High-impact jumping mitigates the short-term effects of low energy availability on bone resorption but not formation in regularly menstruating females:A randomized control trial

Low energy availability (LEA) is prevalent in active individuals and negatively impacts bone turnover in young females. High-impact exercise can promote bone health in an energy efficient manner and may benefit bone during periods of LEA. Nineteen regularly menstruating females (aged 18–31 years) participated in two three-day conditions providing 15 (LEA) and 45 kcals kg fat-free mass−1 day−1 (BAL) of energy availability, each beginning 3 ± 1 days following the self-reported onset of menses. Participants either did (LEA+J, n = 10) or did not (LEA, n = 9) perform 20 high-impact jumps twice per day during LEA, with P1NP, β-CTx (circulating biomarkers of bone formation and resorption, respectively) and other markers of LEA measured pre and post in a resting and fasted state. Data are presented as estimated marginal mean ± 95% CI. P1NP was significantly reduced in LEA (71.8 ± 6.1–60.4 ± 6.2 ng mL−1, p 0.999, d = 0.19), and these effects were significantly different (time by condition interaction: p = 0.007). Morning basal bone formation rate is reduced following 3 days LEA, induced via dietary restriction, with or without high-impact jumping in regularly menstruating young females. However, high-impact jumping can prevent an increase in morning basal bone resorption rate and may benefit long-term bone health in individuals repeatedly exposed to such bouts

Association Between Different Non-Invasively Derived Thresholds with Lactate Threshold during Graded Incremental Exercise.

International Journal of Exercise Science 11(4): 391-403, 2018. We compared lactate threshold (TLac)with non-invasive markers of an aerobic-anaerobic transition; namely, ventilatory (VT) and tissue saturation index (TSIT) thresholds. While identification of a breakpoint in blood lactate concentration ([BLa]) is common for determination of an aerobic-anaerobic transition, non-invasive measures, VT and NIRS, have also received attention as a means of determining this critical exercise intensity. We hypothesised that one or other of these non-invasive measures would have a strong association with TLac. Thirty-one (n=31) competitive male athletes (mean ± SD, age 29±9 yr, height 1.81±0.1 m, body mass 77.7±10.0 kg) performed graded incremental cycling to volitional exhaustion. Heart rate, TSI and gas exchange data were measured throughout and [BLa] was determined at fixed intervals. Threshold detection involved a segmented linear regression analysis minimising the squared sum of the residuals to determine TLac, TSIT and VT. Workload and HR at TLac, VT and TSIT were analysed using repeated measures ANOVA and correlation assessed using Pearson’s and interclass correlation coefficients. Thresholds at TSIT and TLac were not significantly different (255±35 vs. 249±30 W, P\u3e0.05), suggesting that limitations in O2 delivery could be closely linked to an aerobic-anaerobic transition. However, poor correlation (r=0.55, ICC=0.54 and 95%LoA of +67 and -54 W) suggested other factors may exert an influence. Mean VT occurred at a significantly higher workload than TLac (271 ±35 vs 249±30 W, P\u3c0.001). Consequently, VT proved less useful, giving an indication of when an aerobic-anaerobic transition had already occurred. In conclusion, non-invasive markers of the aerobic transition are not concurrent with TLac

High-impact jumping mitigates the short-term effects of low energy availability on bone resorption but not formation in regularly menstruating females: A randomized control trial

Low energy availability (LEA) is prevalent in active individuals and negatively impacts bone turnover in young females. High-impact exercise can promote bone health in an energy efficient manner and may benefit bone during periods of LEA. Nineteen regularly menstruating females (aged 18–31 years) participated in two three-day conditions providing 15 (LEA) and 45kcalskg fat-free mass−1day−1 (BAL) of energy availability, each beginning 3±1days following the self-reported onset of menses. Participants either did (LEA+J, n=10) or did not (LEA, n=9) perform 20 high-impact jumps twice per day during LEA, with P1NP, β-CTx (cir?culating biomarkers of bone formation and resorption, respectively) and other markers of LEA measured pre and post in a resting and fasted state. Data are presented as estimated marginal mean±95% CI. P1NP was significantly reduced in LEA (71.8±6.1–60.4±6.2ngmL−1, p0.999, d=0.19), and these effects were significantly different (time by condition interaction: p=0.007). Morning basal bone formation rate isreduced following 3days LEA, induced via dietary restriction, with or without high-impact jumping in regularly menstruating young females. However, high-impact jumping can prevent an increase in morning basal bone resorption rate and may benefit long-term bone health in individuals repeatedly exposed to such bouts.</p

