MALTAIS, D., O. BAR-OR, M. PIERRYNOWSKI, and V. GALEA. Repeated Treadmill Walks Affect Physiologic Responses in Children with Cerebral Palsy. Med. Sci. Sports Exerc., Vol. 35, No. 10, pp. 1653–1661, 2003.
To determine whether physiologic responses during treadmill walking in children with cerebral palsy (CP) are affected by repeated walking bouts on different days, and whether effects are different at different speeds.
Three girls and five boys (9.2–15.7 yr, 23.3–64.4 kg) with mild CP received 12–15 min of treadmill walking practice and had their fastest walking speed (FWS) determined during an introductory visit. During each of three subsequent visits (day 1, day 2, day 3), subjects walked for 3 min at 60, 75, and 90% FWS. Resting physiologic measures were taken on day 1.
From day 1 to day 3, net ventilation (V̇E), and net heart rate (HR) at 90% FWS decreased by 3.6 L·min−1 and 8 beats·min−1, respectively. There were no differences between day 1 and day 2 or day 1 and day 3 for any other physiologic variable at any speed. Day 3 was less than day 2 for net HR (60% FWS) and, independent of speed, net V̇O2 (per kilogram of body mass and per stride) and net energy expenditure (kJ·min−1). Between-day reliability (R) of physiologic responses was ≥ 0.95, except respiratory rate (R = 0.75). Intrasubject, between-day variability for the V̇O2 measures was 7.6–12.9%.
Because there were no day 1 to day 3 reductions in metabolic variables, day 1 to day 3 reductions at 90% FWS in net HR may reflect decreased emotional stress over time and reductions in net V̇E, an uncoupling of V̇O2 and V̇E. Despite between-day differences, reliable net physiologic and stable net metabolic variables may be collected in subjects with mild CP after one treadmill walking practice session.
1Children’s Exercise and Nutrition Centre, Department of Pediatrics, McMaster University, Hamilton, CANADA; and
2School of Rehabilitation Science, McMaster University, Hamilton, CANADA
Address for correspondence: Désirée Maltais, Children’s Exercise and Nutrition Centre, Department of Pediatrics, Chedoke Hospital Division, Hamilton, ON L8N 3Z5, Canada; E-mail: firstname.lastname@example.org.
Submitted for publication February 2003.
Accepted for publication June 2003.