Anomalous relationship of heart rate to oxygen consumption in children with hemiplegic cerebral palsy

  • Angeline Nnsenga-Leunkeu Université de Picardie Jules Verne, Amiens
  • Roy J. Shephard University of Toronto
  • Said Ahmaidi Université de Picardie Jules Verne, Amiens
Keywords: Co-contraction, Exercise prescription, Heart rate predictions, Isometric Testing, Rehabilitation, Spastic contractions, Sub-maximal testing

Abstract

Background: Co-contraction and spasticity may distort the normal relationship between heart rate and oxygen consumption in cerebral palsy.

Purpose. To compare cardio-respiratory responses to sustained isometric exercise (SET) at 50% of maximal torque between children with hemiplegic cerebral palsy (CP) and healthy controls,

Methods. Participants were 10 children with right-sided CP (nine males, one female; age 13 2 years), and 10 age- and sex-matched controls.

Results. Cybex Norm II testing showed that in CP both affected and unaffected legs had a reduced muscle volume and a low absolute maximal isometric torque. When expressed per litre of muscle volume (anthropometric estimate), torque was reduced in the affected leg, but normal for the unaffected leg. Cosmed K4b2 gas analysis during SET at 50% of maximal torque showed disproportionately high oxygen consumptions relative to heart rate and ventilation in CP, whichever leg was being tested.

Conclusions. Correction of weakness in the unaffected leg of children with CP depends on increasing muscle volume by resistance training and appropriate nutrition. Other factors such as co-contraction and spasticity compound weakness per unit volume of muscle in the affected leg. During SET, the oxygen consumption is disproportionately high relative to heart rate and ventilation. The added oxygen consumption probably reflects co-contraction and spasticity in muscles where blood flow is not restricted by the required action. This issue complicates estimates of oxygen consumption from heart rate during isometric effort, and may also modify the heart rate/oxygen consumption relationship during aerobic activity.

Author Biographies

Angeline Nnsenga-Leunkeu, Université de Picardie Jules Verne, Amiens
Laboratoire de Recherche EA: 3300 "APS et Conduites Motrices: Adaptations et Rdaptations", Facultdes Sciences du Sport.
Roy J. Shephard, University of Toronto
Professor Emeritus, Faculty of Kinesiology & Physical Education, University of Toronto
Said Ahmaidi, Université de Picardie Jules Verne, Amiens
Laboratoire de Recherche EA: 3300 "APS et Conduites Motrices: Adaptations et Rdaptations", Facultdes Sciences du Sport,
Published
2014-01-30
How to Cite
Nnsenga-Leunkeu, A., Shephard, R., & Ahmaidi, S. (2014). Anomalous relationship of heart rate to oxygen consumption in children with hemiplegic cerebral palsy. The Health & Fitness Journal of Canada, 7(1), 14-25. https://doi.org/10.14288/hfjc.v7i1.154
Section
ARTICLES

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