Reliability testing of the patellofemoral joint reaction force (PFJRF) measurement during double-legged squatting in healthy subjects: A pilot study

Effects of Knee Flexion Angles on the Joint Force and Muscle Force during Bridging Exercise: A Musculoskeletal Model Simulation

Bridging exercise is commonly used to increase the strength of the hip extensor and trunk muscles in physical therapy practice. However, the effect of lower limb positioning on the joint and muscle forces during the bridging exercise has not been analyzed. The purpose of this study was to use a musculoskeletal model simulation to examine joint and muscle forces during bridging at three different knee joint angle positions. Fifteen healthy young males (average age: 23.5 ± 2.2 years) participated in this study. Muscle and joint forces of the lumbar spine and hip joint during the bridging exercise were estimated at knee flexion angles of 60°, 90°, and 120° utilizing motion capture data. The lumbar joint force and erector spinae muscle force decreased significantly as the angle of the knee joint increased. The resultant joint forces were 200.0 ± 23.2% of body weight (%BW), 174.6 ± 18.6% BW, and 150.5 ± 15.8% BW at 60°, 90°, and 120° knee flexion angles, respectively. On the other hand, the hip joint force, muscle force of the gluteus maxims, and adductor magnus tended to increase as the angle of the knee joint increased. The resultant joint forces were 274.4 ± 63.7% BW, 303.9 ± 85.8% BW, and 341.1 ± 85.7% BW at a knee flexion angle of 60°, 90°, and 120°, respectively. The muscle force of the biceps femoris decreased significantly with increased knee flexion during the bridging exercise. In conclusion, the knee flexion position during bridging exercise has different effects on the joint and muscle forces around the hip joint and lumbar spine. These findings would help clinicians prescribe an effective bridging exercise that includes optimal lower limb positioning for patients who require training of back and hip extensor muscles.

The effect of quadriceps kinesiotaping on the dynamic balance of young healthy women after fatigue: A randomized controlled trial

BACKGROUND

Balance is a key factor in performing daily activities and the quadriceps muscle plays an important role in regaining balance following imbalance. Quadriceps fatigue may cause disruption in sending proprioception signals to the central nervous system and may, ultimately, lead to motor dysfunction and increased fluctuating dynamic and static balance which is followed by an increased risk of falling. Based on conclusions from previous studies it is proposed that kinesiotaping (KT) might be effective in the reduction of muscle fatigue and eventually balance.

OBJECTIVE

To investigate the effect of quadriceps KT on the dynamic balance of young healthy non-athlete women following local fatigue.

DESIGN

A Single-blind parallel randomized clinical trial.

METHOD

28 healthy women aged from 18 to 30 years were selected using the convenience sampling method. They were thoroughly evaluated with regard to the inclusion and exclusion criteria and randomly divided into two groups of kinesiotaping (n = 14) and non-tape (n = 14) using coin tossing. Balance measurement was performed on both groups before and after fatigue using the Y balance test. Both groups performed the fatigue protocol, but only the KT group was taped.

RESULTS

Results demonstrated that, the mean of normalized reach distances at anterior (KT: 1.014 ± 0.073, non-tape: 0.964 ± 0.097), posteromedial (KT: 0.816 ± 0.125, non-tape: 0.809 ± 0.076) and posterolateral (KT: 0.794 ± 0.102, non-tape: 0.753 ± 0.093) directions in the Y balance test had no significant difference between both groups after fatigue (p > 0.05).

CONCLUSION

Our findings indicated no significant effect of quadriceps KT on the dynamic balance of young healthy women after fatigue.

Methods to assess patellofemoral joint stress: A systematic review

Changes in patellofemoral joint (PFJ) stress are related to the development and course of PFJ dysfunctions. Different methods for PFJ stress calculation have been used, making the comparison of PFJ stress values across different studies difficult. The purpose of this study was to systematically review the methods for PFJ stress calculation and highlight the differences among the methods. A systematic literature search was conducted in Medline, Embase, CINAHL, SPORTDiscus and Web of Science databases. Included studies examined PFJ stress in subjects with or without musculoskeletal conditions. Of 12,670 identified studies, 53 were included, with a total of 1134 subjects evaluated. The main differences among the methods to calculate PFJ stress were: i) method to calculate PFJ contact area; ii) method to calculate a constant (coefficient k) that defines the relation between quadriceps force and PFJ reaction force; iii) the inclusion of adjustments for sagittal plane forces. Considerable variability in PFJ stress results was observed. The greatest PFJ stress value was 55.03 MPa during a dance jump and the lowest value was 1.9 MPa during walking at the speed of 1.4 m/s. Most studies applied methods which use data from previous studies. However, methods which use data from their own participants for most parts of the calculation might be preferred to minimize potential errors. When direct measures are not possible, a standard method could be applied to facilitate comparisons among studies.

Kinematic and Kinetic Analysis of the Single-Leg Triple Hop Test in Women With and Without Patellofemoral Pain

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To compare the biomechanical strategies of the trunk and lower extremity during the transition period between the first and second hop of a single-leg triple hop test in women with and without patellofemoral pain (PFP).

BACKGROUND

Recent literature has shown that PFP is associated with biomechanical impairments of the lower extremities. A number of studies have analyzed the position of the trunk and lower extremities for functional activities such as walking, squatting, jumping, and the step-down test. However, studies on more challenging activities, such as the single-leg triple hop test, may be more representative of sports requiring jumping movements.

METHODS

Women between 18 and 35 years of age (control group, n = 20; PFP group, n = 20) participated in the study. Three-dimensional kinematic and kinetic data were collected during the transition period between the first and second hops while participants performed the single-leg triple hop test.

RESULTS

Compared to the control group, women with PFP exhibited greater (P<.05) anterior and ipsilateral trunk lean, contralateral pelvic drop, hip internal rotation and adduction, and ankle eversion, while exhibiting less hip and knee flexion. A significant difference (P<.05) in time to peak joint angle was also found between groups for all the variables analyzed, except anterior pelvic tilt and hip flexion. In addition, women with PFP exhibited greater (P<.05) hip and knee abductor internal moments.

CONCLUSION

Compared to the control group, women with PFP exhibited altered trunk, pelvis, hip, knee, and ankle kinematics and kinetics.

The contemporary management of anterior knee pain and patellofemoral instability

In this review the evidence for the management of patients with patellofemoral disorders is presented confined to anterior knee pain and patellar dislocation (excluding patellofemoral arthritis). Patients present along a spectrum of these two problems and are best managed with both problems considered. The key to managing these patients is by improving muscle function, the patient losing weight (if overweight), and judicious use of analgesics if pain is an important feature. Hypermobility syndrome should always be looked for since this is a prognostic indicator for a poor operative outcome. Operations should be reserved for those with correctable anatomical abnormalities that have failed conservative therapy. The current dominant operation is a medial patellofemoral ligament reconstruction.