Forward step down test - clinical rating is correlated with joint angles of the pelvis and hip: an observational study.

BACKGROUND: Clinical methods for assessing quality of movement and functional tests are important to clinicians. Typical deviations from normal kinematics during the clinical test of Forward Step Down Test (FSDT) are pelvic tilt and hip adduction which are associated with the risk of knee pain. OBJECTIVES: (1) to examine the correlation between clinical assessment of the FSDT and joint angle measurements of pelvis, hip, knee and ankle joints in males and females; (2) to examine the differences in joint angles between individuals rated as good, fair or poor in a FSDT performance test. METHODS: Ninety-two healthy individuals performing FSDT were video-taped with two-dimensional digital video cameras. The clinical assessment of the FSDT was rated by two experienced physical therapists as good, fair, or poor based on a Crossley et al. (2011) validated scale. Measurements of pelvic drop, hip adduction and knee valgus were taken using Image J software. RESULTS: Out of 177 lower limbs, 74 (37 in each limb) were clinically rated as "good/fair" (41.80%) while 103 (52 in the dominant leg and 51 in the non-dominant leg) were rated as "poor" (58.19%). No significant differences were observed between dominant and non-dominant legs or between males and females in clinical rating of the FSDT. Pelvic drop angle was significantly higher and hip adduction angle was significantly lower for "poor" clinical rating compared to "good/fair" in both dominant and non-dominant legs (p < 0.001) in males and females. Females demonstrated higher pelvic drop, lower hip adduction and higher knee valgus angles compared with males (p < 0.05). CONCLUSIONS: This study showed that the clinical rating of FSDT is correlated with joint angle measurements suggesting that this assessment can be utilized in clinical practice. Individuals with poor quality performance of FSDT showed higher pelvic drop and hip adduction movement. Further studies examining different populations with diverse disorders or pathologies are essential.

The relationship between ankle dorsiflexion range of motion, frontal plane projection angle, and patellofemoral pain syndrome.

BACKGROUND: Ankle range of motion abnormalities have been often linked with alteration in knee kinematics leading to the development of patellofemoral pain syndrome (PFPS). Literature exploring the relationship between ankle dorsiflexion range of motion (DF ROM) and knee kinematics during functional tasks is scanty. This study aims to assess the relation between ankle DF ROM and frontal plane projection angle (FPPA), one of the knee kinematic variables, in individuals with and without PFPS during a step-down test. METHODS: This is a case-control study in which seventy PFPS patients and other 70 asymptomatic control subjects had their ankle DF ROM measured using an inclinometer with the knee flexed and extended. Their FPPA angles were measured using Kinovea software while doing the step-down test. RESULTS: When the two groups were compared, ankle DF ROM measured with the knee flexed was higher in the control group (33.15 ± 4.96) than in the PFPS group (30.20 ± 6.93) (p = 0.03). In both the PFPS group and the control group, the correlation between FPPA and ankle DF ROM with the knee flexed was statistically insignificant (p = 0.075 and 0.323 respectively). CONCLUSION: Decreased ankle DF ROM can be one of the contributing factors to the development of PFPS in the context of greater dynamic knee valgus.

The effects of repetitive transcranial magnetic stimulation on the cognition and neuronal excitability of mice.

This study aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) on the cognition and neuronal excitability of Kunming mice during the natural aging of the brain. Twenty young (2-3-month-old) female mice, 20 adult (9-10-month-old) female mice and 12 aged (14-15-month-old) female mice were divided into two groups (control and rTMS treatment). rTMS-treated groups were subjected to high-frequency (20 Hz) rTMS treatment for 15 days. Novel object recognition (NOR) and step-down tests were performed to examine cognition of learning and memory. The whole-cell patch clamp technique was used to record the resting membrane potential (RMP) and action potential (AP), and the intrinsic properties of the AP were analyzed (the frequence of AP, the after hyperpolarizing potential (AHP), the AP peak amplitude, the time to AP amplitude, the average rise/down slope). Results showed that the cognition and neuronal excitability of hippocampal dentate gyrus (DG) granule cells were significantly declined only in aged animals while no statistic differences were found between young and adult animals. Chronic high-frequency rTMS could significantly improve the age-related cognitive impairment in parallel with enhancing the DG granule cells' neuronal excitability.

