A randomized controlled trial to compare the interface pressures of alternating pressure overlay with gel pad versus gel pad alone during prolonged surgery.

INTRODUCTION: Prolonged surgery is a known risk of pressure ulcer formation. Pressure ulcers affect the quality of life, are a significant cause of morbidity and mortality, and pose a burden on the healthcare system. This study aimed to compare the effectiveness of an alternating pressure (AP) overlay with Gel pad against the Gel pad in reducing interface pressure (IP) during prolonged surgery. METHODS: A total of 180 participants from a tertiary hospital were randomized to AP overlay with Gel pad group (n = 90) and Gel pad group (n = 90). Patients were placed supine on the pressure redistributing surfaces, and IP data under the sacrum and ischial tuberosities were collected at an interval of 30 min from 0 min up to a maximum of 570 min. RESULTS: Based on data from 133 participants, the average IPs during all the deflation cycles of the AP overlay (with Gel pad) were significantly lower than the average continuous IP recorded for Gel pad throughout the measuring period (p < 0.001). Only three patients (2.26% of study participants) - Gel pad group (n = 2; 2.99%) and AP overlay with Gel pad group (n = 1; 1.52%) developed post-operative pressure ulcer (p = 0.5687). CONCLUSIONS: The lower IP during deflation cycles of the AP overlay (with Gel pad) suggests its potential effectiveness in preventing pressure ulcer formation in patients undergoing prolonged surgery. The prevention and reduction of pressure ulcers will have a considerable impact on the improved quality of life and cost savings for the patient. The study findings may facilitate the formulation of policies for preventing pressure ulcer development in the perioperative setting.

Tissue temperature, flux and oxygen of sacral and trochanteric area under pressure of healthy subjects: A quasi-experimental study.

AIM: To evaluate the changes that take place in the perfusion, oxygenation and local temperature of the skin of the sacrum and trochanter when subjected to direct pressure for 2 h. METHODS: Quasi-experimental study in the preclinical phase with healthy subjects acting as their own controls (intrasubject control). The outcome variables were measured with a laser Doppler system (local temperature and oxygenation) and by near-infrared spectroscopy (perfusion). The pressure exerted was measured with a capacitive pressure sensor. No more than one week elapsed between the sacrum and trochanter measurements. RESULTS: The study sample consisted of 18 persons. The comparative analysis of the fluctuations in the parameters measured on the skin of the trochanters and sacrum, according to the time elapsed, revealed a statistically significant increase in temperature and in the pressure exerted. On the other hand, the changes in capillary blood flow and in SaO2 were not statistically significant. CONCLUSION: Our study results show that changes found in terms of temperature and pressure should be taking into account when planning personalised repositioning to patients according to biomechanical and biological situations that vary between anatomical areas. In future research, the changes reported could be evaluated in patients with risk factors for the development of pressure ulcers, thus facilitating the introduction of more personalised planning in the care and prevention of these injuries.

Sacral electroacupuncture as a treatment for urge urinary incontinence: a prospective case series.

OBJECTIVE: To examine the impact of electroacupuncture (EA) at the 'four sacral points' on urge urinary incontinence (UUI). METHODS: Twenty-five patients diagnosed with UUI or urgency-predominant mixed urinary incontinence (MUI) were treated by EA at the 'four sacral points'. EA was performed in the sacrococcygeal region using disposable sterile 0.40-mm-diameter acupuncture needles that were either 100 or 125 mm in length. Treatments were delivered once every other day. Before and after treatment, a questionnaire measuring symptom severity and quality of life associated with UUI was administered. RESULTS: The median total score (interquartile range) from the severity of symptoms and the quality of life questionnaire (Q-score) of the participants was significantly reduced from 12 (7.5, 15) before treatment to 3 (0, 6) after 6 (6, 12) EA treatments. The Q-score of urgency-predominant MUI and UUI was 8 (5, 14.5) and 12.5 (11, 15), respectively, before treatment; after treatment these were reduced to 2 (0, 7.5) and 4.5 (2, 6), respectively. There was no statistically significant difference in the Q-score between urgency-predominant MUI and UUI before and after treatment. Upon treatment completion, seven patients (28%) were 'cured' (improvement rate 100%). Treatments were considered 'markedly effective' (improvement rate 75% to <100%) in four patients (16%), 'effective' (improvement rate 50% to <75%) in eight patients (32%), 'minimally effective' (improvement rate 25% to <50%) in three patients (12%), and 'ineffective' (improvement rate <25%) in three patients (12%). The overall success rate (comprising 'cured', 'markedly effective' and 'effective' categories) was 76%, and no adverse effects associated with acupuncture treatment were reported. CONCLUSION: EA at the 'four sacral points' was associated with statistically significant improvements in UUI.

