Neuromuscular coordination of squat lifting, I: Effect of load magnitude.

  title={Neuromuscular coordination of squat lifting, I: Effect of load magnitude.},
  author={John P. Scholz and J P Millford and Amy Gross McMillan},
  journal={Physical therapy},
  volume={75 2},
BACKGROUND AND PURPOSE In this study, we examined changes in kinematic and electromyographic (EMG) measurements of the coordination (ie, the relative timing of joint movements and muscle activity) of a squat-lifting task in response to lifting increasing loads. SUBJECTS Fifteen male industrial workers served as a sample of convenience. METHODS Subjects lifted a weighted crate containing 15% to 75% of their maximum lifting capacity using a symmetrical squat-lift technique. Movement… 
Fatigue-related changes in the coordination of lifting and their effect on low back load.
The adaptability of the neural control appeared to be sufficient to accommodate the strong changes of the input-output characteristics of the muscles caused by fatigue so that an essentially constant performance of the movement act was maintained.
Changes in the surface EMG signal and the biomechanics of motion during a repetitive lifting task
Time-frequency analysis procedures to compute the instantaneous median frequency (IMDF) suggest an association between muscle fatigue at the lumbar region and the way the subject manipulates the box during the exercise.
The effect of fatigue on multijoint kinematics, coordination, and postural stability during a repetitive lifting test.
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Effect of velocity on muscular coordination during isokinetic lifting: a preliminary study on healthy subjects
Except for the starting and final positions, no instruction was given to the subjects relating to the lifting technique, and the lifting was carried out as fast and strong as possible betweenastandardisedstarting and final position.
Effects of body mechanics training on performance of repetitive lifting.
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  • Medicine
    The American journal of occupational therapy : official publication of the American Occupational Therapy Association
  • 2000
Intensive instruction in body mechanics provided during the work-hardening treatment produced major changes in lifting styles, in terms of both starting postures and dynamic aspects of repetitive lifting.
Effects of repetitive lifting on kinematics: inadequate anticipatory control or adaptive changes?
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Delayed-Onset Muscle Soreness Does Not Alter the Kinematics and Kinetics of the Squat-Lifting Technique
Examination of the effects of delayed-onset muscle soreness (DOMS) in the thigh musculature on kinematic and kinetic variables associated with the squat-lifting technique found no effect on L5/S1 torque and shear or compression, hip torque and range of motion, or knee torque andrange of motion during lifting.
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  • 2015
Lifting characteristics of functionally limited elders.
Hip extensor strength correlated positively with box jerk, as did box jerk and peak trunk angular momentum between subjects, and there was an inverse correlation between peak upper body angular momentum when lifting a box from floor to knee height, and gait speed normalized to body weight.
Quantification of the Safe Maximal Lift in Functional Capacity Evaluations: Comparison of Muscle Recruitment Using SEMG and Therapist Observation
Convergent validity of the bench to shoulder lift of the WorkHab FCE was not established as no relationship between the muscle recruitment using SEMG and SML, as determined by therapist observation was identified during this lift.


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The greater ES and OA muscle activity occurring during the crucial initial period in the BBI lift may provide the best protection for the lumbar spine.
Spinal loading in static and dynamic postures: EMG and intra-abdominal pressure study.
The quantitative pattern of gradual increase and decrease of stress as measured by EMG of erectores spinae at T12 and L3 and intraabdominal pressure (IAP) due to steady progressive loading and unloading in static stooping posture was studied and compared with that of stoop lifting of the same weight.
Hip load moments and muscular activity during lifting.
The EMG levels of seven different hip muscles were normalized and expressed as a percentage of the recorded level of each muscle group during an isometric maximum voluntary contraction, and the initial activity in the hamstrings was higher in the straight knee lift compared to flexed knees.
The load on the lumbo-sacral joint and trunk muscle activity during lifting.
Four modes of lifting 12-8 kg from floor to table were studied on healthy subjects and the proportion of the mentioned maximum loading moments of force for L5-S1 which is caused by the weights of the body-segments was found of be ∼ 70% for all lifts.
Strategies for muscle activation during isometric torque generation at the human elbow.
It is argued that, for the human elbow joint at least, fixed muscle synergies are rather uncommon and that relationships between muscle activities are situation dependent, and that biceps brachii is often most active when brachioradialis and brachialis are least active.
Effect of attempted lifting speed on forces and torque exerted on the lumbar spine.
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  • Engineering
    Medicine and science in sports and exercise
  • 1985
Heavier loads were found to result in significantly higher values of mean compressive force, mean shear force, and maximum myoelectric activity, and faster target lifting times resulted inificantly higher mean and maximum values of all the variables quantified except intra-abdominal pressure.
Load on knee joint structures and muscular activity during lifting.
The load on the knee joints during lifting has been less studied than low back load and the three lifts were compared and discussed from a biomechanical and ergonomical point of view.
Responses of ankle musculature of healthy subjects and hemiplegic patients to sinusoidal anterior-posterior movements of the base of support.
The responses of the medical gastrocnemius and tibialis anterior muscles to continuous sinusoidal perturbation of the base of support were studied and a less discrete pattern, characterized by tonic contraction and periods of coactivation of the two muscles, was seen in older subjects who had difficulties in maintaining stance on the moving platform.
Electromyographic studies of the lumbar trunk musculature during the development of axial torques
The myoelectric activity of selected trunk muscles at the L3 level was studied during the development of a controlled isometric axial torque, suggesting that a considerable amount of the muscle contraction was used to control the posture.
Intra-abdominal pressure and trunk muscle activity during lifting. II. Chronic low-back patients.
The oblique abdominal muscles seem to be of no decisive importance to the intra-abdominal pressure during lifting in low-back patients and in healthy controls and the IAP was the same in the two groups despite the difference in abdominal muscle strength.