Exercise-induced muscle damage (EIMD) impairs muscle function and subsequent performance. While research investigating the protective role of animal-derived protein is widespread, investigations into sustainable alternatives are lacking. The present study examined the effects of a novel, salmon-derived protein peptide (SPP) on muscle recovery. In a single-blind, parallel-design, 33 recreationally active adults (age: 23.9 ± 4.0 years, body mass index: 23.7 ± 4.0) were randomly assigned to one of three groups: (a) SPP, (b) whey protein, or (c) carbohydrate control. In addition to a controlled 1.0 g·kg body mass-1·day-1 dietary protein intake, participants consumed either 0.9 g·kg body mass-1·day-1 supplemental protein or isoenergetic carbohydrate for 4 days following EIMD (10 × 10 unilateral eccentric knee extensions). Maximal voluntary contraction, countermovement jump height, muscle soreness, thigh circumference, creatine kinase, and lactate dehydrogenase were assessed at baseline and +1, +4, +24, +48, and +72 hr post EIMD. Significant time effects were observed for all variables. Countermovement jump height was greater in the SPP versus carbohydrate groups at +72 hr and across all time points when pooling the two protein groups, creating a higher protein versus normal protein group comparison. There were no significant group effects for all remaining outcomes. High-quality protein supplementation >1.0 g·kg body mass-1·day-1 appears to have only a modest effect on the rate of recovery following EIMD, with a potential role in alleviating muscle damage, particularly in the later stage of recovery. Furthermore, the SPP supplement was not inferior to a high-quality protein source (whey protein), indicating that it may represent a sustainable and effective alternative for muscle recovery.
It is recommended that endurance athletes modulate their daily carbohydrate intake according to the demands of training, but there is limited evidence of how this is currently practiced by athletes during real-world, day-to-day training. The purpose of this observational study was to report the dietary intake of endurance athletes across a 12-week period with an emphasis on the relationship between training load and carbohydrate intake. Self-selected training and dietary intake were self-reported using a smartphone app by 46 endurance athletes (61% male) daily for 12 weeks, representing a total of 3,718 days of dietary assessments and 3,160 days of training. Fasted-state training was regularly performed by 65% of athletes and was more common in men (33.6% vs. 17.2% of training days, p = .023). Average daily carbohydrate intake for each athlete ranged from 1.2 to 7.2 g/kg (M = 3.9 ± 1.5). At the group level, significant correlations were found between mean daily carbohydrate intake and both percentage of training sessions performed in the fasted state (r = -.39, p = .008) and weekly training volume (r = .42, p = .004). Participant-level correlations between daily training load and carbohydrate intake ranged from -.42 to .83. Overall, athletes adjust daily carbohydrate intake based on exercise duration, but at the individual level, many athletes do not align carbohydrate intake with training load as recommended or do so with minimal adjustment.
The International Standards for Anthropometric Assessment (International Society for the Advancement of Kinanthropometry [ISAK]) have been developed and refined over a period of over 30 years in order to guide the landmarking and measurement of a wide range of surface anthropometrical variables in able-bodied individuals in order for such measures to be reliable, repeatable, and valid. While numerous researchers and practitioners have undertaken anthropometrical assessments on individuals with motor disability, there is a lack of consistency in the processes used, and the ISAK protocol currently does not guide adaptations for measurement or interpretation in this population. Therefore, the ISAK working group on motor disability has reviewed the literature and provided recommendations to follow when undertaking and interpreting anthropometrical assessments in individuals with a motor disability. Prior to undertaking any assessment, practitioners and researchers are encouraged to first consider the purpose and validity of what they wish to measure in each individual, as they present with their own unique characteristics. Most importantly, the safety and dignity of each individual must be respected.
