Running economy and energy cost of running with backpacks

Impact of Backpacks on Ergonomics: Biomechanical and Physiological Effects: A Narrative Review

(1) Background: the effects of load carriage packs on human gait biomechanics, physiology and metabolism depend on the weight carried, the design of the pack and its interaction with the user. (2) Methods: An extensive search in the PubMed database was performed to find all the relevant articles using the following keywords: backpack, rucksack, backpack ergonomy and sports backpack; 60 articles were included. (3) Results and significance: Double pack (DP) and T-pack (TP) designs are recommended solutions for school children, compared with backpacks (BP). For soldiers and hikers, a backpack remains the best compromise. A hip belt is recommended for BPs as well as for the back of DPs. Shorter and stiffer shoulder straps combined with a higher and tighter load placement on the back provide the best combination in terms of balance, muscle activation and energy expenditure. It is, therefore, possible to determine guidelines for designing the optimal load carriage system, depending on the application. (4) Conclusions: based on the available evidence, DP and TP are advantageous in terms of posture. DP is better than conventional BPs in terms of balance and muscle activation, but has the disadvantage of limited visibility, thermal sensation and obstructed ventilation. In general, it is desirable not to exceed 40% of body mass (BM).

Minimalist style boot improves running but not walking economy in trained men

This study examined movement economy under load with 1000 g minimalist (MIN) vs. 1600 g traditional (TRD) style boots. Fourteen trained, male participants completed a VO_2peak test (46.6 ± 7.3 ml/kg/min) while wearing a 16 kg external load. Treadmill speeds for the running economy (RE) trials were determined by the slowest pace in which participants completed a full stage with a running gait pattern during the VO_2peak test. Walking economy (WE) pace was 1.6 km/h slower than RE pace. During the second session, participants completed 5-min exercise bouts at WE and RE pace under load wearing MIN and TRD. There were no differences for any measured variables during WE trials. In contrast, RE (MIN = 2.95 ± 0.28 vs. TRD = 3.04 ± 0.30 L/min; p = .003: Cohen's d = 0.32), respiratory exchange ratio (p < .001), and perceptual measures (p < .05) were all improved while wearing MIN. Practitioner summary: In trained men, 1000 g/pair minimalist style boots (MIN) resulted in improvements of approximately 3% and 5% for running economy and respiratory exchange ratio versus 1600 g/pair traditional boots while wearing a 16 kg kit. Perceptual responses, including comfort, also favoured MIN. These effects were not found at walking pace. Abbreviations: MIN: minimalist style boots; TRD: traditional style boots; RE: running economy; WE: walking economy; ES: effect size; RER: respiratory exchange ratio; HR: heart rate.

The Optimal Weight Carriage System for Runners: Comparison Between Handheld Water Bottles, Waist Belts, and Backpacks

In endurance running, where fluid and nutritional support is not always readily available, the carriage of water and nutrition is essential. To compare the economy and physiological demands of different carriage systems, 12 recreational runners (mean age 22.8 ± 2.2 years, body mass index 24.5 ± 1.8 kg m⁻², VO₂max 50.4 ± 5.3 ml kg⁻¹ min⁻¹), completed four running tests, each of 60-min duration at individual running speeds (mean running speed 9.5 ± 1.1 km h⁻¹) on a motorized treadmill, after an initial exercise test. Either no load was carried (control) or loads of 1.0 kg, in a handheld water bottle, waist belt, or backpack. Economy was assessed by means of energy cost (CR), oxygen cost (O₂ cost), heart rate (HR), and rate of perceived exertion (RPE). CR [F(2,20) = 37.74, p < 0.01, η_p² = 0.79], O₂ cost [F(2,20) = 37.98, p < 0.01, η_p² = 0.79], HR [F(2,18) = 165.62, p < 0.01, η_p² = 0.95], and RPE [F(2,18) = 165.62, p < 0.01, η_p² = 0.95] increased over time, but no significant differences were found between the systems. Carrying a handheld water bottle, waist belt, or backpack, weighing 1.0 kg, during a 60-min run exhibited similar physiological changes. Runners’ choice may be guided by personal preference in the absence of differences in economy (CR, O₂ cost, HR, and RPE).