High‐impact jumping mitigates the short‐term effects of low energy availability on bone resorption but not formation in regularly menstruating females: A randomized control trial

Low energy availability (LEA) is prevalent in active individuals and negatively impacts bone turnover in young females. High‐impact exercise can promote bone health in an energy efficient manner and may benefit bone during periods of LEA. Nineteen regularly menstruating females (aged 18–31 years) participated in two three‐day conditions providing 15 (LEA) and 45 kcals kg fat‐free mass−1day−1 (BAL) of energy availability, each beginning 3 ± 1 days following the self‐reported onset of menses. Participants either did (LEA+J, n = 10) or did not (LEA, n = 9) perform 20 high‐impact jumps twice per day during LEA, with P1NP, β‐CTx (circulating biomarkers of bone formation and resorption, respectively) and other markers of LEA measured pre and post in a resting and fasted state. Data are presented as estimated marginal mean ± 95% CI. P1NP was significantly reduced in LEA (71.8 ± 6.1–60.4 ± 6.2 ng mL−1, p −1, p −1, p = 0.002, d = 1.11) but not in LEA+J (0.65 ± 0.08–0.65 ± 0.08 ng mL−1, p > 0.999, d = 0.19), and these effects were significantly different (time by condition interaction: p = 0.007). Morning basal bone formation rate is reduced following 3 days LEA, induced via dietary restriction, with or without high‐impact jumping in regularly menstruating young females. However, high‐impact jumping can prevent an increase in morning basal bone resorption rate and may benefit long‐term bone health in individuals repeatedly exposed to such bouts.</p

A fish-derived protein hydrolysate induces postprandial aminoacidaemia and skeletal muscle anabolism in an in vitro cell model using ex vivo human serum

Fish-derived proteins, particularly fish protein hydrolysates (FPH), offer potential as high-quality sources of dietary protein, whilst enhancing economic and environmental sustainability. This study investigated the impact of a blue whiting-derived protein hydrolysate (BWPH) on aminoacidaemia in vivo and skeletal muscle anabolism in vitro compared with whey protein isolate (WPI) and an isonitrogenous, non-essential amino acid (NEAA) control (0.33 g·kg−1 body mass−1) in an ex vivo, in vitro experimental design. Blood was obtained from seven healthy older adults (two males, five females; age: 72 ± 5 years, body mass index: 24.9 ± 1.6 kg·m2 ) in three separate trials in a randomised, counterbalanced, double-blind design. C2C12 myotubes were treated with ex vivo human serum-conditioned media (20%) for 4 h. Anabolic signalling (phosphorylation of mTOR, p70S6K, and 4E-BP1) and puromycin incorporation were determined by immunoblotting. Although BWPH and WPI both induced postprandial essential aminoacidaemia in older adults above the NEAA control, peak and area under the curve (AUC) leucine and essential amino acids were more pronounced following WPI ingestion. Insulin was elevated above baseline in WPI and BWPH only, a finding reinforced by higher peak and AUC values compared with NEAA. Muscle protein synthesis, as measured by puromycin incorporation, was greater after incubation with WPI-fed serum compared with fasted serum (P = 0.042), and delta change was greater in WPI (P = 0.028) and BWPH (P = 0.030) compared with NEAA. Myotube hypertrophy was greater in WPI and BWPH compared with NEAA (both P = 0.045), but was similar between bioactive conditions (P = 0.853). Taken together, these preliminary findings demonstrate the anabolic potential of BWPH in vivo and ex vivo, thus providing justification for larger studies in older adults using gold-standard measures of acute and chronic MPS in vivo