RESUMEN
BACKGROUND: Hurrying and turning are each associated with falls in older adults. Losing balance sideways when turning increases the likelihood of hip fracture. Yet 99â¯% of failures when turning unexpectedly have been traced to an inability to curb forward momentum regardless of age. RESEARCH QUESTION: Do age-based differences exist in spatial-temporal gait adaptations related to medial-lateral (M-L) balance and posterior-anterior (P-A) propulsion upon approach of turns relative to continuing straight, across walking speeds and whether direction is known in advance? METHODS: Healthy young (n=10) and older adults (n = 10) walked at preferred and fast test speeds while randomly cued for direction either early upon initiating gait or late 1-2 steps before entering a spatially defined turning area. An instrumented 4.6â¯m carpet recorded spatial-temporal changes up to the penultimate footfall prior to turning 900 or continuing straight. RESULTS: When approaching the turning zone across interactions of walking test speed, cue time and direction, other than stride-length being shorter in older adults, both age-groups showed similar adjustments in gait speed and stride-length in managing P-A deceleration perturbations, and similar adaptations in right and left heel-to-heel base of support (BOS) in managing M-L balance destabilizing forces. A three-way interaction (p<.027) suggests a similar foot strategy of BOS narrowing may be used approaching turns relative to straight walks when direction is cued early walking fast (p<.020) and late walking preferred speed (p<.014). SIGNIFICANCE: The findings were interpreted within the context of regulating center of mass acceleration and processing environmental regulatory conditions to maintain a personal space safety margin. The study supports that in otherwise healthy older adults, gait training for turns include practice to not only manage perturbations which accelerate the body sideways but also those which decelerate forward progression.
Asunto(s)
Adaptación Fisiológica , Señales (Psicología) , Marcha , Equilibrio Postural , Velocidad al Caminar , Humanos , Velocidad al Caminar/fisiología , Anciano , Adaptación Fisiológica/fisiología , Masculino , Femenino , Marcha/fisiología , Adulto , Adulto Joven , Equilibrio Postural/fisiología , Fenómenos Biomecánicos , Caminata/fisiología , Accidentes por Caídas/prevención & control , Factores de Edad , Envejecimiento/fisiologíaRESUMEN
OBJECTIVE: The aim of this study was to compare the effects of verbal, tactile-verbal, and visual feedback on muscle activation of the lumbar stabilizers relative to extremity movers during an abdominal drawing-in maneuver when feedback is withheld. METHODS: This quasi-experimental study equally divided 54 healthy adults into 3 feedback groups (verbal, tactile-verbal, and visual) who trained twice per week over a 4-week period to perform supine abdominal drawing-in maneuvers. The percentage of maximum voluntary isometric contraction of rectus abdominis, multifidus (MF), erector spinae, and hamstrings (HS) as an outcome measure was acquired using surface electromyography. A 2-way factorial analysis of variance with bootstrapping allowed for comparison of post-pre difference scores across the interaction of feedback and muscle groups. RESULTS: Hamstring activation decreased in those receiving tactile-verbal feedback relative to an increase in participants given visual feedback. Furthermore, when using verbal feedback, HS activity increased relative to a decline in rectus abdominis, and when presenting visual feedback, HS activity increased relative to a decrease in MF. However, no post-pre changes were seen across muscles with tactile-verbal feedback. CONCLUSION: Although tactile-verbal feedback did not increase MF recruitment, it produced less HS activity than visual feedback. Undesirable HS recruitment may reflect boredom or feedback dependency.