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At least 19 recordsLinked to original sources
PubMed2006

Safe lifting in patients with chronic low back pain: comparing FCE lifting task and Niosh lifting guideline.

INTRODUCTION: Both the floor-to-waist lifting task of the Isernhagen Work Systems Functional Capacity Evaluation (IWS FCE) and recommended weight limit (RWL) of the NIOSH produce safe lifting weights and are used world-wide nowadays. It is unknown whether they produce similar safe lifting weights. Aim of this study was to compare FCE performance on the floor-to-waist lifting task and RWL of the NIOSH lifting guideline for this task, in patients with chronic low back pain (CLBP). METHODS: Ninety-two patients performed the FCE lifting task. RWL was calculated for this task. Performance was compared with RWL. A lifting index was calculated by dividing performance by RWL. Differences between groups with a lifting index < or =1, 1-3, and >3 were calculated for pain intensity, scores on the Roland Morris Disability Questionnaire (RMDQ) and work status. RESULTS: Men lifted on average 32.5 kg (SD 15.4) and women 18.8 kg (SD 7.8). RWL for this task was 12.8 kg. Mean difference between performance and RWL was 15.0 kg (SD 14.7; range -8.8 to 59.2). The Roland Morris Disability score of patients with a lifting index < or =1 was significantly lower than patients with a lifting index 1-3 and >3. No difference in pain intensity and work status was found between groups. CONCLUSION: It was concluded that performance on the FCE floor-to-waist lifting task and RWL of the NIOSH for this task produce different safe lifting weights in individual patients with CLBP, which may result in contradictory recommendations about need for rehabilitation and return to work.

Adolescent↗
PubMed2000

Back lift versus leg lift: an index and visualization of dynamic lifting strategies.

The description of a lifting strategy is typically provided in qualitative terms. A quantitative static descriptor or index differentiates the starting postures but not the primary moving segments. This technical note proposes an index that quantitatively characterizes different dynamic postural strategies employed during sagittal plane lifting. Dynamic lifting strategies are modeled in the velocity domain as different schemes of partitioning postural changes between the torso and leg segments. The index consists of two parameters, assigned to two leg segments, quantifying their contributions relative to the torso. Given a measured lifting movement, its index parameters values, ranging from 0.1 to 10, are estimated through an enumeration search process with the objective of minimizing the fitting error. The use of this index is illustrated by applying it to 24 lifting movements performed by six subjects assuming either a back-lift or a leg-lift strategy. Results indicate that a lifting strategy, in terms of whether the leg or the back is generally the prime mover, can be differentiated and visualized using this simple two-parameter index. In addition, indistinct intermediate strategies are also discerned, as the involvement of each segment in a lifting movement is quantified. The index is however limited in that it does not accommodate arm motion contributions to a lift nor possible time-dependent strategic changes during a lift. Potential future applications include time-efficient movement prediction and simulation for computerized biomechanical or ergonomic analysis.

Algorithms↗
PubMed1990

Lifting in four restricted lifting conditions: psychophysical, physiological and biomechanical effects of lifting in stooped and kneeling postures.

Many underground coal mines are less than 1.2 m in height, and require that manual lifting tasks be performed in restricted postures (usually stooped or kneeling). Unfortunately, little is known about how these postures affect the underground coal miner's capabilities to perform such work. A previous Bureau of Mines study indicated that lifting capacity is greater when stooped than kneeling when lifting under a 1.2 m roof height (Gallagher et al, 1988). However, many low-seam coal mines present even more restricted headroom than 1.2 m. Therefore, a study was conducted to: (1) examine the psychophysical lifting capacity of low-seam coal miners under four restricted lifting conditions, (2) investigate the associated metabolic costs, and (3) analyse the electromyography (EMG) of trunk muscles when lifting in these restricted positions. Subjects were 12 coal miners accustomed to handling materials in restricted postures (mean age = 35.9 yrs +/- 6.4 SD). Results of this study indicated that lifting capacity was greater when the subjects could assume a stooped posture than when kneeling (p < 0.01). Furthermore, the metabolic cost was greater in the kneeling posture for heart rate (p < 0.001), oxygen consumption (p < 0.001), minute ventilation (p < 0.05] ), and respiratory exchange ratio (p < 0.05), despite the fact that miners lifted less weight in this posture. Analysis of the EMG data indicated increased activity of the electores spinae when kneeling (p < 0.001), but higher latissimus dorsi activity when stopped (p < 0.001). The findings of this study indicate that the weight of supply items should be reduced approximately 14-18% when the kneeling posture must be used for lifting.

