Impairments in peroneal muscle size and activation in individuals with patellofemoral pain in weight-bearing position.

BACKGROUND: Patellofemoral pain (PFP) is characterized by chronic pain in the anterior aspect of the knee during loading activities. Many studies investigating muscle morphology changes for individuals with PFP focus on the proximal joints, however, few studies have investigated muscles of the foot and ankle complex. This study aimed to explore the differences in peroneal muscle size and activation between individuals with PFP and healthy controls using ultrasound imaging in weight-bearing. METHODS: A case-control study in a university lab setting was conducted. Thirty individuals with PFP (age: 20.23 ± 3.30 years, mass: 74.70 ± 27.63 kgs, height: 161.32 ± 11.72 cm) and 30 healthy individuals (age: 20.33 ± 3.37 years, mass: 64.02 ± 11.00 kgs, height: 169.31 ± 9.30 cm) participated. Cross-sectional area (CSA) images of the peroneal muscles were taken in non-weight bearing and weight-bearing positions. The functional activation ratio from lying to single-leg standing (SLS) was calculated. RESULTS: There was a statistically significant (p = 0.041) group (PFP, healthy) by position (non-weight-bearing, weight-bearing) interaction for the peroneal muscle CSA with a Cohen's d effect size of 0.2 in non-weight-bearing position and 0.7 in weight-bearing position. The functional activation ratio for the healthy group was significantly more (p = 0.01) than the PFP group. CONCLUSION: Peroneal muscles were found to be smaller in size in those with PFP compared to the healthy subjects in the weight-bearing SLS position. This study found that those with PFP have lower activation of peroneal muscles in functional position.

Poor Mental Health Indicators in Individuals With Patellofemoral Pain.

CONTEXT: Patellofemoral pain (PFP) is a common source of knee pain in active individuals, accounting for a large number of knee injuries examined in sports medicine clinics. As a chronic condition, PFP can affect mental health. However, this effect has not yet been studied in individuals with PFP. OBJECTIVE: To determine how subjective physical and mental health measures in individuals with PFP differed from those measures in pain-free individuals. DESIGN: Case-control study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Volunteers for the study were 30 people with PFP (19 women, 11 men; age = 20.23 ± 3.32 years, height = 166.69 ± 6.41 cm, mass = 69.55 ± 13.15 kg) and 30 matched pain-free individuals (19 women, 11 men; age = 20.33 ± 3.37 years, height = 169.31 ± 9.30 cm, mass = 64.02 ± 11.00 kg). MAIN OUTCOME MEASURE(S): Current and worst pain levels in the past 24 hours were determined using a visual analog scale (VAS). The Anterior Knee Pain Scale, Fear Avoidance Belief Questionnaire, and Lower Extremity Functional Scale were administered. Physical and mental health measures were obtained using a modified 12-item Short Form Health Survey. Scores for 2 subscales on the modified Short Form-12 were weighted and calculated: physical component and mental component.Independent t tests were calculated to compare variables between groups. Coefficient correlations were used to measure the associations between the variables. RESULTS: Individuals with PFP reported lower levels of physical (pain free: 56.13 ± 1.63, PFP: 50.54 ± 7.10, P < .001) and mental (pain-free: 53.32 ± 4.71, PFP: 48.64 ± 10.53, P = .03) health. In the PFP group, we found moderate negative correlations between the VAS score for current pain and mental health (r = -0.52, P < .01) and between the VAS score for worst pain in the past 24 hours and mental health (r = -0.46, P = .01) and between activity limitations in individuals with PFP and fear avoidance beliefs (r = -0.61, P < .01). CONCLUSIONS: Our results should encourage clinicians, especially musculoskeletal rehabilitation professionals, to acknowledge the importance of a whole-person approach when treating or planning rehabilitation programs for individuals with PFP.

Intrinsic foot muscle size and quality in a single leg weight bearing position across foot posture types in individuals with Patellofemoral Pain compared to healthy.