The Benefit of Perineural Injection Treatment with Dextrose for Treatment of Chondromalacia Patella in Participants Receiving Home Physical Therapy: A Pilot Randomized Clinical Trial.

Introduction: Chondromalacia patella is the degeneration of articular cartilage on the posterior facet of the patella and may indicate the onset of osteoarthritis. Conservative management is the main treatment option, and surgical intervention is considered the last option in a small percentage of patients. Perineural Injection Treatment (PIT) is a recently developed treatment option that is directed adjacent to the peripheral nerves that are the source of pathology causing neurogenic inflammation and pain. Objective: The objective of this study was to evaluate the efficacy of PIT combined with a home physical therapy program in patients with a diagnosis of chondromalacia patella compared with a control group receiving physical therapy only. Methods: Two patient groups were involved in this randomized clinical trial. The first received PIT combined with physical therapy (PIT + PT group) and the second was managed with physical therapy alone (PT group). Both groups were indicated to follow a 6-week home therapy plan afterward. The Western Ontario and McMaster Osteoarthritis Index was used to assess the patients at baseline and 6 months after therapy interventions. Results: Fifty patients (38 women and 12 men, median age 54.7 ± 14.8 years) were included; sex distribution and age did not differ between groups. Both groups had chondromalacia grade II or III, but the degree of gonarthrosis did not differ significantly between groups. The PIT + PT group outperformed PT group for pain (7.3 ± 3.5 vs. 3.2 ± 2.9 points; p < 0.010), stiffness (3 ± 1.69 vs. 1.6 ± 1.5 points; p < 0.010), and functional capacity (23.2 ± 10.7 vs. 11.1 ± 8.9 points; p < 0.010). Conclusions: Compared with physical therapy alone, PIT plus physical therapy reduced pain and stiffness and restored functional capacity. ClinicalTrials.gov Register Number #NCT03515720.

An Investigation of Pressure Ulcer Risk, Comfort, and Pain in Medical Imaging.

INTRODUCTION: Pressure ulcers present significant trauma to patients and are expensive to manage. In medical imaging (MI), no study has been conducted to rigorously investigate interface pressure (IP) risk on MI table surfaces. IP is defined as the pressure between human body and a supporting surface. The aims of this research were to investigate whether IP risks exist on MI table surfaces and to assess pain and comfort when lying on MI table surfaces. METHODS: A calibrated XSENSOR mat was used to measure IP for three jeopardy areas (head, sacrum, and heels) in healthy volunteers on an x-ray table surface with no mattress, an x-ray table surface with a thin radiolucent mattress, and a computed tomography table surface, after which they completed a pain and comfort questionnaire. RESULTS: The sample consisted of 26 females and 23 males aged 18-59 years (mean = 34.6; standard deviation [SD] = 10.5). Analysis of variance identified statistically significant differences in the mean IP for the jeopardy areas across the three MI table surfaces (P ≤ .001). Results also indicated high mean IP value for the head (75.9 mmHg; SD = 6.9) on the x-ray table with no mattress. Seventy percent of the volunteers found lying on the x-ray table with no mattress to be very uncomfortable. Sixty-seven percent experienced most pain whilst lying on the x-ray table with no mattress and over 81% of the pain occurred at the head. CONCLUSION: IP risk exists on x-ray tables with no mattress. This could increase the risk of developing pressure ulcers in patients accessing prolonged radiography/radiology procedures.

The effect of Aloe Vera gel on prevention of pressure ulcers in patients hospitalized in the orthopedic wards: a randomized triple-blind clinical trial.