Journal Article↗
PubMed1997

Back pain in the workplace. What you lift or how you lift matters far less than whether you lift or when.

In spite of more than 50 years of concerted effort to diminish task demand, the incidence of compensable back injuries has not wavered. Before we persist for another 50 years in the quest for the "right way to lift," we should consider recent multivariate clinical investigations that suggest alternative approaches. Because task context is at least as important as task content in this regard, it follows that including regional backache under the rubric of "compensable injury" demands reconsideration. Likewise, rather than pursuing the "right way to lift," the more reasonable and humane quest might be for workplaces that are comfortable when we are well and accommodating when we are ill.

Adolescent↗
PubMed1994

A comparison of isokinetic lifting strength with static strength and maximum acceptable weight with special reference to speed of lifting.

A laboratory study was conducted to determine the effects of the speed of lifting and box size on isokinetic strength and to compare isokinetic lifting strengths with static lifting strengths and psychophysically determined maximum acceptable weights. Nine male college students lifted three different boxes (250, 380 and 510 mm wide) from the floor to a bench height of 0.8 m using a free-style lifting technique at a rate of 0.2 lifts min-1. For each lifting task static strength was measured at the origin of lift. Isokinetic lifting strength was measured at 0.41, 0.51 and 0.6 ms-1 using a Biokinetic ergometer and attaching boxes to the load cell. Ratings of perceived exertion were recorded for the low back. There was a progressive decrease in mean and peak isokinetic lifting strengths both with an increase in lifting speed and with an increase in box width (p < 0.01). The lifting speed had a much greater effect (29% and 27%) than the box width (18% and 15%) on mean and peak isokinetic lifting strengths. However, high speed lifting was perceived subjectively to be less stressful (RPE = 10.7) than slow speed lifting (RPE = 12.7). Static strength and maximum acceptable weight had higher correlations with mean isokinetic strength (r = 0.65 and 0.82) than with peak isokinetic strength (r = 0.52 and 0.73). At 0.41 ms-1, mean isokinetic strength peak 6% greater than the mean static strength (p > or = 0.05). Extrapolation of mean isokinetic strength data showed that at 0.73 ms-1 the estimated mean isokinetic strengths were within 6% of maximum acceptable weights. It is concluded that isokinetic strength is highly dependent upon the speed of lifting. At a slow speed (0.41 ms-1), mean isokinetic strength is equal to mean static strength; and, at a high speed (0.73 ms-1), it appears to be equal to the maximum acceptable weight. It is recommended that both speed of lifting and box width should be controlled carefully to stimulate job-specific isokinetic lifting strength.

Adult↗
PubMed1994

Influence of lifting technique on perceptual and cardiovascular responses to submaximal repetitive lifting.

Oxygen consumption (VO2), heart rate, ventilation and central rating of perceived exertion (RPE) in repetitive lifting while executing squat and stoop techniques were investigated in ten male forestry workers. In all five mass/frequency combinations studied, VO2 was significantly higher for the squat than for the stoop technique. No differences were found in RPE between the techniques. The VO2 and RPE recordings were also related to those obtained during maximal repetitive lifting (same lifting technique) and maximal treadmill running. The VO2 expressed as a percentage of that obtained during maximal repetitive lifting with the same lifting technique was defined as relative aerobic intensity (% VO2max,lifting). The % VO2max,lifting was not significantly different between the techniques except for the lowest mass lifted (1 kg). This study therefore would support the hypothesis that RPE is more closely related to % VO2max,lifting than to absolute aerobic intensity. Related to maximal treadmill running, it was demonstrated for both lifting techniques that relative RPE (percentage of the RPE during maximal running) was more accurate than relative VO2 (percentage of maximal VO2 during maximal running) for determining the % VO2max,lifting in repetitive lifting. The study showed that the higher VO2 during squat lifting compared to stoop lifting was caused by the VO2 expended in lifting and lowering the body rather than the VO2 expended lifting and lowering the external mass. It was concluded that the stoop technique was not superior to the squat technique in terms of central RPE. Based on % VO2max,lifting, there may be a rationale for choosing the stoop technique during repetitive lifting with light masses, but not with heavy masses.

