Knee muscle forces during walking and running in patellofemoral pain patients and pain-free controls (original) (raw)
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Journal of Athletic Training
Context: Patellofemoral pain (PFP) is typically exacerbated by repetitive activities that load the patellofemoral joint, such as running. Understanding the mediating effects of changes in pain in individuals with PFP might inform injury progression, rehabilitation, or both. Objective: To investigate the effects of changing pain on muscular strength and running biomechanics in those with PFP. Design: Crossover study. Setting: University research laboratory. Patients or Other Participants: Seventeen participants (10 men, 7 women) with PFP. Intervention(s): Each participant completed knee pain-reducing and pain-inducing protocols in random order. The pain-reducing protocol consisted of 15 minutes of transcutaneous electric nerve stimulation (TENS) around the patella. The pain-inducing protocol was sets of 20 repeated single-legged squats (RSLS). Participants completed RSLS sets until either their pain was within at least 1 cm of their pain during an exhaustive run or they reached...
The purpose of this study was to determine if persons with patellofemoral pain (PFP) exhibit differences in patellofemoral joint reaction forces (PFJRFs) during functional activities. Forty females (20 PFP, 20 controls) underwent two phases of data collection: (1) magnetic resonance imaging (MRI) and (2) biomechanical analysis during walking, running, stair ascent, and stair descent. A previously described three-dimensional model was used to estimate PFJRFs. Resultant PFJRFs and the orthogonal components were reported. The PFP group demonstrated lower peak resultant PFJRFs and posterior component and superior component of the PFJRFs compared with the control group across all conditions. However, the PFP group had a higher peak lateral component of the PFJRF in three out of the four conditions evaluated. The lower resultant PFJRFs suggested that individuals with PFP may employ strategies to minimize patellofemoral joint loading, but it did not result in diminished lateral forces acting on the patella. Patellofemoral pain (PFP) is one of the most common conditions affecting the lower extremity. 1-3 Despite its high incidence, however, the pathomechanics underlying this disorder remains uncertain. A commonly cited theory states that PFP is the result of elevated patellofemoral joint reaction forces (PFJRFs), which contribute to excessive joint stress and articular cartilage pathology. 4 Studies comparing joint reaction forces between persons with PFP and pain-free controls are few and have reported inconsistent results. For example, Heino Brechter and Powers reported a 22% reduction in peak PFJRF in females with PFP compared with a control group during walking; however, no significant group differences were found during fast walking. 5 In a separate study, the same authors reported a 32% reduction in peak PFJRFs in a group of individuals with PFP during stair ascent when compared with a control group, but no significant group differences were found during stair descent. 6 In both studies, Heino Brechter and Powers 5 and Brechter and Powers 6 attributed the lower PFJRFs in their PFP group to lower knee extensor moments and smaller knee joint excursions during the stance phase of gait. It was proposed that persons with PFP may have been employing compensatory strategies to minimize PFJRFs and subsequent pain. This premise is supported by the work of Salsich et al, 7 who reported that subjects with PFP demonstrated reduced peak knee extensor moments during both stair ascent and descent. Although previous authors have reported decreased PFJRFs in persons with PFP, these studies have been limited by two-dimensional modeling approaches. As the magnitude of the medial/lateral component of the PFJRF has been implicated in this disorder, it would appear that a more physiologic representation of the patello-femoral joint is needed to determine whether joint forces are altered in the PFP population. In a previous publication, we described a subject-specific, three-dimensional (3D) model to assess PFJRFs. 8 This model incorporates subject-specific anatomical parameters (as obtained through MRI) and lower extremity biomechanics to estimate patellofemoral joint loading during dynamic activities. The purpose of the current study was to determine if persons with PFP demonstrate differences in PFJRFs compared with pain-free controls during walking, running, stair ascent, and stair descent. Based on the above noted limitations of previous work in this area, as well as the long-standing belief that PFP is the result of excessive joint loading, we hypothesized that persons with PFP would demonstrate greater resultant PFJRFs, as well as greater components of the PFJRF (ie, greater anterior/posterior, superior/inferior, and medial/lateral forces). Methods Subjects A total of 40 subjects were recruited for this study. Twenty females between the ages of 18 and 45 with PFP constituted the experimental group while 20 age and size-matched (height and weight) pain-free females served as a control group (Table 1). The determination of sample size was based on a prior sample size calculation using the patellofemoral joint reaction force data reported by Heino Brechter and Powers 5 and Brechter and Powers. 6 Based on this analysis it was estimated that a sample size of 40 would achieve 80% power to detect group differences across the varied conditions evaluated (using an alpha level of .05 and an effect size of 0.5).