BACKGROUND: One of the most common orthopedic problems is the incidence of pressure ulcer followed by immobility. This study aimed to investigate the effect of Aloe Vera gel on the prevention of pressure ulcer in patients hospitalized in the orthopedic ward. METHOD: This study is a randomized, triple-blind clinical trial which was done on 80 purposefully selected patients in orthopedic ward in Arak town, Iran, 2016. Patients were randomly assigned into two intervention and control groups based on blocking sampling method. In each group the routine daily cares to prevent bed sores were performed by nurses. In the intervention group in addition to routine nursing care to prevent bed sores, twice a day (hours of 9 and 21) pure Aloe Vera gel on the areas of hip, sacrum and heel were rubbed, but in the control group placebo (gel of water and starch) were used. Then sacral, hip and heel of both groups on days 3, 7 and 10 for of signs of pressure ulcers was evaluated. RESULTS: The mean age of patients in the control group was (42.34 ± 12.19) and in the intervention group Was (41.71 ± 11.50) years, respectively. In the intervention group 1 patient afflicted with sore of hip and two people with sacral pressure ulcer. In the control group 3 patients affiliated with sore of hip, 8 people with sacral pressure ulcer, and 1 person had pressure sore of heel. Analysis of the data showed that both groups had statistically significant differences in the incidence of pressure ulcers (P = 0.047). This means that Aloe Vera gel could prevent the occurrence of pressure ulcers in the intervention group. CONCLUSION: Due to the effect of Aloe Vera gel to prevent a rise in temperature, non-blanchable redness, swelling and pain of the skin of regions under study in hospitalized patients in the orthopedic ward, applying of it toward the prevention of pressure ulcers in patients at risk of pressure ulcer development is recommended. TRIAL REGISTRATION: This study was registered in Iranian Registry of Clinical. Trials in 07/09/2016 with the IRCT ID: IRCT2016051027825N1 .

Sacral Soft Tissue Deformations When Using a Prophylactic Multilayer Dressing and Positioning System: MRI Studies.

PURPOSE: The sacrum is the most common location of pressure injuries (PIs) in bedridden patients. The purpose of this study was to measure the effect of specific pressure preventive devices on sacral skeletal muscle, subcutaneous fat, and skin tissue deformations. SUBJECTS AND SETTING: The sample comprised 3 healthy adults residing in a community setting in Tel Aviv, Israel. DESIGN: Descriptive, comparative design. METHODS: Tissue thickness changes of 3 healthy adults were measured using magnetic resonance imaging (MRI) in weight-bearing sacral skin, subcutaneous fat, and muscle. Changes in tissue thickness were compared under the following conditions: (1) lying supine on a rigid surface (unpadded MRI table), (2) lying on a standard foam mattress, (3) lying on a mattress after application of a prophylactic multilayer dressing, and (4) lying on a standard foam mattress with a prophylactic multilayer dressing and a positioning system. One-way analysis of variance and post hoc Tukey-Kramer multiple pairwise comparisons were used to compare outcomes. RESULTS: The mattress, the prophylactic multilayer dressing, and the turning and positioning device when applied together resulted in significantly lower deformation levels of each of the soft tissue layers (ie, skin, subcutaneous fat, and muscle separately) as well as of the total soft tissue bulk, with respect to the rigid MRI table (P < .05). CONCLUSION: Study findings suggest that a combination of preventive interventions may reduce the risk of developing a sacral PI.

What Is New in Neuromodulation for Overactive Bladder?

We reviewed the available studies on efficacy and safety of percutaneous tibial nerve stimulation (PTNS) and sacral nerve modulation (SNM) for overactive bladder (OAB) symptoms not responsive to conservative treatments. We limited our search to randomized trials, in English, with at least 20 adult patients, and 6 mo and 12 wk of follow-up for SNM and PTNS, respectively, published between January 1998 and December 2017. Therapeutic success ranges from 61% to 90% for SNM and from 54% to 79% for PTNS. Both techniques are effective and safe, with no life-threatening adverse effects. PTNS is a less invasive technique that gives good results in short time with fewer side effects. PATIENT SUMMARY: Sacral nerve modulation and percutaneous tibial nerve stimulation are effective and safe in patients with overactive bladder syndrome not responsive to standard medical therapy.