The study aimed to examine the independent and combined effects of a 90-min early afternoon (12:30 p.m.) nap (NAP) and an early evening (6:00 p.m.) moderate dose of caffeine (CAF; 5 mg/kg) on afternoon's variation of subjective sleepiness and reaction time and evening (7:00 p.m.) physical performance. In a randomized, counterbalanced, and double-blind design, 13 physical education students completed four conditions separated by 3-7 days: placebo (PLA), NAP, CAF, and combined nap plus caffeine (NAP + CAF). Assessments included simple and choice reaction times and the Epworth Sleepiness Scale at 12:30 p.m., before napping/resting, and every hour between 3:00 p.m. and 7:00 p.m. Jumping performance (squat jump and countermovement jump) and the repeated modified agility test were assessed once at 7:00 p.m. No significant effects of CAF, NAP, and CAF + NAP on simple reaction time, choice reaction time, and Epworth Sleepiness Scale were found. Repeated modified agility test performance improved across all interventions compared with PLA, with no difference between interventions. All interventions enhanced squat jump performance relative to PLA, with the greatest improvements observed under NAP + CAF compared with CAF (p < .05, d = 0.37, mean difference [MD] = 1.92 cm; p < .05, d = 0.38, MD = 0.07 m/s; p < .05, d = 0.01, MD = 0.01 W/kg) and NAP (p < .01, d = 0.63, MD = 2.91 cm; p < .01, d = 0.68, MD = 0.11 m/s; p < .01, d = 0.02, MD = 0.02 W/kg), respectively, for squat jump, take-off velocity, and relative power. Napping and caffeine independently enhanced repeated agility and explosivity performances, and their combination had no additional benefits on repeated agility. However, the combination further enhanced explosivity, which may benefit evening competitions in team and racket sports. Its limited effects on nonexplosive tasks and potential sleep disruption constrain broader application.
Discrete time-series measurements collected at predefined timepoints are widely used in sport nutrition and exercise metabolism research, including tolerance tests, tracer studies, and physiological responses to experimental interventions. These data sets are commonly summarized using derived metrics such as area under the curve. The original Time Series Response Analyser, introduced in 2020 as a spreadsheet-based tool, aimed to standardize these calculations and reduced the risk of manual errors. However, spreadsheet implementations can be difficult to maintain, extend, and version control, and provide limited transparency regarding exactly how outputs are derived. Here, we present Time Series Response Analyser v2.0, a web-based successor designed to improve accessibility, usability, and long-term maintainability while preserving the analytical purpose of the original tool. The application runs in a standard web browser and guides users through a structured workflow consisting of data setup, file interpretation screening, interactive analysis, and export of results. It retains the core summary metrics of the original version while expanding visualization capabilities and export options. In summary, Time Series Response Analyser v2.0 is a free, open-source web-based application for researchers analyzing discrete time-series experiments across both repeated-measures and independent-groups designs, supporting transparent and reproducible analytical workflows while enabling future development through a code-based platform.
Beetroot juice (BRJ) has been proposed as an ergogenic aid due to its high nitrate content, yet evidence from field-based studies in elite swimmers remains limited. This study investigated the acute effects of concentrated BRJ ingestion on performance and physiological responses during repeated maximal 200-m front-crawl efforts in elite male swimmers. Twelve elite swimmers (age: 20 ± 2 years, body fat: 7.1% ± 2.5%, 200-m personal best: 115.7 ± 3.4 s) completed a randomized, double-blind, counterbalanced trial. Participants consumed either 140 ml of concentrated BRJ (Beet It Sport) or a custom-made, nitrate-depleted placebo (PL) matched for sensory characteristics, 2 hr before performing two maximal 200-m front-crawl time trials, separated by 60 min of passive recovery. Blood samples were collected upon arrival and immediately after each time trials, and 200-m completion time, blood lactate concentrations, and ratings of perceived exertion were recorded. No significant differences were observed in completion time for either the first (PL: 116.7 ± 3.0 vs. BRJ: 117.2 ± 3.1 s, p = .19) or the second 200-m time trial (PL: 117.8 ± 2.6 vs. BRJ: 117.8 ± 3.3 s, p = .98), nor in the change between trials (PL: 1.1 ± 1.5 vs. BRJ: 0.5 ± 1.3 s, p = .40). Likewise, lactate concentrations and ratings of perceived exertion values did not differ between conditions (p > .05). In conclusion, acute BRJ supplementation did not enhance 200-m front-crawl performance, lactate responses, or perceived exertion in elite swimmers under competition-like conditions.
