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Facial rejuvenation: a combined conventional and endoscopic assisted lift.

This article describes our personal approach for facial rejuvenation combining conventional and endoscopic procedures. For a forehead lift we use an endoscopic assisted technique. However, for the face and neck we still prefer the conventional lift. Good candidates for subperiosteal endoscopic midface lifts without skin resection are young or middle-age patients with midface ptosis and pronounced nasolabial/nasoyugal folds, without significant skin excess. Ptosis of the temporo-malar or facial area is also a good indication for subcutaneous endoscopic assisted lift. Aesthetic improvement of the forehead is evaluated with objective data of preoperative and postoperative measurements. We find this minimally invasive technique less traumatic and time consuming. It allows a greater range of possibilities for individual needs because it limits the incision and dissection to the required areas and has a higher level of acceptance by the patients. It is also a good complement to a conventional face lift.

Adult↗

Plasma volume change during heavy-resistance weight lifting.

Blood samples were obtained from six young men before, and over a 60-min period following a bout of heavy-resistance weight lifting to determine changes in plasma volume. Weight lifting consisted of three sets of four exercises (arm curl, bench press, bent-arm row, and squat) performed using 70% of one-repetition maximum for as many repetitions as possible. Plasma volume change was determined from haematocrit and haemoglobin concentration. During weight lifting, mean oxygen uptake and heart rate were 1.96 L X min-1 and 158 bt X min-1, respectively. Plasma volume was decreased -14.3% (p less than 0.05) immediately following exercise and -7.0% (p less than 0.05) at 15 min into recovery, but had returned to the resting level within 30 min. It was concluded that heavy-resistance weight lifting elicits a significant decrease in plasma volume, which is similar in magnitude to that observed during running and cycling at 80-95% of maximal oxygen uptake.

Adult↗

Serum and urinary markers of skeletal muscle tissue damage after weight lifting exercise.

The purpose of this study was to determine whether high intensity weight lifting exercise produces elevations of urinary 3-methylhistidine (3-MH), serum creatine kinase activity (CK), and serum myoglobin concentration (MY), and whether trained weight lifters differed in such responses when compared to a group of untrained subjects. Ten experienced male weight lifters (EWL) and seven untrained male subjects (IWL) performed three sets of six weight lifting exercises at 70%-80% of 1 RM. All subjects consumed a meat-free diet. The 3-MH:creatinine (3-MH:CR) values decreased 24 h and 48 h following exercise (P less than 0.05). The 12-h and 24-h postexercise CK response and the 12-h postexercise MY response increased for both EWL and IWL (P less than 0.05). However, EWL had a lower 24-h postexercise CK response and lower 12-h and 24-h postexercise MY responses compared to IWL (P less than 0.05). Within 48 h following weight lifting exercise, skeletal muscle protein degradation (as assessed by 3-MH:CR values) decreased regardless of prior training experience whereas skeletal muscle tissue damage (as assessed by CK and MY responses) increased. However, prior weight lifting training appeared to diminish the extent of muscle tissue damage.

Adult↗

Growth hormone responses during intermittent weight lifting exercise in men.

Five normal male volunteers performed two intermittent weight lifting exercises of equal total external work output and duration (20 min) with identical work-rest intervals but different load and frequency of movements. Exercise I consisted of seven sets of seven vertical leg lifts at 85% of the subject's Seven Repetition Maximum (SRM) and, 5 days later, seven sets of 21 vertical leg lifts with one-third of the previously used load (Exercise II). Blood was sampled throughout the exercise and recovery periods for growth hormone, lactate, and glucose analysis. Growth hormone increased after 20 min of Exercise I to a peak during the recovery period. Significantly elevated growth hormone (GH) levels were found 5, 10, and 15 min (P less than 0.025, P less than 0.05, P less than 0.025 respectively) of recovery after Exercise I. No significant elevations of GH occurred in Exercise II. Significant linear correlations (r = 0.99, P less than 0.01) with a time lag of 16 min were found between lactate and GH levels in Exercise I (lactate increases preceded those of GH). No significant differences in plasma glucose concentrations were detected. The results suggests that in intermittent weight lifting exercises of equal total external work output and duration as well as identical work-rest intervals, the load and/or frequency of an exercise are determinant factors in the regulation of plasma GH levels.

