Objective To identify suggestions for future research on spinal movement variability (SMV) in individuals with low back pain (LBP) by investigating (1) the methodologies and statistical tools used to assess SMV; (2) characteristics that influence the direction of change in SMV; (3) the methodological quality and potential biases in the published studies; and (4) strategies for optimizing SMV in LBP patients. Methods We searched literature databases (CENTRAL, Medline, PubMed, Embase, and CINAHL) and comprehensively reviewed the relevant papers up to 5 May 2020. Eligibility criteria included studies investigating SMV in LBP subjects by measuring trunk angle using motion capture devices during voluntary repeated trunk movements in any plane. The Newcastle-Ottawa risk of bias tool was used for data quality assessment. Results were reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews. Results Eighteen studies were included: 14 cross-sectional and 4 prospective studies. Seven linear and non-linear statistical tools were used. Common movement tasks included trunk forward bending and backward return, and object lifting. Study results on SMV changes associated with LBP were inconsistent. Two of the three interventional studies reported changes in SMV, one of which was a randomized controlled trial (RCT) involving neuromuscular exercise interventions. Many studies did not account for the potential risk of selection bias in the LBP population. Conclusion Designers of future studies should recognize that each of the two types of statistical tools assesses functionally different aspects of SMV. Future studies should also consider dividing participants into subgroups according to LBP characteristics, as three potential subgroups with different SMV characteristics were proposed in our study. Different task demands also produced different effects. We found preliminary evidence in a RCT that neuromuscular exercises could modify SMV, suggesting a rationale for well-designed RCTs involving neuromuscular exercise interventions in future studies.

[Purpose] The aim of this study was to investigate differences in selective voluntary motor control of the lower extremities by objective assessment and determine the relationship between selective voluntary motor control and knee extensor strength in children with spastic diplegia. [Subjects and Methods] Forty individuals who had spastic cerebral palsy, with Gross Motor Function Classification System levels ranging from I to III, were assessed using the Selective Control Assessment of the Lower Extremity and by testing the maximum knee extensor strength. The unaffected side was defined as the lower limb with the higher score, and the affected side was defined as the lower limb with the lower score. [Results] The Selective Control Assessment of the Lower Extremity score on the affected side had a lower average than that on the unaffected side. The scores showed a significant inverse correlation with the maximum knee extensor strength. [Conclusion] There was bilateral difference in the selective voluntary motor control of the lower extremities in children with spastic diplegia, and the selective voluntary motor control of the lower extremity was related to maximum knee extensor strength.

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[Purpose] The purpose of this study is to evaluate the applicability of the calf circumference as a tool for screening sarcopenia. [Subjects and Methods] One hundred sixteen community-dwelling elderly females were enrolled. Calf circumference of the dominant leg was measured using a plastic measuring tape. Subjects were divided into 3 groups based on body mass index (BMI); subjects with the values for BMI <18.5 kg/m2; those with BMI 18.5 to 25.0; those with BMI ≥25.0 kg/m2. Positive predictive value and negative predictive value of sarcopenia were calculated based on the obtained cut off values of calf circumference and the diagnosis of sarcopenia in each group. [Results] Prevalence rate of sarcopenia was 9.4% (n=10). Cut off value of the calf circumference was 32.8 cm (sensitivity: 73.0%, specificity: 80.0%, AUC: 0.792). Each BMI group showed high negative predictive value of sarcopenia based on the calf circumference cut off value of 32.8 cm. [Conclusion] These results suggested that to identify non-sarcopenia by larger calf circumference is more reasonable and useful than to identify sarcopenia due to the smaller calf circumference regardless of BMI.

[Purpose] The aim of this study was to identify the most effective method of performing ankle pumping exercises. [Subjects and Methods] The study subjects were 10 men. We measured time-averaged maximum flow velocity and peak systolic velocity in the common femoral vein using a pulse Doppler method with a diagnostic ultrasound system during nine ankle pumping exercises (three different ankle positions and three exercise intervals). Changes of blood flow velocity during ankle pumping exercises with different ankle positions and exercise intervals were compared. [Result] Peak systolic velocity of the leg-up position showed significantly lower values than those of the supine and head-up positions. For all exercise intervals, the increased amount of blood flow velocity in the leg-up position was significantly lower than that in the head-up and supine positions. [Conclusion] Ankle positions and exercise intervals must be considered when performing effective ankle pumping exercises.