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Cureus Oct 2023The rise of ultraendurance sports in the past two decades warrants evaluation of the impact on the heart and vessels of a growing number of athletes participating.... (Review)
Review
The rise of ultraendurance sports in the past two decades warrants evaluation of the impact on the heart and vessels of a growing number of athletes participating. Blood pressure is a simple, inexpensive method to evaluate one dimension of an athlete's cardiovascular health. No systematic review or meta-analysis to date has chronicled and delineated the effects of ultraendurance races, such as ultramarathons, marathons, half-marathons, and Ironman triathlon events, specifically on heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP) measurements in supine and standing positions before and after the event. This meta-analysis reviews the effects of ultraendurance events on positional and calculated hemodynamic values. Data were extracted from 38 studies and analyzed using a random effects model with a total of 1,645 total blood pressure measurements. Of these, 326 values were obtained from a standing position, and 1,319 blood pressures were taken supine. Pre-race and post-race measurements were evaluated for clinical significance using established standards of hypotension and orthostasis. HR and calculated BP features, such as PP and MAP, were evaluated. Across all included studies, the mean supine post-race HR increased by 21±8 beats per minute (bpm) compared to pre-race values. The mean standing post-race HR increased by 23±14 bpm when compared with pre-race HR. Overall, there was a mean SBP decrease of 19±9 mmHg and a DBP decrease of 9±5 mmHg post-race versus pre-race values. MAP variations reflected SBP and DBP changes. The mean supine and standing pre-race blood pressures across studies were systolic (126±7; 124±14) and diastolic (76±6; 75±12), suggesting that some athletes may enter races with existing hypertension. The post-race increase in the mean HR and decline in mean blood pressure across examined studies suggest that during long-term events, ultramarathon athletes perform with relatively asymptomatic hypotension.
PubMed: 37954749
DOI: 10.7759/cureus.46801 -
Scandinavian Journal of Work,... Oct 2023The association between occupational mechanical exposures and low-back pain (LBP) has been studied in several systematic reviews. However, no systematic review... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
The association between occupational mechanical exposures and low-back pain (LBP) has been studied in several systematic reviews. However, no systematic review addressing chronic LBP exists. The aim of this systematic review and meta-analysis was to examine the association between occupational mechanical exposures and chronic LBP.
METHODS
The study was registered in PROSPERO. We used an existing systematic review to identify articles published before January 2014. For studies published between January 2014 and September 2022, a systematic literature search was conducted in six databases. Two authors independently excluded articles, extracted data, and assessed risk of bias and level of evidence (GRADE). Meta-analyses were conducted using random-effects models comparing highest versus lowest exposure group with sensitivity analyses based on study quality (low/moderate versus high risk of bias), study design (cohort versus case-control), and outcome definition (non-specific LBP versus specific chronic LBP).
RESULTS
Twenty-six articles were included. Highest pooled odd ratios (OR) were found for combined mechanical exposures [OR 2.2, 95% confidence interval (CI) 1.4-3.6], lifting/carrying loads (OR 1.7, 95% CI 1.4-2.2), and non-neutral postures (OR 1.5, 95% CI 1.2-1.9). For the remaining mechanical exposures (ie, whole-body vibrations, standing/walking, and sitting), OR ranged between 1.0 and 1.4. In the sensitivity analyses, generally, higher pooled OR were found in low/moderate risk of bias studies, case-control studies, and studies of specific chronic LBP.
CONCLUSIONS
Moderate evidence of an association was found for lifting/carrying loads, non-neutral postures, and combined mechanical exposures. Low or very low evidence was found for whole-body vibrations, standing/walking, and sitting. Studies using standardized exposure definition, metric, and technical measurements are highly warranted.
Topics: Humans; Low Back Pain; Back Pain; Risk Factors; Sitting Position; Occupational Exposure; Chronic Pain
PubMed: 37581384
DOI: 10.5271/sjweh.4114 -
International Journal of Environmental... Oct 2021The objective of this systematic review and meta-analysis was to examine the reliability of isokinetic measurements of hip strength in flexion and extension in healthy... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The objective of this systematic review and meta-analysis was to examine the reliability of isokinetic measurements of hip strength in flexion and extension in healthy subjects and athletes.