Adult↗

Relationship between oxidative stress in muscle tissue and weight-lifting-induced muscle damage.

We examined whether oxidative stress-induced muscle damage occurs during weight-lifting exercise using the rat model. Male Wistar rats were subjected to a single exhaustive session of weight-lifting exercise, and dynamics of blood volume and hemoglobin levels in the exercising muscle were monitored by near-infrared spectroscopy. Total muscle damage was evaluated by the efflux of serum creatine kinase (CK) and uptake of [(3)H]thymidine. The production of reactive oxygen species (ROS) in the muscle was estimated by serial changes in total superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) activities (established indirect markers). Immunohistochemical detection of GPX was also performed. A relatively anoxic state occurred repeatedly after every exercise set in exercising muscle following rapid blood reperfusion and was similar to an ischemia-reperfusion state. Serum CK and mitotic activity in the muscle consistently increased, and damaged muscle fibers that reacted positively to anti-GPX antibody were also observed after exercise. Serial changes in total SOD, GPX, and CAT activities were biphasic and exhibited peaks immediately and 24-72 h after exercise. The first increase was caused by a repeated ischemia-reperfusion-like state following weight-lifting exercise, and the second was dependent on the accumulation of infiltrated phagocytic cells at the damaged portions. These results suggest that ROS-induced muscle fiber damage occurred as a consequence of weight-lifting exercise.

Animals↗

Role of intra-abdominal pressure in the unloading and stabilization of the human spine during static lifting tasks.

The role of intra-abdominal pressure (IAP) in unloading the spine has remained controversial. In the current study, a novel kinematics-based approach along with a nonlinear finite-element model were iteratively used to calculate muscle forces, spinal loads, and stability margin under prescribed postures and loads measured in in vivo studies. Four coactivity levels (none, low, moderate, and high) of abdominal muscles (rectus abdominis, external oblique, and internal oblique) were considered concurrently with a raise in IAP from 0 to 4 kPa when lifting a load of 180 N in upright standing posture and to 9 kPa when lifting the same load in forward trunk flexions of 40 degrees and 65 degrees. For comparison, reference cases with neither abdominal coactivity nor IAP were investigated as well. A raise in IAP unloaded and stabilized the spine when no coactivity was considered in the foregoing abdominal muscles for all lifting tasks regardless of the posture considered. In the upright standing posture, the unloading action of IAP faded away even in the presence of low level of abdominal coactivity while its stabilizing action continued to improve as abdominal coactivity increased to moderate and high levels. For lifting in forward-flexed postures, the unloading action of IAP disappeared only with high level of abdominal coactivities while its stabilizing action deteriorated as abdominal coactivities increased. The unloading and stabilizing actions of IAP, hence, appear to be posture and task specific.

Abdominal Muscles↗

A comparison of two lifting assessment approaches in patients with chronic low back pain.

UNLABELLED: The Progressive Isoinertial Lifting Evaluation (PILE) and the lifting test of the WorkWell Systems Functional Capacity Evaluation (WWS) are well known as lifting performance tests. The objective of this study was to study whether the PILE and the WWS can be used interchangeably in patients with Chronic Low Back Pain (CLBP) and to explore whether psychosocial variables can explain possible differences. METHODS: 53 Patients (32 men and 21 women) with CLBP were tested twice in a counter balanced design. Pearson Correlation Coefficient of r > 0.75 and non-significant differences on two-tailed t tests were considered as good comparability. RESULTS: Pearson Correlation Coefficient was 0.75 (p < 0.01). Lifting performance on the WWS was a mean of 6.0 kg higher compared to the PILE (p < 0.01). The difference between the PILE and the WWS was unrelated to psychological variables. CONCLUSION: It can be concluded that the PILE and the WWS cannot be used interchangeably. Psychosocial variables cannot explain the differences between both tests.

Adaptation, Psychological↗

Muscular and centre of pressure response to sudden release of load in symmetric and asymmetric stoop lifting tasks.

