Understanding training methods to elicit the appropriate adaptation to the determinants of endurance performance is of interest to both athletes and coaches. The ExogenTM exoskeleton technology by LilaTM is a compressive garment designed to allow small weights (50-200grams) to be applied to all areas of the body for site-specific loading. The experimental studies in this thesis sort to describe how the relative loading of both the proximal (i.e. thigh) lower limb (PLL) and distal (i.e. calf) lower limb (DLL) impact the metabolic cost of submaximal running. In study one, 20 (40.8 ± 8.2 years; 75.4 ± 9.2 kg) endurance trained runners (59.6 ± 7.9 ml·kgˉ1·minˉ1) completed six submaximal running trials with the PLL either un-loaded or loaded with 1, 2, 3, 4 and 5% of their own body weight. We found a 1.59% (±0.62%) increase in oxygen consumption for every 1%BM of addition load. Inferential based analysis identified that loading of at least 3%BM was needed to elicit any substantial responses, with a likely moderate increase (ES ± 90%CI: 0.24 ±0.07), while maximal loading (5%BM) elicit a most likely very large increase (0.43 ± 0.07). Using the heart rate (HR) data collected, a training load score (TLS) was extrapolated to help quantify the amount of internal stress each loaded trial would have over a 10-minute running period. For every 1%BM of additional load there is an extra 0.17(±0.06) estimated increase in training load. PLL loading of at least 3%BM was needed to elicit any substantial responses in lactate (La) production, with a very likely large increase (ES ± 90%CI: 0.41 ± 0.18). No loads reported substantial increases above 4mmol/L.
In study two, 15 (37.8 ± 6.4 years; 72.5 ± 9.8) endurance trained runners (58.9 ± 7.4 ml·kgˉ1·minˉ1) completed seven submaximal running trials with DLL either un-loaded or loaded with 0.5, 1, 1.5, 2, 2.5 and 3% of their own body weight. We found a 2.56% (±0.75) increase in oxygen consumption for every 1%BM of addition load. Inferential based analysis identified that loading of at least 1%BM was needed to elicit any substantial responses, with a possible small increase (ES ± 90%CI: 0.22 ± 0.12), while maximal loading (3%BM) produced a most likely very large increase (0.51 ± 0.09). As with Study 1, using the HR data collected, a TLS was extrapolated to help quantify the amount of internal stress each loaded trial would have over a 10-minute running period. For every 1%BM of additional load there is an extra 0.39(±0.06) increase in internal stress. DLL loading elicit substantial increases in La production from the lightest loading (0.5%BM), with a likely moderate increase (0.49 ± 0.28). No loads reported substantial increases in La production above 4mmol/L.
This thesis provides evidence on the sensitivity of loading the PLL and DLL between 0.5-5%BM on the metabolic cost of submaximal running. The metabolic data collected by both studies will help guide future studies investigating the impact of lower body limb loading both acutely and longitudinally.