vendex and Patellofemoral-Pain-Syndrome

To compare the effectiveness of adding anteromedial versus posterolateral hip musculature strengthening to knee strengthening in women with patellofemoral pain (PFP).. Randomized controlled trial.. University physiotherapy clinic.. Fifty-two women with PFP were randomized to receive either anteromedial (AMHG) or posterolateral (PLHG) hip musculature strengthening.. The primary outcomes were pain intensity by the numeric pain rating scale and function by the Anterior Knee Pain Scale in six weeks. Secondary outcomes were pain and function at six months, global perceived effect at six weeks and six months, pain in step down, isometric torque of abductors, adductors and hip rotators measured with hand-held dynamometer, and dynamic knee valgus by step down in six weeks.. Both groups showed improvement in primary outcomes; however, no differences were found between groups in pain intensity and function in six weeks and the secondary outcomes. Group x time interaction found superior gains in abductor strength in the PLHG and increase in the strength of the adductors and internal rotators in AMHG.. There was no difference between the addition of anteromedial or posterolateral hip musculature strengthening to knee strengthening in improving pain and function in women with PFP.

Topics: Adult; Exercise Therapy; Female; Hip; Humans; Knee; Muscle Strength; Muscle Strength Dynamometer; Muscle, Skeletal; Pain; Pain Measurement; Patellofemoral Pain Syndrome; Torque

Quadriceps strengthening exercises are part of the treatment of patellofemoral pain (PFP), but the heavy resistance exercises may aggravate knee pain. Blood flow restriction (BFR) training may provide a low-load quadriceps strengthening method to treat PFP.. Seventy-nine participants were randomly allocated to a standardised quadriceps strengthening (standard) or low-load BFR. Both groups performed 8 weeks of leg press and leg extension, the standard group at 70% of 1 repetition maximum (1RM) and the BFR group at 30% of 1RM. Interventions were compared using repeated-measures analysis of variance for Kujala Patellofemoral Score, Visual Analogue Scale for 'worst pain' and 'pain with daily activity', isometric knee extensor torque (Newton metre) and quadriceps muscle thickness (cm). Subgroup analyses were performed on those participants with painful resisted knee extension at 60°.. Sixty-nine participants (87%) completed the study (standard, n=34; BFR, n=35). The BFR group had a 93% greater reduction in pain with activities of daily living (p=0.02) than the standard group. Participants with painful resisted knee extension (n=39) had greater increases in knee extensor torque with BFR than standard (p<0.01). No between-group differences were found for change in Kujala Patellofemoral Score (p=0.31), worst pain (p=0.24), knee extensor torque (p=0.07) or quadriceps thickness (p=0.2). No difference was found between interventions at 6 months.. Compared with standard quadriceps strengthening, low load with BFR produced greater reduction in pain with daily living at 8 weeks in people with PFP. Improvements were similar between groups in worst pain and Kujala score. The subgroup with painful resisted knee extension had larger improvements in quadriceps strength from BFR.. 12614001164684.

Topics: Adult; Double-Blind Method; Exercise Therapy; Female; Humans; Male; Muscle Strength; Pain Measurement; Patellofemoral Pain Syndrome; Quadriceps Muscle; Resistance Training; Torque; Young Adult

Female adolescents with patellofemoral pain are characterized by altered neuromuscular knee control and reduced maximal quadriceps torque. The purpose of this study is to investigate whether exercise therapy and patient education are associated with larger improvements in neuromuscular knee control and maximal quadriceps torque compared with patient education alone.. This is an ancillary analysis of a cluster randomized controlled trial investigating the effect of patient education and exercise therapy on self-reported recovery in 121 adolescents with patellofemoral pain. A random subsample of 57 female adolescents was included and tested at baseline and after 3months. Neuromuscular control of the knee was quantified as the complexity of surface electromyography of the vastus lateralis and vastus medialis during stair descent. Secondary outcomes were complexity of knee flexion/extension kinematics and maximal quadriceps torque.. There was an 8-15% greater decrease in the complexity of surface electromyography suggesting an improvement in neuromuscular knee control among those randomized to exercise therapy (0.08

Topics: Adolescent; Biomechanical Phenomena; Electromyography; Exercise Therapy; Female; Humans; Knee; Muscle Strength; Patellofemoral Pain Syndrome; Quadriceps Muscle; Torque; Young Adult

Altered movement patterns of the trunk and lower limbs have been associated with patellofemoral pain (PFP). It has been assumed that increasing the strength of the hip and trunk muscles would improve lower limb and trunk kinematics in these patients. However, evidence in support of that assumption is limited.. To determine whether increases in the strength of hip muscles and endurance of trunk muscles in response to functional stabilization training will mediate changes in frontal plane lower limb kinematics in patients with PFP.. Controlled laboratory study.. Thirty-one female athletes were randomized to either a functional stabilization training group that emphasized strengthening of the trunk and hip muscles or a standard training group that emphasized stretching and quadriceps strengthening. Patients attended a baseline assessment session, followed by 8 weeks of intervention, and were then reassessed at the end of the intervention period. The potential mediators that were evaluated included eccentric torque of hip muscles and endurance of the trunk muscles. The outcome variables were the lower limb and trunk kinematics in the frontal plane assessed during a single-legged squat task.. The eccentric strength of the gluteus muscles showed a mediation effect ranging from 18% to 32% on changes to frontal plane kinematics (decreased ipsilateral trunk inclination, pelvis contralateral depression, and hip adduction excursions) observed in the functional stabilization training group after intervention.. Although the mediation effects were small, the results suggest that improvements in the strength of the gluteus muscles can influence the frontal plane movement patterns of the lower limb and trunk in women with PFP.. Patients with PFP might benefit from strengthening of the hip muscles to improve frontal plane lower limb and trunk kinematics during functional tasks.