[Repetitive transcranial magnetic stimulation significantly improves cognitive impairment and neuronal excitability during aging in mice].

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation technique that has been paid attention to with increasing interests as a therapeutic neural rehabilitative tool. Studies confirmed that high-frequency rTMS could improve the cognitive performance in behavioral test as well as the excitability of the neuron in animals. This study aimes to investigate the effects of rTMS on the cognition and neuronal excitability of Kunming mice during the natural aging. Twelve young mice, 12 adult mice, and 12 aged mice were used, and each age group were randomly divided into rTMS group and control group. rTMS-treated groups were subjected to high-frequency rTMS treatment for 15 days, and control groups were treated with sham stimulation for 15 days. Then, novel object recognition and step-down tests were performed to examine cognition of learning and memory. Whole-cell patch clamp technique was used to record and analyze resting membrane potential, action potential (AP), and related electrical properties of AP of hippocampal dentate gyrus (DG) granule neurons. Data analysis showed that cognition of mice and neuronal excitability of DG granule neurons were degenerated significantly as the age increased. Cognitive damage and degeneration of some electrical properties were alleviated under the condition of high-frequency rTMS. It may be one of the mechanisms of rTMS to alleviate cognitive damage and improve cognitive ability by changing the electrophysiological properties of DG granule neurons and increasing neuronal excitability.

Dynamic postural control during step down task in patients with patellofemoral pain syndrome.

[Purpose] This study aimed to examine the differences in dynamic postural control during forward step down (FSD) task in patients with patellofemoral pain syndrome (PFPS). [Participants and Methods] Sixty-eight participants (34 males and 34 females) were divided into the following 2 groups: 34 PFPS patients (17 males and 17 females) and 34 healthy controls (17 males and 17 females). Each participant performed FSD task from a height of 20 cm. A force platform was used to extract the center of pressure parameters during FSD task for calculation of time to stabilization (TTS) in the anterior-posterior (A/P) and medial-lateral (M/L) direction. [Results] PFPS group took longer time to stabilize than the healthy control group in A/P and M/L directions. A main effect for direction was found, and this indicated that the A/P TTS of 8.43 ± 0.79s was longer than the M/L TTS of 5.56 ± 1.95s in healthy participants and A/P TTS of 9.09 ± 0.82s was longer than the M/L TTS of 7.15 ± 2.11s in PFPS. [Conclusion] These findings suggest that dynamic postural control can be affected in PFPS patients.

A new class of powerful and informative simultaneous confidence intervals.

Step-down tests uniformly improve single-step tests with regard to power and the average number of rejected hypotheses. However, when extended to simultaneous confidence intervals (SCIs), the resulting SCIs often provide no additional information to the sheer hypothesis test. We speak, in this case, of a non-informative rejection. Non-informative rejections are particularly problematic in clinical trials with multiple treatments, where an informative rejection is required to obtain useful estimates of the treatment effects. The extension of single-step tests to confidence intervals does not have this deficiency. As a consequence, step-down tests, when extended to SCIs, do not uniformly improve single-step tests with regard to informative rejections. To overcome this deficiency, we suggest the construction of a new class of simultaneous confidence intervals that uniformly improve the Bonferroni and Holm SCIs with regard to informative rejections. This can be achieved using a dual family of weighted Bonferroni tests, with the weights depending continuously on the parameter values. We provide a simple algorithm for these computations and show that the resulting lower confidence bounds have an attractive shrinkage property. The method is extended to union-intersection tests, such as the Dunnett procedure, and is investigated in a comparative simulation study. We further illustrate the utility of the method with an example from a real clinical trial in which two experimental treatments are compared with an active comparator with respect to non-inferiority and superiority.

Sequential Tests of Multiple Hypotheses Controlling Type I and II Familywise Error Rates.