METHODS
The databases used were Web of Science, SCOPUS, Medline and PubMed. R was used for all statistical analyses.
RESULTS
Hip flexion shows moderate reliability in the supine position (ICC = 0.72; 95% CI: 0.46-0.99) and good reliability in the standing position (ICC = 0.79; 95% CI: 0.54-1.04). Hip extension shows excellent reliability in the supine position (ICC = 0.90; 95% CI: 0.85-0.96) and moderate reliability in the standing position (ICC = 0.72; 95% CI: 0.48-0.96). Flexion of 120°/s and 180°/s showed excellent reliability (ICC = 0.93; 95% CI: 0.85-1.00), (ICC = 0.96; 95% CI: 0.92-1.01). The 60°/s and 120°/s extension showed good reliability (ICC = 0.90; 95% CI: 0.82-0.98), (ICC = 0.87; 95% CI: 0.75-0.99). The 180°/s extension presented excellent reliability (ICC = 0.93; 95% CI: 0.82-1.03).
CONCLUSIONS
The standing position shows good reliability for hip flexion and the supine position shows excellent reliability for hip extension, both movements have excellent reliability at velocities between 120°/s to 180°/s.
Topics: Athletes; Healthy Volunteers; Humans; Muscle Strength; Muscle Strength Dynamometer; Muscle, Skeletal; Range of Motion, Articular; Reproducibility of Results
PubMed: 34769842
DOI: 10.3390/ijerph182111326 -
PloS One 2021To synthesise and analyse the current evidence regarding changes in joint position sense (JPS) and standing balance in people with whiplash-associated disorder (WAD)... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To synthesise and analyse the current evidence regarding changes in joint position sense (JPS) and standing balance in people with whiplash-associated disorder (WAD) taking the presence or absence of dizziness into account.
DATA SOURCES
PubMed, CINAHL Plus, Web of Science, Embase, MEDLINE and APA PsycINFO were searched by two independent reviewers from inception until August 2020 and reference lists of all included studies were also reviewed.
STUDY SELECTION
Only cross-sectional studies that measured JPS and/or standing balance between people with WAD vs. healthy controls (HC) or people with WAD complaining of dizziness (WADD) vs. those not complaining of dizziness (WADND) were selected.
DATA EXTRACTION
Relevant data were extracted using specific checklists and quality assessment was performed using Downs and Black Scale (modified version).
DATA SYNTHESIS
Twenty-six studies were included. For JPS, data were synthesized for absolute error in the primary plane of movement for separate movement directions. For standing balance, data were synthesized for traditional time- and frequency domain sway parameters considering the conditions of eyes open (EO) and eyes closed (EC) separately. For meta-analysis, reduced JPS was observed in people with WAD compared to HC when the head was repositioned to a neutral head position (NHP) from rotation (standardised mean difference [SMD] = 0.43 [95%: 0.24-0.62]) and extension (0.33 [95%CI: 0.08-0.58]) or when the head was moved toward 50° rotation from a NHP (0.50 [0.05-0.96]). Similarly, people with WADD had reduced JPS compared to people with WADND when the head was repositioned to a NHP from rotation (0.52 [0.22-0.82]). Larger sway velocity and amplitude was found in people with WAD compared to HC for both EO (0.62 [0.37-0.88] and 0.78 [0.56-0.99], respectively) and EC (0.69 [0.46-0.91] and 0.80 [0.58-1.02]) conditions.
CONCLUSION
The observed changes of JPS and standing balance confirms deficits in sensorimotor control in people with WAD and especially in those with dizziness.
