In this study, we investigated the fluctuation characteristics of micro vertical acceleration of center of mass (vCOMacc) in standing and examined the usefulness of vCOMacc as an aging marker for standing control abilities. Sixteen young and 18 older adults participated in this experiment. Data for vCOMacc were calculated as the vertical ground reaction force value divided by each participant’s body mass using a force plate. The COMacc frequency structure was determined using the continuous wavelet transform to analyze the relative frequency characteristics. For time domain analysis, we determined the root mean square (RMS) and maximum amplitude (MA) of the integrated power spectral density. We also analyzed the correlation between vCOMacc and lower limb muscle activity. The relative frequency band of vCOMacc was higher in older than young adults, and the time domain indicators were sufficient to distinguish the effects of aging. Regarding the relationship between vCOMacc during standing and muscle activity, a correlation was found with the soleus muscle in young adults, while it was moderately correlated with the gastrocnemius muscle in older adults. The cause of vCOM may be related to differences in muscle activity, and vCOMacc may be utilized to more easily assess the effects of aging in standing control.

Our aim was to clarify the effect of aging on the coherence of electromyograms of plantar flexor pairs during bipedal stance and to clarify the relationship between coherence and center-of-mass acceleration (COMacc). The subjects were 16 adults and 18 older adults. Intra- and intermuscular coherence and phase analyses were used to analyze the muscle pairs of bilateral and unilateral plantar flexor muscle groups. The relationship between coherence value and anterior–posterior COMacc of the plantar flexor muscle pairs was also examined to determine whether the connectivity of the lower limb muscle pairs is functionally important. The older adults showed higher coherence in the frequency range of 0–4 Hz for muscle pairs than the younger adults. In phase analysis, the older adults showed a phase difference between bilateral heteronymous muscle pairs in the frequency range of 0–6 Hz, which was one of the characteristics not seen in the younger adults. Correlation analysis showed that all the muscle pairs were moderately correlated with COMacc in the older adults. Not only does aging affects the organization of the bilateral and unilateral postural muscle activity of the plantar flexors during bipedal stance, but such organization may also be related to the increased COMacc characteristics of older adults.

The purpose of this study was to clarify the lower limb joint motor coordination of para-athletes during running motion from frequency characteristics and to propose this as a method for evaluating their performance. The subject used was a 43-year-old male para-athlete who had suffered a left cerebral infarction. Using a three-dimensional motion analysis system, the angles of the hip, knee, and ankle joints were measured during 1 min of running at a speed of 8 km/h on a treadmill. Nine inter- and intra-limb joint angle pairs were analyzed by coherence and phase analyses. The main characteristic of the stroke patient was that there were joint pairs with absent or increased coherence peaks in the high-frequency band above 4 Hz that were not found in healthy subjects. Interestingly, these features were also observed on the non-paralyzed side. Furthermore, a phase analysis showed different phase differences between the joint motions of the stroke patient and healthy subjects in some joint pairs. Thus, we concluded there was a widespread functional impairment of joint motion in the stroke patient that has not been revealed by conventional methods. The coherence analysis of joint motion may be useful for identifying joint motion problems in para-athletes.

