Evaluating eccentric hip torque and trunk endurance as mediators of changes in lower limb and trunk kinematics in response to functional stabilization training in women with patellofemoral pain.

BACKGROUND: 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. PURPOSE: 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. STUDY DESIGN: Controlled laboratory study. METHODS: 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. RESULTS: 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. CONCLUSION: 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. CLINICAL RELEVANCE: Patients with PFP might benefit from strengthening of the hip muscles to improve frontal plane lower limb and trunk kinematics during functional tasks.

Effects of functional stabilization training on pain, function, and lower extremity biomechanics in women with patellofemoral pain: a randomized clinical trial.

STUDY DESIGN: Randomized clinical trial. OBJECTIVES: To compare the effects of functional stabilization training (FST) versus standard training on knee pain and function, lower-limb and trunk kinematics, trunk muscle endurance, and eccentric hip and knee muscle strength in women with patellofemoral pain. BACKGROUND: A combination of hip- and knee-strengthening exercise may be more beneficial than quadriceps strengthening alone to improve pain and function in individuals with patellofemoral pain. However, there is limited evidence of the effectiveness of these exercise programs on the biomechanics of the lower extremity. METHODS: Thirty-one women were randomized to either the FST group or standard-training group. Patients attended a baseline assessment session, followed by an 8-week intervention, and were reassessed at the end of the intervention and at 3 months after the intervention. Assessment measures were a 10-cm visual analog scale for pain, the Lower Extremity Functional Scale, and the single-leg triple-hop test. A global rating of change scale was used to measure perceived improvement. Kinematics were assessed during the single-leg squat. Outcome measures also included trunk endurance and eccentric hip and knee muscle strength assessment. RESULTS: The patients in the FST group had less pain at the 3-month follow-up and greater global improvement and physical function at the end of the intervention compared to those in the standard-training group. Lesser ipsilateral trunk inclination, pelvis contralateral depression, hip adduction, and knee abduction, along with greater pelvis anteversion and hip flexion movement excursions during the single-leg squat, were only observed in the FST group after the intervention. Only those in the FST group had greater eccentric hip abductor and knee flexor strength, as well as greater endurance of the anterior, posterior, and lateral trunk muscles, after training. CONCLUSION: An intervention program consisting of hip muscle strengthening and lower-limb and trunk movement control exercises was more beneficial in improving pain, physical function, kinematics, and muscle strength compared to a program of quadriceps-strengthening exercises alone.

Effect of plyometric training on lower limb biomechanics in females.

OBJECTIVE: To verify the effects of plyometric training on lower limb kinematics, eccentric hip and knee torques, and functional performance. DESIGN: Cohort study. SETTING: Research laboratory. PARTICIPANTS: Thirty-six females were divided into a training group (TG; n = 18) that carried out the plyometric training for 8 weeks, and a control group (CG; n = 18) that carried out no physical training. INTERVENTIONS: Twenty-four plyometric training sessions during approximately 8 weeks with 3 sessions per week on alternate days. MAIN OUTCOMES MEASURES: Lower limb kinematics (maximum excursion of hip adduction, hip medial rotation, and knee abduction during the single leg squat), eccentric hip (abductor, adductor, medial, and lateral rotator) isokinetic peak torques and knee (flexor and extensor) isokinetic peak torques, and functional performance (triple hop test and the 6-m timed hop test). RESULTS: After 8 weeks, only the TG significantly reduced the values for the maximum excursion of knee abduction (P = 0.01) and hip adduction (P < 0.001). Similarly, only the TG significantly increased the eccentric hip abductor (P < 0.001) and adductor (P = 0.01) torques. Finally, only the TG significantly increased the values in the triple hop test (P < 0.001) and significantly decreased the values in the 6-m timed hop test (P < 0.001) after intervention. CONCLUSION: Plyometric training alters lower limb kinematics and increases eccentric hip torque and functional performance, suggesting the incorporation of these exercises in preventive programs for ACL injuries.

Effects of the use of oral contraceptives on hip and knee kinematics in healthy women during anterior stair descent.

