Recent evidence indicates that regular physical activity enhances brain plasticity (i.e. the ability to reorganise neural connections) and improves neurocognitive function. However, effect of on human motor cortex function is unknown. The purpose this study was examine for a small hand muscle in highly active sedentary individuals. Electromyographic recordings were obtained from left abductor pollicis brevis (APB) 14 subjects (aged 18-38 yrs). extent assessed by questionnaire, where...

Despite a similar rate of change in average electromyographic (EMG) activity, previous studies have observed different rates mean arterial pressure, heart rate, perceived exertion, and fluctuations motor output during the performance fatiguing contractions that involved types loads. To obtain more direct measure from spinal cord, purpose this study was to compare discharge characteristics same unit biceps brachii two contractions. In separate tests with upper arm vertical elbow flexed 1.57...

This study examined changes in corticomotor excitability and plasticity after a thumb abduction training task young old adults. Electromyographic (EMG) recordings were obtained from right abductor pollicis brevis (APB, target muscle) digiti minimi (ADM, control 14 (18-24 yr) (61-82 The consisted of 300 ballistic abductions the to maximize peak acceleration (TAAcc). Transcranial magnetic stimulation (TMS) left primary motor cortex was used assess APB ADM evoked potentials (MEPs)...

Regular physical activity is associated with enhanced plasticity in the motor cortex, but effect of a single session aerobic exercise on neuroplasticity unknown. The aim this study was to compare corticospinal excitability and upper limb cortical representation following lower cycling at either low or moderate intensity, control condition. We recruited 25 healthy adults take part three experimental sessions. Cortical examined using transcranial magnetic stimulation elicit motor-evoked...

Abstract Previous studies with transcranial magnetic stimulation (TMS) have shown that advancing age may influence plasticity induction in human motor cortex (M1), but these changes been assessed TMS‐induced paradigms or simple tasks. The aim of this study was to examine corticospinal excitability and intracortical inhibition as markers corticomotor following complex training young old adults. Electromyographic recordings were obtained from the right first dorsal interosseous (FDI) muscle 16...

The purpose of the study was to examine age-related differences in electromyographic (EMG) responses transcranial magnetic stimulation (TMS) during functional isometric contractions left and right hands. EMG were recorded from first dorsal interosseus muscle following TMS 10 young (26.6 +/- 1.3 yr) old (67.6 2.3 right-handed subjects. Muscle evoked potentials (MEPs) silent-period durations obtained hands index finger abduction, a precision grip, power scissor while held constant at 5%...

This study examined the strength of motor unit synchronisation based on time- and frequency-domain measures during postural, shortening lengthening contractions a hand muscle in young adults. Single activity was recorded with intramuscular electrodes left first dorsal interosseus as subject held index finger at constant position while supporting light load for 2-5 min. The then performed slow (1.7 deg s(-1)) to lift lower load. movement required subjects perform 10-25 constant-velocity over...

Despite limited data on humans, previous studies suggest that there is an association between the duration of daily muscle activity and proportion type I fibers. We quantified limb muscles in healthy men women during normal use compared these measurements with published reports fiber-type proportions. Seven (age range = 21–28 yr) seven 18–26 participated two 10-h recording sessions. Electromyogram (EMG) four nondominant upper (first dorsal interosseus biceps brachii) lower limbs (vastus...

The purpose of this study was to determine the effect eccentric exercise on correlated motor unit discharge (motor synchronization and coherence) during low-force contractions human biceps brachii muscle. Eight subjects (age, 25 +/- 7 yr) performed three tasks involving isometric contraction elbow flexors while EMG (surface intramuscular) records were obtained from brachii. Tasks 1) maximum voluntary (MVC); 2) constant-force at various submaximal targets; 3) sustained pairs concurrently...

The purpose of this study was to determine the effect eccentric exercise on ability exert steady submaximal forces with muscles that cross elbow joint. Eight subjects performed two tasks requiring isometric contraction right flexors: a maximum voluntary (MVC) and constant-force task at four target (5, 20, 35, 50% MVC) while electromyography (EMG) recorded from flexor extensor muscles. These were before, after, 24 h after period (fatigue muscle damage) or concentric only). MVC force declined...

The purpose of this study was to investigate how healthy young subjects with one three variants the brain-derived neurotrophic factor (BDNF) gene modulate motor cortex excitability following experimentally induced and use-dependent plasticity interventions. Electromyographic recordings were obtained from right first dorsal interosseous (FDI) muscle 12 Val/Val, ten Val/Met seven Met/Met genotypes (aged 18-39 years). Transcranial magnetic stimulation left hemisphere used assess changes in FDI...

Motor-unit synchronization, which is a measure of the near simultaneous discharge action potentials by motor units, has potential to influence spike-triggered average force and steadiness low-force isometric contraction. The purpose study was estimate contribution motor-unit synchronization larger forces decreased exhibited old adults. Eleven young (age 19-30 yr) 14 63-81 adults participated in study. activity recorded with two fine-wire intramuscular electrodes first dorsal interosseus...

The purpose of the study was to quantify strength motor-unit coherence from left and right first dorsal interosseous muscles in untrained, skill-trained (musicians), strength-trained (weightlifters) individuals who had long-term specialized use their hand muscles. quantified a total 394 pairs 13 subjects using data previous which differences were found synchronization depending on training status. In present study, we that significantly greater compared with untrained right-handed largest...

After participating in a 4-wk intervention that reduced normal usage of the elbow flexor muscles, all six women, but only one men, experienced marked increase endurance time during low-force fatiguing contraction. The was associated with an altered pattern muscle activation did not involve commonly observed progressive activity. Rather, activity comprised intermittent motor unit In those individuals who exhibited this behavior, novel present immediately after 4 wk limb immobilization and...