Purpose: The relevance and importance of load carriage in recreational and occupational tasks has stimulated a large body of research. Exercise protocols have been criticised for a lack of relevance to occupational activities; accordingly the aim of this study was to assess the reliability of a preloaded time-trial protocol for load carriage assessment.
Methods: After full familiarisation, eight healthy males performed two trials separated by one week. Each trial comprised 60min walking at 6.5km[middle dot]h-1 and 0% gradient (LC), 15 min seated recovery followed by a 2.4km time-trial (LCTT). All trials were performed wearing a 25 kg backpack.
Results: Performance time was 16.71 +/- 1.82 min and 16.37 +/- 1.78 min for LCTT one and two respectively; with a mean difference of -0.34 +/- 0.89 min. Using log ratio limits of agreement the mean bias was 1.02 and random error component of the agreement ratio was 1.11. The intra-class correlation (ICC) was 0.85, coefficient of variation (CV) was 10.5% and Cohen's d was 0.35. The protocol demonstrated a very good level of reliability.
Conclusions: We present a novel and reliable pre-loaded time-trial protocol that more closely reflects operational activities and can be used to quantify load carriage performance. This protocol provides greater ecologically validity with respect to physical demands of load carriage activities than those adopted previously and provides an excellent tool for the strength and conditioning practitioner to assess individual load carriage performance.
Copyright (C) 2014 by the National Strength & Conditioning Association.