Sudden changes in load during asymmetric lifting may be associated with a particularly high risk of loss of balance and spinal injury. Centre of pressure (COP) motions and electromyographic responses of trunk and lower limb muscles were studied in 10 normal male volunteers during sudden release of 20, 40, 60 and 80N stoop lifting loads in symmetric and asymmetric postures. Similar overall COP responses and muscular response strategies to sudden release of load were seen in both postures, although the asymmetric posture showed a larger medio-lateral COP displacements and greater co-contraction asymmetries. While sudden release of load in asymmetric stoop lifting does not seem to involve a greater risk of fall than symmetric lifting, the muscular response results in more complex and asymmetric loading of the trunk, indicating greater localised segmental loading and therefore increased risk of tissue injury.

Abdominal Muscles↗

The three-year economic benefits of a ceiling lift intervention aimed to reduce healthcare worker injuries.

Ceiling lifts are frequently advocated to mitigate risk of injury to healthcare workers when lifting, transferring, or repositioning patients. A longitudinal case-study was conducted in an extended care facility to evaluate the efficacy of overhead lifts in reducing the risk of injury beyond that previously reported for the first year post-intervention (Am. Assoc. Occup. 50 (3) (2002) 120-127, 128-134). Analysis of injury trends spanning 3 years pre-intervention and 3 years post-intervention, found a significant and sustained decrease in days lost, workers' compensation claims, and direct costs associated with patient handling injuries. The payback period was estimated assuming that pre-intervention injury costs would either continue to increase (0.82 years) or plateau (2.50 years) in the year immediately preceding intervention. The rapid economic gains and sustained reduction in the frequency and cost of patient handling injuries beyond the first year strongly advocate for ceiling lift programs as an intervention strategy.

Accident Prevention↗

Wrapping of trunk thoracic extensor muscles influences muscle forces and spinal loads in lifting tasks.

BACKGROUND: An improved assessment of risk of spinal injury during lifting activities depends on an accurate estimation of trunk muscle forces, spinal loads and stability margin which in turn requires, amongst others, an accurate description of trunk muscle geometries. The lines of action of erector spinae muscles are often assumed to be linear despite the curved paths of these muscles in forward flexion postures. METHODS: A novel approach was introduced that allowed for the proper simulation of curved paths for global extensor muscles in our Kinematics-driven finite element model. The lever arms of global muscles at different levels were restrained either to remain the same or decrease only by 10% relative to their respective values in upright posture. Based on our earlier measurements, static lifting tasks at two trunk flexions (40 degrees and 65 degrees ) and three lumbar postures (free style, lordotic and kyphotic) with 180 N in hands were analyzed. FINDINGS: Muscle forces and spinal compression at all levels substantially decreased as the global extensor muscles took curved paths. In contrast, the shear force at lower levels increased. Allowing for a 10% reduction in these lever arms during flexion increased muscle forces and compression forces at all levels. Despite smaller muscle forces, wrapping of global muscles slightly improved the spinal stability. INTERPRETATION: Consideration of global extensor muscles with curved paths and realistic lever arms is important in biomechanical analysis of lifting tasks. Reduction in the erector spinae lever arms during flexion tasks could vary depending on the lumbar posture. Results advocate small flattening of the lumbar curvature in isometric lifts yielding smaller compression and shear forces at the critical L5-S1 level.

Abdominal Muscles↗

Physiological effects of back belt wearing during asymmetric lifting.

This study investigated the effect of wearing a back belt on subjects' heart rate, oxygen consumption, systolic and diastolic blood pressure, and respiratory frequency during asymmetric repetitive lifting. Thirty subjects with materials-handling experience utilized three different belts (ten subjects per belt). Subjects completed six 30-min lifting sessions--three while wearing a belt and three without. Data analyses were conducted on the second, third, and fourth lifting periods. A 9.4 kg box, without handles, was lifted 3 times/min, starting at 10 cm above the floor, ending at 79 cm, with a 60 degree twist to the right. Data analysis indicates that belt-wearing did not have a significant effect on the overall mean values for heart rate, systolic and diastolic blood pressure, and respiratory frequency. Belt-wearing had a significant effect on the overall mean oxygen consumption of the subjects.

