Indeed, Correlation Does Not Indicate Causation!

Author response to the Letter to the Editor-in-Chief "Lower-Limb Kinematics and Clinical Outcomes: Correlation Does not Imply Causality" .

Real-life implementation of a G6PD deficiency screening qualitative test into routine vivax malaria diagnostic units in the Brazilian Amazon (SAFEPRIM study).

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency greatly hinders Plasmodium vivax malaria radical cure and further elimination due to 8-aminoquinolines-associated hemolysis. Although the deleterious health effects of primaquine in G6PD deficient individuals have been known for over 50 years, G6PD testing is not routinely performed before primaquine treatment in most P. vivax endemic areas.

Y-Balance Test Asymmetry and Frontal Plane Knee Projection Angle During Single-leg squat as Predictors of Patellofemoral Pain in Male Military Recruits.

Objectives: Investigate prospectively whether dynamic balance and frontal plane knee projection angle (FPKPA) are risk factors for the development of patellofemoral pain (PFP) in male military recruits.

Study Design: Prospective cohort.

Setting: Military training center.

The relationship between urinary C-Telopeptide fragments of type II collagen, knee joint load, pain, and physical function in individuals with medial knee osteoarthritis.

Objective: Considering the osteoarthritis (OA) model that integrates the biological, mechanical, and structural components of the disease, the present study aimed to investigate the association between urinary C-Telopeptide fragments of type II collagen (uCTX-II), knee joint moments, pain, and physical function in individuals with medial knee OA.

Methods: Twenty-five subjects radiographically diagnosed with knee OA were recruited. Participants were evaluated through three-dimensional gait analysis, uCTX-II level, the WOMAC pain and physical function scores, and the 40m walk test.

Translation, adaptation and validation of the Nurse-Work Instability Scale to Brazilian Portuguese.

Objective: to translate, adapt and test the psychometric properties of the Brazilian Nurse-Work Instability Scale.

Method: this was a methodological study following the translation steps: synthesis, back-translation, specialist´s committee, semantics analysis, pretest, and psychometric tests. The committee was composed of 5 specialists.

Cryotherapy reduces muscle hypertonia, but does not affect lower limb strength or gait kinematics post-stroke: a randomized controlled crossover study.

Background: Based on the premise that spasticity might affect gait post-stroke, cryotherapy is among the techniques used to temporarily reduce spasticity in neurological patients. This effective technique would enhance muscle performance, and ultimately, functional training, such as walking. However, understanding whether a decrease in spasticity level, if any, would lead to improving muscle performance and gait parameters is not based on evidence and needs to be clarified.

The role of hip abductor strength on the frontal plane of gait in subjects with medial knee osteoarthritis.

Objective: This study aimed to investigate the relationship of hip abductor strength with external hip and knee adduction moments, pain and physical function, and trunk, pelvis, and hip kinematics in the frontal plane during walking in subjects with medial knee osteoarthritis.

Methods: Twenty-five subjects with medial knee osteoarthritis were evaluated through an isokinetic strength test for hip abductor, three-dimensional gait analysis (kinetics and kinematics), and pain and physical function scores. Regression models were used to control the influence of other parameters such as pain, age, gender, severity, walking speed, mass, and height.

Effects of three gait retraining techniques in runners with patellofemoral pain.

Objectives: Analyze the effects of 3 gait retraining: forefoot landing (FFOOT), 10% step rate increase (SR10%) and forward trunk lean (FTL) on lower limb biomechanics and clinical measurements in patellofemoral pain (PFP) runners.

Design: Case series report.

Settings: Biomechanical laboratory and treadmill running.

Patellofemoral joint stress measured across three different running techniques.

Background: Patellofemoral pain (PFP) is the most common running-related injury. It has been shown in previous studies that gait retraining may have a beneficial effect on patellofemoral joint stress (PFJS).

Research Question: Is there a reduction of PFJS across 4 running conditions: 1.

Relationship of hip and ankle range of motion, trunk muscle endurance with knee valgus and dynamic balance in males.

Objectives: Investigate the relationship of hip internal rotation (IR) and ankle dorsiflexion (DF) range of motion (ROM), trunk flexor, extensor, and lateral flexor muscle endurance with frontal plane knee projection angle (FPKPA) and Y-balance test (YBT).

Study Design: Cross-sectional study.

Setting: Armed Force training site.

Core stability, shoulder peak torque and function in throwing athletes with and without shoulder pain.

Objective: This study compared core stability, shoulder isokinetic peak torque and shoulder function in throwers with and without shoulder pain.

Design: Cross-sectional study.

Settings: Throwing athletes.

Performances on the Timed Up and Go Test and subtasks between fallers and non-fallers in older adults with cognitive impairment.

This work aimed to compare performances on the Timed Up and Go (TUG) test and its subtasks between faller and non-faller older adults with mild cognitive impairment (MCI) and mild Alzheimer's disease (AD). A prospective study was conducted, with 38 older adults with MCI and 37 with mild AD. Participants underwent an assessment at baseline (the TUG and its subtasks using the Qualisys ProReflex system) and the monitoring of falls at the six-month follow up.

