title: The effect of pillow height on muscle activity of the neck and mid-upper back and patient perception of comfort.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the comfort and the electromyographic (EMG) activity of the neck and mid-upper back of asymptomatic adults using foam pillows of 3 different heights.
  
  
  METHODS
  Twenty-one asymptomatic adults used foam pillows of 3 different heights (1: 5 cm, 2: 10 cm, and 3: 14 cm). Comfort was assessed using a 100-mm visual analog scale. Electromyographic activity was assessed in the lateral position. We calculated the root mean square (RMS) in 500-millisecond windows of bilateral EMG activity of the sternocleidomastoid and upper and middle trapezius, normalized by maximal isometric contraction of each individual. The RMS of the EMG signals was compared among pillow heights using repeated-measures analysis of variance (P < .05).
  
  
  RESULTS
  The middle trapezius muscle of the down-side showed the highest RMS in height 1 when compared with heights 2 (P = .0163) and 3 (P = .0313), with no statistical significance between pillow heights 2 and 3 for this muscle. There were no statistical differences between pillows 2 and 3 in any muscle activity. Height 2 was considered the most comfortable (P < .001) compared with heights 1 and 3, and height 1 the least comfortable (P < .001) compared with the other heights.
  
  
  CONCLUSIONS
  For the participants in this study, there was an association among pillow height, myoelectric activity, and comfort.
authors.affiliation: Associate Professor, Physical Therapy, Speech and Occupational Therapy Department, School of Medicine, University of São Paulo, São Paulo, Brazil. Electronic address: icnsacco@usp.br.
authors.forename: Isabel C N
authors.initials: IC
authors.lastname: Sacco
authors.affiliation: MSc, Physiotherapist, Speech and Occupational Therapy Department, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Ivye L R
authors.initials: IL
authors.lastname: Pereira
authors.affiliation: MSc, Physical Educator, Physical Therapy, Speech and Occupational Therapy Department, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Roberto C
authors.initials: RC
authors.lastname: Dinato
authors.affiliation: Physiotherapist, Speech and Occupational Therapy Department, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Vivian C
authors.initials: VC
authors.lastname: Silva
authors.affiliation: Physiotherapist, Speech and Occupational Therapy Department, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Friso
authors.affiliation: Physiotherapist, Speech and Occupational Therapy Department, School of Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Samires F
authors.initials: SF
authors.lastname: Viterbo
mesh_terms: D000328:Adult; D064131:Back Muscles / Q000502:physiology*; D001416:Back Pain / Q000517:prevention & control*; D001512:Bedding and Linens; D004576:Electromyography / Q000379:methods; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D009334:Neck Muscles / Q000502:physiology*; D019547:Neck Pain / Q000517:prevention & control*; D058748:Pain Perception / Q000502:physiology; D011187:Posture / Q000502:physiology; D013035:Spasm / Q000517:prevention & control; D055815:Young Adult
keywords: Bedding and Linens; Electromyography; Neck Muscles; Sleep