This paper addresses the following general scenario: A scientist wishes to perform a battery of experiments, each generating a sequential stream of data, to investigate some phenomenon. The scientist would like to control the overall error rate in order to draw statistically-valid conclusions from each experiment, while being as efficient as possible. The between-stream data may differ in distribution and dimension but also may be highly correlated, even duplicated exactly in some cases. Treating each experiment as a hypothesis test and adopting the familywise error rate (FWER) metric, we give a procedure that sequentially tests each hypothesis while controlling both the type I and II FWERs regardless of the between-stream correlation, and only requires arbitrary sequential test statistics that control the error rates for a given stream in isolation. The proposed procedure, which we call the sequential Holm procedure because of its inspiration from Holm's (1979) seminal fixed-sample procedure, shows simultaneous savings in expected sample size and less conservative error control relative to fixed sample, sequential Bonferroni, and other recently proposed sequential procedures in a simulation study.

Development and Validation of an Active Muscle Simplified Finite Element Human Body Model in a Standing Posture.

Active muscles play an important role in postural stabilization, and muscle-induced joint stiffening can alter the kinematic response of the human body, particularly that of the lower extremities, under dynamic loading conditions. There are few full-body human body finite element models with active muscles in a standing posture. Thus, the objective of this study was to develop and validate the M50-PS+Active model, an average-male simplified human body model in a standing posture with active musculature. The M50-PS+Active model was developed by incorporating 116 skeletal muscles, as one-dimensional beam elements with a Hill-type material model and closed-loop Proportional Integral Derivative (PID) controller muscle activation strategy, into the Global Human Body Models Consortium (GHBMC) simplified pedestrian model M50-PS. The M50-PS+Active model was first validated in a gravity standing test, showing the effectiveness of the active muscles in maintaining a standing posture under gravitational loading. The knee kinematics of the model were compared against volunteer kinematics in unsuited and suited step-down tests from NASA's active response gravity offload system (ARGOS) laboratory. The M50-PS+Active model showed good biofidelity with volunteer kinematics with an overall CORA score of 0.80, as compared to 0.64 (fair) in the passive M50-PS model. The M50-PS+Active model will serve as a useful tool to study the biomechanics of the human body in vehicle-pedestrian accidents, public transportation braking, and space missions piloted in a standing posture.

Immediate and cumulative effects of high-frequency repetitive transcranial magnetic stimulation on cognition and neuronal excitability in mice.

This study primarily explored the potential effects of high-frequency (20 Hz) repetitive transcranial magnetic stimulation (rTMS) with different intervention protocols on cognition and neuronal excitability in mice. Mice were randomly divided into 4 groups: a control group that received sham stimulation, an rTMS in vitro group whose acute brain slices received high-frequency stimulation, an rTMS 1 d group that received high-frequency stimulation for only 1 d, and an rTMS 15 d group that received high-frequency stimulation for 15 d. The novel object recognition and step-down tests were used to assess cognitive ability. The patch-clamp technique was used to record the membrane potentials and neural discharges of dentate gyrus granule cells to evaluate neuronal excitability. Results revealed that cognition and neuronal excitability in the rTMS 15 d group were significantly increased than that in the control and rTMS 1 d groups. The neuronal excitability in the rTMS in vitro group was also significantly increased than that in the control and rTMS 1 d groups. No significant changes were observed between the control and rTMS 1 d groups. These results suggested that high-frequency rTMS applied to the acute brain slices of mice in vitro exerted an immediate effect on increasing neuronal excitability. Chronic high-frequency rTMS applied to the brain of mice in vivo exerted a cumulative effect in improving cognition and increasing neuronal excitability.

Evaluation and Validation of a Joint Stress Test to Induce Activity-Related Knee Joint Discomfort - a Prospective Case-Control Study.

