Generation of forward angular impulse with different initial conditions.

Generation of angular impulse during foot contact is regulated by controlling the relative orientation between the total body center of mass (CoM) and the reaction force (RF) applied to the feet. Between-task differences in initial CoM horizontal momentum were hypothesized to alter how forward angular impulse was generated during two forward translating tasks. Five skilled athletes performed standing (SFS) and running (RFS) forward somersaulting dives. Sagittal plane kinematics and RFs were obtained during the take-off phase of both tasks. The initial CoM momentum differences resulted in significant differences in control of the CoM relative to the RF, RF generation mechanisms, and knee and hip net joint moments (NJMs). During the RFS, angular impulse was generated by positioning the feet anterior to the CoM at initial contact so that the RF passed posterior to the CoM throughout the take-off phase. During the SFS, angular impulse was generated by positioning the CoM anterior to the feet prior to the push interval so that the RF passed posterior to the CoM. Task-specific differences in segment kinematics and RF direction contributed to the redistribution of knee and hip NJMs. These results suggest that initial conditions influence strategies the nervous system uses to satisfy task objectives.

Effect of pursed-lip breathing and forward trunk lean positions on regional chest wall volume and ventilatory pattern in older adults: An observational study.

ABSTRACT: Pursed-lip breathing (PLB) and forward trunk lean posture (FTLP) are commonly used to relieve dyspnea and improve ventilation in a rehabilitation program. However, their effect on chest wall volumes and movements in older adults without chronic obstructive pulmonary disease has never been investigated. This observational study aimed to identify the effect of combined PLB and FTLP on total and regional chest wall volumes, ventilatory pattern, and thoracoabdominal movement using in older adults. It was hypothesized that the combined PLB with FTLP would result in the highest chest wall volumes among the experimental tasks. Twenty older adults performed 2 breathing patterns of quiet breathing (QB) and PLB during a seated upright (UP) position and FTLP. An optoelectronic plethysmography system was used to capture the chest wall movements during the 4 experimental tasks. Tidal volume (VT) was separated into pulmonary ribcage, abdominal ribcage, and abdomen volume. The changes in anterior-posterior (AP) and medial-lateral (ML) chest wall diameters at 3 levels were measured and used to identify chest wall mechanics to improve chest wall volumes. The PLB significantly improved ventilation and chest wall volumes than the QB (P < .05). VT of pulmonary ribcage, VT of abdominal ribcage, and VT were significantly higher during the PLB + UP (P < .05) and during the PLB + FTLP (P < .01) as compared to those of QB performed in similar body positions. However, there was no significant in total and regional lung volumes between the PLB + UP and the PLB + FTLP. The AP diameter changes at the angle of Louis and xiphoid levels were greater during the PLB + UP than the QB + UP and the QB + FTLP (P < .01). The AP diameter changes at the umbilical level and the ML diameter changes at the xiphoid level were significantly larger during the PLB + FTLP than the QB + FTLP and the QB + UP (P < .05). The ML diameter changes at the umbilical level were significantly greater during the PLB + FTLP than the QB + UP (P < .05). However, no significant difference in the relative regional chest wall volumes and phase angle among the experimental tasks (P > .05). In conclusion, a combined PLB performed in an FTLP or UP sitting could be used as a strategy to improve chest wall volumes and ventilation in older adults.

The effect of unsupported arm elevations on regional chest wall volumes and thoracoabdominal asynchrony in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To compare the effect of unsupported arm elevation (UAE) in different planes on chest wall volumes, thoracoabdominal asynchrony (TAA), ventilatory demands, dyspnea, and arm fatigue in patients with chronic obstructive pulmonary disease (COPD) and healthy subjects. METHODS: Twenty-one patients with COPD and healthy-matched subjects performed UAE in shoulder flexion, scaption, abduction, and resting. Pulmonary total and regional chest wall volumes (VRCp), abdominal rib cage volume, abdominal volume, TAA, and ventilatory demands during arm positions were measured using optoelectronic plethysmography. RESULTS: In both groups, VRCp and TAA were significantly affected during UAEs compared with the resting position. The healthy subjects had significantly decreased VRCp (L) (p < 0.05) during scaption (0.14 ± 0.07) and abduction (0.15 ± 0.06) than during flexion (0.18 ± 0.07) and no significantly different TAA between UAEs. The COPD group had no significantly different VRCp between UAEs, had significantly increased TAA (p < 0.05) during scaption (31.1°±9.5°) and abduction (32.3°±9.9°) than during flexion (29.7°±9.1°); and had significantly worse VRCp (p = 0.007), TAA (p = 0.0001), ventilatory demands (p < 0.05), dyspnea ((p = 0.03), and arm fatigue (p = 0.002). CONCLUSIONS: In patients with COPD, UAE in different planes similarly restricted the upper chest wall volume. Shoulder scaption and abduction significantly impaired TAA, ventilation, dyspnea, and arm fatigue compared with flexion. These results may help to select the appropriate UAE during physical activities.