Adult↗
PubMed2003

Maximum acceptable weight of lift for asymmetric lifting.

10 undergraduate men were tested to determine the effects of lifting mode and frequency on psychophysically established maximum acceptable weight of lift for 4 hr. of work. The heart rate and rate of perceived exertion (RPE) of the individuals while lifting the maximum acceptable weight of lift were measured. When performing a 90 degrees asymmetric lifting, subjects lifted approximately 10% less weight than lifted in symmetric lifting. Nonsignificant differences in maximum acceptable weight of lift, heart rate, and RPE values were found between asymmetric lifting with trunk rotation and asymmetric lifting with leg rotation. The lifting frequency significantly affected the maximum acceptable weight of lift, heart rate, and RPE. Heart rate and RPE increased with lifting frequency. The maximum acceptable weight of lift at 2 lifts/min. and 4 lifts/min. were approximately 91.5% and 82.5% of that of 1 lift/ min., respectively.

Adult↗
PubMedDate not supplied

Deep-plane face-lift vs superficial musculoaponeurotic system plication face-lift: a comparative study.

OBJECTIVE: To evaluate deep-plane face-lift vs superficial musculoaponeurotic system (SMAS) plication face-lift in correcting the melolabial fold, jowl, and cheek areas of the face in short-term follow-up. DESIGN: Masked, randomized review by 4 board-certified facial plastic surgeons experienced in rhytidectomy of full-face (frontal, oblique, and lateral views) before-and-after photographs of 20 patients who underwent deep-plane face-lift and 20 who underwent SMAS plication face-lift. Participants rated the melolabial fold, jowl, and cheek areas for overall correction of the deformities pertaining to the aesthetic results for deep-plane vs SMAS plication face-lift. Categories were excellent, good, average, acceptable, and poor. RESULTS: Three categories of results were determined: best, average, and poorest. Overall, SMAS plication face-lifts scored higher than deep-plane face-lifts. In the best category, there were more SMAS plication face-lifts. In the average category, there were more deep-plane face-lifts. In the poorest category, there were equal numbers of deep-plane and SMAS face-lifts. Patients were divided into the following age groups: 50 to 59, 60 to 69, and 70 to 80 years. In the 2 younger groups, SMAS face-lifts scored higher than deep-plane face-lifts. In the oldest group, deep-plane face-lifts scored slightly higher than SMAS face-lifts. CONCLUSION: Deep-plane face-lift does not seem to offer superior results over SMAS plication face-lift in patients younger than 70 years.

Aged↗
PubMed2005

Lifting strengths in different horizontal distances of objects to be lifted.

This study recruited eleven healthy males and thirteen healthy females to examine their maximum two-handed isometric back lifting strength, upper-body lifting strength, arm lifting strength and shoulder lifting strength in three different horizontal distances of objects to be lifted (toes were anterior to, aligned with, and posterior to the exerted handle). The results showed that human lifting strength decreased significantly as the toe position shifted from anterior of the vertical plane of the exerted handle to posterior of the vertical plane of the exerted handle. The strength order relationship between back lifting strength and upper-body lifting strength was dependent on the horizontal distance of objects to be lifted. This study also observed that the effects of the horizontal distance of objects to be lifted on human lifting postural angles for the four assessed lifting types mainly occurred in the upper extremities. This study recommends that practitioners should not overlook the effects of the horizontal distance of objects to be lifted on lifting strength when evaluating workers' lifting strength for screening purposes.

Adult↗
PubMed2001

Anticipatory control of vertical lifting force and momentum during the squat lift with expected and unexpected loads.