BACKGROUND: The assessment of improvement or maintenance of joint health in healthy subjects is a great challenge. The aim of the study was the evaluation of a joint stress test to assess joint discomfort in subjects with activity-related knee joint discomfort (ArJD). RESULTS: Forty-five subjects were recruited to perform the single-leg-step-down (SLSD) test (15 subjects per group). Subjects with ArJD of the knee (age 22-62 years) were compared to healthy subjects (age 24-59 years) with no knee joint discomfort during daily life sporting activity and to subjects with mild-to-moderate osteoarthritis of the knee joint (OA, Kellgren score 2-3, age 42-64 years). The subjects performed the SLSD test with two different protocols: (I) standardization for knee joint discomfort; (II) standardization for load on the knee joint. In addition, range of motion (ROM), reach test, acute pain at rest and after a single-leg squat and knee injury, and osteoarthritis outcome score (KOOS) were assessed. In OA and ArJD subjects, knee joint discomfort could be reproducibly induced in a short time interval of less than 10 min (200 steps). In healthy subjects, no pain was recorded. A clear differentiation between study groups was observed with the SLSD test (maximal step number) as well as KOOS questionnaire, ROM, and reach test. In addition, a moderate to good intra-class correlation was shown for the investigated outcomes. CONCLUSIONS: These results suggest the SLSD test is a reliable tool for the assessment of knee joint health function in ArJD and OA subjects to study the improvements in their activities. Further, this model can be used as a stress model in intervention studies to study the impact of stress on knee joint health function.

Comparison of muscle activation levels and knee valgus between individuals with medial patellofemoral ligament reconstruction and healthy individuals during fatiguing step down task.

BACKGROUND: Medial patellofemoral ligament reconstruction becomes first-choice surgical procedure for patients with a history of lateral patellar dislocations but there is limited knowledge about neuromuscular activation patterns of individuals with a history of patellar dislocation who underwent medial patellofemoral ligament reconstruction. OBJECTIVE: The aim of this study was to compare muscle activation levels and knee valgus during step down performance test between individuals with a history of medial patellofemoral ligament reconstruction and healthy individuals. METHODS: Fifteen individuals with medial patellofemoral ligament reconstruction and 15 healthy individuals were included. Vastus medialis obliquus, vastus lateralis and gluteus medius muscle activation levels and knee valgus were measured during 60-s- step down performance test. Two-way repeated-measures of analysis of covariance was used for statistical analysis. FINDINGS: Compared to the healthy individuals, individuals with medial patellofemoral ligament reconstruction showed lower vastus medialis obliquus (p = .04) and gluteus medius (p = .005) activation levels, and higher knee valgus (p = .002) in last period of the step down performance test. INTERPRETATION: Since the significant results were only observed in the fatiguing section of the test, endurance tests may provide more information about neuromuscular control of the individuals with history of medial patellofemoral ligament reconstruction. Future studies should investigate whether endurance exercises that target to improve vastus medialis obliquus and gluteus medius activity result in better clinical outcomes than conventional programs for individuals with medial patellofemoral ligament reconstruction.

Evidence for Reliability and Validity of Functional Performance Testing in the Evaluation of Nonarthritic Hip Pain.

CONTEXT: The single-legged-squat test (SLST) and step-down test (SDT) are 2 functional performance tests commonly used to evaluate active people with nonarthritic hip pain and dysfunction. However, evidence to support the use of the SLST and SDT in this population is lacking. OBJECTIVE: To offer evidence of reliability and validity for the SLST and SDT in evaluating patients with nonarthritic hip pain. DESIGN: Cross-sectional study. SETTING: Orthopaedic surgeon's clinical office. PATIENTS OR OTHER PARTICIPANTS: Forty-five patients (27 female and 18 male participants; age = 28.5 ± 10 years, height = 171.6 ± 10.1 cm, weight = 73.9 ± 15.2 kg, and body mass index = 25 ± 4.1) diagnosed with nonarthritic hip pain. MAIN OUTCOME MEASURE(S): Participants performed the SLST and SDT. Interrater reliability and validity of passive internal rotation of the hip, visual analog scale (VAS) scores, and hip outcome scores (HOSs) for limitations in activities of daily living and sport-related activities (SRAs) were collected. RESULTS: Interrater reliability was moderate to excellent for both the SLST (0.603-0.939) and SDT (0.745-0.943). Participants who passed or failed the SLST and SDT differed on the following measures: VAS for the SLST (F1,43 = 16.21, P < .001); VAS for the SDT (F1,43 = 13.41, P = .001); HOS-activities of daily living for the SLST (F1,40 = 5.15, P = .029); HOS-SRAs for the SLST (F1,40 = 7.48, P = .009); and HOS-SRAs for the SDT (F1,40 = 6.42, P = .015). CONCLUSIONS: Our study offers evidence for the use of the SLST and SDT as reliable and valid functional performance tests in the evaluation of physical function for patients with nonarthritic hip pain.

