title: On the effect of thermal agents in the response of the brachial biceps at different contraction levels.
abstract: The objective of this study was to assess electromyographic features of the brachial biceps muscle after the application of cryotherapy and short-wave diathermy. Sixty healthy volunteers participated in the study and were equally divided into three groups: cryotherapy - application of ice packs for 30 min; short-wave diathermy for 20 min; and control. The thermal agents were applied to the anterior and posterior regions of the non-dominant arm. The electromyographic (EMG) signal from the brachial biceps was recorded before and after the application of thermal agents during flexion of the elbow joint at 25%, 50%, 75% of a maximum voluntary isometric contraction defined at least two days before the actual experiments (MVICbl). The volunteers also were asked to execute a free MVIC before and after the application of the thermal agents (MVIC free). A linear regression model with mixed effects (random and fixed) was used. Intra-group analysis showed a reduction in root mean square (RMS) at MVIC free, with no change in the median frequency of the EMG signal at any contraction level for the short-wave diathermy group. An increase on RMS values and a decrease on median frequencies were found after the application of cryotherapy for all contraction levels. The results imply that cryotherapy plays an important role on changing neuromuscular responses at various levels of muscle contraction. Therapists should be aware of that and carefully consider its use prior to activities in which neuromuscular precision is required.
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Larissa Martins
authors.initials: LM
authors.lastname: Garcia
authors.affiliation: Faculty of Electrical Engineering, Biomedical Engineering Lab, Federal University of Uberlândia, Uberlândia, MG, Brazil.
authors.forename: Alcimar Barbosa
authors.initials: AB
authors.lastname: Soares
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Camila
authors.initials: C
authors.lastname: Simieli
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Alessandra Vairo Peres
authors.initials: AV
authors.lastname: Boratino
authors.affiliation: Department of Biomechanics, Medicine and Rehabilitation of the Locomotor System, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil. Electronic address: rguirro@fmrp.usp.br.
authors.forename: Rinaldo Roberto de Jesus
authors.initials: RR
authors.lastname: Guirro
mesh_terms: D000293:Adolescent; D000328:Adult; D001132:Arm / Q000502:physiology*; D017679:Cryotherapy / Q000379:methods*; D003972:Diathermy / Q000379:methods*; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D016014:Linear Models; D018482:Muscle, Skeletal / Q000502:physiology*; D055815:Young Adult
keywords: Cryotherapy; Diathermy; Electromyography; Neuromuscular control; Short-wave