STUDY DESIGN: Mixed, repeated measures design. OBJECTIVES: To determine if previous experience with loads of similar weight influences the anticipatory lifting force and postural adjustments during the squat lift. To examine a multijoint, functional task for coordination between stability and movement. To determine if lifting unexpected loads results in trunk loading patterns associated with greater injury risk. BACKGROUND: Workers are increasingly exposed to variability in materials handling thereby increasing the risk of injury. Understanding the control processes underlying lifting will support clinical decision making for preparing injured workers to return to realistic working conditions. METHODS AND MEASURES: Subjects (19 men, 4 women; mean age, 25.4 +/- 3.5 y) lifted a series of boxes weighing 5%, 20%, and 35% of their maximal lifting capacity. The loads were delivered via a gravity conveyor. The identical-appearing loads were ordered so that the subjects lifted several loads of similar weight, immediately followed by a lighter or heavier than expected load based on the previous lift. RESULTS: Generally, the vertical lifting force, force rate, horizontal momentum, and angular momentum increased with an increase in expected load. Higher peak lumbar extensor moments occurred with lighter than expected loads (expected 20% and lifted 5% load = 238.2 +/- 91.2 N-m; expected 35% and lifted 5% load = 278.2 +/- 101.8 N-m) compared to expected loads of similar weight (expected and lifted 5% load = 205.0 +/- 73.2 N-m). Heavier than expected loads led to eccentric trunk movements when there were large mismatches between the expected and actual loads. CONCLUSIONS: The vertical lifting forces and whole body momentum were predictively scaled according to the expected load. The loading phase relationships indicated coordination between the lifting force, force rate, horizontal momentum, and angular momentum. Trunk loading during the lifts with unexpected loads showed patterns associated with increased injury risk.

Adult↗
PubMed2006

[Maximum acceptable weight of lift for manual lifting tasks].

OBJECTIVE: To explore the maximum acceptable weight of lift (MAWL) in different lifting conditions and the suitable lifting equation for the stipulation of occupational health standard of manual lifting tasks in China. METHODS: The MAWL was investigated among the thirteen male and ten female students using psychophysical methodology and the recommended weight of limit (RWL) was compared. RESULTS: The MAWL of male and female subjects was decreased gradually with the increase of lifting height. Once the height of lifting was over shoulder, the MAWL was decreased dramatically. The RWL was greater than the MAWL at 25 cm horizontal distance in male subjects, but the RWL was smaller than the MAWL at the distance of 45 cm and 63 cm. The average MAWL of male subjects was 30.8% greater than that of female subjects. The MAWL was decreased gradually with increase of the horizontal distance at the same height of lifting. The result of the male subjects was consistent with that of the female subjects. For the asymmetric lifting tasks of the male subjects, the bigger the angle of rotation was, the less the MAWL became. The angle of rotation had negative correlation with the capability of lifting (r = -0.996 6, P < 0.01). When the subjects performed asymmetric lifting tasks, the RWL was smaller than the MAWL and the difference was significant. CONCLUSION: The revision is sufficient for the horizontal distance and asymmetric lifting in the NIOSH lifting equation, but it is not suitable for height, especially for the task of lifting over shoulder. The RWL for the task of lifting over shoulder should be lowered. The factor of gender should be taken into account in the lifting equation and the constant of gender S can be added. Then S = 1 for male while S = 0.692 for female.

Adult↗
PubMed2005

Maximum isoinertial lifting capabilities for different lifting ranges and container dimensions.

The aim of this study was to examine the effects of lifting range and container dimension on human maximum isoinertial lifting capability in the sagittal plane. Ten young and experienced lifters were tested for their maximum isoinertial lifting capabilities for 12 different lifting conditions (three lifting ranges x four container dimensions). The results showed that lifting range and container dimension significantly affected human maximum isoinertial lifting capability. The order for the highest to lowest lifting capability for the three lifting ranges was FK (from floor to knuckle height, 0-74 cm), FS (from floor to shoulder height, 0-141 cm) and KS (from knuckle height to shoulder height, 74-141 cm) regardless of the container dimension, and for the four container dimensions was 50 x 35 x 15 cm(3), 70 x 35 x 15 cm(3), 50 x 50 x 15 cm(3) and 70 x 50 x 15 cm(3) regardless of the lifting range. The mean(SD) maximum isoinertial lifting capability ranged from 29.3(3.3) kg for the combination of KS range and 70 x 50 x 15 cm(3) container to 53.2(5.7)kg for the combination of FK range and 50 x 35 x 15 cm(3) container. The results of this study can help our knowledge of human maximum isoinertial lifting capability and designing the upper limit of lifting weight.