PURPOSE: Our aim was to evaluate the effects of the use of oral contraceptives (OC) on the hip and knee kinematics of healthy women during anterior stair descent. METHODS: Forty volunteers aged from 18 to 26 years were divided into two groups: 1-Group of women who had used OC for at least 3 months prior to evaluation (n = 20) and 2-Group of women who did not use OC (n = 20). The knee flexion/extension and abduction/adduction, hip flexion/extension, abduction/adduction and medial/lateral rotation excursions (degrees) were calculated for the dominant (supporting) limb during anterior stair descent. T tests for independent samples were used to compare the kinematic differences between the groups (α = 0.05). RESULTS: No significant difference was verified between the groups regarding the maximum excursion of knee flexion (n.s.) and abduction (n.s.) or hip flexion (n.s.), adduction (n.s.) and medial rotation (n.s.). When considering the knee flexion at 50°, no significant difference was verified between the groups regarding the excursion of knee abduction (n.s.) or hip flexion (n.s.) adduction (n.s.) and medial/lateral rotation (n.s.). CONCLUSION: These results suggest that the use of OC does not influence the hip and knee kinematics during anterior stair descent. Therefore, the role of this medication as a protective factor against anterior cruciate ligament injuries remains questionable.

Effect of functional stabilization training on lower limb biomechanics in women.

PURPOSE: This study aimed to verify the effects of functional stabilization training on lower limb kinematics, functional performance, and eccentric hip and knee torques. METHODS: Twenty-eight women were divided into a training group (TG; n = 14), which carried out the functional stabilization training during 8 wk, and a control group (CG; n = 14), which carried out no physical training. The kinematic assessment of the lower limb was performed during a single-leg squat, and the functional performance was evaluated by way of the single-leg triple hop and the timed 6-m single-leg hop tests. The eccentric hip abductor, adductor, lateral rotator, medial rotator, and the knee flexor and extensor torques were measured using an isokinetic dynamometer. RESULTS: After 8 wk, the TG significantly reduced the values for knee abduction (from -6.86° to 1.49°), pelvis depression (from -10.21° to -7.86°) and femur adduction (from 7.08° to 5.19°) as well as increasing the excursion of femur lateral rotation (from -0.55° to -3.67°). Similarly, the TG significantly increased the values of single-leg triple hop (from 3.52 to 3.92 m) and significantly decreased the values of timed 6-m single-leg hop tests (from 2.43 to 2.14 s). Finally, the TG significantly increased the eccentric hip abductor (from 1.31 to 1.45 N · m · kg(-1)), hip lateral rotator (from 0.75 to 0.91 N · m · kg(-1)), hip medial rotator (from 1.45 to 1.66 N · m · kg(-1)), knee flexor (from 1.43 to 1.55 N · m · kg(-1)), and knee extensor (from 3.46 to 4.40 N · m · kg(-1)) torques. CONCLUSIONS: Strengthening of the hip abductor and lateral rotator muscles associated with functional training improves dynamic lower limb alignment and increases the strength and functional performance.

Relationships between eccentric hip isokinetic torque and functional performance.

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

Relationship between eccentric hip torque and lower-limb kinematics: gender differences.

The purposes of this study were to compare lower-limb kinematics between genders, and determine the relationships among eccentric hip abductor and lateral rotator torques and lower-limb kinematics. The movements of the pelvis, femur, and knee were calculated for 16 women and 16 men during the single-leg squat. Eccentric hip abductor and lateral rotator torques were measured using an isokinetic dynamometer. The results showed that women had greater contralateral pelvic depression, femur adduction, and knee abduction than men. The eccentric hip abductor and lateral rotator torques were correlated with coronal plane femur and knee movements in the overall sample. When the genders were analyzed separately, it was observed that women with greater eccentric hip abductor torque exhibited less femur adduction and femur medial rotation, and greater knee adduction excursion. No significant relationship was observed between the isokinetic and kinematic variables in the male group. The differences between the genders help to explain the greater rate of knee disorders observed in women. Moreover, the eccentric hip abduction action seemed to be more important in women to control the lower-limb movements.

Relationship among eccentric hip and knee torques, symptom severity and functional capacity in females with patellofemoral pain syndrome.

