Patellofemoral Kinetics Research Articles

Influence of cross-fit footwear on patellofemoral kinetics during running activities

The aim of this work was to examine the effects of barefoot, cross-fit, minimalist and conventional footwear on patellofemoral loading during running. Twelve cross-fit athletes ran at 4.0 m/s in each of the four footwear conditions. Lower limb kinematics were collected using an 8 camera motion analysis system and patellofemoral loading was estimated using a mathematical modelling approach. Differences between footwear were examined using one-way repeated measures ANOVA. The results showed the peak patellofemoral force and stress were significantly reduced when running barefoot (force = 3.42 BW & stress = 10.71 MPa) and in minimalist footwear (force = 3.73 BW & stress = 11.64 MPa) compared to conventional (force = 4.12 BW & stress = 12.69 MPa) and cross-fit (force = 3.97 BW & stress = 12.30 MPa) footwear. In addition, the findings also showed that patellofemoral impulse was significantly reduced when running barefoot (0.35 BW·s) and in minimalist footwear (0.36 BW·s) compared to conventional (0.42 BW·s) and cross-fit (0.38 BW·s) footwear. Given the proposed association between patellofemoral loading and patellofemoral disorders, the outcomes from the current investigation suggest that cross-fit athletes who select barefoot and minimalist footwear for their running activities may be at reduced risk from patellofemoral joint pathology in comparison to conventional and cross-fit footwear conditions.

Effects of semi-custom and off-the-shelf orthoses on Achilles tendon and patellofemoral kinetics in female runners

Background The aim of the current investigation was to examine the effects of semi-custom and off-the-shelf orthotics on the loads experienced by the patellofemoral joint and the Achilles tendon in female runners. Material/Methods Twelve female recreational runners ran at 4.0 m.s 1 whilst wearing no orthotics, semi-custom orthotics and off-the-shelf orthotics. Kinetics and kinematics of running were obtained via a force platform and a motion capture system. Differences between orthotic conditions were contrasted using one-way repeated measures ANOVA. Results The results showed that both patellofemoral contact force and pressure were significantly lower in the no-orthotic (force = 3.21 B.W & pressure = 8.18 MPa) condition in comparison to the off-the-shelf (force = 3.60 MPa & pressure = 9.07 B.W) and semi-custom orthoses (force = 3.69 B.W & pressure = 9.30 MPa). Conclusions The current investigation indicates that foot orthoses such as those examined in the current investigation may place female runners at increased risk from patellofemoral disorders, although future prospective research is required before this can be substantiated.

Relationship of the Frontal Knee Alignment Measured by the HKA-Angle with the Relative Activation of the Quadriceps Muscles

Purpose: The purpose of this study was to compare Hip-Knee-Ankle(HKA) angle and muscle activation ratio between vastus medialis(VM), rectus femoris(RF), and vastus lateralis (VL), and by this, to examine their relationship. It is aimed to explore how the activation ratio among the muscles involved in patellofemoral kinetics would vary in relation with the frontal alignment of the lower extremity. Subjects and Methods: 26 healthy subjects were recruited for the study. The HKA angles were measured with radiograph. The VM, RF, VL muscle activation level were measured by surface electromyography while each participant performed 4 different types of movement (isometric knee extension, squat, ambulation, step-up) and VM/RF, VM/VL, RF/VL ratios were calculated. Pearson correlation was used to estimate the relationship between the HKA angle and the muscle ratio. Results: There was significant moderate correlation between HKA angle and VM: RF on the left side during ambulation (p<0.05). Moderate correlations were also observed during step-up and squat with less significance (p<0.1). Conclusion: The frontal alignment of the knee measured by the HKA angle was conditionally associated with muscle activation ratio between VM and RF (VM:RF); On the left, during ambulation, step-up, and squat, the more valgus knee tended to correlate with the more VM muscle activation ratio, which is expected to induce more stabilizing effect to the patella and its tracking. It suggests that the frontal alignement measured by the HKA-angle can affect PF kinetics. It also indicates a possibility that increase in valgus alignment of the knee, by the HKA measurement, may not act unfavorably to generate PFP.

Trunk and Shank Position Influences Patellofemoral Joint Stress in the Lead and Trail Limbs During the Forward Lunge Exercise.

