The metabolic and physiological responses to scootering exercise in a field-setting

Background: This study quantified the metabolic and physiological responses towards a range of scootering speeds in a field-setting. Methods: Ten participants (eight male, two female; mean ± standard deviation [SD] age: 21 ± 1 years; peak oxygen uptake [V̇O 2peak ]: 51.5 ± 6.0 mL/kg/min) completed a cycling V̇O 2peak test and a 30-min scootering protocol. Energy expenditure (EE), metabolic equivalents (METs) and heart rate (HR) were recorded throughout. Results: Mean ± SD EE and METs increased (P < 0.001) linearly when scootering at; 6.0 km/hr (4.3 ± 1.9 kcal/min, 4.1 ± 0.4), 7.5 km/hr (5.2 ± 2.7 kcal/min, 4.7 ± 0.5), 9.0 km/hr (6.4 ± 2.6 kcal/min, 5.2 ± 0.6), 10.5 km/hr (6.9 ± 2.8 kcal/min, 5.8 ± 0.6) and 12.0 km/hr (8.2 ± 1.7 kcal/min, 6.3 ± 0.8), respectively. When scootering at these speeds, mean ± SD percentage of maximal HR were 51 ± 11%, 55 ± 7%, 60 ± 9%, 64 ± 11% and 71 ± 9%. Conclusions: Scootering speeds of 6.0–10.5 km/hr meet the criteria for moderate-intensity exercise (3.0–5.9 METs). Scootering is an alternate form of exercise and mode of active transport, which may be included in the latest Compendium of Physical Activities guidelines and improve cardiorespiratory fitness if undertaken regularly

The reliability and validity of the Affinity Altitude hypoxic generators in acute and chronic conditions

Objectives: This study investigated the reliability of the Affinity Altitude hypoxic generator within-day, between-day and between-generator under acute and chronic hypoxic conditions. An additional objective was to assess the validity of the fraction of inspired oxygen (FiO2) values in relation to the claimed manufacture’s reference values to ensure the accuracy and safety of the product. Method: Three altitude generators (Affinity Altitude Ltd., Sussex, UK) were assessed across all available settings during a test-retest design for equivalent FiO2 and output volume. This consisted of two phases: 1) acute exposure (10 min per setting) and 2) chronic exposure (8 h per setting). FiO2 and volume data were calculated from 1 min collection samples using the Douglas bag method for acute and chronic exposures.Results: There were low variations in FiO2 data across all settings within the acute exposure for within-day (coefficient of variation [CV] range: 0.0¬¬¬¬¬–2.6%), between-day (0.2–1.3%), and between-generator analysis (0.7–1.4%). This was similarly found for volume data within-day (0.1–3.7%), between-day (0.7–5.4%), and between-generator (1.2–3.0%). Equally, for chronic exposure trials, CV for FiO2 (&lt;4.0%) and volume (&lt;5.0%) across each of the generators presented low variations. The FiO2 values were similar compared to reference values, however, significant differences were found for settings 4 (-0.3% [17.6% vs. 17.9% reference value]) and 5 (-0.1% [15.8% vs. 15.9% reference value], both p &lt; 0.05).Conclusion: A ‘good’ level of reliability and validity were found within and between the Affinity Altitude’s generators. However, a review of the reference values is warranted, and long-term experimental studies are required to determine the efficacy of this device for the purpose of physiological adaptations

Volume and Intensity of Locomotor Activity in International Men's Field Hockey Matches Over a 2-Year Period

The locomotor demands of international men's field hockey matches were investigated across positions (DEF, MID, FWD) and playing quarters. Volume (i.e., total values) and intensity (i.e., relative to playing time) data were collected using 10-Hz GPS/100-Hz accelerometer units from the #11 world-ranked (WR) team, during 71 matches, against 24 opponents [WR 12 ± 11 (range, 1–60)]. Mean ± SD team total distance (TD) was 4,861 ± 871 m, with 25% (1,193 ± 329 m) “high-speed running” (>14.5 km h−1) and 8% (402 ± 144 m) “sprinting” (>19.0 km h−1). Reduced TD (range, −3 to 4%) and average speed (range, −3.4 to 4.7%) occurred through subsequent quarters, vs. Q1 (p 2 m s−2; DEF, 48 ± 12; MID, 51 ± 11; FWD, 50 ± 14). Intensity variables similarly revealed positional differences (p < 0.05) but with a different pattern between positions; average speed (DEF, 115 ± 10 m min−1; MID, 132 ± 10 m min−1; FWD, 134 ± 15 m min−1), sprinting (DEF, 7 ± 3 m min−1; MID, 12 ± 4 m min−1; FWD, 14 ± 4 m min−1), and accelerations (DEF, 1.1 ± 0.3 n min−1; MID, 1.4 ± 0.2 n min−1; FWD, 1.5 ± 0.3 n min−1). Physical outputs reduced across playing quarters, despite unlimited substitutions, demonstrating the importance of optimizing physical preparation prior to international competition. Volume and intensity data highlight specific positional requirements, with forwards displaying shorter playing durations but greater high-intensity activities than defenders

The efficacy of a home-use metabolic device (Lumen) in response to a short-term low and high carbohydrate diet in healthy volunteers