Topics: Athletes; Biomechanical Phenomena; Exercise Therapy; Female; Hip; Humans; Lower Extremity; Middle Aged; Movement; Muscle Strength; Muscle, Skeletal; Patellofemoral Pain Syndrome; Pelvis; Torque; Torso

Patellofemoral pain syndrome (PFPS) is a common musculoskeletal pain condition, especially in females. Decreased hip muscle strength has been implicated as a contributing factor. Isolated open kinetic chain hip abductors and lateral rotators exercises were added by many authors to the rehabilitation program. However, Closed Kinetic Chain (CKC) exercises focusing on hip and knee muscles were not investigated if they can produce similar effect of hip strengthening and decreasing pain without the need of isolated exercises for hip musculature.. The aim of the present study was to determine the effect of a CKC exercises program with or without additional hip strengthening exercises on pain and hip abductors and lateral rotators peak torque.. Prospective randomized clinical trial.. Patients with patellofemoral pain syndrome referred to the outpatient physical therapy clinic of the faculty of physical therapy, cairo university.. Thirty two patients who had patellofemoral pain syndrome with age ranged from eighteen to thirty years.. Patients were randomly assigned into two groups: CKC group and CKC with hip muscles strengthening exercises as a control (CO) group. Treatment was given 3 times/week, for 6 weeks. Patients were evaluated pre- and post-treatment for their pain severity using VAS, function of knee joint using Kujala questionnaire, hip abductors and external rotators concentric/eccentric peak torque.. There were significant improvements in pain, function and hip muscles peak torque in both groups (P<0.05). However, there was no statistically significant difference between groups in hip muscles torque (P<0.05) but pain and function improvements were significantly greater in the CO group (P<0.05).. Six weeks CKC program focusing on knee and hip strengthening has similar effect in improving hip muscles torque in patients with PFPS as a CKC exercises with additional hip strengthening exercises. However, adding isolated hip strengthening exercises has the advantage of more pain relief.. CKC exercises with additional hip strengthening could be more beneficial in decreasing pain in PFPS than CKC exercises alone.

Topics: Adolescent; Adult; Analysis of Variance; Egypt; Exercise Therapy; Female; Hip Joint; Humans; Kinetics; Knee Joint; Male; Muscle Strength; Pain Measurement; Patellofemoral Pain Syndrome; Prospective Studies; Resistance Training; Torque; Treatment Outcome; Young Adult

A common treatment for patients with patellofemoral pain syndrome (PFPS) is strength (force-generating capacity) training of the vastus medialis oblique muscle (VMO). Hip adduction in conjunction with knee extension is commonly used in clinical practice; however, evidence supporting the efficacy of this exercise is lacking.. The objective of this study was to determine the surplus effect of hip adduction on the VMO.. This study was a randomized controlled trial.. The study was conducted in a kinesiology laboratory.. Eighty-nine patients with PFPS participated.. Participants were randomly assigned to 1 of 3 groups: hip adduction combined with leg-press exercise (LPHA group), leg-press exercise only (LP group), or no exercise (control group). Training consisted of 3 weekly sessions for 8 weeks.. Ratings of worst pain as measured with a 100-mm visual analog scale (VAS-W), Lysholm scale scores, and measurements of VMO morphology (including cross-sectional area [CSA] and volume) were obtained before and after the intervention.. Significant improvements in VAS-W ratings, Lysholm scale scores, and VMO CSA and volume were observed after the intervention in both exercise groups, but not in the control group. Significantly greater improvements for VAS-W ratings, Lysholm scale scores, and VMO volume were apparent in the LP group compared with the control group. There were no differences between the LP and LPHA groups for any measures.. Only the VMO was examined by ultrasonography. The resistance level for hip adduction and the length of intervention period may have been inadequate to induce a training effect.. Similar changes in pain reduction, functional improvement, and VMO hypertrophy were observed in both exercise groups. Incorporating hip adduction with leg-press exercise had no impact on outcome in patients with PFPS.

Topics: Adult; Electromyography; Exercise Therapy; Female; Hip Joint; Humans; Knee Joint; Male; Middle Aged; Muscle, Skeletal; Pain Measurement; Patellofemoral Pain Syndrome; Range of Motion, Articular; Single-Blind Method; Torque; Weight-Bearing