Shaping the Output of Lumbar Flexor Motoneurons by Sacral Neuronal Networks.

The ability to improve motor function in spinal cord injury patients by reactivating spinal central pattern generators (CPGs) requires the elucidation of neurons and pathways involved in activation and modulation of spinal networks in accessible experimental models. Previously we reported on adrenoceptor-dependent sacral control of lumbar flexor motoneuron firing in newborn rats. The current work focuses on clarification of the circuitry and connectivity involved in this unique modulation and its potential use. Using surgical manipulations of the spinal gray and white matter, electrophysiological recordings, and confocal microscopy mapping, we found that methoxamine (METH) activation of sacral networks within the ventral aspect of S2 segments was sufficient to produce alternating rhythmic bursting (0.15-1 Hz) in lumbar flexor motoneurons. This lumbar rhythm depended on continuity of the ventral funiculus (VF) along the S2-L2 segments. Interrupting the VF abolished the rhythm and replaced it by slow unstable bursting. Calcium imaging of S1-S2 neurons, back-labeled via the VF, revealed that ∼40% responded to METH, mostly by rhythmic firing. All uncrossed projecting METH responders and ∼70% of crossed projecting METH responders fired with the concurrent ipsilateral motor output, while the rest (∼30%) fired with the contralateral motor output. We suggest that METH-activated sacral CPGs excite ventral clusters of sacral VF neurons to deliver the ascending drive required for direct rhythmic activation of lumbar flexor motoneurons. The capacity of noradrenergic-activated sacral CPGs to modulate the activity of lumbar networks via sacral VF neurons provides a novel way to recruit rostral lumbar motoneurons and modulate the output required to execute various motor behaviors. SIGNIFICANCE STATEMENT: Spinal central pattern generators (CPGs) produce the rhythmic output required for coordinating stepping and stabilizing the body axis during movements. Electrical stimulation and exogenous drugs can reactivate the spinal CPGs and improve the motor function in the absence of descending supraspinal control. Since the body-stabilizing sacral networks can activate and modulate the limb-moving lumbar circuitry, it is important to clarify the functional organization of sacral and lumbar networks and their linking pathways. Here we decipher the ascending circuitry linking adrenoceptor-activated sacral CPGs and lumbar flexor motoneurons, thereby providing novel insights into mechanisms by which sacral circuitry recruits lumbar flexors, and enhances the motor output during lumbar afferent-induced locomotor rhythms. Moreover, our findings might help to improve drug/electrical stimulation-based therapy to accelerate locomotor-based rehabilitation.

The within-day and between-day reliability of using sacral accelerations to quantify balance performance.

OBJECTIVES: To investigate the between-day and within-day reliability of a sacral mounted accelerometer to quantify balance performance and different balance metrics. DESIGN: Experimental, cross-sectional. SETTING: Laboratorial experiment. PARTICIPANTS: Thirty healthy volunteers. MAIN OUTCOME MEASURES: Balance tasks were double leg stance, tandem stance and single leg stance with eyes open and closed. Performance was measured by converting accelerations into path length (PL, length of the sway trace), jerk (jerkiness of sway trace) and root mean square (RMS) of the accelerations. RESULTS: Within-day ICC for PL were excellent (mean 0.78 95%CI 0.68-0.89), with Jerk and RMS demonstrating means of 0.60 and 0.47, respectively. The mean percentage minimal detectable change (MDC) within-day were small for PL (mean 6.7%, 95%CI 5.3-8.1). Between-day ICC were good for PL (mean 0.61, 95%CI 0.50-0.71), but more varied for Jerk and RMS. The mean percentage MDC was small for PL (mean 6.1%, 95%CI 5.0-7.2). No significant differences were determined for measurements between-days for any metric or task. PL had the highest discriminatory value between the 8 tasks. CONCLUSIONS: The sacral mounted accelerometer reliably measured balance performance within- and between-days. The PL is the recommended metric as it was the most reliable, most discriminatory and most sensitive to change.

A Comparison of Pressure Mapping Between Two Pressure-Reducing Methods for the Sacral Region.