Background Based on stoichiometric assumptions, and real-time assessment of expired carbon dioxide (%CO2) and flow rate, the Lumen device provides potential for consumers/athletes to monitor metabolic responses to dietary programs outside of laboratory conditions. However, there is a paucity of research exploring device efficacy. This study aimed to evaluate Lumen device response to: i) a high-carbohydrate meal under laboratory conditions, and ii) a short-term low- or high-carbohydrate diet in healthy volunteers. Methods Following institutional ethical approval, 12 healthy volunteers (age: 36 ± 4 yrs; body mass: 72.1 ± 3.6 kg; height: 1.71 ± 0.02 m) performed Lumen breath and Douglas bag expired air measures under fasted laboratory conditions and at 30 and 60 min after a high-carbohydrate (2 g·kg−1) meal, along with capilliarized blood glucose assessment. Data were analyzed using a one-way ANOVA, with ordinary least squares regression used to assess the model between Lumen expired carbon dioxide percentage (L%CO2) and respiratory exchange ratio (RER). In a separate phase, 27 recreationally active adults (age: 42 ± 2 yrs; body mass: 71.9 ± 1.9 kg; height: 1.72 ± 0.02 m) completed a 7-day low- (~20% of energy intake [EI]; LOW) or high-carbohydrate diet (~60% of EI; HIGH) in a randomized, cross-over design under free-living conditions. L%CO2 and derived Lumen Index (LI) were recorded daily across morning (fasted and post-breakfast) and evening (pre/post meal, pre-bed) periods. Repeated measures ANOVA were employed for main analyses, with Bonferroni post-hoc assessment applied (P ≤ 0.05). Results Following the carbohydrate test-meal, L%CO2 increased from 4.49 ± 0.05% to 4.80 ± 0.06% by 30 min, remaining elevated at 4.76 ± 0.06% by 60 min post-feeding (P < 0.001, ηp2 = 0.74). Similarly, RER increased by 18.1% from 0.77 ± 0.03 to 0.91 ± 0.02 by 30 min post-meal (P = 0.002). When considering peak data, regression analysis demonstrated a significant model effect between RER and L%CO2 (F = 5.62, P = 0.03, R2 = 0.20). Following main dietary interventions, no significant interactions (diet × day) were found. However, main diet effects were evident across all time-points assessed, highlighting significant differences for both L%CO2 and LI between LOW and HIGH conditions (P < 0.003). For L%CO2, this was particularly noted under fasted (4.35 ± 0.07 vs. 4.46 ± 0.06%, P = 0.001), pre-evening meal (4.35 ± 0.07 vs. 4.50 ± 0.06%, P < 0.001), and pre-bed time-points (4.51 ± 0.08 vs. 4.61 ± 0.06%, P = 0.005). Conclusion Our findings demonstrated that a portable, home-use metabolic device (Lumen) detected significantly increased expired %CO2 in response to a high-carbohydrate meal, and may be useful in tracking mean weekly changes to acute dietary carbohydrate modifications. Additional research is warranted to further determine the practical and clinical efficacy of the Lumen device in applied compared to laboratory settings

The Impact of Decaffeinated Green Tea Extract on Fat Oxidation, Body Composition and Cardio-Metabolic Health in Overweight, Recreationally Active Individuals

This study investigated the effect of decaffeinated green tea extract (dGTE), with or without antioxidant nutrients, on fat oxidation, body composition and cardio-metabolic health measures in overweight individuals engaged in regular exercise. Twenty-seven participants (20 females, 7 males; body mass: 77.5 ± 10.5 kg; body mass index: 27.4 ± 3.0 kg·m2; peak oxygen uptake (O2peak): 30.2 ± 5.8 mL·kg−1·min−1) were randomly assigned, in a double-blinded manner, either: dGTE (400 mg·d−1 (−)-epigallocatechin−3-gallate (EGCG), n = 9); a novel dGTE+ (400 mg·d−1 EGCG, quercetin (50 mg·d−1) and α-lipoic acid (LA, 150 mg·d−1), n = 9); or placebo (PL, n = 9) for 8 weeks, whilst maintaining standardised, aerobic exercise. Fat oxidation (‘FATMAX’ and steady state exercise protocols), body composition, cardio-metabolic and blood measures (serum glucose, insulin, leptin, adiponectin, glycerol, free fatty acids, total cholesterol, high [HDL-c] and low-density lipoprotein cholesterol [LDL-c], triglycerides, liver enzymes and bilirubin) were assessed at baseline, week 4 and 8. Following 8 weeks of dGTE+, maximal fat oxidation (MFO) significantly improved from 154.4 ± 20.6 to 224.6 ± 23.2 mg·min−1 (p = 0.009), along with a 22.5% increase in the exercise intensity at which fat oxidation was deemed negligible (FATMIN; 67.6 ± 3.6%O2peak, p = 0.003). Steady state exercise substrate utilisation also improved for dGTE+ only, with respiratory exchange ratio reducing from 0.94 ± 0.01 at week 4, to 0.89 ± 0.01 at week 8 (p = 0.004). This corresponded with a significant increase in the contribution of fat to energy expenditure for dGTE+ from 21.0 ± 4.1% at week 4, to 34.6 ± 4.7% at week 8 (p = 0.006). LDL-c was also lower (normalised fold change of −0.09 ± 0.06) for dGTE+ by week 8 (p = 0.038). No other significant effects were found in any group. Eight weeks of dGTE+ improved MFO and substrate utilisation during exercise, and lowered LDL-c. However, body composition and cardio-metabolic markers in healthy, overweight individuals who maintained regular physical activity were largely unaffected by dGTE