Exercise-induced fatigue reduces muscle force production and motoneuron pool excitability. However, it is unclear if patients with patellofemoral pain (PFP) experience further loss in quadriceps neuromuscular function due to fatigue during exercise and postexercise.. To observe how quadriceps maximal strength, activation, and force-generating capacity change during and after repetitive bouts of isokinetic knee-extension exercise in patients with PFP.. Cross-sectional study.. Laboratory.. Twenty-two patients with PFP (visual analog scale mean pain severity = 4.2 of 10 cm, mean symptom duration = 38.6 months) and 19 healthy control individuals matched on age and body mass index.. Quadriceps peak torque (PT), central activation ratio (CAR), and rate of torque development (RTD) were assessed at baseline and immediately after every 5 sets of knee-extension exercise (times 1-5). Participants continued knee-extension exercises until the baseline quadriceps PT dropped below 50% for 3 consecutive contractions.. No group-by-time interaction was observed for quadriceps PT (F5,195 = 1.03, P = .40). However, group-by-time interactions were detected for quadriceps CAR (F5,195 = 2.63, P= .03) and RTD (F5,195 = 3.85, P = .002). Quadriceps CAR (-3.6%, P = .04, Cohen d = 0.53) and RTD (-18.9%, P = .0008, Cohen d = 1.02) decreased between baseline and time 1 in patients with PFP but not in their healthy counterparts (CAR -1.9%, P = .86; RTD -9.8%, P = .22). Quadriceps RTD also decreased between times 4 and 5 in patients with PFP (-24.9%, P = .002, Cohen d = 0.89) but not in the healthy group (-0.9%, P = .99).. Patients with PFP appeared to experience an additional reduction in quadriceps activation, force-generating capacity, or both during the early and late stages of exercise compared with healthy individuals. Clinicians should be aware of such possible acute changes during exercise and postexercise and use fatigue-resistant rehabilitation programs for patients with PFP.

Topics: Cross-Sectional Studies; Fatigue; Humans; Knee; Knee Joint; Muscle Strength; Patellofemoral Pain Syndrome; Quadriceps Muscle; Torque

Individuals with patellofemoral pain (PFP) have kinesiophobia and hip and knee strength deficits. These factors may be related to kinematic alterations of pelvic, hip and knee during a more demanding functional activity, such as jumping landing. The aim was to investigate the relationships between kinesiophobia and hip/knee torque to pelvic/hip/knee kinematics during the single-leg drop vertical jump in women with PFP.. Thirty women with PFP were assessed with Tampa Scale for Kinesiophobia; isokinetic dynamometry of the hip extensor, hip abductor, and knee extensor; and three-dimensional motion analysis system during the single-leg drop vertical jump. A Pearson correlation matrix was used to investigate relationship among variables.. Fair correlations were found between increased kinesiophobia and increased peak hip internal rotation angle (r = 0.43; p = 0.018) as well as between greater peak knee extensor torque and greater peak knee flexion (r = 0.41; p = 0.022). Moderate to good correlation was found between increased peak hip abductor torque and increased peak contralateral pelvic drop (r = 0.52; p = 0.003). No other significant correlations were found between variables.. Kinesiophobia is associated with hip kinematics, but not with knee kinematics, during the single-leg vertical drop jump in women with PFP. The greater hip abductor torque is associated with greater contralateral pelvic drop. The positive relationship between knee extensor torque and knee flexion indicates that rehabilitation programs involving quadriceps muscle strengthening may assist women with PFP in control knee flexion and improve load absorption during jumping landing.

Topics: Biomechanical Phenomena; Cross-Sectional Studies; Female; Humans; Kinesiophobia; Knee Joint; Leg; Muscle Strength; Patellofemoral Pain Syndrome; Rotation; Torque

Compare lower extremity muscle volume in females with patellofemoral pain (PFP) to a cohort of pain-free females and investigate the relationship between thigh and hip muscle volume and torque.. Cross-sectional.. Twenty-one females, 13 with PFP and 8 pain-free controls.. Versus pain-free individuals, females with PFP had smaller muscle volume of the anterior hip (P < 0.019; d = 0.97-2.42), deep external rotators (P < 0.006; d = 1.0-3.93), hamstrings (P < 0.009; d = 1.09-2.12), rectus femoris (P < 0.001; d = 1.79), and vastus intermedius (P < 0.001; d = 1.88). There was no difference in muscle volume of the gluteus maximus (P = 0.311; d = 0.22), gluteus medius (P = 0.087; d = 0.87), vastus lateralis (P = 0.22; d = 0.39), and vastus medialis (P = 0.47; d = 0.04). Gluteus maximus volume was moderately correlated to hip abduction torque (r = 0.60; P = 0.03). Vasti muscles and semitendinosus volume were moderately correlated to knee extension (r = 0.57-0.69; P < 0.05) and flexion (r = 0.66; P = 0.01) torque, respectively.. Females with PFP present with lesser thigh and hip muscle volumes, with variability in volumetric profiles across participants. Lower extremity knee extension and hip abduction strength are moderately associated with the vasti and gluteus maximus muscle volume, respectively.

Topics: Buttocks; Case-Control Studies; Cross-Sectional Studies; Female; Humans; Muscle Strength; Muscle, Skeletal; Patellofemoral Pain Syndrome; Torque

Impaired knee extension biomechanics and spinal excitability have been reported in women with patellofemoral pain, but their relationship has not been explored. A significant relationship between them could indicate the need for investigating the potential benefits of disinhibitory interventions for women with patellofemoral pain. Thus, this study aimed to investigate the relationship between vastus medialis Hoffmann reflex and (1) maximal isometric, concentric and eccentric knee extensor strength and rate of torque development; (2) knee extensor torque steadiness; and (3) knee extensor moment during functional tasks; in women with patellofemoral pain.. Spinal excitability of twenty-four participants was assessed by the amplitude of maximal vastus medialis Hoffmann reflex. Knee extensor strength, rate of torque development and torque steadiness were assessed using an isokinetic dynamometer. Knee extensor moment during step-down and stair descent tasks were obtained using a three-dimensional motion analysis system.. A moderate negative relationship was found between vastus medialis Hoffmann reflex and knee extensor torque steadiness (r = -0.35; p = 0.05); whereas a moderate positive relationship was found with maximal isometric knee extensor strength (r = 0.37; p = 0.044). No significant relationships were found between vastus medialis Hoffmann reflex and the other variables.. Our findings provide insight on the relationship between spinal excitability and neuromuscular control of maximal and submaximal isometric torque production in women with patellofemoral pain. Conversely, spinal excitability does not seem to be related with dynamic torques and moments of the knee extensors in women with patellofemoral pain.