Study Design Controlled laboratory study, repeated-measures design. Background The effects of trunk and shank position on patellofemoral joint stress of the lead limb have been well studied; however, the effects on the trail limb are not well understood. Objectives To test the hypothesis that trunk and shank position may influence patellofemoral joint stress in both limbs during the forward lunge exercise. Methods Patellofemoral kinetics were quantified from 18 healthy participants performing the lunge exercise with different combinations of trunk and shank positions (vertical or forward). A 2-by-3 (limb-by-lunge variation) repeated-measures analysis of variance was performed, using paired t tests for post hoc comparisons. Results The trail limb experienced greater total patellofemoral joint stress relative to the lead limb, regardless of trunk and shank position (P<.0001). The lunge variation with a vertical shank position resulted in significantly greater peak patellofemoral joint stress in the trail limb relative to the lead limb (P<.0001). A forward trunk and shank position resulted in the highest patellofemoral stress in the lead limb (P<.0001). Conclusion Trunk and shank positions have a significant influence on patellofemoral joint loading of both limbs during the forward lunge, with the trail limb generally experiencing greater total joint stress. Restricting forward translation of the lead-limb shank may reduce patellofemoral joint stress at the expense of increased stress in the trail limb. Technique recommendations should consider the demands imposed on both knees during this exercise. J Orthop Sports Phys Ther 2017;47(1):31-40. Epub 4 Nov 2016. doi:10.2519/jospt.2017.6336.

INFLUENCE OF RUN AND CUT MANOEUVRES ON PATELLOFEMORAL KINETICS AND KINEMATICS

Patellofemoral pain syndrome is the most common knee pathology. Those with patellofemoral pain are much more likely to be physically active than age-matched controls. The prevalence of patellofemoral pain in...

Effects of a 10 week footstrike transition in habitual rearfoot runners with patellofemoral pain

Patellofemoral pain is the most common pathology in runners. Mid/fore foot runners experience lower patellofemoral loading compared to those who use a rearfoot strike. The aim of this study was to examine the efficacy of a 10-week intervention allowing runners with patellofemoral pain to transition from a rearfoot strike pattern. Nine male runners with patellofemoral pain were given a graduated 10-week program which allowed them to convert their habitual rearfoot strike pattern. Lower extremity kinematics, tibial accelerations, loading rates, patellofemoral kinetics and Achilles tendon kinetics were collected. Self-reported knee and Achilles tendon pain were examined using the Knee injury and Osteoarthritis Outcome Score and numeric pain rating scale. Data were collected before and after the 10-week transition. Reductions were found in peak patellofemoral force/pressure (pre-transition = 4.76 body weight (BW) and 13.10 MPa and post-transition = 4.27 BW and 11.48 MPa). Improvements were shown for Knee injury and Osteoarthritis Outcome Score subscales pain (pre-transition = 62.04 and post-transition = 78.41), sport (pre-transition = 53.61 and post-transition = 72.67), function and daily living (pre-transition = 67.68 and post-transition = 80.08). Increases were however found for peak Achilles tendon force (pre-transition = 5.07 BW and post-transition = 5.58 BW) and Achilles tendon pain (pre-transition = 1.06 and post-transition = 2.67). Transitioning from a rearfoot strike pattern reduces patellofemoral loading and pain symptoms. The key implication is that rearfoot strike runners with patellofemoral pain can reduce their pain symptoms by altering their footstrike pattern; although this may be at the expense of increased pain at the Achilles tendon.

Sex differences in lower extremity kinematics and patellofemoral kinetics during running

ABSTRACTThe incidence of patellofemoral pain (PFP) is 2 times greater in females compared with males of similar activity levels; however, the exact reason for this discrepancy remains unclear. Abnormal mechanics of the hip and knee in the sagittal, frontal, and transverse planes have been associated with an increased risk of PFP. The purpose of this study was to compare the mechanics of the lower extremity in males and females during running in order to better understand the reason(s) behind the sex discrepancy in PFP. Three-dimensional kinematic and kinetic data were collected as male and female participants completed overground running trials at a speed of 4.0 m · s−1 (±5%). Patellofemoral joint stress (PFJS) was estimated using a sagittal plane knee model. The kinematics of the hip and knee in the frontal and transverse planes were also analysed. Male participants demonstrated significantly greater sagittal plane peak PFJS in comparison with the female participants (P < .001, ES = 1.9). However, the female participants demonstrated 3.5° greater peak hip adduction and 3.4° greater peak hip internal rotation (IR). As a result, it appears that the sex discrepancy in PFP is more likely to be related to differences in the kinematics of the hip in the frontal and transverse planes than differences in sagittal plane PFJS.