Topics: Animals; Cross-Sectional Studies; Dizziness; Head; Humans; Movement; Postural Balance; Whiplash Injuries
PubMed: 33831060
DOI: 10.1371/journal.pone.0249659 -
Journal of Applied Biomechanics Dec 2022Load carriage experiments are typically performed from a linear perspective that assumes that movement variability is equivalent to error or noise in the neuromuscular... (Review)
Review
Load carriage experiments are typically performed from a linear perspective that assumes that movement variability is equivalent to error or noise in the neuromuscular system. A complimentary, nonlinear perspective that treats variability as the object of study has generated important results in movement science outside load carriage settings. To date, no systematic review has yet been conducted to understand how load carriage dynamics change from a nonlinear perspective. The goal of this systematic review is to fill that need. Relevant literature was extracted and reviewed for general trends involving nonlinear perspectives on load carriage. Nonlinear analyses that were used in the reviewed studies included sample, multiscale, and approximate entropy; the Lyapunov exponent; fractal analysis; and relative phase. In general, nonlinear tools successfully distinguish between unloaded and loaded conditions in standing and walking, although not in a consistent manner. The Lyapunov exponent and entropy were the most used nonlinear methods. Two noteworthy findings are that entropy in quiet standing studies tends to decrease, whereas the Lyapunov exponent in walking studies tends to increase, both due to added load. Thus, nonlinear analyses reveal altered load carriage dynamics, demonstrating promise in applying a nonlinear perspective to load carriage while also underscoring the need for more research.
Topics: Humans; Walking; Movement; Standing Position; Entropy; Nonlinear Dynamics
PubMed: 36170973
DOI: 10.1123/jab.2022-0062 -
Frontiers in Cardiovascular Medicine 2022Physical counter pressure maneuvers (CPM) are movements that are recommended to delay or prevent syncope (fainting) by recruiting the skeletal muscle pump to augment... (Review)
Review
Physical counter pressure maneuvers (CPM) are movements that are recommended to delay or prevent syncope (fainting) by recruiting the skeletal muscle pump to augment cardiovascular control. However, these recommendations are largely based on theoretical benefit, with limited data evaluating the efficacy of CPM to prevent syncope in the real-world setting. We conducted a semi-systematic literature review and meta-analysis to assess CPM efficacy, identify literature gaps, and highlight future research needs. Articles were identified through a literature search (PubMed, April 2022) of peer-reviewed publications evaluating the use of counter pressure or other lower body maneuvers to prevent syncope. Two team members independently screened records for inclusion and extracted data. From 476 unique records identified by the search, 45 met inclusion criteria. Articles considered various syncopal conditions (vasovagal = 12, orthostatic hypotension = 8, postural orthostatic tachycardia syndrome = 1, familial dysautonomia = 2, spinal cord injury = 1, blood donation = 10, healthy controls = 11). Maneuvers assessed included hand gripping, leg fidgeting, stepping, tiptoeing, marching, calf raises, postural sway, tensing (upper, lower, whole body), leg crossing, squatting, "crash" position, and bending foreword. CPM were assessed in laboratory-based studies ( = 28), the community setting ( = 4), both laboratory and community settings ( = 3), and during blood donation ( = 10). CPM improved standing systolic blood pressure (+ 14.8 ± 0.6 mmHg, < 0.001) and heart rate (+ 1.4 ± 0.5 bpm, = 0.006), however, responses of total peripheral resistance, stroke volume, or cerebral blood flow were not widely documented. Most patients experienced symptom improvement following CPM use (laboratory: 60 ± 4%, community: 72 ± 9%). The most prominent barrier to employing CPM in daily living was the inability to recognize an impending faint. Patterns of postural sway may also recruit the skeletal muscle pump to enhance cardiovascular control, and its potential as a discrete, proactive CPM needs further evaluation. Physical CPM were successful in improving syncopal symptoms and producing cardiovascular responses that may bolster against syncope; however, practical limitations may restrict applicability for use in daily living.
PubMed: 36312294
DOI: 10.3389/fcvm.2022.1016420 -
Topics in Spinal Cord Injury... 2023Incomplete spinal cord injury (iSCI) often results in impaired balance leading to functional impairments. Recovery of standing balance ability is an important aim of... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Incomplete spinal cord injury (iSCI) often results in impaired balance leading to functional impairments. Recovery of standing balance ability is an important aim of rehabilitative programs. However, limited information is available on effective balance training protocols for individuals with iSCI.
OBJECTIVES
To assess the methodological quality and effectiveness of various rehabilitation interventions for improving standing balance in individuals with iSCI.
METHODS
A systematic search was performed in SCOPUS, PEDro, PubMed, and Web of Science from inception until March 2021. Two independent reviewers screened articles for inclusion, extracted data, and evaluated methodological quality of the trials. PEDro Scale was used to assess the quality of randomized controlled trials (RCT) and crossover studies while pre-post trials were assessed using the modified Downs and Black tool. A meta-analysis was performed to quantitatively describe the results. The random effects model was applied to present the pooled effect.