PURPOSE: The objective of this study was to quantify tissue interface pressures that occurred in the sacrum, shoulder, and buttock/thigh regions while using (1) pillows or (2) a wedge system for off-loading of sacral pressures. SUBJECTS AND SETTING: Twenty-one volunteers (11 females and 10 males) residing near a Midwestern, university community consented to participate in the study. Testing was conducted in a hospital bed with pillows and a commercially available wedge system. METHODS: Pressures were measured under 3 test conditions: (1) bed alone, (2) pillows positioned above and below the sacral region, and (3) wedges positioned above and below the sacral region. Each condition was tested with the elevation of the head of the bed at 3 different angles with respect to the foot of the bed (0°, 20°, and 30°). Two pressure mats were used to capture data; one was located in the shoulder region and the other in the sacral/buttocks/thigh region. RESULTS: Between the pillows and the wedge, the wedge system was the most effective in reducing pressures on the sacral area. In comparison to the bed condition, both the pillow and wedge conditions produced significantly lower mean sacral pressures than the bed alone (P < .05). Because the pillow and wedge systems tilted the body onto one side, higher pressures were identified on the buttock/thigh when compared to the bed alone (P < .05). CONCLUSIONS: Pressure reduction occurred in the sacral region with the pillow and wedge systems; however, this reduction resulted in increased pressures in the posterior-lateral regions of the buttocks and thighs. When using off-loading devices, consideration should be given to all factors, including tissue interface pressures on the sacrum, increased pressures on other body locations, and the likelihood that these increased pressures will result in tissue damage.

Trunk active response and spinal forces in sudden forward loading: analysis of the role of perturbation load and pre-perturbation conditions by a kinematics-driven model.

Understanding the central nervous system (CNS) response strategy to trunk perturbations could help in prevention of back injuries and development of rehabilitation and treatment programs. This study aimed to investigate biomechanical response of the trunk musculoskeletal system under sudden forward loads, accounting for pre-perturbation conditions (preloading, initial posture and abdominal antagonistic coactivation) and perturbation magnitudes. Using a trunk kinematics-driven iterative finite element (FE) model, temporal profiles of measured kinematics and external load along with subjects' weights were prescribed to predict thoracolumbar muscle forces/latencies and spinal loads for twelve healthy subjects when tested in six conditions during pre- and post-perturbation periods. Results demonstrated that preloading the trunk significantly (i.e., p<0.05) increased pre-perturbation back muscle forces but significantly decreased post-perturbation peak muscle active forces and muscle latencies. Initial trunk flexion significantly increased muscle active and passive forces before the perturbation and their peak values after the perturbation, which in turn caused much larger spinal loads. Abdominal muscles antagonistic pre-activation did not alter the internal variables investigated in this study. Increase in sudden applied load increased muscle reflex activities and spinal forces; a 50 N increase in sudden load (i.e., when comparing 50 N to 100 N) increased the L5-S1 compression force by 1327 N under 5 N preload and by 1374 N under 50 N preload. Overall, forces on the spine and hence risk of failure substantially increased in sudden forward loading when the magnitude of sudden load increased and when the trunk was initially in a flexed posture. In contrast, a higher initial preload diminished reflex latencies and compression forces.

Microstimulation of afferents in the sacral dorsal root ganglia can evoke reflex bladder activity.

AIMS: Pudendal afferent fibers can be excited using electrical stimulation to evoke reflex bladder activity. While this approach shows promise for restoring bladder function, stimulation of desired pathways, and integration of afferent signals for sensory feedback remains challenging. At sacral dorsal root ganglia (DRG), the convergence of pelvic and pudendal afferent fibers provides a unique location for access to lower urinary tract neurons. Our goal in this study was to demonstrate the potential of microstimulation in sacral DRG for evoking reflex bladder responses. METHODS: Penetrating microelectrode arrays were inserted in the left S1 and S2 DRG of six anesthetized adult male cats. While the bladder volume was held at a level below the leak volume, single and multiple channel stimulation was performed using various stimulation patterns. RESULTS: Reflex bladder excitation was observed in five cats, for stimulation in either S1 or S2 DRG at 1 Hz and 30-33 Hz with a pulse amplitude of 10-50 µA. Bladder relaxation was observed during a few trials. Adjacent electrodes frequently elicited very different responses. CONCLUSIONS: These results demonstrate the potential of low-current microstimulation to recruit reflexive bladder responses. An approach such as this could be integrated with DRG recordings of bladder afferents to provide a closed-loop bladder neuroprosthesis.

