title: Assessment of forearm and plantar foot load in the elderly using a four-wheeled walker with armrest and the effect of armrest height.
abstract: BACKGROUND
  Patients with hand and/or wrist pathology are recommended to have a four-wheeled walker with an arm rest (FWW-AR) rather than a standard walker or a standard four-wheeled walker (FWW). However, only a few quantitative studies have been performed to compare upper and lower extremity weight bearing. The aim of this study was to evaluate forearm and foot weight bearing using a FWW-AR and the effect of the armrest height.
  
  
  METHODS
  Eleven elderly women (mean age 80.1±5.3 years; mean height 148.5±4.0 cm; mean weight 51.2±9.0 kg) were enrolled. The subjects walked with an FWW-AR, with the elbow in either 90 degree (D90) or 130 degree (D130) flexion, for a distance of 10 m. Surface electromyographic signals were recorded for the upper, middle, and lower trapezius, anterior deltoid, and erector spinae muscles; walking velocity was measured with the subjects weight bearing on their feet and forearms while walking. Simultaneously, the maximum plantar and forearm loads during walking with an FWW-AR were measured.
  
  
  RESULTS
  The normalized foot plantar loads were lower at D90 than at D130, while the normalized forearm load was higher at D90 than at D130 (all P<0.05; left foot, 7.9±0.1 N/kg versus 8.8±0.1 N/kg; right foot, 8.6±0.2 N/kg versus. 9.6±0.1 N/kg; left forearm, 1.8±0.5 N/kg versus 0.8±0.2 N/kg; and right forearm, 2.0±0.5 N/kg versus 1.0±0.2 N/kg, respectively). The surface electromyographic activity of the muscles involved in shoulder elevation and the walking velocity were both lower with the elbow at D90 than at D130 (all P<0.05; left upper trapezius, 98.7%±19.5% versus 132.6%±16.9%; right upper trapezius, 83.4%±10.6% versus 108.1%±10.5%; left anterior deltoid, 94.1%±12.8% versus 158.6%±40.4%; right anterior deltoid, 99.1%±15.0% versus 151.9%±19.4%; and velocity, 0.6±0.1 m/sec versus 0.7±0.1 m/sec, respectively).
  
  
  CONCLUSIONS
  Weight bearing on the lower extremities is significantly reduced when the upper extremities are supported during walking with an FWW-AR. Furthermore, the weight bearing profile is dependent on the armrest height.
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Chang-Yong
authors.initials: CY
authors.lastname: Ko
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Sol-Bi
authors.initials: SB
authors.lastname: Kim
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Hyuk-Jae
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Yunhee
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Sungjae
authors.initials: S
authors.lastname: Kang
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Yoon
authors.initials: Y
authors.lastname: Heo
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Jeicheong
authors.initials: J
authors.lastname: Ryu
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Gyoosuk
authors.initials: G
authors.lastname: Kim
authors.affiliation: Korea Orthopedics and Rehabilitation Research Center, Incheon, South Korea.
authors.forename: Museong
authors.initials: M
authors.lastname: Mun
mesh_terms: D061725:Accelerometry; D000368:Aged; D000369:Aged, 80 and over; D001827:Body Height; D004576:Electromyography; D004867:Equipment Design; D005260:Female; D005528:Foot / Q000503:physiopathology*; D005542:Forearm / Q000503:physiopathology*; D006801:Humans; D014853:Walkers; D016138:Walking / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*
keywords: armrest height; forearm; four-wheeled walker with armrest; plantar foot; weight bearing