The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia

David T Sims; Gladys L Onambélé-Pearson; Adrian Burden; Carl Payton; Christopher I Morse

doi:10.3389/fphys.2018.00410

The Oxygen Consumption and Metabolic Cost of Walking and Running in Adults With Achondroplasia

Front Physiol. 2018 Apr 18:9:410. doi: 10.3389/fphys.2018.00410. eCollection 2018.

Authors

David T Sims¹, Gladys L Onambélé-Pearson¹, Adrian Burden¹, Carl Payton¹, Christopher I Morse¹

Affiliation

¹ Health, Exercise and Active Living Research Centre, Department of Exercise and Sport Science, Manchester Metropolitan University, Manchester, United Kingdom.

Abstract

The disproportionate body mass and leg length of Achondroplasic individuals may affect their net oxygen consumption ([Formula: see text]O₂) and metabolic cost (C) when walking at running compared to those of average stature (controls). The aim of this study was to measure submaximal [Formula: see text]O₂ and C during a range of set walking speeds (SWS; 0.56 - 1.94 m⋅s^-1, increment 0.28 m⋅s^-1), set running speeds (SRS; 1.67 - 3.33 m⋅s^-1, increment 0.28 m⋅s^-1) and a self-selected walking speed (SSW). [Formula: see text]O₂ and C was scaled to total body mass (TBM) and fat free mass (FFM) while gait speed was scaled to leg length using Froude's number (Fr). Achondroplasic [Formula: see text]O_2TBM and [Formula: see text]O_2FFM were on average 29 and 35% greater during SWS (P < 0.05) and 12 and 18% higher during SRS (P < 0.05) than controls, respectively. Achondroplasic C_TBM and C_FFM were 29 and 33% greater during SWS (P < 0.05) and 12 and 18% greater during SRS (P < 0.05) than controls, respectively. There was no difference in SSW [Formula: see text]O_2TBM or [Formula: see text]O_2FFM between groups (P > 0.05), but C_TBM and C_FFM at SSW were 23 and 29% higher (P < 0.05) in the Achondroplasic group compared to controls, respectively. [Formula: see text]O_2TBM and [Formula: see text]O_2FFM correlated with Fr for both groups (r = 0.984 - 0.999, P < 0.05). Leg length accounted for the majority of the higher [Formula: see text]O_2TBM and [Formula: see text]O_2FFM in the Achondroplasic group, but further work is required to explain the higher Achondroplasic C_TBM and C_FFM at all speeds compared to controls. New and Noteworthy: There is a leftward shift of oxygen consumption scaled to total body mass and fat free mass in Achondroplasic adults when walking and running. This is nullified when talking into account leg length. However, despite these scalars, Achondroplasic individuals have a higher walking and metabolic cost compared to age matched non-Achondroplasic individuals, suggesting biomechanical differences between the groups.

Keywords: Achondroplasia; metabolic cost; oxygen consumption; running; walking.