OBJECTIVE: To identify if any differences exist in IFM size and quality in single leg weight bearing position between healthy and PFP participants based on foot posture. DESIGN: Cross-sectional, matched case-comparison study SETTING: University Laboratory Setting PARTICIPANTS: 35 PFP (age:20.46 ± 3.79yrs, mass:73.28 ± 26.58 kg, height:170.80 ± 11.91 cm) and 35 healthy (age:20.40 ± 3.16yrs, mass:64.76 ± 11.52 kg, height:169.55 ± 9.10 cm) participants METHODS: After measuring Foot Posture Index (FPI), ultrasound images (USI) of Abductor Hallucis (AH), Flexor Digitorum Brevis (FDB) and Quadratus Plantae (QP) were taken in a single limb weight bearing position. Cross-sectional area (CSA) and echogenicity were measured on the USI. RESULTS: FPI was not different between groups (PFP:2.34 ± 3.76, Healthy:2.34 ± 3.10, 9 pronated and 26 non-pronated in both groups). AH CSA was smaller in PFP than healthy group (PFP:0.030 ± 0.01 cm (Smith et al., 2018)/kg, Healthy:0.042 ± 0.01 cm (Smith et al., 2018)/kg, P < 0.001) with a large effect (d = -1.20(-1.71, -0.69). There were no other significant group main effects or group-by-FP interactions in AH/FDB/QP CSA or echogenicity. CONCLUSION: AH CSA was smaller in PFP than healthy controls, but no difference in CSA or echogenicity of FDB/QP exist, as well as no difference in foot posture between groups. While single limb weight bearing, the PFP group presented with a smaller IFM which provides eccentric control of medial longitudinal arch, which may have implications up the chain during weight bearing functional tasks.

Lower Extremity Biomechanics During a Drop-Vertical Jump and Muscle Strength in Women With Patellofemoral Pain.

CONTEXT: Patellofemoral pain (PFP) is one of the most prevalent knee conditions observed in women. Current research suggests that individuals with PFP have altered muscle activity, kinematics, and kinetics during functional tasks. However, few authors have examined differences in lower extremity biomechanics in this population during the drop-vertical jump (DVJ). OBJECTIVE: To determine how lower extremity electromyography, kinematics, and kinetics during a DVJ and lower extremity isometric strength differed between women with and those without PFP. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Fifteen healthy women (age = 20.23 ± 1.39 years, height = 169.32 ± 5.38 cm, mass = 67.73 ± 9.57 kg) and 15 women with PFP (age = 22.33 ± 3.49 years, height = 166.42 ± 6.01 cm, mass = 65.67 ± 13.75 kg). INTERVENTION(S): Three trials of a DVJ. MAIN OUTCOME MEASURE(S): Surface electromyography, kinematics, and kinetics were collected simultaneously during a DVJ. Lower extremity strength was measured isometrically. Independent-samples t tests were performed to assess group differences. RESULTS: Normalized muscle activity in the vastus medialis (healthy group = 120.84 ± 80.73, PFP group = 235.84 ± 152.29), gluteus maximus (healthy group = 43.81 ± 65.63, PFP group = 13.37 ± 13.55), and biceps femoris (healthy group = 36.68 ± 62.71, PFP group = 11.04 ± 8.9) during the landing phase of the DVJ differed between groups. Compared with healthy women, those with PFP completed the DVJ with greater hip internal-rotation moment (0.04 ± 0.28 N/kg versus 0.06 ± 0.14 N/kg, respectively) and had decreased knee-flexion excursion (76.76° ± 7.50° versus PFP = 74.14° ± 19.85°, respectively); they took less time to reach peak trunk flexion (0.19 ± 0.01 seconds versus 0.19 ± 0.02 seconds, respectively) and lateral trunk flexion (0.12 ± 0.07 seconds versus 0.11 ± 0.04 seconds, respectively). CONCLUSIONS: During the DVJ, women with PFP had increased hip internal-rotation moment and decreased knee-flexion excursion with less time to peak trunk flexion and lateral flexion. Muscle activation was increased in the vastus medialis but decreased in the gluteus maximus and biceps femoris. This suggests that altered motor-unit recruitment in the hip and thigh may result in changes in biomechanics during a DVJ that are often associated with an increased risk of injury.

