Distinct brain activation patterns for human maximal voluntary eccentric and concentric muscle actions

Maximum Symmetric and Asymmetric Isoinertial Lifting Capabilities from Floor to Knuckle Height

“…Notably, increasing a container's length or width would not only decrease human maximum isoinertial lifting capability due to a longer moment arm for the exerted muscles but also impose a more hazardous condition to the musculoskeletal system since the muscles contracts at a longer muscle length. It is well known that skeletal muscles are more prone to injuries during eccentric contractions than isometric or concentric contractions [18][19][20][21] due to the muscle tension produce being distributed over a smaller number of active fibers, increasing the load for individual fibers and thus the risk of damage 22) . This physiological phenomenon and the experimental data of lifting capability encourage a necessity for designing an optimal containers dimension for manual materials handling tasks.…”

Intracortical Inhibition Assessed with Paired-Pulse Transcranial Magnetic Stimulation is Modulated during Shortening and Lengthening Contractions in Young and Old Adults

“…Previous studies using electroencephalography (EEG) in young subjects have reported that movement related cortical potentials are greater during lengthening than shortening contractions [10,11], suggesting that reductions in inhibitory tone should be greatest during muscle lengthening. However, a more recent study using functional magnetic resonance imaging (fMRI) has localised this increased cortical activity during lengthening contractions to higher order motor areas, such as the pre-supplementary motor area and anterior cingulate cortex [9].…”

“…This includes observations that voluntary activation, electromyography (EMG), force generation and spinal motoneuron excitability are all different during lengthening contractions [1,2]. Furthermore, recent evidence from studies using a range of neurophysiological and neuroimaging techniques have provided compelling support for distinct patterns of cortical activity during lengthening contractions [3][4][5][6][7][8][9][10][11]. In addition, lengthening contractions are also associated with reduced motor performance [12][13][14].…”

Acute neuromuscular response during eccentric overload protocol by using a mechanical device to increase the load

“…Another explanation is the contribution of the passive elements during the ECC action to compensate the lack of the contractile materials (i.e. fewer cross bridges) 3,24 which might have an effect on the neuromuscular activation.…”

“…Distinct patterns of muscle activation and strength production between eccentric (ECC) and concentric (CON) muscle actions have been detected during resistance training [1][2][3][4] with a higher capacity to produce strength during ECC actions [5][6] . Training where ECC actions were overload (ECC overload [EO] training), performed with more load than during CON action it was verified after training an increase on the size of type IIX fibres 7 , a higher increase at isokinetic and isometric force production 8 and higher neuromuscular activation [8][9][10] .…”