Topics: Biomechanical Phenomena; Electromyography; Female; Humans; Knee; Knee Joint; Patellofemoral Pain Syndrome; Quadriceps Muscle; Reflex; Torque

Different muscular activities of the quadriceps components for producing necessary torque may change in patients with patellofemoral pain syndrome (PFPS). The aim of the current study, therefore, was to assess the contribution of each component of the quadriceps femoris muscle for producing external torque in patients with PFPS.. Twelve females with PFPS (24.7 ± 2.3 years) and twelve healthy matched females (25.4 ± 2.4 years) performed three consecutive knee flexion and extension movements with maximum effort at 45°/s and 300°/s using a Biodex system 3 dynamometer. Simultaneously, electromyographic (EMG) activities of the vastus medialis oblique (VMO), RF (rectus femoris) and vastus lateralis (VL) muscles were recorded using a DataLog instrument. Standard multiple regressions were used to assess the ability of EMG activities of the VMO, RF and VL muscles to predict normalized quadriceps femoris isokinetic concentric and eccentric torques at 45°/s and 300°/s in the normal and patient groups.. In the normal group, the VL and the VMO were the good predictors of quadriceps concentric torque at 45°/s and 300°/s, respectively. The VL and the RF were the good predictors of quadriceps eccentric torque at 300°/s in the patient group. No other conditions showed a considerable prediction for quadriceps torque in the normal or patient group.. Females with PFPS differ with normal females in terms of the contribution of each component of the quadriceps femoris for producing external torque. Training the VMO for concentric contraction at both high and low velocities should be included in the management of the patients with PFPS.

Topics: Electromyography; Female; Humans; Muscle, Skeletal; Patellofemoral Pain Syndrome; Quadriceps Muscle; Torque

Deficits in knee flexor strength and rate of torque development (RTD) might be present in women with patellofemoral pain (PFP). In addition, maximal strength and RTD of the knee flexors and extensors might be related with subjective and objective function in women with PFP. However, both conjectures are still poorly understood.. Do women with PFP have deficits in the maximal strength and RTD of the knee flexors and extensors during isometric, concentric, and eccentric contractions? Is there a relationship between maximal strength and RTD of the knee flexors and extensors with subjective and objective function in women with PFP?. Fifty-six women with, and 46 women without, PFP participated. Maximal strength and RTD (to 30% and 60% maximal torque) during isometric, concentric, and eccentric contractions of the knee flexors and extensors were assessed using an isokinetic dynamometer. Objective assessment included single leg hop test (SLHT) and forward step-down test (FSDT). Subjective assessment involved the anterior knee pain scale.. Women with PFP had small to large deficits in maximal strength and RTD of the knee flexors and extensors during isometric, concentric and eccentric contractions (Effect sizes: -0.43 to -1.10; p ≤ 0.016). Small to moderate correlations of maximal concentric and eccentric knee flexor strength and RTD with SLHT and FSDT (r = 0.28 to 0.41; p ≤ 0.037) were identified. Subjective or objective function were not correlated with maximal isometric knee flexor strength and RTD, or any knee extensor measures (p > 0.05).. Maximal strength and RTD deficits of the knee flexors and extensors were identified in this female PFP cohort, but they were unrelated to subjective function. The relationship of concentric and eccentric knee flexor strength and RTD deficits with poor objective function should be considered in future exercise trials for women with PFP.

Topics: Adult; Female; Humans; Knee Joint; Patellofemoral Pain Syndrome; Torque; Young Adult

To investigate the relationship between: (1) knee flexor strength, rate of torque development (RTD), and flexibility with pain level; (2) knee flexor strength and RTD with the performance in the single leg bridge test (SLBT) in women and men with patellofemoral pain (PFP).. Cross-sectional.. Laboratory-based study.. 39 women and 36 men with PFP.. Knee flexor strength, RTD, and flexibility; performance in the SLBT, current, and worst pain level.. Moderate to strong significant negative relationships were identified between the current pain level with knee flexor strength (r = -0.57 to -0.34) and flexibility (r = -0.44 to -0.35); and between knee flexor strength and RTD with the performance in the SLBT (r = 0.34 to 0.57) in women and men with PFP. Knee flexor RTD was not related to any pain level and no significant relationships were identified between the worst pain level with knee flexor strength and flexibility in women and men with PFP.. Our results support the potential value of assessing knee flexor strength and flexibility in women and men with PFP. The SLBT may be a useful tool to assess knee flexor muscle capacity in individuals with PFP in a clinical setting.