Adult↗
PubMed2005

Scaling of lifting forces in relation to object size in whole body lifting.

Subjects prepare for a whole body lifting movement by adjusting their posture and scaling their lifting forces to the expected object weight. The expectancy is based on visual and haptic size cues. This study aimed to find out whether lifting force overshoots related to object size cues disappear or persist over a number of repeated lifts. In addition, the influence of the degree of alternation between load sizes, and the influence of knowledge of actual object weights prior to the lifts, were investigated with regard to their effect on force overshoots. Four experiments were performed using a large and a small box, each of 8.4 kg weight, and varying degrees of alternation between boxes. In two of the experiments, subjects were informed about the weight of the objects, while in the other two experiments they were not informed about the weight of the objects. When boxes were lifted 15 times before switching to the other box, rapid diminishing of force scaling errors was observed. However, when boxes were alternated each lift or after three lifts, persisting force scaling overshoots were found in lifting the large box compared to the small one. When participants were given information regarding the actual object weight, force overshoots in the first pair of large and small box lifts were not different from overshoots in experiments where subjects were not informed about the weight of the objects. This shows that, for occupational lifting, risks related to force overshoots in lifting large objects can persist despite experience in lifting the objects and despite the use of labels indicating the weight of the objects.

Adult↗
PubMed1995

Effect of lifting belts, foot movement, and lift asymmetry on trunk motions.

Whether or not lifting belts protect workers from injury is a topic of considerable interest in industry. Not only is the protective effect uncertain, but the biomechanical basis for belt function is unclear. The objective of this study was to determine if lifting belts provide a means for controlling trunk motions during asymmetric material-handling tasks. We recruited 16 nursing personnel as experienced lifters to participate in two lifting sessions. A lifting belt was worn in one session and for a week prior to this session during the subjects' routine work activities. Each session required 42 lifts, distributed across three asymmetry conditions (0, 45, and 90 deg) and temporally spaced 30 s apart. Foot motion was not permitted in half the lifts. Results indicated that during lifting, lateral bending and twisting motions were reduced by both the lifting belt and foot motion; the most pronounced effect was observed at 90 deg of asymmetry. Trunk motions in the sagittal plane during lifting were not affected by the lifting belt. These results appear to support the use of lifting belts in asymmetric lifting conditions, but more research is needed to determine whether the muscles in the torso benefit from the reduced motion or are working harder to overcome this resistance to motion, causing increased internal loads on the spine during asymmetric material-handling tasks.

Adult↗
PubMed1997

Biomechanical assessment of lifting dynamics, muscle activity and spinal loads while using three different styles of lifting belt.

OBJECTIVE: To demonstrate the influence of different types of lifting belts on trunk motion, muscle activity and spine loading during symmetric and asymmetric lifting exertions. DESIGN. IN VIVO: measurements were achieved representing lifting dynamics, applied trunk moments and myoelectric activity. Dynamic spinal loads were determined from a validated biomechanical model of lifting. BACKGROUND: There is a great deal of controversy as to whether lifting belts are a benefit or a liability to manual materials-handling activities. A review of the literature demonstrates that there is a large amount of conflicting evidence and few definitive, well-executed studies upon which to base an opinion regarding these devices. METHODS: Fifteen subjects lifted boxes of 14 kg and 23 kg from sagitally symmetric and asymmetric origins to an upright posture. Dynamic trunk motions, lifting moments, myoelectric activity and modelled spinal loads were examined as a function of three belt styles (elastic, leather, and orthotic) and compared with results from a no-belt condition. RESULTS: Lifting belts reduced peak trunk angles, velocities and accelerations in the sagittal, lateral and transverse planes. However, only the elastic belt successfully reduced trunk motions in all three dimensions. The orthotic belt significantly increased the lifting moment associated with a given weight. A minor redistribution in muscle activity was observed when wearing an elastic belt. A statistically significant reduction in spinal load was associated with the elastic belt. However, a great deal of variability between subjects was noted. Some subjects experienced increased spinal load while wearing the elastic lifting belt. CONCLUSIONS: These results demonstrate that the biomechanical operation of lifting can be influenced by the type of lifting belts used.