Regulation of Forward Angular Impulse in Tasks With Backward Translation.

Studying how elite athletes satisfy multiple mechanical objectives when initiating well-practiced, goal-directed tasks provides insights into the control and dynamics of whole-body movements. This study investigated the coordination of multiple body segments and the reaction force (RF) generated during foot contact when regulating forward angular impulse in backward translating tasks. Six highly skilled divers performed inward somersaults (upward and backward jump with forward rotation) and inward timers (upward and backward jump without rotation) from a stationary platform. Sagittal plane kinematics and RFs were recorded simultaneously during the takeoff phase. Regulation of the forward angular impulse was achieved by redirecting the RF about the total body center of mass. Significantly more backward-directed RF was observed during the first and second peak horizontal RF of the inward somersaults than the inward timers. Modulation of the horizontal RF altered the RF direction about the center of mass and the lower-extremity segments. Backward leg and forward trunk orientation and a set of relatively large knee extensor and small hip flexor net joint moments were required for forward angular impulse generation. Understanding how the forward angular impulse is regulated in trained individuals provides insights for clinicians to consider when exploring interventions related to fall prevention.

Effects of pursed-lip breathing and forward trunk lean postures on total and compartmental lung volumes and ventilation in patients with mild to moderate chronic obstructive pulmonary disease: An observational study.

ABSTRACT: This study identified the effects of pursed-lip breathing (PLB), forward trunk lean posture (FTLP), and combined PLB and FTLP on total and compartmental lung volumes, and ventilation in patients with chronic obstructive pulmonary disease (COPD). Sixteen patients with mild to moderate COPD performed 2 breathing patterns of quiet breathing (QB) and PLB during FTLP and upright posture (UP). The total and compartmental lung volumes and ventilation of these 4 tasks (QB-UP, PLB-UP, QB-FTLP, PLB-FTLP) were evaluated using optoelectronic plethysmography. Two-way repeated measures ANOVA was used to identify the effect of PLB, FTLP, and combined strategies on total and compartmental lung volumes and ventilation. End-expiratory lung volume of ribcage compartment was significantly lower in PLB-UP than QB-UP and those with FTLP (P < .05). End-inspiratory lung volume (EILV) and end-inspiratory lung volume of ribcage compartment were significantly greater during PLB-FTLP and PLB-UP than those of QB (P < .05). PLB significantly and positively changed end-expiratory lung volume of abdominal compartment (EELVAB ) end-expiratory lung volume, EILVAB, tidal volume of pulmonary ribcage, tidal volume of abdomen, and ventilation than QB (P < .05). UP significantly increased tidal volume of pulmonary ribcage, tidal volume of abdomen, and ventilation and decreased EELVAB, end-expiratory lung volume, and EILVAB than FTLP (P < .05). In conclusion, combined PLB with UP or FTLP demonstrates a positive change in total and compartmental lung volumes in patients with mild to moderate COPD.

Fear of Falling, Lower Extremity Strength, and Physical and Balance Performance in Older Adults with Diabetes Mellitus.

Fear of falling (FoF) is known to affect the physical activities and quality of life of older adults with type 2 diabetes mellitus (DM). Many complications of DM, especially ones distressing lower extremity (LE), could lead to increased fall risk and FoF. This study aimed to explore the relationship between FoF, LE muscle strength, and physical performance in older adults without diabetes mellitus (ONDM) and with DM (ODM) with varying degrees of balance impairment. The participants comprised 20 ONDM and 110 ODM. The ODM was grouped by the number of failed performances of the modified clinical test of sensory interaction and balance (mCTSIB). The scores of FoF, balance performance of mCTSIB, physical performance of TUG, and LE muscle strength were compared between groups. The results showed that FoF was present in 30% and 60% of the ONDM and ODM, respectively. Forty percent of the ODM failed one condition of the mCTSIB, while 18% and 16% failed two and three conditions, respectively. As the number of failed performances on the mCTSIB increased, the proportions of participants with FoF significantly increased. The psychosocial domain of FoF, LE muscle strength, and TUG score was significantly different between groups and more affected in the ODM with a greater number of failed performances on the mCTSIB. In conclusion, the mCTSIB can differentiate the varying degrees of balance impairment among ODM. FoF, LE muscle strength, and physical performance are more affected as the degree of balance impairment increases. Comprehensive management related to balance and falls in the ODM should include a regular evaluation and monitoring of standing balance, LE muscle strength, physical performance, and FoF.