Topics: Adolescent; Adult; Cross-Sectional Studies; Exercise Test; Female; Humans; Knee; Male; Muscle Strength; Muscle, Skeletal; Patellofemoral Pain Syndrome; Self Report; Torque; Young Adult

Ferreira, AS, de Oliveira Silva, D, Barton, CJ, Briani, RV, Taborda, B, Pazzinatto, MF, and de Azevedo, FM. Impaired isometric, concentric, and eccentric rate of torque development at the hip and knee in patellofemoral pain. J Strength Cond Res 35(9): 2492-2497, 2021-The aims of this study were to compare maximal muscle strength and rate of torque development (RTD) of knee extensor and hip abductor during isometric, concentric, and eccentric contractions between women with and without patellofemoral pain (PFP). Thirty-eight women with PFP (PFPG) and 38 pain-free women (CG) participated in this study. Isometric, concentric, and eccentric maximal torque and RTD of knee extensor and hip abductor were assessed using an isokinetic dynamometer. Rate of torque development was calculated as the change in torque over the change in time from torque onset to 30, 60, and 90% of the maximal torque (RTD30%, RTD60%, and RTD90%) during isometric, concentric, and eccentric contractions. PFPG had lower isometric, concentric, and eccentric knee extensor maximal torque (29.9, 28.3, and 26.7%) compared with the CG. For knee extensor RTD, PFPG had slower isometric RTD30% (17.8%), RTD60% (21.5%), and RTD90% (23.4%); slower concentric RTD30% (35.7%), RTD60% (29.3%), and RTD90% (28.2%); and slower eccentric RTD30% (20.5%), RTD60% (25.2%), and RTD90% (22.5%) compared with the CG. PFPG had lower isometric, concentric, and eccentric hip abductor maximal torque (28.3, 21.8, and 17%) compared with the CG. For hip abductor RTD, PFPG had slower isometric RTD30% (32.6%), RTD60% (31.1%), and RTD90% (25.4%); slower concentric RTD90% (11.5%); and slower eccentric RTD30% (19.8%), RTD60% (26.4%), and RTD90% (24%) compared with the CG. In conclusion, women with PFP presented deficits in both maximal strength and RTD of knee extensor and hip abductor during isometric, concentric, and eccentric contractions, which highlight the potential importance of addressing different aspects of muscle function through exercise therapy.

Topics: Female; Humans; Isometric Contraction; Knee Joint; Muscle, Skeletal; Patellofemoral Pain Syndrome; Torque

To compare rate of force development (RFD) and isometric muscle strength of the hip abductors and extensors; and the thickness and the amount of non-contractile tissue of the gluteus medius and maximus between females with and without patellofemoral pain (PFP).. Cross-sectional study.. Fifty-four physically active females (27 with PFP and 27 healthy individuals) were studied. Hip muscle isometric strength and RFD was evaluated using isokinetic dynamometry. RFD was measured until 30%, 60%, and 90% of the maximal isometric torque (MIT). Hip muscle morphology was evaluated using ultrasonography.. The PFP group possessed slower RFD compared to the control group by 33% for hip abductors until 90%MIT (-0.23%/ms, 95%CI -0.44 to -0.02, ES=0.59); by 51% for hip extensors until 30%MIT (-0.42%/ms, 95%CI -0.66 to -0.18, ES=0.97); and by 55% for hip extensors until 60%MIT (-0.36%/ms, 95%CI -0.60 to -0.12, ES=0.81). The PFP group possessed reduced isometric torque compared to the control group by 10% for hip abduction (-16.0Nm/kg×100, 95% CI -30.2 to -1.9, ES=0.61) and by 15% for hip extension (-30.1Nm/kg×100, 95%CI -51.4 to -8.9, ES=0.76). No significant between group differences for the thickness and the amount of non-contractile tissue of the gluteus medius and maximus were identified.. Females with PFP have deficits in isometric strength and RFD in hip abduction and extension. RFD deficits are greater than strength deficits which may highlight their potential importance. Hip muscle strength and RFD deficits do not appear to be explained by muscle thickness or proportion of non-contractile tissue of the gluteal musculature as measured by ultrasound.

Topics: Adolescent; Adult; Case-Control Studies; Cross-Sectional Studies; Female; Hip; Humans; Isometric Contraction; Muscle Strength; Muscle Weakness; Muscle, Skeletal; Patellofemoral Pain Syndrome; Torque; Ultrasonography; Young Adult

The present study aimed at investigating whether the neuromuscular system behaves differently (in terms of force and muscle activity generation) as a function of the task being performed (i.e. maximal voluntary efforts vs stair negotiation) and the presence of patellofemoral pain (PFP) and possible influences of pain intensity. Thirty-eight women with (n = 19) and without PFP (n = 19) had their knee strength (extension joint torque) measured during maximal voluntary isometric contractions (MVIC) and electromyography (EMG) data recorded during both MVIC and stair ascent tasks, which were performed before and after a loading protocol designed to exacerbate pain symptoms. Women with PFP displayed lower levels of vastus medialis (p = 0.002) and vastus lateralis (p = 0.032) EMG activation during MVIC assessments. Conversely, the PFP group showed higher levels of vastus medialis muscle activity during stair climbing (p = 0.007), which happened exclusively after the loading protocol. Similarly, women with PFP displayed lower knee extensor torque only during the MVIC tests performed after the loading protocol, which was moderately correlated with the increase in self-reported pain (p = 0.041, r = 0.37), whereas the changes in EMG activity during stair ascent were not correlated with changes in pain intensity (p = 0.215, r = 0.12). These results suggest that, in comparison to pain-free controls, women with PFP display lower levels of quadriceps EMG activation during maximal contractions, but higher activation during dynamic tasks (stair ascent). In addition, the moderate association between the decrease in knee extensor torque and increase in self-reported pain indicates that care should be taken by clinicians during quadriceps strength evaluation in women with PFP, as misleading outcomes may emerge if the intensity of knee pain is not considered during screening. Additionally, rehabilitation strategies should focus on both restoring neuromuscular control and increasing muscle strength.