Effect of tilt and recline on ischial and coccygeal interface pressures in people with spinal cord injury.

OBJECTIVE: Clinicians commonly recommend that power wheelchair users with spinal cord injury perform wheelchair tilt and recline maneuvers to redistribute seating loads away from the ischial tuberosities. However, ischial pressure reduction may be accompanied by coccygeal pressure increases. Although the coccyx is among the most common sites of pressure ulcers, few studies have reported coccygeal interface pressure. The purpose of this study was to investigate both ischial and coccygeal interface pressures in response to changes in wheelchair tilt and recline angles. DESIGN: Thirteen power wheelchair users were recruited into this study. Six combinations of wheelchair tilt (15, 25, and 35 degrees) and recline (10 and 30 degrees, corresponding to traditional recline conventions of 100 and 120 degrees, respectively) angles were tested in random order. Each combination was tested with 5 mins of upright sitting, 5 mins of tilt and recline, as well as 5 mins of maximal pressure relief recovery. Peak pressure indices were calculated at the ischial and coccygeal sites. RESULTS: Ischial pressures monotonically decreased in response to increasing combinations of tilt and recline. Increments of 15 degrees of tilt did not produce significant differences under either recline angle, whereas increments of 25 degrees of tilt produced significant differences under both recline angles. Coccygeal pressures increased in response to the four smallest (of six) combinations of tilt and recline, whereas they decreased in response to the largest two combinations. CONCLUSIONS: Ischial pressures seemed to be redistributed to the coccyx in response to the four smallest angle combinations and redistributed to the back support in response to the two largest angle combinations. Future work should confirm this pressure redistribution to the back support and determine the back support locations of redistribution.

Sensory neuron development in mouse coccygeal vertebrae and its relationship to tail biopsies for genotyping.

A common method of genotyping mice is via tissue obtained from tail biopsies. However, there is no available information on the temporal development of sensory neurons in the tail and how their presence or absence might affect the age for performing tail biopsies. The goals of this study were to determine if afferent sensory neurons, and in particular nociceptive neurons, are present in the coccygeal vertebrae at or near the time of birth and if not, when they first can be visualized on or in those vertebrae. Using toluidine blue neuronal staining, transmission electron microscopy, and calcitonin-related gene peptide immunostaining, we found proximal to distal maturation of coccygeal nerve growth in the C57BL/6J mouse. Single nerve bundles were first seen on postpartum day (PPD) 0. On PPD 3 presumptive nociceptive sensory nerve fibers were seen entering the vertebral perichondrium. Neural development continued through the last time point (PPD 7) but at no time were neural fibers seen entering the body of the vertebrae. The effect of age on the development of pain perception in the neonatal mouse is discussed.

Sacral neuromodulation for refractory overactive bladder, interstitial cystitis, and painful bladder syndrome.

Various pelvic floor conditions, including overactive bladder syndrome and chronic pelvic pain, have been successfully managed with the neuromodulation of sacral nerves. Sacral neuromodulation is a minimally invasive procedure involving the implantation of a programmable pulse generator that delivers low-amplitude electrical current via quadripolar tined leads through the S3 foramen. Durable efficacy has been demonstrated in retrospective studies, but questions regarding ideal patient candidacy and optimal technical considerations remain unanswered.

Trunk motion and gait characteristics of pregnant women when walking: report of a longitudinal study with a control group.