Bilateral spatiotemporal postural control impairments are present in participants with chronic ankle instability.

OBJECTIVES: This study evaluated center-of-pressure (COP) and time-to-boundary (TTB) measures of postural control during a Lateral Step-Down Test in participants with chronic ankle instability (CAI). DESIGN: Cohort study. SETTING: Biomechanics laboratory. PARTICIPANTS: Physically active adults with CAI (n = 15) and matched controls (n = 15). MAIN OUTCOME MEASURES: Traditional COP and TTB measures of postural control were computed in the medial/lateral (ML) and anterior/posterior (AP) directions. RESULTS: No significant results were found for the traditional COP measures (p > 0.05). The CAI group exhibited a lower TTB ML absolute minimum on their affected limb compared to the matched limb of the control group (p < 0.001). Additionally, on average the CAI group displayed significantly lower TTB ML mean of minima (p = 0.004) and TTB standard deviation of minima in the ML (p < 0.001) and AP directions (p = 0.002) regardless of limb. CONCLUSIONS: Sensorimotor impairments associated with CAI negatively alter spatiotemporal postural control and may cause a maladaptive reorganization of centrally mediated motor control strategies that results in bilateral postural control deficits during the Lateral Step-Down Test. In addition, traditional COP measures did not reveal any postural control deficits suggesting that a spatiotemporal analysis should be used when assessing postural control in participants with CAI.

The decline step-down test measuring the maximum pain-free flexion angle: A reliable and valid performance test in patients with patellofemoral pain.

OBJECTIVES: Patients with patellofemoral pain (PFP) experience pain while descending stairs. To date no reliable and valid performance-test exists to assess the maximum pain-free knee flexion angle (MPFFA) as outcome measure during a step-down task. Therefore, the intra- and inter-observer reliability and construct validity of the decline step-down test (DSDT) measuring the MPFFA in patients with PFP were evaluated. DESIGN: Reliability and construct validity. SETTING: Private practices in Nijmegen and Utrecht, the Netherlands. PARTICIPANTS: Patients with PFP. MAIN OUTCOME MEASURES: The reliability was assessed by repeated measurements of the MPFFA during the DSDT. The construct validity was assessed by correlating the measurements on the DSDT with the Anterior Knee Pain Scale Dutch Version (AKPS-DV) based on a pre-set hypothesis. RESULTS: Thirty-two participants (forty-eight knees) were eligible for inclusion. The intraclass correlation coefficient (ICC) for intra-observer reliability was ICC2,1 = 0.83 and ICC2,1 = 0.85 for inter-observer reliability. The 95% limits of agreement (LoA) showed a width of 27.56° for intra-observer reliability and a width of 24.42° for inter-observer reliability. There was an average positive correlation between the DSDT and the total score on the AKPS-DV (rs = 0.31, p = 0.030). CONCLUSION: The DSDT measuring the MPFFA is reliable and valid in patients with PFP.

2D AND 3D KINEMATICS DURING LATERAL STEP-DOWN TESTING IN INDIVIDUALS WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION.

