This chapter addresses the issue of associating the location and nature of the electric field sources below the surface of a conductive medium with the corresponding potential distribution on that surface. Single-point sources... more
This chapter addresses the issue of associating the location and nature of the electric field sources below the surface of a conductive medium with the corresponding potential distribution on that surface. Single-point sources (monopoles), pairs of opposite sources (dipoles), and pairs of dipoles (tripoles or quadrupoles) are investigated together with the detection modalities of the surface potential (monopolar, differential, etc.). The electric potentials generated by sources moving under these detection systems are described using a qualitative approach. The general concept of a spatial filter is introduced.
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The aim of the study was to non-invasively determine if vastus lateralis (VL) and vastus medialis obliquus (VM) muscles are equally affected by age-related fiber atrophy. Multichannel surface electromyography was used since it allows to... more
The aim of the study was to non-invasively determine if vastus lateralis (VL) and vastus medialis obliquus (VM) muscles are equally affected by age-related fiber atrophy. Multichannel surface electromyography was used since it allows to estimate muscle fiber conduction velocity (CV), which has been demonstrated to be related to the size of recruited muscle fibers. Twelve active elderly men (age 69 ± 4 years) and 12 active young men (age 23 ± 2 years) performed isometric knee extension at 30%, 50%, and 70% of maximal voluntary contraction. Electromyographic signals were recorded from VL and VM muscles of the dominant limb using arrays with eight electrodes and CVs were estimated for each contraction. CV estimates showed a different behavior in the two muscles: in VL at 50% and 70% of maximum voluntary contraction they were greater in young than in elderly; whereas such a difference was not observed in VM. This finding suggest that in active elderly VM seems to be less affected by the age-related fibers atrophy than VL. Hence, the common choice of studying VL as a muscle representative of the whole quadriceps could generate misleading findings. Indeed, it seemed that the sarcopenic ageing effects might be heterogeneous within quadriceps muscle.
Research Interests: Biomedical Engineering, Aging, Medicine, Spinal Muscular Atrophy, Elderly, and 15 moreHumans, Sarcopenia, Knee, Male, Electromyography, Medical Physiology, Aged, Skeletal Muscle, Atrophy, Isometric Exercise, Electrical And Electronic Engineering, Isometric Contraction, Vastus Lateralis, Quadriceps Muscle, and Vastus Medialis
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Research Interests: Biomedical Engineering, Fractals, Medicine, Physical Medicine and Rehabilitation, Humans, and 15 moreMale, Young Adult, Electromyography, Medical Physiology, Aged, Motor Unit, Muscle Fatigue, Muscle contraction, Fractal Dimension, Electrical And Electronic Engineering, Nerve Conduction Velocity, Vastus Lateralis, Muscle fibers skeletal, Quadriceps Muscle, and Vastus Medialis
Because rate of force development (RFD) is an emerging outcome measure for the assessment of neuromuscular function in unfatigued conditions, and it represents a valid alternative/complement to the classical evaluation of pure maximal... more
Because rate of force development (RFD) is an emerging outcome measure for the assessment of neuromuscular function in unfatigued conditions, and it represents a valid alternative/complement to the classical evaluation of pure maximal strength, this scoping review aimed to map the available evidence regarding RFD as an indicator of neuromuscular fatigue. Thus, following a general overview of the main studies published on this topic, we arbitrarily compared the amount of neuromuscular fatigue between the “gold standard” measure (maximal voluntary force, MVF) and peak, early (≤100 ms) and late (>100 ms) RFD. Seventy full-text articles were included in the review. The most-common fatiguing exercises were resistance exercises (37% of the studies), endurance exercises/locomotor activities (23%), isokinetic contractions (17%), and simulated/real sport situations (13%). The most widely tested tasks were knee extension (60%) and plantar flexion (10%). The reason (i.e., rationale) for eva...
