Protein intake above the Recommended Dietary Allowance (RDA) and resistance training are known anabolic stimuli to support healthy aging. Specifically, protein supplementation after resistance exercise and nightly are strategies to maximize utilization of protein intake above the RDA in healthy adults. As such, the primary objective was to examine the efficacy of protein supplementation and nutritional counseling resulting in either moderate (MOD: ~1.0 g·kg−1·d−1) or higher (HIGH: ~1.6 g·kg−1·d−1) protein intake during resistance training on strength (one-repetition maximum, 1-RM; isokinetic and isometric peak torque) in healthy middle-aged adults. Exploratory analyses include diet-exercise effects on lean body mass (LBM), clinical biomarkers, gut microbiota, and diet composition. 50 middle-aged adults (age: 50 ± 8 y, BMI: 27.2 ± 4.1 kg·m-2) were randomized to either MOD or HIGH protein intake during a 10-week resistance training program (3 × week). Participants received dietary counseling and consumed either 15 g (MOD) or 30 g (HIGH) of protein from lean beef in the immediate post-exercise period and each evening. Maximal strength (1-RM) for all upper and lower body exercises significantly increased with no effect of protein intake (P<0.050). There was a main effect of time for LBM (P<0.005). Cardiovascular, renal, or glycemic biomarkers were not affected by the intervention. Gut microbiota were associated with several health outcomes (P<0.050). In conclusion, higher protein intake above moderate amounts does not potentiate resistance training adaptations in previously untrained middle-aged adults. This trial was registered at clinicaltrials.gov as NCT03029975.

(1) Background: The purpose of this study was to examine the symptoms of low energy availability (LEA) and risk of relative energy deficiency in sport (RED-S) symptoms in para-athletes using a multi-parameter approach. (2) Methods: National level para-athletes (n = 9 males, n = 9 females) completed 7-day food and activity logs to quantify energy availability (EA), the LEA in Females Questionnaire (LEAF-Q), dual energy X-ray absorptiometry (DXA) scans to assess bone mineral density (BMD), and hormonal blood spot testing. (3) Results: Based on EA calculations, no athlete was at risk for LEA (females < 30 kcal·kg−1 FFM·day−1; and males < 25 kcal·kg−1 FFM·day−1; thresholds for able-bodied (AB) subjects). Overall, 78% of females were “at risk” for LEA using the LEAF-Q, and 67% reported birth control use, with three of these participants reporting menstrual dysfunction. BMD was clinically low in the hip (<−2 z-score) for 56% of female and 25% of male athletes (4) Conclusions: Based on calculated EA, the risk for RED-S appears to be low, but hormonal outcomes suggest that RED-S risk is high in this para-athlete population. This considerable discrepancy in various EA and RED-S assessment tools suggests the need for further investigation to determine the true prevalence of RED-S in para-athlete populations.

Carbohydrate (CHO) ingestion is an established strategy to improve endurance performance. Race fuels should not only sustain performance but also be readily digested and absorbed. Potatoes are a whole-food-based option that fulfills these criteria, yet their impact on performance remains unexamined. We investigated the effects of potato purée ingestion during prolonged cycling on subsequent performance vs. commercial CHO gel or a water-only condition. Twelve cyclists (70.7 ± 7.7 kg, 173 ± 8 cm, 31 ± 9 yr, 22 ± 5.1% body fat; means ± SD) with average peak oxygen consumption (V̇o2peak) of 60.7 ± 9.0 mL·kg−1·min−1 performed a 2-h cycling challenge (60–85% V̇o2peak) followed by a time trial (TT; 6 kJ/kg body mass) while consuming potato, gel, or water in a randomized-crossover design. The race fuels were administered with [U-13C6]glucose for an indirect estimate of gastric emptying rate. Blood samples were collected throughout the trials. Blood glucose concentrations were higher ( P < 0.001) in potato and gel conditions compared with water condition. Blood lactate concentrations were higher ( P = 0.001) after the TT completion in both CHO conditions compared with water condition. TT performance was improved ( P = 0.032) in both potato (33.0 ± 4.5 min) and gel (33.0 ± 4.2 min) conditions compared with water condition (39.5 ± 7.9 min). Moreover, no difference was observed in TT performance between CHO conditions ( P = 1.00). In conclusion, potato and gel ingestion equally sustained blood glucose concentrations and TT performance. Our results support the effective use of potatoes to support race performance for trained cyclists. NEW & NOTEWORTHY The ingestion of concentrated carbohydrate gels during prolonged exercise has been shown to promote carbohydrate availability and improve exercise performance. Our study aim was to expand and diversify race fueling menus for athletes by providing an evidence-based whole-food alternative to the routine ingestion of gels during training and competition. Our work shows that russet potato ingestion during prolonged cycling is as effective as carbohydrate gels to support exercise performance in trained athletes.

Creatine (Cr) supplementation is a well-established strategy to enhance gains in strength, lean body mass, and power from a period of resistance training. However, the effectiveness of creatyl-L-leucine (CLL), a purported Cr amide, is unknown. Therefore, the purpose of this study was to assess the effects of CLL on muscle Cr content. Twenty-nine healthy men (n = 17) and women (n = 12) consumed 5 g/day of either Cr monohydrate (n = 8; 28.5 ± 7.3 years, 172.1 ± 11.0 cm, 76.6 ± 10.7 kg), CLL (n = 11; 29.2 ± 9.3 years, 170.3 ± 10.5 cm, 71.9 ± 14.5 kg), or placebo (n = 10; 30.3 ± 6.9 years, 167.8 ± 9.9 cm, 69.9 ± 11.1 kg) for 14 days in a randomized, double-blind design. Participants completed three bouts of supervised resistance exercise per week. Muscle biopsies were collected before and after the intervention for quantification of muscle Cr. Cr monohydrate supplementation which significantly increased muscle Cr content with 14 days of supplementation. No changes in muscle Cr were observed for the placebo or CLL groups. Cr monohydrate supplementation is an effective strategy to augment muscle Cr content while CLL is not.

Although muscular strength has been linked to greater cognitive function across different cognitive domains, the mechanism(s) through which this occurs remain(s) poorly understood. Indeed, while an emerging body of literature suggests peripheral myokines released from muscular contractions may play a role in this relationship, additional research is needed to understand this link. Accordingly, this study sought to compare the influences of a particular myokine, Cathepsin B (CTSB), and muscular strength on hippocampal-dependent relational memory and cognitive control in 40 adults (age = 50.0±7.3 yrs). Overnight fasted venous blood draws were taken to assess plasma CTSB and muscular strength was assessed as maximal isokinetic strength testing using a Biodex dynamometer. Cognitive performance was assessed using a Spatial Reconstruction Task to assess relational memory and a modified Flanker task to assess cognitive control. Neuroelectric function for cognitive control was assessed using event-related potentials (ERPs) recorded during the Flanker task. Initial bivariate correlational analyses revealed that neither sex, age, lean body mass, or muscular strength was associated with CTSB. However, CTSB was inversely associated with reaction time and fractional peak latency of the P3 component of the Flanker task. Muscular strength was also inversely associated with reaction time and positively associated with relational memory performance. However, the influence of muscular strength on relational memory did not persist following adjustment for covariates. Greater circulating CTSB was selectively associated with greater cognitive control as well as faster information processing speed. These findings are the first to link circulating CTSB to both cognitive control and neuroelectric function. Future intervention studies are needed to examine the effects of changes in muscular strength, circulating myokines, and different domains of cognitive function.