Topics: Biomechanical Phenomena; Electromyography; Female; Humans; Isometric Contraction; Knee Joint; Muscle Strength; Pain Measurement; Patellofemoral Pain Syndrome; Quadriceps Muscle; Stair Climbing; Torque; Volition; Young Adult

To compare the knee performance and pain in athletes with patellofemoral pain syndrome (PFPS) before and after applying Kinesio Tape. Fifteen participants (10 females, five males) with unilateral PFPS were examined and compared under taped and untaped conditions.. VMO of the involved leg was taped from origin to insertion, with 75% of KT's maximal length tension.. Maximal eccentric and concentric peak torques of quadriceps were measured at 60 and 180°/s angular velocities by an isokinetic dynamometer. Functional performance and pain were evaluated by functional tests (step-down and bilateral squat) and visual analog scale, respectively.. Paired t-test showed statistically significant increase in VMO peak torque and also repetition of step-down test and bilateral squat after using KT. Pain intensity was also decreased significantly following KT application (p < 0.05).. KT application over VMO can decrease pain and improve the functional performance, generally and quadriceps muscle strength, particularly, in athletes with PFPS. However, more research is needed to evaluate the long-term effects of this therapeutic procedure.

Topics: Adult; Athletes; Athletic Tape; Humans; Male; Muscle Strength; Muscle Strength Dynamometer; Muscle, Skeletal; Patellofemoral Pain Syndrome; Quadriceps Muscle; Torque; Young Adult

It is theorized that increased dynamic knee valgus relates to decreased hip posterolateral muscle strength.. The aim here was to assess the relationship between the frontal plane projection angle (FPPA) of the knee and hip and trunk muscle strength in women with and without patellofemoral pain (PFP).. The sample comprised 43 women: Patellofemoral Pain Group (PPG, n = 22) and Control Group (CG, n = 21). Muscle strength for hip abduction, extension, external rotation and lateral core were measured using a handheld dynamometer. The FPPA was recorded during step-down.. The PPG showed a deficit for hip muscles torque and increased FPPA (P < 0.05). Negative correlation of the FPPA-Peak was found in the CG for the hip abductor (r = -0.31) and posterolateral complex (r = -0.32) (P < 0.05). In the PPG, the FPPA-Peak showed a moderate negative correlation to the torque of external rotators and posterolateral hip muscles, although this correlation did not reach statistical significance.. These findings suggest that women with patellofemoral pain present greater dynamic knee valgus and hip muscle weakness. Abductor and posterolateral hip muscles strength are associated with increased FPPA only in the pain-free population.

Topics: Adolescent; Adult; Biomechanical Phenomena; Case-Control Studies; Cross-Sectional Studies; Female; Hip Joint; Humans; Knee Joint; Middle Aged; Muscle Strength; Muscle Weakness; Muscle, Skeletal; Patellofemoral Pain Syndrome; Rotation; Torque; Torso; Young Adult

The aim of this study was to investigate the correlation between quadriceps to hamstring (Q:H) ratio and the functional outcomes in Patellofemoral Pain (PFP) patients.. The study included forty-four women diagnosed with unilateral PFP. Eccentric and concentric quadriceps and hamstring strength were recorded. Conventional Q:H ratio was calculated as the concentric quadriceps to concentric hamstring peak torque (Ratio 1). Functional ratios were calculated as the eccentric quadriceps to concentric hamstring peak torque (Ratio 2) and as the concentric quadriceps to eccentric hamstring torque (Ratio 3). Functional levels of the patients were determined by using Kujala scores, hop test and step test. Pain levels during activities were recorded. The relationship among Ratio 1, Ratio 2 and Ratio 3 with functional outcomes and pain levels were evaluated using Spearman's correlation coefficient test.. Eccentric and concentric quadriceps and hamstring strength were lower on involved side than uninvolved side. Ratio 2 correlated stronger with Kujala score (r=0.69) than Ratio 1 (r=0.49) and Ratio 3 (r=0.30). Step test (r=0.35) and hop test (r=0.38) only correlated with Ratio 2. Pain levels correlated more with Ratio 2 (r values ranged between 0.38 and 0.48).. Eccentric quadriceps to concentric hamstring ratio was observed more related to the functional outcomes and painful activities in patients with PFP.. Cross-sectional study.

Topics: Adult; Cross-Sectional Studies; Female; Hamstring Muscles; Humans; Muscle Contraction; Muscle Strength; Pain Measurement; Patellofemoral Pain Syndrome; Quadriceps Muscle; Recovery of Function; Torque; Young Adult

Hip and knee strength abnormalities have been implicated in patellofemoral pain (PFP) in multiple studies. However, the relationship is unclear, as many of these studies have been retrospective.. To compare prospective hip and knee isokinetic strength in young female athletes who subsequently went on to develop PFP relative to their uninjured, healthy peers.. Descriptive epidemiology study.. Adolescent female athletes (N = 329) were tested for isokinetic strength of the knee (flexion and extension) and hip (abduction) and screened for the prevalence of PFP before their basketball seasons. After exclusion based on current PFP symptoms, 255 participants were prospectively enrolled in the study. A 1-way analysis of variance was used to determine between-group differences in incident PFP and the referent (no incident PFP) participants.. The cumulative incidence rate for the development of PFP was 0.97 per 1000 athlete-exposures. Female athletes who developed PFP demonstrated increased normalized hip abduction strength (normalized torque, 0.013 ± 0.003) relative to the referent control group (normalized torque, 0.011 ± 0.003) (P < .05). Unlike hip strength, normalized knee extension and knee flexion strength were not different between the 2 groups (P > .05).. The findings in this study indicate that young female athletes with greater hip abduction strength may be at an increased risk for the development of PFP. Previous studies that have looked at biomechanics indicated that those with PFP have greater hip adduction dynamic mechanics.. Combining the study data with previous literature, we theorize that greater hip abduction strength may be a resultant symptom of increased eccentric loading of the hip abductors associated with increased dynamic valgus biomechanics, demonstrated to underlie increased PFP incidence. Further research is needed to verify the proposed mechanistic link to the incidence of PFP.