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Research Interests: Psychology and Medicine
BACKGROUND Fatigue in Parkinson's Disease (PD) compromises patients' physical activity and poses questions on how to plan correct rehabilitation training. In addition, the relationship between subjective perceived fatigue and... more
BACKGROUND Fatigue in Parkinson's Disease (PD) compromises patients' physical activity and poses questions on how to plan correct rehabilitation training. In addition, the relationship between subjective perceived fatigue and fatigue in motor performance is not yet entirely understood. As a consequence, a conclusive interpretation of muscular mechanisms of fatigue in PD has not yet been achieved. Among the various instrumental evaluations for fatigue, multichannel surface electromyography (sEMG) is a recognized tool that permits the study of myoelectric manifestations of fatigue. AIM To assess if muscles in PD show a different myoelectric fatigue pattern compared to the muscles of healthy age-matched subjects. DESIGN Observational controlled study. POPULATION Idiopathic Parkinson's Disease, Hohen &Yahr II and III stage, Parkinsonian Fatigue Scale average score ≥ 2.95, no therapy modification in the 4 weeks preceding the study; exclusion criteria: Mini Mental State Examination ≤ 24, upper limb disease/symptoms that might interfere with sEMG analysis, presence of other fatiguerelated conditions. Twenty patients were selected according to these criteria. Twenty untrained healthy subjects were matched. METHODS All subjects underwent a muscle fatigue protocol and a sEMG analysis of the right biceps brachii muscle during electrically stimulated and voluntary contractions in order to obtain a myoelectric fatigue muscular pattern. The myoelectric pattern is characterized by the modifications of the following sEMG variables: reduction of mean frequency and muscle fibre conduction velocity, increase of average rectified value. RESULTS No statistical differences where observed between groups for sEMG variables and muscular electric behaviour in all contraction conditions (all p> .05). CONCLUSIONS Our results show that parkinsonian muscles does not differ from the muscles of healthy age-matched subjects in developing peripheral myoelectric fatigue. Nevertheless, the role of fatigue perception at rest and particularly during physical activity must be clearly understood in order to further target the rehabilitative approach for fatigued parkinsonian patients and to reduce hypomobility. CLINICAL REHABILITATION IMPACT In rehabilitative terms, these findings allow us to highlight the possibility of performing sustained training with isometric contractions in PD subjects; therefore, fatigue "per se" does not constitute a barrier for the execution of muscular exercises, likewise intensive.
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ABSTRACT Carpal Tunnel syndrome (CTS) is one of the most common compartmental syndromes and nerve conduction studies are widely considered as the standard to diagnose the pathology. The purpose of this pilot study was to investigate... more
ABSTRACT Carpal Tunnel syndrome (CTS) is one of the most common compartmental syndromes and nerve conduction studies are widely considered as the standard to diagnose the pathology. The purpose of this pilot study was to investigate whether multichannel surface electromyography can detect muscle alterations in patients diagnosed with severe CTS. Surface EMG signals were recorded at 10, 20, 30, and 80% MVC from the flexor and abductor pollicis brevis muscles of five patients with CTS and five control subjects. Subjects with severe CTS showed different interference patterns, lower signal amplitude, lower neuromuscular efficiency, and lower myoelectric manifestations of fatigue with respect to the control group. At submaximal levels, action potentials recorded from the flexor and abductor pollicis brevis muscles of the CTS group were characterized by lower conduction velocity and lower mean spectral frequency than the healthy group. These findings support, among others, the hypothesis of a selective loss of fast motor units (type II fiber) associated with CTS.
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ALBERTO RAINOLDI, TOSHIO MORITANI, AND GENNARO BOCCIA Professor of Physiology, Department of Medical Sciences, Motor Science Research Center, SUISM University of Turin, Turin, Italy Professor of Applied Physiology, Graduate School of... more
ALBERTO RAINOLDI, TOSHIO MORITANI, AND GENNARO BOCCIA Professor of Physiology, Department of Medical Sciences, Motor Science Research Center, SUISM University of Turin, Turin, Italy Professor of Applied Physiology, Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, Japan Motor Science Research Center, SUISM University of Turin, Turin, Italy; and CeRiSM Research Center “Sport, Mountain, and Health,” Rovereto (TN), Italy
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Purpose:The present study aimed to verify if practicing tackles during rugby union training sessions would affect the players’ internal training load and acute strength loss.Method:A total of 9 male ItalianSerie Arugby union players (age:... more
Purpose:The present study aimed to verify if practicing tackles during rugby union training sessions would affect the players’ internal training load and acute strength loss.Method:A total of 9 male ItalianSerie Arugby union players (age: 21 [2] y) were monitored by means of an integrated approach across 17 sessions, 6 with tackles (WT) and 11 with no tackles (NT). Edwards training load was quantified using heart-rate monitoring. Global positioning system devices were used to quantify the total distance and time at >20 W. Work-to-rest ratio was quantified by means of a video analysis. Before (PRE) and after (POST) the session, the players’ well-being and rating of perceived exertion were measured, respectively. The countermovement jump and plyometric push-up jump tests were performed on a force plate to record the players’ PRE–POST concentric peak force. Linear mixed models were applied to quantify the differences between WT and NT in terms of training load and PRE–POST force del...
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This study aimed to highlight the relationship between moderate-to-vigorous physical activity (MVPA) as assessed by accelerometer devices and the Physical Activity Questionnaire for Children (PAQ-C) to estimate the convergent validity of... more
This study aimed to highlight the relationship between moderate-to-vigorous physical activity (MVPA) as assessed by accelerometer devices and the Physical Activity Questionnaire for Children (PAQ-C) to estimate the convergent validity of the questionnaire. A systematic review and a meta-analysis were applied by collecting pertinent studies (PubMed, Web of Science, PsycINFO, and SCOPUS) from 1997 until November 2020. The relationship between PAQ-C and MVPA scores was estimated considering correlation coefficients such as the effect size. Fisher’s transformation was used to convert each correlation coefficient into an approximately normal distribution. The pooled correlations between PAQ-C and MVPA scores were measured by r values after converting the Fisher’s z values back into correlation coefficients for presentation. A total of 13 studies were included in the meta-analysis, and a random effects model was adopted. The pooled correlation between PAQ-C and MVPA scores was significant...