RESULTS
Ten RCTs with a total of 222 participants and 15 pre-post trials with 967 participants were analyzed. The mean PEDro score and modified Downs and Black score was 7/10 and 6/9, respectively. The pooled standardized mean difference (SMD) for controlled and uncontrolled trials of body weight-supported training (BWST) interventions was -0.26 (95% CI, -0.70 to 0.18; = .25) and 0.46 (95% CI, 0.33 to 0.59; < .001), respectively. The pooled effect size of -0.98 (95% CI, -1.93 to -0.03; = .04) indicated significant improvements in balance after a combination of BWST and stimulation. Pre-post studies analyzing the effect of virtual reality (VR) training interventions on Berg Balance Scale (BBS) scores in individuals with iSCI reported a mean difference (MD) of 4.22 (95% CI, 1.78 to 6.66; = .0007). Small effect sizes were seen in pre-post studies of VR+stimulation and aerobic exercise training interventions indicating no significant improvements after training on standing balance measures.
CONCLUSION
This study demonstrated weak evidence to support the use of BWST interventions for overground training for balance rehabilitation in individuals with iSCI. A combination of BWST with stimulation however showed promising results. There is a need for further RCTs in this field to generalize findings. Virtual reality-based balance training has shown significant improvement in standing balance post iSCI. However, these results are based on single group pre-post trials and lack appropriately powered RCTs involving a larger sample size to support this intervention. Given the importance of balance control underpinning all aspects of daily activities, there is a need for further well-designed and appropriately powered RCTs to evaluate specific features of training interventions to improve standing balance function in iSCI.
Topics: Humans; Spinal Cord Injuries; Postural Balance; Exercise; Standing Position; Virtual Reality
PubMed: 37235196
DOI: 10.46292/sci21-00065 -
Clinical Biomechanics (Bristol, Avon) Oct 2023Falls are major health concerns in older adults. Sit-to-stand transfer is an important functional movement that can predict falling risk in older adults.... (Review)
Review
Biomechanical and neuromuscular control characteristics of sit-to-stand transfer in young and older adults: A systematic review with implications for balance regulation mechanisms.
BACKGROUND
Falls are major health concerns in older adults. Sit-to-stand transfer is an important functional movement that can predict falling risk in older adults. Aging-associated declines in neuromechanical control of movement may negatively impact sit-to-stand performance. This systematic review aims to summarize differences in neuromechanical characteristics of younger vs. older adults that likely affect balance regulation during sit-to-stand.
METHODS
Five databases (Academic search complete, MEDLINE, APA PsycInfo, Pubmed, and SPORTDiscus) were systematically searched from January 1985 through March 2023. Three reviewers assessed the quality of methodology, study design, results, and risk of bias using the Appraisal tool for Cross-Sectional Studies. Studies reported neuromuscular and biomechanical characteristics during sit-to-stand in young versus older adults were included.
FINDINGS
Seventeen studies (343 older and 225 younger adults) were included. Compared to younger adults, older adults showed slower sit-to-stand time, higher trunk flexion, postural sway, agonist-antagonist muscle co-activation of the ankle and knee muscles, and lower ankle dorsiflexion torque. Lower magnitude and rate of vertical ground reaction force development and lower vertical momentum during rising were observed with aging during fast-speed sit-to-stand. There was heterogeneity among studies on sit-to-stand speed, foot position, use of arms, and seat height adjustability.
INTERPRETATIONS
Higher trunk angular displacement and velocity accompanied by higher anterior momentum, likely to compensate for knee extensor muscle weaknesses, may lead to higher postural sway upon standing and therefore require higher knee and ankle muscle co-activation to maintain balance stability. Thus, additional attention to trunk control strategies is needed during clinical evaluations.
Topics: Humans; Aged; Cross-Sectional Studies; Movement; Standing Position; Motion; Foot; Biomechanical Phenomena; Postural Balance
PubMed: 37639862
DOI: 10.1016/j.clinbiomech.2023.106068 -
Clinical Spine Surgery Apr 2024Systematic review and meta-analysis. (Meta-Analysis)
Meta-Analysis
STUDY DESIGN
Systematic review and meta-analysis.