Topics: Adolescent; Athletes; Basketball; Child; Female; Humans; Incidence; Knee; Knee Joint; Patellofemoral Pain Syndrome; Prospective Studies; Range of Motion, Articular; Torque

This prospective cohort study investigated proprioception and motor control changes in patients with patellofemoral pain syndrome (PFPS), and how these changes related to knee function, pain, muscle strength and muscle endurance.. The study included 43 women diagnosed with unilateral patellofemoral pain syndrome. Thirty-one healthy women were recruited as control group. Peak quadriceps femoris and hamstring muscle isokinetic torques were recorded at 60 and 180°/s. Joint position sense was tested by active reproduction of joint position during horizontal squat performance. Muscle coordination and motor control ability were tested by a multi-joint lower limb tracking-trajectory test. Muscle endurance was tested using a computerized functional squat system. Severity of pain in during stair ascent/descent, squatting, and prolonged sitting with knees 90° flexed were measured using a 10 category modified visual analogue scale. Functional levels of patients were determined using Kujala patellofemoral scores.. Active reproduction of joint position did not differ between PFPS and control groups. However, tracking-trajectory error was significantly higher in PFPS group than control subjects. Hamstring and quadriceps peak isokinetic torque and muscle endurance scores were significantly lower in the PFPS group. Kujala patellofemoral score displayed significant relationships with peak isokinetic quadriceps torque, knee pain, and joint position sense scores. Pain during stair descent, sitting, and quadriceps torque at 180°/s explained 57.7 % of the variation in Kujala patellofemoral score.. Although lower extremity joint position sense did not differ between groups, the PFPS group displayed a target-trajectory muscular coordination deficit, decreased muscular endurance, and decreased muscular strength compared to control group subjects. Pain level directly related to motor control performance while joint position sense scores did not. Knee pain and impaired strength related more to functional performance impairment than joint position sense scores in patients with PFPS.

Topics: Adult; Female; Humans; Knee Joint; Middle Aged; Muscle Strength; Patellofemoral Pain Syndrome; Proprioception; Prospective Studies; Torque

Controlled laboratory study using a cross-sectional design.. To determine whether there are any differences between the sexes in trunk, pelvis, hip, and knee kinematics, hip strength, and gluteal muscle activation during the performance of a single-leg squat in individuals with patellofemoral pain syndrome (PFPS) and control participants.. Though there is a greater incidence of PFPS in females, PFPS is also quite common in males. Trunk kinematics may affect hip and knee function; however, there is a lack of studies of the influence of the trunk in individuals with PFPS.. Eighty subjects were distributed into 4 groups: females with PFPS, female controls, males with PFPS, and male controls. Trunk, pelvis, hip, and knee kinematics and gluteal muscle activation were evaluated during a single-leg squat. Hip abduction and external rotation eccentric strength was measured on an isokinetic dynamometer. Group differences were assessed using a 2-way multivariate analysis of variance (sex by PFPS status).. Compared to controls, subjects with PFPS had greater ipsilateral trunk lean (mean ± SD, 9.3° ± 5.3° versus 6.7° ± 3.0°; P = .012), contralateral pelvic drop (10.3° ± 4.7° versus 7.4° ± 3.8°; P = .003), hip adduction (14.8° ± 7.8° versus 10.8° ± 5.6°; P<.0001), and knee abduction (9.2° ± 5.0° versus 5.8° ± 3.4°; P<.0001) when performing a single-leg squat. Subjects with PFPS also had 18% less hip abduction and 17% less hip external rotation strength. Compared to female controls, females with PFPS had more hip internal rotation (P<.05) and less muscle activation of the gluteus medius (P = .017) during the single-leg squat.. Despite many similarities in findings for males and females with PFPS, there may be specific sex differences that warrant consideration in future studies and when clinically evaluating and treating females with PFPS.

Topics: Adolescent; Adult; Buttocks; Confidence Intervals; Cross-Sectional Studies; Electromyography; Female; Hip Joint; Humans; Isometric Contraction; Knee; Male; Muscle Strength; Patella; Patellofemoral Pain Syndrome; Pelvis; Sex Factors; Torque; United States; Weight Lifting; Young Adult

Patellofemoral pain syndrome (PFPS) is a commonly experienced knee disorder that can result in altered muscle activation of the surrounding musculature. There is little evidence on effects of aerobic exercise on quadriceps torque and EMG activation of the vastus medialis obliquus (VMO), vastus lateralis (VL), and gluteus medius (GM). In this study 20 healthy individuals and 20 patients with PFPS had measures of torque and muscle activation taken following aerobic exercise. A modified Balke-Ware protocol was used for the exercise intervention. Baseline and post-aerobic measurements of knee extension torque and VMO, VL, and GM activation during a single leg anterior reaching task. These measurements were only taken on the injured limb. Following exercise, knee extension torque was lower in PFPS patients when compared to controls (p=0.03). Patients reporting no pain after exercise experienced decreases (p=0.021) in GM activation following exercise. There was a decrease in VMO (p=0.010) and VL (p=0.021) activation in PFPS patients with elevated knee pain. Recreationally active individuals with PFPS may experience different responses in the quadriceps and GM after exercise. Responses may be confounded by whether or not pain is exacerbated by exercise.