Effects of Different Modes of Upper Limb Training in Individuals With Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis.

OBJECTIVE: To determine effects of different modes of upper limb training on dyspnea and quality of life of individuals with chronic obstructive pulmonary disease (COPD) having different disease severity. METHODS: Randomized clinical trials were retrieved from five electronic databases. Risk of bias and quality of evidence were assessed using the Cochrane Collaboration's tool and the GRADE approach, respectively. Effects of upper limb training compared to control were identified using standardized mean difference and 95% confidence interval. RESULTS: Fifteen studies with 514 subjects were included. When compared to control, upper limb endurance and strength training with moderate quality of evidence resulted in significant improvement in dyspnea. However, quality of life was not significantly different between upper limb training of all modes of and the control. The upper limb training was more effective in reducing dyspnea in patients with severe COPD than in those with mild to moderate levels of COPD. Although quality of life was slightly improved by upper limb training for those with moderate or severe level of COPD, such improvement did not reach a significant level when compared to the control. CONCLUSION: Upper limb endurance and strength training could significantly improve dyspnea in individuals with chronic obstructive pulmonary disease. Thus, incorporating the upper limb training into pulmonary rehabilitation is recommended to reduce dyspnea, especially for those with severe patients. Further studies with larger sample size and standardized training protocol are needed to confirm these finding (Registration No. CRD42018102805).

Effects of Breathing Exercises in Patients With Chronic Obstructive Pulmonary Disease: Systematic Review and Meta-Analysis.

OBJECTIVE: To update evidence on the effects of breathing exercises (BEs) on ventilation, exercise capacity, dyspnea, and quality of life (QoL) in chronic obstructive pulmonary disease (COPD) patients. METHODS: Randomized controlled trials investigating the effects of BEs in COPD patients published through May 2018, were retrieved from five electronic databases (MEDLINE, CINAHL, Cochrane, Scopus, and ScienceDirect). Risk of bias and quality of evidence were assessed, using Cochrane Collaboration's tool, and the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) approach, respectively. RESULTS: Nineteen studies (n=745), were included. Quality of evidence, was low to moderate. When compared to the control groups, respiratory rate significantly (p≤0.001) improved in the pursed-lip breathing (PLB), ventilatory feedback (VF) plus exercise, diaphragmatic breathing exercise (DBE), and combined BEs. Additionally, PLB significantly improved tidal volume (p<0.001), inspiratory time (p=0.007), and total respiratory time (p<0.001). VF plus exercise significantly improved inspiratory capacity (p<0.001), and singing significantly improved the physical component of QoL, than did the control groups (p<0.001). All BEs did not significantly improve dyspnea, compared to the controls (p>0.05). CONCLUSION: PLB, VF plus exercise, DBE, combined BEs, and singing could be used to improve ventilation and QoL. Based on low to moderate quality of evidence, use of these BEs to improve ventilation and QoL in COPD patients is conditional (Registration No. CRD42018102995).

Scapular Upward Rotation During Passive Humeral Abduction in Individuals With Hemiplegia Post-stroke.

OBJECTIVE: To describe scapular upward rotation during passive humeral abduction in individuals with hemiplegia post-stroke compared to normal subjects. METHODS: Twenty-five individuals with hemiplegia post-stroke and 25 age- and gender-matched normal subjects voluntarily participated in this study. Scapular upward rotation during resting and passive humeral abduction at 30°, 60°, 90°, 120°, and 150° were measured using a digital inclinometer. RESULTS: In both groups, scapular upward rotation significantly increased as humeral abduction increased (p<0.001). Scapular upward rotation was significantly less in the hemiplegic group compared to that in the control at 90° (p=0.002), 120° (p<0.001), and 150° of humeral abduction (p<0.001). The mean difference in scapular upward rotation between these two groups ranged from 6.3° to 11.38°. CONCLUSION: Passive humeral abductions ranging from 90° to 150° can significantly alter scapular upward rotation in individuals with hemiplegia post-stroke compared to those of matched normal subjects. The magnitude of reduction of the scapular upward rotation may potentially lead to the development of hemiplegic shoulder pain after prolonged repetitive passive movement. Scapular upward rotation should be incorporated during passive humeral abduction in individuals with hemiplegia post-stroke, especially when the humeral is moved beyond 90° of humeral abduction. Combined movements of scapular and humeral will help maintain the relative movement between the scapula and humerus. However, further longitudinal study in patients with shoulder pain post-stroke is needed to confirm these findings.