Patellofemoral kinetics during running in heelless and conventional running shoes

Recreational running is a popular recreational activity often used to improve health and well-being of the participants. Sustaining injuries that stop people from running can therefore be detrimental. One of the most prevalent overuse injuries in recreational running populations (Chang et al., 2012; Ellapen et al., 2013) has been reported as patellofemoral pain which is a result of the pressure experienced between the posterior surface of the patella and the anterior distal aspect of the femur. Footwear designers have attempted to develop shoes to reduce rate of injuries in populations. One such design is a heelless shoe that appears to adjust the footstrike pattern of the participant during running (Sinclair et al., 2014). Such adaptation to movement may influence knee joint kinetics and kinematics altering the pressure between the patella and the femur.

Influence of step length and landing pattern on patellofemoral joint kinetics during running.

Elevated patellofemoral joint kinetics during running may contribute to patellofemoral joint symptoms. The purpose of this study was to test for independent effects of foot strike pattern and step length on patellofemoral joint kinetics while running. Effects were tested relative to individual steps and also taking into account the number of steps required to run a kilometer with each step length. Patellofemoral joint reaction force and stress were estimated in 20 participants running at their preferred speed. Participants ran using a forefoot strike and rearfoot strike pattern during three different step length conditions: preferred step length, long (+10%) step length, and short (-10%) step length. Patellofemoral kinetics was estimated using a biomechanical model of the patellofemoral joint that accounted for cocontraction of the knee flexors and extensors. We observed independent effects of foot strike pattern and step length. Patellofemoral joint kinetics per step was 10-13% less during forefoot strike conditions and 15-20% less with a shortened step length. Patellofemoral joint kinetics per kilometer decreased 12-13% using a forefoot strike pattern and 9-12% with a shortened step length. To the extent that patellofemoral joint kinetics contribute to symptoms among runners, these running modifications may be advisable for runners with patellofemoral pain.

Pilot validation study on a quasi-static weight-bearing knee rig

This article presents a pilot study on a quasi-static knee rig designed to investigate the influence of pathologies and surgical interventions on the patellofemoral kinetics of cadaveric knees. The knee rig allows cadaveric knees to flex and extend under a simulated body weight by transmitting a force to the quadriceps tendon. During the squat simulation, the ground reaction force stays within physiological values. Before using this device to answer clinical questions, two knee specimens were tested to assess the repeatability of the rig. Four repeated flexion-extension cycles were performed under a simulated body weight of 700 N, with an isolated force on the quadriceps tendon up to 2700 N and with a ground reaction force close to 350 N. The resulting patellofemoral contact area shifted from distal to proximal during knee flexion. From 20 degrees to 60 degrees of knee flexion, the mean contact area and pressure increased from 80.2 +/- 3.3 to 349.5 +/- 10.1 mm2 and from 0.9 +/- 0.2 to 5.9 +/- 0.7 MPa, respectively. The transmitted force on the quadriceps tendon, the ground reaction force and the patellofemoral contact area and pressure were continuously measured and showed a relative variability of 1.6%, 2.4%, 2.8% and 3.2%, respectively. The presented knee rig shows a good repeatability that allows us to use this knee rig to quantify the influence of anatomical changes on the patellofemoral contact area and pressures during a squat simulation.

Influence of Gender and Leg Dominance on Q-angle Among Young Adult Nigerians

The quadriceps femoris muscle angle (Q-angle) is a known index of knee function and patellofemoral kinetics. This study reports normal values of the Q-angle measured bilaterally in a sample of young adult Nigerians aged 17 - 30 years and the influence of leg dominance and gender on the Q-angle. Four hundred healthy volunteers (200 males and 200 females) with no history of musculoskeletal pathology that could influence the Q-angle participated in the study, using the non-probability sample of convenience. The Q-angle was measured using a universal goniometer with the subject in the erect weight-bearing position. Results showed that in the male subjects, the Q-angles were 12.30 ± 4.0E and 10.38 ± 3.49E for the right and left lower limbs respectively, while in the female subjects, the Q-angles were 17.06 ± 3.64E and 14.84 ± 3.47E for the right and left lower limbs respectively. Analysis revealed a significant contra-lateral difference. Generally, the right Q-angle was significantly higher than the left (p< 0.05) in both the male and female subjects. The females had significantly higher Q-angles than their male counterparts (p< 0.05). Leg dominance did not have a significant influence (p > 0.05), as the right Q-angle was higher than the left in subjects with right leg dominance as well as those with left leg dominance. From these results, the assumption that Q-angles in the right and left limbs are equal is contending, and it is therefore recommended that measures of Q-angles should be documented as either right or left in the clinics as well as in research reports. KEY WORDS: Q-angle, leg dominance, gender influence