BACKGROUND:Water turnover (rH2O) is related to water balance including preformed water intake (WI), metabolic, inspired, and transcutaneous water. Literature is scarce on athletes. This study aimed to estimate and compare rH2O and its components during one athletic season (preparatory and competition phases), adjusting for body composition and energy expenditure (EE). METHODS:This longitudinal observational study included 112 athletes (19.8 ± 4.9 years, 39 females). Doubly labeled water determined total EE, rH2O, and the remaining components through specific equations. Total body water was determined by deuterium dilution and fat-free mass by the four-compartment model. Resting EE was assessed by indirect calorimetry. RESULTS:During the preparatory phase, male athletes showed higher rH2O [5.03 (0.14) kg/day] compared with females [3.64 (0.19) kg/day, p < .001], even adjusting for body mass (p = .024), but not for fat-free mass, total body water, and EE. Triathletes showed higher values of rH2O after adjustments (p < .05). Over the athletic season, no changes occurred for rH2O or preformed WI within or between sexes or sports, even adjusting for body composition while some changes occurred adjusting for EE (p < .05). Over the season, metabolic water increased (p < .001), while inspired and transcutaneous water showed both increases and reductions (p < .05). A small prevalence (∼16%) of low WI (WI ≤ 35 ml/kg of body mass/day) was persistent in both timepoints. CONCLUSION:While rH2O and preformed WI did not differ over the season, cross-sectional differences were observed between sports but not between sexes, highlighting the variability of rH2O and impact of contributing factors. Low preformed WI was present throughout the athletic season.
Although dietary fiber is widely recognized for its health benefits in the general population, including reduced risk of cardiovascular disease and improved metabolic regulation, its role in athletic performance and recovery remains comparatively underexplored. Current sports nutrition guidelines lack specific recommendations for fiber intake, despite evidence linking adequate consumption to gut microbiome stability, immune modulation, and body composition optimization. Athletes face unique physiological demands that influence gastrointestinal tolerance, nutrient absorption, and energy availability, particularly under high training loads. Although excessive fiber intake may lead to gastrointestinal discomfort or reduced caloric intake, moderate and periodized consumption has been associated with enhanced immune function, improved energy metabolism, and preservation of skeletal muscle mass. Recent findings suggest potential benefits in attenuating exercise-induced inflammation and regulating substrate utilization. Nevertheless, observational data indicate that many athletes fail to meet general population intake targets, often due to precompetition dietary restrictions or concerns about digestive comfort. This review critically synthesizes current evidence on the physiological impacts of dietary fiber in athletic populations, focusing on gastrointestinal health, immune function, body composition, and performance outcomes. It further outlines practical, evidence-based strategies to optimize intake according to individual needs and sport-specific demands, including fiber periodization, source selection, and gradual adaptation.
In elite road cycling, nutrition is a critical pillar of performance, with culinary support evolving from a logistical necessity to a core competitive determinant. The collaboration among performance chefs, registered dietitian/nutritionist(s), and soigneurs, collectively termed the Culinary Nutrition Team, is central to translating evidence-based nutrition strategies into practical, palatable food provision. Through an applied lens, this review positions the Culinary Nutrition Team as the operational link through which complex nutrition, physiological, and sport science principles are translated and delivered in day-to-day practice within professional road cycling. The overlapping skill sets of Culinary Nutrition Team members are described, alongside respective roles and responsibilities, in executing nutrition strategies through real-time menu adjustments, management of special dietary needs, and adaptation to environmental and logistical challenges. While common principles underpin effective culinary nutrition support, how those principles are executed in practice is shaped by practitioner training and scope of practice, team structure and maturity, communication pathways, staff dynamics and trust, and the broader cultural and logistical context in which teams operate. In this context, digital tools and technologies (e.g., workload-derived data integration, centralized nutrition management platforms, and biometric wearables) are gaining prominence as innovative approaches to inform energy requirements, support rapid food provision adjustments, and facilitate team-wide communication. However, their effectiveness depends on appropriate validation, integration within established workflows, regulatory approval for in-race, and skilled interpretation. Ultimately, an athlete-centered, systems-based approach to culinary nutrition support embedded within the wider performance team is no longer a marginal gain but a competitive necessity in modern professional road cycling.
