title: Acute effects of incremental inspiratory loads on compartmental chest wall volume and predominant activity frequency of inspiratory muscle.
abstract: OBJECTIVE
  This research aims to analyze the acute effect of incremental inspiratory loads on respiratory pattern and on the predominant activity frequency of inspiratory muscle, taking into account differences in gender responses. Optoelectronic Plethysmography was performed during loads in 39 healthy subjects (20 women), placing 89 markers on the thoracic-abdominal wall to obtain total and regional volumes. Surface electromyography (SEMG) was taken simultaneously on the Sternocleidomastoid and Diaphragm muscles, to calculate the predominant muscle activity frequency through wavelet analysis. Inspiratory loads were performed using Threshold(®)with 2 min of breathing at different levels, ranging from a load of 10 cmH(2)O plus 5 cmH(2)O to 40 cmH(2)O or fatigue.
  
  
  RESULTS
  Inspiratory Time increased during loads. Total and compartmental volumes increased with different regions, changing at different loads. These changes in volume occur earlier in women (20 cmH(2)O) than in men (30 cmH(2)O). The predominant activity frequency of Sternocleidmastoid muscle decreased at 30 cmH(2)O, while Diaphragm activity decreased at 40 cmH(2)O.
  
  
  CONCLUSIONS
  The acute effects of incremental inspiratory loads are increases of total and regional volumes and inspiratory time. As for muscle activity, the predominant activity frequency declined in Sternocleidomastoid and Diaphragm muscles, but at different loads. Such respiratory and SEMG patterns and gender differences should be considered when clinical interventions are performed.
authors.affiliation: Department of Physiotherapy of Universidade Federal de Pernambuco, Recife, Brazil.
authors.forename: Alana Elza Fontes
authors.initials: AE
authors.lastname: Da Gama
authors.forename: Larissa
authors.initials: L
authors.lastname: de Andrade Carvalho
authors.forename: Larissa Andrade
authors.initials: LA
authors.lastname: Feitosa
authors.forename: Jasiel Frutuoso
authors.initials: JF
authors.lastname: do Nascimento Junior
authors.forename: Marilú Gomes Netto Monte
authors.initials: MG
authors.lastname: da Silva
authors.forename: César F
authors.initials: CF
authors.lastname: Amorim
authors.forename: Andréa
authors.initials: A
authors.lastname: Aliverti
authors.forename: Daniel
authors.initials: D
authors.lastname: Lambertz
authors.forename: Marco Aurélio Benedetti
authors.initials: MA
authors.lastname: Rodrigues
authors.forename: Armèle Dornelas
authors.initials: AD
authors.lastname: de Andrade
mesh_terms: D000009:Abdominal Muscles; D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D003430:Cross-Sectional Studies; D003964:Diaphragm / Q000502:physiology; D004576:Electromyography; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D001239:Inhalation / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal; D009929:Organ Size; D010991:Plethysmography; D012132:Respiratory Muscles / Q000502:physiology*; D012727:Sex Characteristics; D035441:Thoracic Wall / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: Breathing exercises; Electromyography; Plethysmography; Respiratory muscles