Adult↗

Maximum acceptable weight of lift by Chinese experienced male manual handlers.

This study uses a psychophysical methodology to determine the maximum acceptable weight of lift (MAWL) for 13 Chinese experienced male subjects, and examines the effects of variations in box size (including 300, 450 and 600 mm, sagittal distance from body) and lifting frequency (including one-time-maximum, 1, 4 and 6 lifts/min) on the MAWL, and the resulting responses [heart rate and rating of perceived exertion (RPE)]. The results are compared with prior studies and lead to the following conclusions: (1) Increases in both the box size and lifting frequency induced a significant decrease in MAWL, and a significant increase in RPE and heart rate. However, overall RPE ratings were not increased significantly with box size. (2) For Chinese inexperienced male subjects, the overall MAWL and heart rate were approximately 85% and 91% of their experienced male counterparts, respectively. The decrement in MAWL with Occidental subjects was about the same for both experienced and inexperienced groups; (3) The average MAWL values of Chinese subjects were smaller than those of Occidental subjects, and the average rate of decrease in MAWL with increasing of lifting frequency for the Chinese subjects was much sharper than in Occidental subjects; (4) There was no significant difference in overall heart rate and RPE ratings between the Chinese subjects and Occidental subjects. However, the body part RPE ratings were different from the previous studies. The present study found the most stressed body parts were the back and wrist, which may have been caused by the height of the table (760 mm) and the smaller body size of the Chinese subjects compared with the Occidental subjects.

Adult↗

Influence of breathing technique on arterial blood pressure during heavy weight lifting.

Arterial hypertension occurring during heavy resistance exercise may be a risk factor for stroke in healthy young adults. Any training method that ameliorates the pressor effect of exercise should reduce the risk of stroke. The objective of this study was to observe the influence of breathing technique on arterial blood pressure (BP) generated during heavy, dynamic weight lifting. BP was recorded in 10 male athletes by radial artery catheterization. Each subject then performed double-leg press sets at 85% and 100% of maximum. Each exercise was performed twice, once with closed glottis Valsalva, and then with slow exhalation during concentric contraction. The mean BP at 100% maximum with Valsalva was 311/284. The highest pressure recorded in an individual was 370/360. With slow exhalation, the mean BP was 198/175 when the same 100% maximum was lifted (p < .005). A reduced pressor response was also noted at 85% maximal lifting with slow exhalation. Arterial hypertension produced during heavy weight lifting with Valsalva is extreme and may be dramatically reduced when the exercise is performed with an open glottis (without Valsalva). It is concluded that heavy resistance exercise is safer when performed while the subject breathes with an open glottis.

Adult↗

Functional brain areas used for the lifting of objects using a precision grip: a PET study.

Positron emission tomography (PET) was performed in 10 normal volunteers to investigate regional cortical and subcortical activation induced by the lifting of an object repetitively using a precision grip between the index finger and thumb. Data were obtained for three object weights (4, 200 and 600 g) and a resting condition. Grip and lift forces on a similar object and the activity of selected muscles in the hand, arm and shoulder were also recorded in separate lifting trials. A comparison between all movement conditions and the resting condition revealed significant activation of the primary motor (M1), primary sensory (S1), dorso-caudal premotor (PM), caudal supplementary motor (SMA) and cingulate motor (CMA) cortices contralateral to the hand used. On the ipsilateral side, activation of the M1, caudal SMA and inferior parietal cortex (BA 40) was also found. In the subcortical areas, the bilateral hemispheres and right vermis of the cerebellum, left basal ganglia and thalamus were activated. Behavioral adaptation to a heavier object weight was revealed in a nearly proportional increase of both grip and lift forces, prolonged force application period and a higher level of hand and arm muscle activities. An increase in the rCBF associated with these changes was noted in several cortical and subcortical areas. However, consistent object weight-dependent activation was observed only in the M1/S1 contralateral to the hand used.

Adult↗

Hydro-resistive measurement of dynamic lifting strength.