Topics: Adolescent; Adult; Electromyography; Exercise; Hip Joint; Humans; Knee Joint; Middle Aged; Muscle, Skeletal; Pain Measurement; Patellofemoral Pain Syndrome; Range of Motion, Articular; Torque; Young Adult

To determine the relationships between eccentric hip and knee torques, symptom severity and functional capacity in females with patellofemoral pain syndrome (PFPS).. Within-subject correlational study.. University biomechanics laboratory.. 10 females diagnosed with PFPS.. Eccentric strength of the hip abductors and lateral rotators, and knee extensors were assessed using an isokinetic dynamometer. A 10-cm visual analog scale was used to determine usual knee pain in the last week. The Anterior Knee Pain Scale (AKPS) was used to determine the functional capacity of the patients.. The study found that the greater the eccentric knee extensor and hip lateral rotator torques, the higher the functional capacity of the patients (p = 0.02, r = 0.72; p = 0.02, r = 0.72). It was also shown that the greater hip lateral rotator torque, the less the usual pain reported in the last week (p = 0.004, r = -0.84). Despite the lack of statistical significance (p = 0.11), it was also found a modest negative relationship between the eccentric knee extensor torque and the usual pain reported in the last week (r = -0.56) that was considered clinically meaningful (d = 1.4).. This study showed that eccentric knee extensor and hip lateral rotator torques were associated with functional capacity and pain level in females with PFPS. Further investigations should be carried out to verify the effects of an intervention program focused on the eccentric action of these muscles with respect to the symptoms in patients with PFPS.

Topics: Adolescent; Adult; Biomechanical Phenomena; Disability Evaluation; Female; Hip Joint; Humans; Knee Joint; Pain Measurement; Patellofemoral Pain Syndrome; Severity of Illness Index; Sex Factors; Sports Medicine; Statistics as Topic; Torque; Young Adult

Controlled laboratory study using a cross-sectional design.. To determine whether females with patellofemoral pain (PFP) demonstrate differences in hip kinematics, hip muscle strength, and hip muscle activation patterns when compared to pain-free controls.. It has been proposed that abnormal hip kinematics may contribute to the development of PFP. However, research linking hip function to PFP remains limited.. Twenty-one females with PFP and 20 pain-free controls participated in this study. Hip kinematics and activity level of hip musculature were obtained during running, a drop jump, and a step-down maneuver. Isometric hip muscle torque production was quantified using a multimodal dynamometer. Group differences were assessed across tasks using mixed-design 2-way analyses of variance and independent t tests.. When averaged across all 3 activities, females with PFP demonstrated greater peak hip internal rotation compared to the control group (mean +/- SD, 7.6 degrees +/- 7.0 degrees versus 1.2 degrees +/- 3.8 degrees; P<.05). The individuals in the PFP group also exhibited diminished hip torque production compared to the control group (14% less hip abductor strength and 17% less hip extensor strength). Significantly greater gluteus maximus recruitment was observed for individuals in the PFP group during running and the step-down task.. The increased peak hip internal rotation motion observed for females in the PFP group was accompanied by decreased hip muscle strength. The increased activation of the gluteus maximus in individuals with PFP suggests that these subjects were attempting to recruit a weakened muscle, perhaps in an effort to stabilize the hip joint. Our results support the proposed link between abnormal hip function and PFP.

Topics: Adolescent; Adult; Biomechanical Phenomena; Case-Control Studies; Cross-Sectional Studies; Female; Hip; Humans; Isometric Contraction; Middle Aged; Muscle Strength; Patellofemoral Pain Syndrome; Range of Motion, Articular; Torque; Young Adult

Patellofemoral pain (PFP) is thought to be related to patellar maltracking due to imbalances in the knee extensor. However, no study has evaluated the in vivo biomechanical properties of the quadriceps tendon in PFP syndrome. Our purpose was to compare the biomechanical properties of the quadriceps tendons in vivo and noninvasively in patients with PFP syndrome to those of control subjects. The null hypothesis was that the quadriceps tendons of PFP subjects would have significantly decreased strain compared with control subjects. Fourteen subjects (7 control, 7 PFP) performed voluntary ramp isometric contractions to a range of torque levels, while quadriceps tendon elongation was measured using ultrasonography. Tendon strain was calculated for the vastus medialis obliquus (VMO) and vastus lateralis (VL) portion of the quadriceps tendon and compared between subjects (control vs. PFP) and within subjects (VMO vs. VL). PFP subjects showed significantly less VMO tendon strain than control subjects (P<0.001), but there was no difference in VL tendon strain between PFP and control subjects (P=0.100). Relative weakness of the VMO is the most likely cause of the decreased tendon strain seen in subjects with PFP. VMO weakness not only explains the decreased medial tendon strain but also explains the presence of increased lateral patellar translation and lateral patellar spin (distal pole rotates laterally) reported in the literature in this population. This technique can potentially be used in a clinical setting to evaluate quadriceps tendon properties and infer the presence of muscle weakness in PFP.

Topics: Biomechanical Phenomena; Case-Control Studies; Elasticity; Humans; Isometric Contraction; Muscle Strength; Muscle Weakness; Patellar Ligament; Patellofemoral Pain Syndrome; Quadriceps Muscle; Tendon Injuries; Time Factors; Torque; Ultrasonography