OBJECTIVE
To report the ratio-of-differences between standing and sitting. To understand how sex and age influence these differences.
SUMMARY OF BACKGROUND DATA
Currently, spinal deformity surgery aims to realign the sagittal profile of the spine with-reference-to the standing posture resulting in overcorrection. New studies report significant disparities between standing and sitting spinal alignment.
METHODS
A comprehensive search and review of the published literature was performed on 4 platforms in accordance with the PRISMA 2009 checklist by 2 authors independently.
RESULTS
From 753 abstracts extracted from the databases, 38 papers involving 5423 patients were identified. sagittal vertical axis was more positive in sitting, with a pooled mean difference of 29.5 mm (95% CI: 17.9-41.0). Pelvic tilt (PT) was larger in sitting, with a pooled mean difference of 16.7 degrees (95% CI: 12.5-20.9), and a pooled odds ratio of 1.2(95% CI:1.1-1.3. P =0.001). Sacral Slope (SS) was smaller and lumbar lordosis (LL) was less lordotic in sitting, with a pooled mean difference of 15.0 degrees (95% CI: 11.918.1) and 21.1 degrees (95% CI:14.5-27.8), respectively, and a pooled odds ratio of 0.7 (95% CI: 0.6-0.8. P <0.001) and 0.7 (95% CI:0.6-0.7, P <0.001), respectively. Pelvic incidence and thoracic kyphosis was similar in sitting. Subgroup meta-analysis comparing odd ratio of standing to sitting showed: Among younger patients (age younger than 50), the PT and LL pooled odds-ratios were 1.4 and 0.7, respectively. Among older patients (age older than or equal to 50), the PT and LL pooled odds-ratios were 1.1 and 0.8, respectively. Among female patients, the SS pooled odds ratio was 0.6. Among male patients, the SS pooled odds ratio was 0.7.
CONCLUSION
When comparing sitting to standing, it gives a more positive sagittal vertical axis, a smaller SS and LL, and a larger PT. pelvic incidence and thoracic kyphosis remained similar. Younger and female patients have pronounced differences in SS, PT, and LL, suggesting the existence of age and sex variations, and its role to be considered when planning for spinal realignment surgeries. Clinical outcome studies are required to ascertain the impact of these findings.
Topics: Humans; Male; Female; Sitting Position; Lordosis; Kyphosis; Posture; Sacrum; Lumbar Vertebrae
PubMed: 37482640
DOI: 10.1097/BSD.0000000000001501 -
Annals of Biomedical Engineering Aug 2023Industrial tasks that involve frequent sitting/standing transitions and squatting activities can benefit from lower-limb industrial exoskeletons; however, their use is... (Review)
Review
Industrial tasks that involve frequent sitting/standing transitions and squatting activities can benefit from lower-limb industrial exoskeletons; however, their use is not as widespread as their upper-body counterparts. In this review, we examined 23 articles that evaluated the effects of using Wearable Chair (WC) and Squat-assist (SA) exoskeletons. Evaluations mainly included assessment of muscular demands in the thigh, shank, and upper/lower back regions. Both types of devices were found to lessen muscular demands in the lower body by 30-90%. WCs also reduced low-back demands (~ 37%) and plantar pressure (54-80%) but caused discomfort/unsafe feeling in participants. To generalize outcomes, we suggest standardizing approaches used for evaluating the devices. Along with addressing low adoption through design upgrades (e.g., ground and body supports/attachments), we recommend that researchers thoroughly evaluate temporal effects on muscle fatigue, metabolic rate, and stability of wearers. Although lower-limb exoskeletons were found to be beneficial, discrepancies in experimental protocols (posture/task/measures) were discovered. We also suggest simulating more realistic conditions, such as walking/sitting interchangeability for WCs and lifting loads for SA devices. The presented outcomes could help improve the design/evaluation approaches, and implementation of lower limb wearable devices across industries.
Topics: Humans; Exoskeleton Device; Posture; Industry; Standing Position; Lower Extremity
PubMed: 37248409
DOI: 10.1007/s10439-023-03242-w