title: Association between energy cost of walking, muscle activation, and biomechanical parameters in older female fallers and non-fallers.
abstract: OBJECTIVE
  To determine the nervous activation, muscle strength, and biomechanical parameters that influence the cost of walking in older fallers and non-fallers.
  
  
  METHODS
  Maximal voluntary isokinetic torque was measured for the hip, knee and ankle of older women. Oxygen consumption was measured at rest and during 8min of walking at self-selected speed. An additional minute of walking was performed to collect kinematic variables and the electromyographic signal of trunk, hip, knee, and ankle muscles, which was analyzed by the linear envelope. Cost of walking was calculated by subtracting resting body mass-normalized oxygen consumption from walking body mass-normalized oxygen consumption. Stride time and length, and ankle and hip range of motion were calculated from kinematic data.
  
  
  RESULTS
  Older adult fallers had 28% lower knee extensor strength (p=0.02), 47% lower internal oblique activation at heel contact (p=0.03), and higher coactivation between tibialis anterior and gastrocnemius lateralis in each of the gait phases (p<0.05). For fallers, a higher activation of gluteus maximus was associated with a higher cost of walking (r=0.55, p<0.05 and r=0.71, p<0.01, before and after heel contact, respectively). For non-fallers, an association between cost of walking and age (r=0.60, p=0.01) and cost of walking and thigh muscle coactivation (r=0.53, p=0.01) existed.
  
  
  CONCLUSIONS
  This study demonstrated that there may be links between lower-extremity muscle weakness, muscle activation patterns, altered gait, and increased cost of walking in older fallers.
authors: Department of Physical Education, São Paulo State University, São Paulo, Brazil. nisermarques@yahoo.com.br
authors: Nise Ribeiro
authors: NR
authors: Marques
authors: Dain Patrick
authors: DP
authors: LaRoche
authors: Camilla Zamfolini
authors: CZ
authors: Hallal
authors: Luciano Fernandes
authors: LF
authors: Crozara
authors: Mary Hellen
authors: MH
authors: Morcelli
authors: Aline Harumi
authors: AH
authors: Karuka
authors: Marcelo Tavella
authors: MT
authors: Navega
authors: Mauro
authors: M
authors: Gonçalves
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D004576:Electromyography; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D010101:Oxygen Consumption; D016059:Range of Motion, Articular / Q000502:physiology; D019415:Torque; D016138:Walking / Q000502:physiology*