This review outlines recent advances in race nutrition support for professional road cycling, emphasizing individualized, context-specific strategies over generic recommendations. Within the past couple of decades, there have been several changes in nutritional demands and practices within road cycling including (1) a change in the distribution of intensity across a stage or 1-day race; (2) an increase in "on-bike" carbohydrate intake coinciding with integrated "training the gut" practices; and (3) better maintenance of neutral energy balance across stage races. Specifically, race tactics now, generally demand a higher intensity earlier within a stage (or 1-day race), thereby also increasing energy and carbohydrate requirements and utilization early on within a stage. Concomitantly, there has been an increase in reported intake of carbohydrates "on-bike," from ∼30 to 60 g/hr pre-2010, to 90 and even 120 g/hr and higher in the present day. There is also evidence that the maintenance of energy balance across stage races has improved over this timeframe. These topics are discussed in detail alongside additional nutritional challenges and strategies relevant to professional road cycling, such as daily energy, fluid, and macronutrient distribution, which are often tailored to rider characteristics (e.g., body size, role, performance goals) and race-specific factors (e.g., course profile, environmental conditions).
This study examined how resistance exercise (RE) volume, a potential key factor in appetite regulation, influences subjective appetite, gut appetite hormones, and energy intake. Eighteen males (aged 21-27 years) completed failure RE (FRE; three sets of failure reps at 70% (at 1 RM), non-FRE (NFRE; 3 × 7 reps at 70% 1 RM), and control (CON) trials. Appetite and acyl-ghrelin, peptide YY, lactate, and glucose were measured pre- and postexercise 0-90 min. Ad libitum meal was provided after exercise. Participants recorded energy intake for the day before, the day of, and the day after each session. The incremental area under the curve (iAUC) for acyl-ghrelin (AG) in the FRE and NFRE were significantly lower than in the CON (p < .001). Peptide YY iAUC and glucose iAUC in the FRE were significantly higher than in the CON (p < .001; p = .003). There was a dose-response for lactate iAUC (FRE > NFRE > CON; p < .001). Appetite iAUC was significantly lower in the FRE than in the CON (p = .012). There were no significant differences in postexercise ad libitum meal and self-reported free-living energy intake between the three sessions (p = .246, p = .226). Acyl-ghrelin was negatively correlated with lactate and positively correlated with overall appetite in both RE sessions. Lactate was negatively correlated with overall appetite in both RE sessions. Moderate-intensity RE with moderate volume-induced temporary appetite suppression, whereas FRE led to prolonged suppression and greater appetite-related hormonal responses, yet neither affected energy intake in young males.
Ramadan-type diurnal fasting, which restricts both food and fluid intake from dawn to sunset, may influence physiological, metabolic, and perceptual responses during high-intensity exercise. However, its acute effects under matched external workload conditions in field-based soccer training remain unclear. This study examined the physiological, neuromuscular, metabolic, and perceptual responses to a matched high-intensity intermittent training session performed under fed and Ramadan-type fasting conditions. Twenty male university-level soccer players completed two counterbalanced sessions. External load was matched using 10-Hz GPS monitoring. Physiological variables, including oxygen uptake, carbon dioxide production, respiratory exchange ratio, minute ventilation, and heart rate, along with blood lactate concentration, session rating of perceived exertion, perceptual scales (thermal discomfort and thirst), neuromuscular performance assessed via countermovement jump height and power, and body mass were measured before and after exercise. External mechanical load did not differ between conditions. Ramadan-type fasting elicited significantly higher minute ventilation, mean and maximal heart rate, and session rating of perceived exertion, whereas carbon dioxide production, respiratory exchange ratio, and peak blood lactate concentration were significantly lower. Oxygen uptake did not differ between conditions. Thermal discomfort and thirst increased from pre- to postexercise in both trials (time effect), with perceived thirst showing a greater increase under fasting conditions (interaction effect). Countermovement jump height and power demonstrated significant pre-to-post reductions (time effect) without condition or interaction effects. Body mass decreased significantly from pre- to postexercise in both trials (time effect), with no condition or interaction effects. These findings indicate that Ramadan-type fasting increases internal physiological and perceptual load during high-intensity intermittent soccer training despite identical external workloads, while neuromuscular performance and exercise-induced body mass loss remain preserved. Practitioners should consider that athletes may experience higher internal strain during fasting-based sessions even when mechanical output is maintained.