Applied Sciences, 2022
Patellofemoral pain (PFP) is a common atraumatic knee pathology in runners, with a complex multifactorial aetiology influenced by sex differences. This retrospective case–control study therefore aimed to evaluate lower limb kinetics and kinematics in symptomatic and control male and female runners using musculoskeletal simulation. Lower extremity biomechanics were assessed in 40 runners with PFP (15 females and 25 males) and 40 controls (15 females and 25 males), whilst running at a self-selected velocity. Lower extremity biomechanics were explored using a musculoskeletal simulation approach. Four intergroup comparisons—(1) overall PFP vs. control; (2) male PFP vs. male control; (3) female PFP vs. female control; and (4) male PFP vs. female PFP—were undertaken using linear mixed models. The overall (stress per mile: PFP = 1047.49 and control = 812.93) and female (peak stress: PFP = 13.07 KPa/BW and control = 10.82 KPa/BW) comparisons showed increased patellofemoral joint stress indi...
2019
Background: Impaired lower extremity kinematics has beenconsidered as a contributing factor to patellofemoral pain (PFP). However, current knowledge about the correlation between lower extremity kinematics and muscle strength is very limited. This study investigated the correlation between lower extremity kinematics and muscle strength, pain, physical activity level, as well as functional status in females with PFP. Methods: Seventy-five females with PFP participated in this analytical cross-sectional study. Lower extremity kinematics, maximal isometric strength of muscles, pain severity, physical activity level, as well as subjective and objective function were assessed using a motion analysis system, a dynamometer, Visual Analog Scale, the International Physical Activity questionnaire, and the Kujala questionnaire and the step-down test, respectively. The hip and knee kinematics were determined during the initial contact and the initial phase of landing. Pearson's correlation...
Effect of patellofemoral pain on strength and mechanics following an exhaustive run
Purpose: To investigate the effects of an exhaustive run on trunk and lower extremity strength and mechanics in patients with and without patellofemoral pain (PFP), we hypothesized that strength would decrease and mechanics would change after the exhaustive run. Methods: Nineteen subjects with PFP and 19 controls participated (10 men and 9 women per group). Lower extremity and trunk mechanics during running, body mass-normalized strength, and pain assessments before and after an exhaustive run were quantified. A repeated-measures ANOVA was used to assess group differences and exhaustion-related changes (P G 0.05), with t-test post hoc analyses performed when significant interactions were identified (P G 0.0125). Results: Pain significantly increased with the exhaustive run in the PFP group (P = 0.021). Hip strength was reduced after the exhaustive run, more so in those with PFP (abduction: before = 0.384 T 0.08, after = 0.314 T 0.08, P G 0.001; external rotation: before = 0.113 T 0.02, after = 0.090 T 0.02, P G 0.001). Persons with PFP also demonstrated increased knee flexion (before = 41.6-T 5.5-, after = 46.9-T 7.5-, P G 0.001), hip flexion (before = 30.4-T 6.8-, after = 42.5-T 9.7-, P G 0.001), and anterior pelvic tilt (before = 7.2-T 5.1-, after = 13.3-T 6.7-, P = 0.001) after the exhaustive run compared to controls. Trunk flexion increased in both PFP (before = 13.09-T 6.2-, after = 16.31-T 5.3-, P G 0.001) and control (before = 1393-T 4.7-, after = 15.99-T 5.9-, P G 0.001) groups. Hip extension (before = j2.09 T 0.49 NImIkg j1 , after = j2.49 T 0.54 NImIkg j1 , P = 0.002) moments increased only in subjects with PFP. Conclusions: Exhaustive running results in reduced hip strength in subjects with PFP; however, this did not result in changes to hip internal rotation or adduction kinematics. Kinematic and kinetic changes after the exhaustive run are more indicative of compensatory changes to reduce pain. Increasing trunk flexion during running might provide pain relief during running; however, reducing anterior pelvic tilt may also warrant attention during treatment.