Influence of Functional Capacity Evaluation on Physician's Assessment of Physical Capacity of Veterans With Chronic Pain: A Retrospective Analysis.

BACKGROUND: Physicians have difficulty predicting patients' occupational limitations, abilities, and success from clinical evaluation (CE) of pathology and impairments, especially in the presence of chronic pain. Additional information from a functional capacity evaluation (FCE) may improve the accuracy of their physical capacity assessments. It is not known whether FCE information will change these assessments. No such study has been published using Veterans or non-Veterans. OBJECTIVE: To determine the influence of FCE data on the physician's assessment of the US Department of Labor's Dictionary of Occupational Titles (DOT) work capacity levels of Veterans with chronic moderate-intensity pain. DESIGN: Retrospective analysis. SETTING: Tertiary care medical center. PARTICIPANTS: Veterans aged 18-60 years with moderate chronic musculoskeletal pain who were seeking employment. METHODS: Two kinesiotherapists performed FCEs on all participants, namely, the lumbar protocol of the EvalTech Functional Testing System (BTE, Inc, Hanover, MD). One physiatrist performed CEs in all participants. Two other physiatrists assessed DOT physical capacity levels using CE data alone and later using combined CE and FCE data. MAIN OUTCOME MEASUREMENTS: DOT physical capacity level (sedentary = 1, light = 2, medium = 3, heavy = 4, very heavy = 5). RESULTS: Of 55 charts reviewed, 27 met inclusion/exclusion criteria. The mean age was 38 years, and there were 25 male and 2 female participants. The predominant pain location was the lower back. DOT scores for 2 physicians were averaged. The mean ± SD DOT scores for CE only and CE+FCE conditions were 2.04 ± 0.33 and 2.40 ± 0.90, respectively. In all, 65% of DOT scores changed (17% decreased and 48% increased at least 1 level) after FCE data were considered. A 1-sample t test revealed that the mean CE+FCE DOT score was significantly greater than the mean CE-only score (by 20%, P = .02). Interrater agreement (weighted κ) for CE+FCE-based DOT scores was much higher than for CE alone (0.715 versus 0.182). CONCLUSION: The addition of FCE data to CE changed the majority of physician-assigned DOT levels. FCE significantly increased the mean DOT physical work capacity level provided by the physician to Veterans with chronic moderate-intensity pain, especially if the initial assessment was designated as "light." FCE may facilitate a more objective and accurate determination of Veterans' work capacity. LEVEL OF EVIDENCE: III.

Regulation of angular impulse during fall recovery.

Maintaining balance and postural stability while performing functional activities is critical to an individual's independence and quality of life. When individuals are unable to maintain their total-body center of mass (COM) within the base of support, a loss of balance may result, leading to a fall. Effective interaction between the environment and the neuromuscular and musculoskeletal systems allows an individual to generate the ground reaction forces relative to the COM necessary for maintaining and recovering balance during expected and unexpected situations. This article reviews the role of the swing and support legs in regulating angular impulse during fall recovery and contrasts the balance recovery strategies used by younger adults and older adult nonfallers and fallers. Multijoint dynamics and neuromuscular control used during fall recovery are discussed at the total-body, joint, and muscle levels. Understanding the fall recovery mechanisms successfully used by younger and older adults will allow us to begin to identify effective intervention strategies that target specific populations.

Regulation of angular impulse during two forward translating tasks.

Angular impulse generation is dependent on the position of the total body center of mass (CoM) relative to the ground reaction force (GRF) vector during contact with the environment. The purpose of this study was to determine how backward angular impulse was regulated during two forward translating tasks. Control of the relative angle between the CoM and the GRF was hypothesized to be mediated by altering trunk-leg coordination. Eight highly skilled athletes performed a series of standing reverse somersaults and reverse timers. Sagittal plane kinematics, GRF, and electromyograms of lower extremity muscles were acquired during the take-off phase of both tasks. The magnitude of the backward angular impulse generated during the push interval of both tasks was mediated by redirecting the GRF relative to the CoM. During the reverse timer, backward angular impulse generated during the early part of the take-off phase was negated by limiting backward trunk rotation and redirecting the GRF during the push interval. Biarticular muscles crossing the knee and hip coordinated the control of GRF direction and CoM trajectory via modulation of trunk-leg coordination.