A device is described for measuring strength and power outputs of dynamic vertical lifts between heights of 0.4 and 2.2 m. The device is safe, robust, and easily transportable. It consists of a water-filled tube 2 m high and 200 mm internal diameter. The subject pulls vertically on a handle which is connected with flexible wire rope via a series of pulleys to a piston suspended inside the tube. The piston has holes which can be closed with bungs. The drag force is proportional to the square of the velocity. The constant of proportionality can be chosen over a more than 100-fold range and is independent of temperature. Manual force is measured using a strain gauged cantilever over which the rope passes. Rope movement is monitored with a shaft encoder. These devices are sampled synchronously by an interfaced computer. Velocity and power are derived from the measurements of displacement, time and force. The device is highly accurate. Power measurements are not significantly different on two separate days although repetitions on one day show a warming-up effect. This device allows the study of dynamic lifts ranging from slow, high force, quasi-isokinetic lifts to lifts where high velocities and accelerations occur.

Biomechanical Phenomena↗

Comparative ability of EMG, optimization, and hybrid modelling approaches to predict trunk muscle forces and lumbar spine loading during dynamic sagittal plane lifting.

OBJECTIVE: To compare the ability of three modelling approaches to resolve the muscle and joint forces in a lumbar spine model during dynamic sagittal plane lifting. DESIGN: Trunk muscle forces, spine compression, and coactivity predicted through double linear optimization, EMG-assisted, and EMG assisted by optimization approaches were compared.Background. The advantages of EMG-based approaches are known from static task analyses. Limited assessment has been made for dynamic lifting. METHODS: Eleven male subjects performed sagittal plane lifting-lowering at fixed cadence from 0 degrees to 45 degrees of trunk flexion with and without an external load of 12 kg. Three-dimensional kinematics and dynamics as well as surface EMG provided inputs to a 12 muscle lumbar spine model. RESULTS: Trunk muscle coactivity was different between the modelling approaches but spine compression was not. Both EMG-based approaches were sensitive to trunk muscle coactivity and imbalance in left-right muscle forces during sagittal plane lifting. Overall, the best correlations between predicted forces and EMG as well as between forces predicted by different modelling approaches were obtained with the EMG-based models. Only the EMG assisted by optimization approach simultaneously satisfied mechanical and physiological validity. CONCLUSIONS: Both EMG-based approaches demonstrated their potential to detect individual trunk muscle strategies. A more detailed trunk anatomy representation would improve the EMG-assisted approach and reduce the adjustment to muscle force gain through EMG assisted by optimization. RELEVANCE: Injury to the lumbar spine could command alternative strategies of motion to attenuate pain and damage. To understand these strategies, the ideal lumbar spine model should predict individual muscle force patterns and satisfy mechanical equilibrium.

Adult↗

Shared memory representations for programming of lifting movements and associated whole body postural adjustments in humans.

This study examined whether the same memory representation is used for the parametric control of precision lifting and associated postural adjustments (APAs). Fifteen adults lifted object of different weights between the thumb and index finger. The employed grip, load (vertical lifting) forces, and ground reaction forces were recorded and the centre of pressure (COP) displacement as well as the corresponding first time derivatives were calculated. A highly significant correlation was found between the maximum rates of the load force, grip force and COP displacement rate. Different loads also influenced the onset of the COP displacement. The results corroborate the idea that the same memory representations which are used to control the manipulative lifting movement also control the APAs.

Adult↗

Anticipatory postural adjustments in a bimanual, whole-body lifting task seem not only aimed at minimising anterior--posterior centre of mass displacements.

Anticipatory postural adjustments (APAs) were studied in a bimanual whole-body lifting task, using a mechanical analysis of the downward movement phase preceding loaded versus unloaded lifts. APAs in the backward ground reaction force were found to lead the perturbing forward box reaction with approximately 400 ms, thus inducing a backward centre of mass momentum. Both the APA onset and magnitude were scaled as a function of the load to be lifted. We conclude that, in this lifting task, the APAs served the generation of an appropriate extending moment of the ground reaction force after box pick-up, rather than the traditionally defined goal of minimising anterior-posterior centre of mass displacements.

Adaptation, Physiological↗