Physical Therapy in Sport, 2018
Objectives: To explore feasibility of recruitment and retention of runners with patellofemoral pain (PFP), before delivering a step rate intervention. Design: Feasibility study Setting: Human performance laboratory Participants: A mixed-sex sample of runners with PFP (n=11). Main Outcome Measures: Average/worst pain and the Kujala Scale were recorded pre/post intervention, alongside lower limb kinematics and surface electromyography (sEMG), sampled during a 3KM treadmill run. Results: Recruitment and retention of a mixed-sex cohort was successful, losing one participant to public healthcare and with kinematic and sEMG data lost from single participants only. Clinically meaningful reductions in average (MD=2.1, d=1.7) and worst pain (MD=3.9, d=2.0) were observed. Reductions in both peak knee flexion (MD=3.7˚, d=0.78) and peak hip internal rotation (MD=5.1˚, d=0.96) were observed, which may provide some mechanistic explanation for the identified effects. An increase in both mean amplitude (d=0.53) and integral (d=0.58) were observed for the Vastus Medialis Obliqus (VMO) muscle only, of questionable clinical relevance. Conclusions: Recruitment and retention of a mixed sex PFP cohort to a step rate intervention involving detailed biomechanical measures is feasible. There are indications of both likely efficacy and associated mechanisms. Future studies comparing the efficacy of different running retraining approaches are warranted.
The Knee, 2019
Beside pathophysiological factors, pain is believed to play a crucial role in the progression of patellofemoral pain (PFP). However, the isolated effect of pain on biomechanics and quadriceps function has not been investigated in PFP. Thus, this study aimed to investigate the effect of pain on quadriceps function and lower limb biomechanics in individuals with PFP. Methods Twenty-one individuals with PFP (11 males and 10 females, age: 29.76 ±6.36 years, height: 1.74 ± 0.09m, mass: 70.12 ±8.56kg) were measured at two different occasions: when not and when experiencing acute pain. Peak quadriceps torque (concentric, eccentric and isometric) and arthrogenic muscle inhibition (AMI) was assessed. Three-dimensional motion analysis and surface electromyography of the quadriceps and hamstrings muscles were collected during running, a single-leg-squat and step-down task. The normality was assessed using the Shapiro-Wilk test and a MANOVA was performed at the 95% confidence interval. Results AMI increased significantly in acute pain. The net muscle activation of the knee extensors and flexors decreased during running in acute pain. The lower limb biomechanics and the quadriceps torque did not change in acute pain. Discussion: It appears that even if individuals with PFP experience pain they can still deliver maximal quadriceps contractions and maintain their moving patterns without biomechanical changes. However, the overall reduced activation of the quadriceps and the increased AMI indicate the presence of quadriceps inhibition in acute pain.
Gait study of patients with patellofemoral pain syndrome
Gait & Posture, 1997
Patellofemoral pain syndrome is a frequent knee impairment in young adults. This study investigated the kinematic and kinetic gait patterns of individuals suffering from patellofemoral pain syndrome (PFPS). It was hypothesized that PFPS subjects modify their gait pattern in order to reduce loading on the painful patellofemoral joint. To verify this, the gait pattern of five subjects with right chronic PFPS was compared with that of five healthy subjects. Spatiotemporal, kinematic and kinetic data were collected from five gait cycles. The joint moments at the hip, knee and ankle joints were calculated using an inverse dynamic approach and the values were normalized to body weight (N-m/kg). Individual joint moments were expressed as a percentage of the support moment in order to quantify possible compensatory strategies. The kinematic analysis revealed a significant reduction of the knee flexion angle (ANOVAs, P < 0.01) occurring at lO%, 20% and 70% of the gait cycle. There were no significant differences between the two groups of subjects (ANOVAs, P > 0.05) as far as the individual joint moments and their contribution to the support moment were concerned. However, modifications were observed in the knee and hip moments between loo/o and 20% of the gait cycle. These modifications may suggest that PFPS subjects alter their gait pattern in order to reduce loading of the patellofemoral joint to avoid pain.
2016
Patellofemoral Pain Syndrome (PFPS) is one of the most common influential disorders on individual's lower limb. A change in kinetics and kinematics of lower limb, structural disorders of lower limb, paresis, the decrease of strength and dynamic malalignment are the risk factors of PFPS. The risk factors playing a role in PFPS development are as follow: kinematic and kinetic changes during functional activities and the decrease of strength and flexibility of knee and thigh joints. Therefore, the goal of the current research is to investigate the influence of 6-week static stretching of quadriceps on pain and kinematics of lower limb during running in individuals with Patellofemoral Pain Syndrome. For this aim, 27 individuals with PFPS in two experimental (age 22/86 ± 2/31, year and BMI 24/89 ± 2/25) and control groups (age 23/38 ± 1/44, year and BMI 23/42 ± 2/94) and also 11 healthy individuals (age 24/27 ± 1/73, year and BMI 24/69 ± 1/74) have been chosen from the volunteers fo...