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Research Interests: Psychology, Adolescent, Medicine, Humans, Performance development, and 14 moreTalent, Female, Achievement, Male, Young Adult, Track and Field, Athletes, Adult, Public health systems and services research, Retrospective Studies, Athletic performance, Elsevier, Sport Specialization, and Competitive Behavior
Background and Purpose. This study evaluated an electromyographic technique for the measurement of muscle activity of the deep cervical flexor (DCF) muscles. Electromyographic signals were detected from the DCF, sternocleidomastoid (SCM),... more
Background and Purpose. This study evaluated an electromyographic technique for the measurement of muscle activity of the deep cervical flexor (DCF) muscles. Electromyographic signals were detected from the DCF, sternocleidomastoid (SCM), and anterior scalene (AS) muscles during performance of the craniocervical flexion (CCF) test, which involves performing 5 stages of increasing craniocervical flexion range of motion—the anatomical action of the DCF muscles. Subjects. Ten volunteers without known pathology or impairment participated in this study. Methods. Root-mean-square (RMS) values were calculated for the DCF, SCM, and AS muscles during performance of the CCF test. Myoelectric signals were recorded from the DCF muscles using bipolar electrodes placed over the posterior oropharyngeal wall. Reliability estimates of normalized RMS values were obtained by evaluating intraclass correlation coefficients and the normalized standard error of the mean (SEM). Results. A linear relationsh...
Research Interests: Skeletal muscle biology, Medicine, Physical Therapy, Humans, Female, and 15 moreMale, Orthopedics, Electromyography, Cervical Vertebrae, Clinical Sciences, Middle Aged, Head Movements, Skeletal Muscle, Adult, Repeatability, Analysis of Variance, Reproducibility of Results, Rotation, Spinal manipulation, and Pliability
Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity... more
Monitoring surface electromyographic (EMG) signals can provide useful insights for characterizing muscle fatigue, which is defined as an exercise-induced strength loss. This experiment investigated the muscle fiber conduction velocity (CV) changes induced by an endurance run. The day before and immediately after a half-marathon run (21.097 km) 11 amateur runners performed maximum voluntary contractions (MVCs) of knee extensor muscles. During the MVC, multichannel EMG was recorded from the vastus lateralis and EMG amplitude and CV were calculated. After the run, knee extensors showed a decreased strength (-13 ± 9%, p = 0.001) together with a reduction in EMG amplitude (-13 ± 10%, p = 0.003) and in CV (-6 ± 8%, p = 0.032). Knee extensor strength loss positively correlated with vastus lateralis CV differences (r = 0.76, p = 0.006). Thus, the exercises-induced muscle fatigue was associated not only with a decrease in EMG amplitude, but also with a reduction in CV. This f...
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PurposeThe aim of this study was to characterise postural control and lower limbs muscular strength in elderly people conditioned to long-term physical activity or sedentariness.MethodsThree groups of elderly males’ average age... more
PurposeThe aim of this study was to characterise postural control and lower limbs muscular strength in elderly people conditioned to long-term physical activity or sedentariness.MethodsThree groups of elderly males’ average age (mean ± SD) (67 ± 5 years) was studied: 11 tennis players (TP), 8 long-distance runners (LD) and 9 sedentary (S). The protocol consisted of standard balance tests with eyes open and closed in bipodalic (60 s) and monopodalic (30 s) conditions. Then, it was required to perform three isometric maximal voluntary contractions (MVCs) at the leg press to select the best one as reference. Postural static balance findings were further compared to a group of 15 young healthy sedentary males (average age 26 ± 1 years) (Y).ResultsTP showed more stability than S (p < 0.05) in bipodalic trials and greater force values during MVC than LD (p < 0.01). This group of elderly athletes showed the most similar postural characteristics to Y group. Post-hoc tests on MVC force showed a statistically significant difference (34 %, p < 0.01) between TP (1,456 ± 635 N) and LD (964 ± 219 N) groups. No statistically significant MVC differences were obtained between active and sedentary (1,129 ± 400 N) elderly groups. In TP force peak was found related with the average speeds in A-P and M-L planes of the balance performance (p < 0.05).ConclusionsIt is possible to conclude that postural stability and lower limb’s muscular strength can be increased in elderly people with a power physical activity, such as tennis. Thus it is also possible to speculate that such a conditioning can be considered promising to decrease risks of falling.