OBJECTIVE: To determine the relationships between eccentric hip and knee torques, symptom severity and functional capacity in females with patellofemoral pain syndrome (PFPS). DESIGN: Within-subject correlational study. SETTING: University biomechanics laboratory. PARTICIPANTS: 10 females diagnosed with PFPS. MAIN OUTCOME MEASURES: 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. RESULTS: 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). CONCLUSIONS: 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.

Diferenças biomecânicas entre os gêneros e sua importância nas lesões do joelho / Biomechanics differences between genders and its role in the knee injuries

Diversas pesquisas têm sido realizadas para determinar os fatores biomecânicos responsáveis pela maior incidência da síndrome da dor femoropatelar e das lesões do ligamento cruzado anterior em mulheres quando comparadas aos homens. Objetivo: O objetivo deste estudo foi realizar uma revisão de literatura não sistemática das diferenças biomecânicas entre os gêneros, especialmente aquelas referentes à articulação do quadril, potencialmente responsáveis pela maior incidência de lesões no joelho em mulheres,bem como verificar as suas implicações na elaboração de intervenções preventivas. Metodologia: Artigos publicados entre 1985 e 2008 foram selecionados por dois revisores independentes nas seguintes bases de dados: LILACS, MEDLINE, Cochrane e PubMed. Foram selecionados estudos teóricos, transversais e de correlação, assim como ensaios clínicos controlados, com desenhos experimentais bem esclarecidos. Resultados e discussão: Os estudos selecionados revelaram que as mulheres realizam atividades funcionais com menores ângulos de flexão de joelho e quadril, assim como maior valgo dinâmico do joelho, adução e rotação medial do quadril. Sugere-se, ainda, que as diferenças observadas nos planos coronal e transversal do quadril são mais significativas para a instalação de lesões nas mulheres do que aquelas que ocorrem unicamente no plano sagital. Por fim, as pesquisas demonstram que o treino neuromuscular melhora o alinhamento dinâmico do membro inferior nas mulheres, diminuindo a incidência de lesões no joelho. Conclusão: Há evidências de que as mulheres apresentam diferenças biomecânicas do padrão demovimento do membro inferior, quando comparadas aos homens, que podem contribuir para as maiores incidências de lesões no joelho observadas nesse gênero.

INTRODUCTION: Several studies have been carried out to determine the biomechanical factors responsible by the greater incidence of patellofemoral pain syndrome and anterior cruciate ligament injury in women, when compared to men. OBJECTIVE: The aim of this study was to perform a non-systematic review of the literature of the biomechanical differences between genders, especially those concerning to the hip joint, related to the higher incidence of knee injuries in women, and verify its implications for developing preventive strategies.METHODOLOGY: Articles published between 1985 and 2008 were selected by two independent reviewers of the follow data bases: LILACS, MEDLINE, Cocharane and PubMed. It was selected theoretical, transversal, and correlational studies as well as controlled clinical trial with experimental designs well defined. RESULTS AND DISCUSSION: The studies selected showed that women perform functional activities with lower angles of knee and hip flexion, as well as greater knee valgus, hip adduction and medial rotation. Furthermore, it is believed that the differences shown in the coronal and transverse planes of the hip are more significant for the development of injuries in women than those occurred only in the sagittal plane. Finally, the studies show that neuromuscular training carried out preventively improves the dynamic alignment of the lower limb in women, reducing the incidence of knee injuries on them. CONCLUSION: There are evidences that women have biomechanics differences of the lower limb movement pattern when compared to men that may contribute for the greater incidence of knee injuries observed in women.

Eccentric hip muscle function in females with and without patellofemoral pain syndrome.

