Does size matter?
In a new RUNSAFE-based publication in JOSPT by Bertelsen et al. the question was asked: do runners with different BMI reduce their running dose accordingly when commencing a self-chosen running regime?
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Background
Overweight and obese novice runners are subjected to a higher load per stride than their normal-weight peers. Yet, do they reduce their running dose accordingly when commencing a self-chosen running regime?
Objectives
To describe and compare the preferred running dose in normal-weight (NWR), overweight (OWR) and obese novice runners (OBR) when they commence a self-chosen running regime.
Methods
The study design was an explorative 7-day prospective cohort study. 914 novice runners were categorized into one of 3 exposure groups based on their body mass index (BMI): (i) NWR (BMI<25, n=405, reference group); (ii) OWR (BMI 25 to <30, n=341); and (iii) OBR (BMI ?30, n=168). All runners were equipped with a GPS running watch which provided information about distance, duration, speed, and date of each running session during the first week of a self-chosen running regime.
Results
During the first session, OWR (difference: -0.5 km/h; 95%CI:-0.8,-0.2; p<0.05) and OBR (-1.7 km/h; 95%CI:-2.0,-1.4; p<0.05) ran slower than NWR. OBR also ran less distance than NWR (-0.4 km, 95%CI:-0.7;-0.2, p<0.05). During the first week, OWR (-0.5 km/h; 95%CI:-0.7,-0.2, p<0.05) and OBR (-1.7 km/h; 95%CI:-2.0,-1.4; p<0.05) ran slower than NWR, while running distance and duration were similar.
Conclusion
OWE and OBR chose a similar training dose as NWR when commencing a self-chosen running regime. This may partly explain the higher running-injury risk among OWR and OBR compared with NWR observed by other studies.
Reference
J Orthop Sports Phys Ther, Epub 22 Jun 2018. doi:10.2519/jospt.2018.8169
Link
The full-text article can be downloaded from the JOSPT website HERE