BACKGROUND: The lateral step-down test is an established clinical evaluation tool to assess quality of movement in patients with knee disorders. However, this test has not been investigated in individuals after anterior cruciate ligament reconstruction (ACLR) in association with quantitative 3D motion analysis. PURPOSES: The purpose of this study was to determine the strength of association between visually-assessed quality of movement during the lateral step-down test and 3D lower limb kinematics in patients with history of ACLR. A second purpose was to compare kinematics between subgroups based on the presence or absence of faulty alignments during the task. The final purpose was to compare visually-assessed quality of movement scores between box heights during lateral step-down testing. METHODS: Twenty subjects at least one year status post-ACLR (18 females, age of 24.5 ± 4.6 years and body mass index of 23.4 ± 2.3 kg/m2) performed the lateral step-down test unilaterally on the surgical limb atop four and six inch boxes. A board-certified orthopedic physical therapist scored overall quality of movement during the lateral step-down test using established criteria during 2D video playback. Lower limb kinematics were simultaneously collected using 3D motion capture. An alpha level of 0.05 was used for all statistical treatments. RESULTS: Overall 2D quality of movement score significantly correlated (r =0.47-0.57) with 3D hip adduction and hip internal rotation across box heights. Across box heights, the presence of faulty pelvic alignment differentiated a subgroup exhibiting less peak knee flexion, and the presence of faulty knee alignment differentiated a subgroup exhibiting greater peak hip adduction. The six inch box elicited worse quality of movement compared to the four inch box. CONCLUSIONS: These results suggest that visually-assessed quality of movement is associated with several kinematic variables after ACLR. 2D movement deviations at the pelvis appear to consistently relate to less knee flexion, and 2D deviations at the knee appear to suggest greater hip adduction. Generally, poorer quality of movement was observed for the six inch box height. Clinically, these data suggest that interventions targeting hip abductor and knee extensor strength and neuromuscular control may be useful in the presence of poor quality of movement during lateral step-down testing. LEVEL OF EVIDENCE: 2b.

Ankle dorsiflexion among healthy men with different qualities of lower extremity movement.

CONTEXT: Lower extremity movement patterns have been implicated as a risk factor for various knee disorders. Ankle-dorsiflexion (DF) range of motion (ROM) has previously been associated with a faulty movement pattern among healthy female participants. OBJECTIVE: To determine the association between ankle DF ROM and the quality of lower extremity movement during the lateral step-down test among healthy male participants. DESIGN: Cross-sectional study. SETTING: Training facility of the Israel Defense Forces. PATIENTS OR OTHER PARTICIPANTS: Fifty-five healthy male Israeli military recruits (age = 19.7 ± 1.1 years, height = 175.4 ± 6.4 cm, mass = 72.0 ± 7.6 kg). INTERVENTION(S): Dorsiflexion ROM was measured in weight-bearing and non-weight-bearing conditions using a fluid-filled inclinometer and a universal goniometer, respectively. Lower extremity movement pattern was assessed visually using the lateral step-down test and classified categorically as good or moderate. All measurements were performed bilaterally. MAIN OUTCOME MEASURE(S): Weight-bearing and non-weight-bearing DF ROM were more limited among participants with moderate quality of movement than in those with good quality of movement on the dominant side (P = .01 and P = .02 for weight-bearing and non-weight-bearing DF, respectively). Non-weight-bearing DF demonstrated a trend toward a decreased range among participants with moderate compared with participants with good quality of movement on the nondominant side (P = .03 [adjusted P = .025]). Weight-bearing DF was not different between participants with good and moderate movement patterns on the nondominant side (P = .10). Weight-bearing and non-weight-bearing ankle DF ROM correlated significantly with the quality of movement on both sides (P < .01 and P < .05 on the dominant and nondominant side, respectively). CONCLUSIONS: Ankle DF ROM was associated with quality of movement among healthy male participants. The association seemed weaker in males than in females.

Chrysophanol attenuates lead exposure-induced injury to hippocampal neurons in neonatal mice.

Previous studies have shown that chrysophanol protects against learning and memory impairments in lead-exposed adult mice. In the present study, we investigated whether chrysophanol can alleviate learning and memory dysfunction and hippocampal neuronal injury in lead-exposed neonatal mice. At the end of lactation, chrysophanol (0.1, 1.0, 10.0 mg/kg) was administered to the neonatal mice by intraperitoneal injection for 15 days. Chrysophanol significantly alleviated injury to hippocampal neurons and improved learning and memory abilities in the lead-poisoned neonatal mice. Chrysophanol also significantly decreased lead content in blood, brain, heart, spleen, liver and kidney in the lead-exposed neonatal mice. The levels of malondialdehyde in the brain, liver and kidney were significantly reduced, and superoxide dismutase and glutathione peroxidase activities were significantly increased after chrysophanol treatment. Collectively, these findings indicate that chrysophanol can significantly reduce damage to hippocampal neurons in lead-exposed neonatal mice.