Differences in Timed Up and Go Subtasks Between Older People With Mild Cognitive Impairment and Mild Alzheimer's Disease.

This study compared performances of timed up and go test subtasks between 40 older people with preserved cognition, 40 with mild cognitive impairment, and 38 with mild Alzheimer's disease. The assessment consisted of anamneses and timed up and go test subtasks (sit-to-stand, walking forward, turn, walking back, and turn-to-sit). Data were captured by Qualisys Track Manager software and processed by Visual3D software.

Performance of Different Timed Up and Go Subtasks in Frailty Syndrome.

Background And Purpose: Gait speed, mobility, and postural transitions should be taken into account in older adults with frailty syndrome and can be assessed by the Timed Up and Go (TUG) Test. However, it is unclear which TUG subtasks have greater influence in identifying frail people and whether prefrail individuals present with any reduced subtask performance. The objective of this study was to investigate the differences in performance of TUG subtasks between frail, prefrail, and nonfrail older adults.

Identification of Directed Interactions in Kinematic Data during Running.

The knowledge of motion dynamics during running activity is crucial to enhance the development of rehabilitation techniques and injury prevention programs. Recent studies investigated the interaction between joints, using several analysis techniques, as cross-correlation, sensitivity analysis, among others. However, the direction of the joints pairing is still not understood.

Inter- and intra-rater reliability of 3D kinematics during maximum mouth opening of asymptomatic subjects.

Previous studies evaluated 3D human jaw movements using kinematic analysis systems during mouth opening, but information on the reliability of such measurements is still scarce. The purpose of this study was to analyze within- and between-session reliabilities, inter-rater reliability, standard error of measurement (SEM), minimum detectable change (MDC) and consistency of agreement across raters and sessions of 3D kinematic variables during maximum mouth opening (MMO). Thirty-six asymptomatic subjects from both genders were evaluated on two different days, five to seven days apart.

The relationship between external knee moments and muscle co-activation in subjects with medial knee osteoarthritis.

Purpose: External knee moments are reliable to measure knee load but it does not take into account muscle activity. Considering that muscle co-activation increases compressive forces at the knee joint, identifying relationships between muscle co-activations and knee joint load would complement the investigation of the knee loading in subjects with knee osteoarthritis. The purpose of this study was to identify relationships between muscle co-activation and external knee moments during walking in subjects with medial knee osteoarthritis.

Cognitive Correlates of Timed Up and Go Subtasks in Older People With Preserved Cognition, Mild Cognitive Impairment, and Alzheimer's Disease.

Objective: To determine whether impaired Timed Up and Go Test (TUG) subtask performances are associated with specific cognitive domains among older people with preserved cognition (PC), mild cognitive impairment (MCI), and mild Alzheimer's disease (AD).

Design: TUG subtasks performances were assessed by the Qualisys motion system. Cognition was assessed by Addenbrooke's Cognitive Examination and the Frontal Assessment Battery (FAB).

Lower limb strength and flexibility in athletes with and without patellar tendinopathy.

Objectives: To compare the hip, knee and ankle torques, as well as knee and ankle flexibility between athletes with patellar tendinopathy and asymptomatic controls.

Design: Cross-sectional study.

Setting: Laboratory setting.

Rehabilitation of Patellar Tendinopathy Using Hip Extensor Strengthening and Landing-Strategy Modification: Case Report With 6-Month Follow-up.

Study Design Case report. Background Although eccentric exercises have been a cornerstone of the rehabilitation of athletes with patellar tendinopathy, the effectiveness of this intervention is sometimes less than ideal. Athletes with patellar tendinopathy have been shown to have different jump-landing patterns and lower hip extensor strength compared to asymptomatic athletes.

Trunk biomechanics and its association with hip and knee kinematics in patients with and without patellofemoral pain.

Patellofemoral pain (PFP) is a common lower extremity condition observed in sports clinics. Recently, it has been suggested that trunk motion could affect hip and knee biomechanics in the frontal plane. Thus, the purpose of the study was compare trunk kinematics, strength and muscle activation between people with PFP and healthy participants.

Test-retest reliability of three-dimensional kinematics using an electromagnetic tracking system during single-leg squat and stepping maneuver.

The electromagnetic tracking system (ETS) has been used to analyze three-dimensional (3D) lower limb kinematics. The single-leg squat and stepping maneuver are useful tasks to evaluate lower extremity alignment in a clinical setting. The purpose of this study was to evaluate the test-retest reliability of trunk, pelvis, hip, and knee 3D kinematics using an ETS during single-leg squat and stepping maneuver and compare 3D kinematics between tasks.

Frontal plane biomechanics in males and females with and without patellofemoral pain.

Purpose: The study's purpose was to compare trunk, pelvis, hip, and knee frontal plane biomechanics in males and females with and without patellofemoral pain syndrome (PFPS) during stepping.

Methods: Eighty recreational athletes were equally divided into four groups: female PFPS, female controls, male PFPS, and male controls. Trunk, pelvis, hip, and knee frontal plane kinematics and activation of the gluteus medius were evaluated at 15°, 30°, 45°, and 60° of knee flexion during the downward and upward phases of the stepping task.