BACKGROUND: A longitudinal repeated measures design over pregnancy and post-birth, with a control group would provide insight into the mechanical adaptations of the body under conditions of changing load during a common female human lifespan condition, while minimizing the influences of inter human differences. The objective was to investigate systematic changes in the range of motion for the pelvic and thoracic segments of the spine, the motion between these segments (thoracolumbar spine) and temporospatial characteristics of step width, stride length and velocity during walking as pregnancy progresses and post-birth. METHODS: Nine pregnant women were investigated when walking along a walkway at a self-selected velocity using an 8 camera motion analysis system on four occasions throughout pregnancy and once post birth. A control group of twelve non-pregnant nulliparous women were tested on three occasions over the same time period. The existence of linear trends for change was investigated. RESULTS: As pregnancy progresses there was a significant linear trend for increase in step width (p = 0.05) and a significant linear trend for decrease in stride length (p = 0.05). Concurrently there was a significant linear trend for decrease in the range of motion of the pelvic segment (p = 0.03) and thoracolumbar spine (p = 0.01) about a vertical axis (side to side rotation), and the pelvic segment (p = 0.04) range of motion around an anterio-posterior axis (side tilt). Post-birth, step width readapted whereas pelvic (p = 0.02) and thoracic (p < 0.001) segment flexion-extension range of motion decreased and increased respectively. The magnitude of all changes was greater than that accounted for with natural variability with re testing. CONCLUSIONS: As pregnancy progressed and post-birth there were significant linear trends seen in biomechanical changes when walking at a self-determined natural speed that were greater than that accounted for by natural variability with repeated testing. Not all adaptations were resolved by eight weeks post birth.

Characterization of sacral interneurons that mediate activation of locomotor pattern generators by sacrocaudal afferent input.

Identification of the neural pathways involved in retraining the spinal central pattern generators (CPGs) by afferent input in the absence of descending supraspinal control is feasible in isolated rodent spinal cords where the locomotor CPGs are potently activated by sacrocaudal afferent (SCA) input. Here we study the involvement of sacral neurons projecting rostrally through the ventral funiculi (VF) in activation of the CPGs by sensory stimulation. Fluorescent labeling and immunostaining showed that VF neurons are innervated by primary afferents immunoreactive for vesicular glutamate transporters 1 and 2 and by intraspinal neurons. Calcium imaging revealed that 55% of the VF neurons were activated by SCA stimulation. The activity of VF neurons and the sacral and lumbar CPGs was abolished when non-NMDA receptors in the sacral segments were blocked by the antagonist CNQX. When sacral NMDA receptors were blocked by APV, the sacral CPGs were suppressed, VF neurons with nonrhythmic activity were recruited and a moderate-drive locomotor rhythm developed during SCA stimulation. In contrast, when the sacral CPGs were activated by SCA stimulation, rhythmic and nonrhythmic VF neurons were recruited and the locomotor rhythm was most powerful. The activity of 73 and 27% of the rhythmic VF neurons was in-phase with the ipsilateral and contralateral motor output, respectively. Collectively, our studies indicate that sacral VF neurons serve as a major link between SCA and the hindlimb CPGs and that the ability of SCA to induce stepping can be enhanced by the sacral CPGs. The nature of the ascending drive to lumbar CPGs, the identity of subpopulations of VF neurons, and their potential role in activating the locomotor rhythm are discussed.

Acute effect of passive static stretching on lower-body strength in moderately trained men.

The purpose of this investigation was conducted to determine the acute effect of passive static stretching (PSS) of the lower-body musculature on lower-body strength in a 1 repetition maximum (1RM) squat exercise in young (18-24 years.) moderately trained men (n = 17). Two supervised warm-up treatments were applied before each performance testing session using a counterbalanced design on nonconsecutive days. The first treatment consisted of an active dynamic warm-up (AD) with resistance machines (i.e., leg extension/leg flexion) and free weights (i.e., barbell squat), whereas the second treatment added PSS of the lower body plus the AD treatment. One repetition maximum was determined using the maximum barbell squat following a progressive loading protocol. Subjects were also asked to subjectively evaluate their lower-body stability during 1RM testing sessions for both the AD and PSS treatments. A significant decrease in 1RM (8.36%) and lower-body stability (22.68%) was observed after the PSS treatment. Plausible explanations for this observation may be related to a more compliant muscle tendon unit and/or altered or impaired neurologic function in the active musculature. It is also possible that strength was impaired by the PSS because of joint instability. The findings of this study suggest that intensive stretching such as lower-body PSS should be avoided before training the lower body or performing the 1RM in the squat exercise in favor of an AD dynamic warm-up using resistance training equipment in the lower-body musculature.