Physical activity levels in individuals with and without patellofemoral pain.

OBJECTIVES: Patellofemoral pain (PFP) is a chronic condition that results in long-term subjective and objective impairments. PFP has been identified to result in modification in activity levels, however it is unknown the extent of activity levels in individuals with and without PFP. DESIGN: Case-control study. PARTICIPANTS: 20 individuals with PFP and 20 healthy individuals. MAIN OUTCOME MEASURES: Physical activity was assessed by steps per day, minutes of mild, moderate, and high activity over 14 consecutive days. Anterior Knee Pain Scale (AKPS), worst pain in last week (WVAS), and Fear Avoidance Belief Questionnaire (FABQ) were also collected. Paired t-tests were used to compare variables between groups. Pearson r correlations were conducted to evaluate relationships between subjective function and activity level. RESULTS: Individuals with PFP took less steps per day (p = 0.004) and completed less daily minutes of mild activity (p = 0.007) and high activity (p = 0.012). Significant correlations were seen between steps per day and subjective function: AKPS (p = 0.002), WVAS (p = 0.016), and FABQ (p = 0.002) in the PFP population. CONCLUSION: Individuals with PFP are less physically active than their healthy counterparts in both steps per day and minutes spent conducting physical activity. A relationship between subjective function and physical activity exists in individuals with PFP.

Longitudinal Changes in Hip Strength and Range of Motion in Female Youth Soccer Players: Implications for ACL Injury, A Pilot Study.

CONTEXT: Risk of anterior cruciate ligament (ACL) injuries in young female athletes increases with age, appearing to peak during maturation. Changes in hip muscle strength and range of motion (ROM) during this time may contribute to altered dynamic movement patterns that are known to increase risk of ACL injuries. Understanding the longitudinal changes in hip strength and ROM is needed to develop appropriate interventions to reduce the risk of ACL injuries. OBJECTIVE: To examine the longitudinal changes in hip strength and ROM in female youth soccer players. DESIGN: Longitudinal descriptive study. SETTING: Field setting. PARTICIPANTS: 14 female youth soccer athletes (14.1 ± 1.1 y, 165.8 ± 5.3 cm, 57.5 ± 9.9 kg) volunteered as part of a multiyear risk factor screening project. MAIN OUTCOME MEASURES: Clinical measures of hip strength and ROM were collected annually over 3 consecutive years. Passive hip internal rotation (IR), external rotation (ER), abduction (ABD), and adduction (ADD) ROM were measured with a digital inclinometer. Isometric hip ABD and extension (EXT) strength were evaluated using a hand-held dynamometer. Separate repeated-measures ANOVAs compared hip strength and ROM values across 3 consecutive years (P < .05). RESULTS: As youth female soccer players increased in age, there were no changes in normalized hip ABD (P = .830) or EXT strength (P = .062) across 3 consecutive years. Longitudinal changes in hip ROM were observed with increases in hip IR (P = .001) and ABD (P < .001), while hip ADD (P = .009) and ER (P < .001) decreased. CONCLUSIONS: Anatomical changes at the hip occur as youth female soccer players increase in age. While there are no changes in hip strength, there is an increase in hip IR and ABD ROM with a concomitant decrease in hip ER and ADD ROM. The resulting asymmetries in hip ROM may decrease the activation and force producing capabilities of the hip muscles during dynamic activities, contributing to altered lower extremity mechanics known to increase the risk of ACL injuries.