Journal Article↗
PubMed2005

Secondary endoscopic forehead lift in patients with previous coronal brow lifts.

INTRODUCTION: The development of endoscopic surgical techniques has allowed an evolution from the standard coronal forehead lift to a minimally invasive one. Endoscopy avoids many of the undesirable results of the coronal approach while it remains very efficacious. The purpose of this study is to evaluate the effectiveness and safety of endoscopic forehead lift in patients who have previously undergone coronal brow lift. MATERIALS AND METHODS: A retrospective review was performed on the medical records of 726 consecutive patients who had undergone endoscopic forehead lift between 1994 and 2004. Sixty-three patients were identified who had undergone prior coronal incision brow lift and then required subsequent elevation of the forehead using endoscopy. Those who had persistent low eyebrows and forehead wrinkles underwent the standard minimal incision endoscopic approach. Patients with severe brow ptosis and excessive height of the forehead underwent a biplanar endoscopic forehead lift. RESULTS: Of the 63 endoscopic forehead lifts performed, 49 used the minimal access technique, while 14 employed the biplanar approach. The subject population consisted of 58 female and 5 male patients whose average age was 57 years (range of 42 to 80 years). Eighty-seven percent of these brow lifts also had concomitant rhytidectomy, and 4% had blepharoplasty. Average follow-up was 21 months (range 1 to 7 years). Following the endoscopic procedure, none of the patients had frontal nerve injury, alopecia, or persistent glabellar wrinkle lines. Complications included 1 forehead dysesthesia, 1 forehead irregularity, 1 eyebrow malposition, 1 persistent horizontal forehead wrinkling, and 2 hematomas. Operative management was not required for any of these complications. CONCLUSION: The secondary endoscopic forehead lift is effective in rejuvenating the upper face in the patient who has had a previous coronal forehead lift. It elevates the eyebrows and reduces both transverse and vertical wrinkles while avoiding further displacement of the hairline. The low rate of complications is comparable to that of primary endoscopic forehead lifts. Finally, serial follow-up indicates that the results are effective at correcting brow ptosis and are long lasting.

Adult↗
PubMed1990

Maximum acceptable weight of lift for side and back lifting.

A series of laboratory experiments were conducted to find maximum acceptable weights in front, side, and back lifting. Fifteen college students participated in the experiment. Experimental trials for each type of lifting were conducted for 10 min for each subject at a rate of 4 lifts/min. Psychophysical methodology was used to find the acceptable weight based upon their perceived feeling of stress in the lower back. It was found that subjects are willing to lift the heaviest load using back lifting (average maximum acceptable weight: 41.5 lbs). Front lifting was the close second with 39.4 lbs. Also, there was a significant difference in maximum acceptable weight of lift between side lifting (average maximum acceptable weight: 25.5 lbs) and the other two types of lifting. It was also found that leg strength was a limiting variable for maximum acceptable weight in front lifting. Composite strength and shoulder strength were found to be limiting variables in side lifting. Composite strength was the limiting variable in the back lifting.

Accidents, Occupational↗
PubMed1982

Perceived exertion during patient lifts. An evaluation of the importance of various factors for the subjective strain during lifting and carrying of patients. A study at a geriatric hospital.

Model experiments and practical studies of patient lifts were carried out with the aim of finding a method for assessing perceived exertion during various types of patient lifts. In the model experiments perceived exertion was rated on the RPE (Borg) scale under standardized conditions with variation of the subject's working posture and the load to be lifted. A strong correlation was found between increased perceived exertion and an un-optimal posture and heavy load respectively. In the practical study of patient lifts the following eight variables were rated: posture, acceleration, the patient's weight, time needed for the lift, the load, patient cooperation, the moment about the fulcrum and the possibilities of getting a good hold. The subjects were asked to rate the perceived exertion on the RPE scale. Six common types of patient lifts were studied. By multiple regression analysis the different variables were analysed in relation to perceived exertion. Strong correlations were found between different variables and perceived exertion, with some variation between the different types of patient lifts. The perceived exertion in various types of patient lifts can therefore be characterized by a small number of variables (the most strongly correlated). By choosing the most characteristic variables for each patient lift, the method can be utilized to study changes in the perceived exertion for different types of patient lifts when the external conditions during the lift are changed.

Adult↗