertrophymance (as indicated by Lysholm tervention, 50% to 52% of the pa- was observed as the result of trainingscale scores) following our exercise tients achieved maximal scores for because the amount of improvement416 f Physical Therapy Volume 89 Number 5 May 2009
  9. 9. Surplus Value of Hip Adduction in Leg-Press Exercise in PFPSwas greater than the measurement intervention period would be of 5 Witvrouw E, Werner S, Mikkelsen C, et al. Clinical classification of patellofemoralerror. This is the first study using interest. pain syndrome: guidelines for non-noninvasive ultrasonography to in- operative treatment. Knee Surg Sports Traumatol Arthrosc. 2005;13:122–130.vestigate changes in VMO morphol- Conclusion 6 Cowan SM, Bennell KL, Hodges, et al. De-ogy in patients with PFPS following The findings suggest that an 8-week layed onset of electromyographic activityLPHA or LP training. We speculate exercise program involving simple of VMO relative to VL in subjects with patellofemoral pain syndrome. Arch Physthat this positive outcome may be LP training (from 45° of knee flexion Med Rehabil. 2001;82:183–189.partially a consequence of VMO hy- to full extension) and stretching can 7 Hubbard JK, Sampson HW, Elledge JR.pertrophy. As all patients were given induce significant VMO hypertro- Prevalence and morphology of the media- lis oblique muscle in human packs before exercise and were phy, improve knee function, and re- Anat Rec. 1997;249:135–142.instructed to stretch and apply cold duce pain in patients with PFPS. We 8 Hubbard JK, Sampson HW, Elledge JR. Thepacks after exercise, it is possible found that adding 50 N of hip adduc- vastus medialis oblique muscle and its re- lationship to patellofemoral joint deterio-that the positive outcomes may not tion to LP exercise had no further ration in human cadavers. J Orthop Sportshave been due to LP exercise alone. beneficial effects on outcome com- Phys Ther. 1998;28:384 –391.A previous study63 demonstrated pared with LP exercise alone after 9 Peeler J, Cooper J, Porter MM, et al. Struc- tural parameters of the vastus medialisthat centralization of the patella can an 8-week intervention in patients muscle. Clin Anat. 2005;18:281–289.result from VMO strengthening and with PFPS. 10 Raimondo RA, Ahmad CS, Blankevoort L,stretching procedures. Further re- et al. Patellar stabilization: a quantitative evaluation of the vastus medialis obliquesearch is needed to determine muscle. Orthopedics. 1998;21:791–795. Ms Song, Dr YF Lin, Dr DH Lin, and Ms Janwhether patellar alignment or track- provided concept/idea/research design. Ms 11 Lieb FJ, Perry J. Quadriceps function: aning is altered with VMO Song and Ms Jan provided writing. Ms Song anatomical and mechanical study using amputated limbs. J Bone Joint Surg Am.hypertrophy. and Mr Wei provided data collection. Ms 1968;50:1535–1548. Song and Dr DH Lin provided data analysis. 12 Lin F, Wang G, Koh JL, et al. In vivo and Ms Jan provided project management, facil-We found that LPHA did not result in noninvasive three-dimensional patellar ities/equipment, and institutional liaisons. Dr tracking induced by individual heads offurther beneficial effects compared YF Lin and Dr DH Lin provided participants. quadriceps. Med Sci Sports Exerc. 2004;with LP exercise alone. It is possible Mr Wei and Ms Yen provided clerical sup- 36:93–101.that hip adductor activation during port. Dr YF Lin provided consultation (in- 13 Toumi H, Poumarat G, Benjamin M, et al. cluding review of manuscript before submis- New insights into the function of the vas-LP training54 subtracted from the tus medialis with clinical implications. sion).effect of additional isometric hip Med Sci Sports Exerc. 2007;39:1153–1159.adduction. However, it also is possi- The study protocol was approved by the Re- 14 Malone T, Davies G, Walsh WM. Muscular search Ethics Committee of National Taiwan control of the patella. Clin Sports Med.ble that isometric hip adduction 2002;21:349 –362. University Hospital.does not preferentially recruit the 15 Karst GM, Jewett PD. ElectromyographicVMO.15,23–25,27 Further study is war- An oral presentation of the results of this analysis of exercises proposed for differ- study was given at the International Con- ential activation of medial and lateral quad-ranted to clarify this issue. riceps femoris muscle components. Phys gress of the World Confederation for Physical Ther. 1993;73:286 –299. Therapy; June 5, 2007; Vancouver, BritishThis study had several limitations. Columbia, Canada. 16 Powers CM. Rehabilitation of patellofemo- ral joint disorders. J Orthop Sports PhysOnly the VMO was examined by ul- Ther. 1998;28:345–354. This article was received June 23, 2008, andtrasonography after exercise inter- 17 Syme G, Rowe P, Martin D, Daly G. Dis- was accepted February 3, 2009.vention, and the VL and other com- ability in patients with chronic patel- DOI: 10.2522/ptj.20080195 lofemoral pain syndrome: a randomisedponents of the quadriceps femoris controlled trial of VMO selective trainingmuscle were not assessed. Addi- versus general quadriceps strengthening. Man Ther. 2008 Apr 22 [Epub ahead oftional investigation is warranted to References print].examine morphological changes in 1 Gerbino PG, Griffin ED, d’Hemecourt PA, 18 Cowan SM, Bennell KL, Crossley KM, et al.individual quadriceps femoris mus- et al. Patellofemoral pain syndrome: eval- Physical therapy alters recruitment of uation of location and intensity of pain. the vasti in patellofemoral pain syn-cles. A second potential limitation Clin J Pain. 2006;22:154 –159. drome. Med Sci Sports Exerc. 2002;34:was the use of 50 N as the force level 2 Zappala FG, Taffel CB, Scuderi GR. Reha- 1879 –1885.for hip adduction. This force level bilitation of patellofemoral joint disorders. 19 Fagan V, Delahunt E. Patellofemoral pain Orthop Clin North Am. 1992;23:555–566. syndrome: a review on associated neuro-may have been inadequate to induce 3 Tria AJ, Palumbo RC, Alicea JA. Conserva- muscular deficits and current treatmenta training effect. 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