title: Side-alternating vibration training for balance and ankle muscle strength in untrained women.
abstract: BACKGROUND
  Side-alternating vibration (SAV) may help reduce the risk of falling by improving body balance control. Such training has been promoted as a strength-training intervention because it can increase muscle activation through an augmented excitatory input from the muscle spindles.
  
  
  OBJECTIVE
  To determine the effect of SAV training on static balance during 3 postural tasks of increasing difficulty and lower limb strength.
  
  
  METHODS
  Randomized controlled clinical trial.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  A total of 21 healthy women were divided into training (n = 11; age = 43.35 ± 4.12 years, height = 169 ± 6.60 cm, mass = 68.33 ± 11.90 kg) and control (n = 10; age = 42.31 ± 3.73 years, height = 167 ± 4.32 cm, mass = 66.29 ± 10.74 kg) groups.
  
  
  METHODS
  The training group completed a 9-week program during which participants performed 3 sessions per week of ten 15-second isometric contractions with a 30-second active rest of 3 exercises (half-squat, wide-stance squat, 1-legged half-squat) on an SAV plate (acceleration = 0.91-16.3g). The control group did not participate in any form of exercise over the 9-week period.
  
  
  METHODS
  We evaluated isokinetic and isometric strength of the knee extensors and flexors and ankle plantar flexors, dorsiflexors, and evertors. Static balance was assessed using 3 tasks of increasing difficulty (quiet bipedal stance, tandem stance, 1-legged stance). The electromyographic activity of the vastus lateralis, semitendinosus, medial gastrocnemius, tibialis anterior, and peroneus longus was recorded during postural task performance, baseline and pretraining, immediately posttraining, and 15 days posttraining.
  
  
  RESULTS
  After training in the training group, ankle muscle strength improved (P = .03), whereas knee muscle strength remained unaltered (P = .13). Improved ankle-evertor strength was observed at all angular velocities (P = .001). Postural sway decreased in both directions but was greater in the mediolateral (P < .001) than anteroposterior (P = .02) direction. The electromyographic activity of the peroneus longus increased during the sharpened tandem (P = .001) and 1-legged tasks (P = .007). No changes were seen in the control group for any measures.
  
  
  CONCLUSIONS
  The SAV training could enhance ankle muscle strength and reduce postural sway during static balance performance. The reduction in mediolateral sway could be associated with the greater use of ankle evertors due to their strength improvement.
authors.affiliation: Department of Physical Education and Sport Sciences at Serres, Aristotle University of Thessaloniki at Serres, Greece.
authors.forename: Styliani I
authors.initials: SI
authors.lastname: Spiliopoulou
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Amiridis
authors.forename: Georgios
authors.initials: G
authors.lastname: Tsigganos
authors.forename: Vassilia
authors.initials: V
authors.lastname: Hatzitaki
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology; D000843:Ankle Joint / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007717:Knee; D007719:Knee Joint / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D064797:Physical Conditioning, Human / Q000379:methods*; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology; D011788:Quality of Life; D055070:Resistance Training; D057185:Sedentary Behavior; D014732:Vibration
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