CONTEXT: Patellofemoral pain syndrome (PFPS) is a common knee condition in athletes. Recently, researchers have indicated that factors proximal to the knee, including hip muscle weakness and motor control impairment, contribute to the development of PFPS. However, no investigators have evaluated eccentric hip muscle function in people with PFPS. OBJECTIVE: To compare the eccentric hip muscle function between females with PFPS and a female control group. DESIGN: Cross-sectional study. SETTING: Musculoskeletal laboratory. PATIENTS OR OTHER PARTICIPANTS: two groups of females were studied: a group with PFPS (n = 10) and a group with no history of lower extremity injury or surgery (n = 10). INTERVENTION(S): Eccentric torque of the hip musculature was evaluated on an isokinetic dynamometer. MAIN OUTCOME MEASURE(S): Eccentric hip abduction, adduction, and external and internal rotation peak torque were measured and expressed as a percentage of body mass (Nm/kg x 100). We also evaluated eccentric hip adduction to abduction and internal to external rotation torque ratios. The peak torque value of 5 maximal eccentric contractions was used for calculation. Two-tailed, independent-samples t tests were used to compare torque results between groups. RESULTS: Participants with PFPS exhibited much lower eccentric hip abduction (t(18) = -2.917, P = .008) and adduction (t(18) = -2.764, P = .009) peak torque values than did their healthy counterparts. No differences in eccentric hip external (t(18) = 0.45, P = .96) or internal (t(18) = -0.742, P = .47) rotation peak torque values were detected between the groups. The eccentric hip adduction to abduction torque ratio was much higher in the PFPS group than in the control group (t(18) = 2.113, P = .04), but we found no difference in the eccentric hip internal to external rotation torque ratios between the 2 groups (t(18) = -0.932, P = .36). CONCLUSIONS: Participants with PFPS demonstrated lower eccentric hip abduction and adduction peak torque and higher eccentric adduction to abduction torque ratios when compared with control participants. Thus, clinicians should consider eccentric hip abduction strengthening exercises when developing rehabilitation programs for females with PFPS.

The effect of additional strengthening of hip abductor and lateral rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot study.

OBJECTIVES: To study the effect of additional strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise rehabilitation programme for patients with the patellofemoral pain syndrome. DESIGN: Randomized controlled pilot trial. SETTING: Clinical setting with home programme. PARTICIPANTS: Fourteen patients with patellofemoral pain syndrome. INTERVENTION: The subjects were randomly assigned to the intervention group (strengthening of quadriceps plus strengthening of hip abductor and lateral rotator muscles) or to the control group (strengthening of quadriceps). Both groups participated in a six-week home exercise protocol. MAIN OUTCOME MEASURES: The perceived pain symptoms, isokinetic eccentric knee extensor, hip abductor and lateral rotator torques and the gluteus medius electromyographic activity were assessed before and after treatment. Parametric and non-parametric tests were used to compare the groups before and after treatment with alpha=0.05. RESULTS: Only the intervention group improved perceived pain symptoms during functional activities (P=0.02-0.04) and also increased their gluteus medius electromyographic activity during isometric voluntary contraction (P=0.03). Eccentric knee extensors torque increased in both groups (P=0.04 and P=0.02). There was no statistically significant difference in the hip muscles torque in either group. CONCLUSION: Supplementation of strengthening of hip abductor and lateral rotator muscles in a strengthening quadriceps exercise programme provided additional benefits with respect to the perceived pain symptoms during functional activities in patients with patellofemoral pain syndrome after six weeks of treatment.

A abordagem funcional dos músculos do quadril no tratamento da síndrome da dor femoro-patelar / Hip muscle's functional approach in the of patellofemoral pain syndrome treatment

A Síndrome da dor femoro-patelar(SDFP) é uma das afecções mais comuns da articulação do joelho. Recentemente, tem-se dado atenção ao fortalecimento e treino funcional da musculatura do quadril no tratamento da SDFP. O objetivo desta revisão foi discutir a função dos músculos do quadril na manifestação e no tratamento da SDFP. Foram encontradas evidências de alterações na função dos músculos abdutores e rotadores laterais do quadril em indivíduos com SDFP quando comparados a indivíduos saudáveis. Os estudos de tratamento da SDFP encontrados, com ênfase na musculkatura do quadril, demonstraram sucesso no tratamento. Assim, a fraqueza e o retardo no tempo de ativação da musculatura do quadril parecem contribuir para a manifestação da SDFP e devem ser consideradas na avaliação e tratamento dos pacientes portadores da SDFP. Estudos com melhor qualidade metodológica são necessários para definir qual a melhor abordagem de tratamento para a melhora funcional e da sintomatologia dolorosa nos pacientes com estas alterações.