Background: Recovery after discharge is a key goal of cancer rehabilitation in patients undergoing gastrointestinal cancer surgery; however, perioperative factors associated with early postdischarge 6-minute walk distance (6MWD) remain unclear. This exploratory prospective cohort study aimed to identify perioperative factors associated with 6MWD approximately 1 month after discharge. Methods: This exploratory prospective cohort study used convenience sampling and included 27 patients who underwent gastric or colorectal cancer surgery. Assessments were conducted preoperatively, at discharge, and during the early postdischarge period. The primary outcome was the 6MWD measured during the early postdischarge period. Candidate factors included demographic and clinical variables, physical function, cancer-related fatigue, instrumental activities of daily living, and albumin. Accelerometer-derived physical activity variables were examined as secondary exploratory measures. Exploratory multivariable linear regression analyses were performed separately for preoperatively (PRE) and at discharge (DIS) models, and Bayesian linear regression was conducted as a complementary analysis. Results: The 6MWD improved after discharge, increasing by 40.4 m from discharge to the early postdischarge assessment, indicating a clinically meaningful recovery. In the DIS model, discharge 6MWD was positively associated with postdischarge 6MWD, whereas age was negatively associated, and postoperative complications showed a negative trend. In the PRE model, preoperative 6MWD was positively associated with postdischarge 6MWD, whereas preoperative mental fatigue was negatively associated. It improved after discharge, increasing by 40.4 m from discharge to the early postdischarge assessment, indicating a clinically meaningful recovery. In the DIS model, discharge 6MWD was positively associated with postdischarge 6MWD, whereas age was negatively associated and postoperative complications showed a negative trend. In the PRE model, preoperative 6MWD was positively associated with postdischarge 6MWD, whereas preoperative mental fatigue was negatively associated. Conclusions: Early postdischarge 6MWD was associated with perioperative functional capacity, age, and preoperative mental fatigue. These exploratory findings should be interpreted cautiously and may help refine perioperative assessment and postdischarge support strategies.

Background: Wrist–forearm orthoses used during self-feeding may alter scapular and shoulder mechanics and increase proximal load, but this has not been quantified. Methods: Seventeen right-hand-dominant young adults performed a spoon-feeding task under free and restricted conditions. A thermoplastic wrist–forearm orthosis positioned the wrist at approximately 30° dorsiflexion at rest and was intended to constrain wrist motion during the task without rigidly immobilizing forearm pronation–supination. Three-dimensional kinematics (scapula, shoulder, trunk, and distal joints) were recorded using inertial sensors, and surface electromyography was obtained from the upper trapezius, middle deltoid, and biceps brachii. Maximum joint angles and mean %MVC over the feeding cycle were compared between conditions (α = 0.05). Results: The restriction condition resulted in a more anteriorly tilted and downwardly rotated scapular posture, greater shoulder abduction and external rotation, and increased thoracic flexion, whereas maximum distal joint angles did not differ, suggesting a functional distal constraint rather than rigid immobilization. Middle deltoid and biceps brachii activities increased significantly, with a nonsignificant trend toward higher upper trapezius activation. Conclusions: In healthy young adults, limited wrist motion and forearm rotation during spoon-feeding were associated with altered proximal coordination, including scapular, shoulder/trunk, and proximal muscle changes.

Introduction: Wrist range of motion (ROM) supports coordinated upper-limb function during self-feeding. Wrist restriction may induce proximal compensation, yet the kinematic consequences of discrete wrist positions remain underexplored. Methods: Ten healthy young women performed a standardized eating task under four wrist positions: free (FP), palmar-flexed (PFP; 20°), intermediate (IP; 0°), and dorsiflexed (DFP; 20°). Upper-limb kinematics were recorded with a wearable IMU system (100 Hz). Discrete outcomes included maximum/minimum joint angles and event-based angles at the end of scooping and mouth reaching. Parametric data were analyzed using repeated-measures ANOVA with Dunnett comparisons versus FP; non-parametric data used Friedman tests with Bonferroni correction (η ² ). Statistical Parametric Mapping (SPM) was applied to time-normalized waveforms to localize condition effects across the movement cycle. Results: Wrist position systematically altered kinematics. Compared with FP, PFP produced the largest deviations, including reduced maximum elbow flexion (108 ± 8° vs 124 ± 8°) and forearm supination (68 ± 12° vs 93 ± 12°; η ² up to 0.44). At mouth reaching, PFP similarly reduced elbow flexion (108 ± 8° vs 123 ± 9°) and supination (67 ± 12° vs 93 ± 12°) and shifted wrist posture toward palmar flexion. IP and DFP showed smaller departures from FP. SPM indicated the largest effects mainly during late transport/mouth reaching for elbow flexion and supination, and near movement initiation/termination for wrist radial/ulnar deviation. Conclusion: Non-neutral wrist positioning—particularly palmar flexion—disrupts self-feeding coordination and elicits proximal compensation. Findings may inform orthosis positioning and exercise progression; confirmation in patient cohorts is warranted.