Walking Economy of Adults with Down Syndrome

Abstract

This study intended to investigate walking economy (WE) in response to different treadmill speeds and grades in adults with Down syndrome (DS) and in non-disabled controls. Eighteen participants (14 males; 4 females) with DS (33.6±7.6 years) and 16 non-disabled (12 males, 4 females) controls (33.3±8.0 years) performed submaximal (2.5 km . h⁻¹ and 4 km . h⁻¹ at 0% grade; 4 km . h⁻¹ at 2.5% and 5% grade, for 5 min each) and maximal treadmill tests with metabolic and heart rate measurements. Oxygen uptake (VO₂) was not different between groups at rest or during the slowest treadmill speed. However, at faster speeds and increased grades, adults with DS presented lower WE than controls (p<0.0001). Subsequent analyses revealed that, despite showing higher delta VO₂ response to the selected speed increments (p<0.0001), individuals with DS produced similar VO₂ increase as controls to grade variations. Therefore, adults with DS exhibit lower WE than non-disabled controls at a speed faster than their preferred walking speed. Additionally, in comparison to controls, individuals with DS show a greater change in energy expenditure with a change in walking speed. In conclusion, lower WE in individuals with DS is mainly related to their inability to adapt efficiently to positive variations in walking speed.

energy expenditure - locomotion - functional capacity - exercise

References

• 1 Baynard T, Unnithan V, Pitetti K, Fernhall B. Determination of ventilatory threshold in adolescents with mental retardation with and without Down syndrome.  Pediatr Exerc Sci. 2004;  16 126-137
• 2 Black D, Smith B, Wu J, Ulrich B. Uncontrolled manifold analysis of segmental angle variability during walking: preadolescents with and without Down syndrome.  Exp Brain Res. 2007;  183 511-521
• 3 Browning R, Kram R. Energetic cost and preferred speed of walking in obese vs.  normal weight women. Obes Res. 2005;  13 891-899
• 4 Buzzi U, Ulrich B. Dynamic stability of gait cycles as a function of speed and system constraints.  Motor Control. 2006;  8 241-254
• 5 Cavagna G, Thys H, Zamboni A. The sources of external work in level walking and running.  J Physiol. 1976;  262 639-657
• 6 Corcoran P, Brengelmann G. Oxygen uptake in normal and handicapped subjects in relation to speed of walking beside velocity-controlled cart.  Arch Phys Med Rehabil. 1970;  51 78-87
• 7 Dubois D, Dubois E. A formula to estimate the approximate surface area if height and weight be known.  Arch Intern Med. 1916;  17 863-871
• 8 Fernhall B, Millar A, Tymeson G, Burkett L. Maximal exercise testing of mentally retarded adolescents and adults: reliability study.  Arch Phys Med Rehabil. 1990;  71 1065-1068
• 9 Fernhall B, Otterstetter M. Attenuated responses to sympathoexcitation in individuals with Down syndrome.  J Appl Physiol. 2003;  94 2158-2165
• 10 Fernhall B, Pitetti K. Limitations to physical work in individuals with mental retardation.  Clin Exerc Physiol. 2001;  3 176-185
• 11 Fernhall B, Pitetti K, Rimmer J, McCubbin J, Rintala P, Millar A, Kittredge J, Burkett L. Cardiorespiratory capacity of individuals with mental retardation including Down syndrome.  Med Sci Sports Exerc. 1996;  28 366-371
• 12 Fernhall B, Unnithan V. Cardiovascular fitness as related to leg strength in adults with mental retardation.  Med Sci Sports Exerc. 2002;  27 423-428
• 13 Guerra M, Roman B, Geronimo C, Violan M, Cuadrado E, Fernhall B. Physical fitness levels of sedentary and active individuals with Down syndrome.  Adapt Phys Activ Q. 2000;  17 310-321
• 14 Kubo M, Ulrich B. Coordination of pelvis-HAT (head, arms and trunk) in anterior–posterior and medio-lateral directions during treadmill gait in preadolescents with/without Down syndrome.  Gait Posture. 2006;  23 512-518
• 15 Mendonca G, Pereira F, Fernhall B. Walking economy in male adults with Down syndrome.  Eur J Appl Physiol. 2009;  105 153-157
• 16 Minetti A, Ardigò L, Saibene F. Mechanical determinants of gradient walking energetics in man.  J Physiol. 1993;  472 725-736
• 17 Minetti A, Ardigò L, Saibene F. Mechanical determinants of the minimum energy cost of gradient running in humans.  J Exp Biol. 1994;  195 211-225
• 18 Parker A, Bronks R, Snyder C. Walking patterns in Down's syndrome.  J Ment Defic Res. 1986;  30 317-330
• 19 Pitetti K, Boneh S. Cardiovascular fitness as related to leg strength in adults with mental retardation.  Med Sci Sports Exerc. 1995;  27 423-428
• 20 Rubin S, Rimmer J, Chicoine B, Braddock D, McGuire E. Overweight prevalence in persons with Down syndrome.  Ment Retard. 1998;  36 175-181
• 21 Smith B, Kubo M, Black D, Holt K, Ulrich B. Effect of practice of a novel-task walking on a treadmill: preadolescents with and without Down syndrome.  Phys Ther. 2007;  87 766-777
• 22 Smith B, Ulrich B. Early onset of stabilizing strategies for gait and obstacles: Older adults with Down syndrome.  Gait Posture. 2008;  28 448-455
• 23 Stanish H, Draheim C. Walking habits of adults with mental retardation.  Ment Retard. 2005;  43 421-427
• 24 Ulrich B, Haehl V, Buzzi U, Kubo M, Holt K. Modeling dynamic resource utilization in populations with unique constraints: Preadolescents with Down syndrome.  Hum Mov Sci. 2004;  23 133-156
• 25 Whipp B. Rate constant for the kinetics of oxygen uptake during light exercise.  J Appl Physiol. 1971;  30 261-263
• 26 Whipp B. The slow component of O2 uptake kinetics during heavy exercise.  Med Sci Sports Exerc. 1994;  26 1319-1326
• 27 Whitt-Glover M, O'Neill K, Stettler N. Physical activity patterns in children with and without Down syndrome.  Pediatr Rehabil. 2006;  9 158-164

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