Caffeine enhances endurance performance but may impair shooting accuracy, creating a potential trade-off for overall biathlon performance. In a randomized, placebo-controlled, crossover study, seven elite male biathletes consumed caffeine (3 mg/kg) or taste-matched placebo 60 min before a simulated biathlon competition consisting of five "laps" of 6-min treadmill skiing interspersed by four five-shot bouts. Participants further performed precision shooting (20 prone and 20 standing) pre- and postcompetition. Caffeine increased distance covered in Laps 1 (1,824 ± 73 vs. 1,772 ± 66 m; p = .03, dz = 1.12) and 2 (1,801 ± 92 vs. 1,776 ± 84 m; p = .02, dz = 1.19) but did not improve total distance (p = .06). Blood lactate (p = .01, ηp2=.85) and ventilation (p < .001, ηp2=.90) increased with caffeine. Heart rate (p = .07) and perceived exertion (p = .69) did not differ between conditions. Caffeine impaired shooting accuracy in standing (72.9 ± 16.0% vs. 82.9 ± 7.6%; p = .03, dz = 0.87), but not prone. Integrated race times did not differ between conditions for individual (71.72 ± 5.27 vs. 71.58 ± 4.57 min), mass start (52.45 ± 3.67 vs. 52.57 ± 3.27 min), or pursuit (44.18 ± 3.18 vs. 44.23 ± 2.83 min; all p > .77) formats. Caffeine impaired postexercise precision shooting in prone position (88.9 ± 6.0% vs. 93.3 ± 7.5%; p = .04, dz = 0.65). Our findings highlight task-specific effects of caffeine, emphasizing the importance of tailoring supplementation to integrated performance demands.
Objective: This study examined the effects of different carbohydrate ingestion patterns on endurance cycling performance and gastrointestinal comfort. It was hypothesized that increasing carbohydrate availability in alignment with decreasing endogenous stores would optimize performance while minimizing gastrointestinal discomfort. Methods: Twelve trained male cyclists completed three randomized trials involving a 180-min intermittent cycling preload, a 15-min all-out performance test, and a maximal sprint to exhaustion. Participants ingested 90 g/hr of carbohydrates in an increasing (INC), decreasing (DEC), or constant (CON) pattern. Performance, substrate oxidation, rate of perceived exertion, and gastrointestinal comfort were assessed. Results: Carbohydrate distribution during exercise had no effect on 15-min all-out performance test (mean [95% confidence limits]: INC-CON-0.1% [-9.9, 11]; INC-DEC 5.9% [-8.6, 23]; DEC-CON-5.4 [-17, 7.8]) or time to exhaustion (INC-CON-0.6 [-3.8, 2.7]; INC-DEC 0.1 [-4.0, 4.4]; DEC-CON-0.7 [-4.0, 2.6]) performance. Carbohydrate oxidation was higher in DEC versus CON (7.1%; 2.7, 11.7) and versus INC (5.8%; -4.1, 15). Conversely, fat oxidation was lower in DEC versus CON (13%; -23, -1.8), while other contrasts were unclear. RPE was lower, but increased more over time in INC than CON. Nausea (standardized difference 1.2; 0.04, 2.3), stomach fullness (0.55; -0.15, 1.27), and abdominal cramping (0.84; -0.03, 1.7) increased over time in INC versus DEC. Conclusion: Carbohydrate intake distribution had little clear effect on performance, though a decreasing pattern may support oxidation and gut comfort later in exercise. Even intake remains advisable, but uneven patterns may be acceptable when needed.
Novel cycling disciplines, such as cycling Esports and gravel racing, have recently seen a surge in participation, media visibility, and the establishment of international competitions. However, there is limited peer-reviewed research into the specific physiological and nutritional demands required for success in these disciplines. As part of the larger UCI Sports Nutrition project, this review utilizes qualitative interviews to gain a deeper understanding of the nutrition practices of athletes currently competing in these events. We contextualize these responses by describing contemporary nutrition strategies and evidence-based practice adopted from other disciplines, along with practical application considering the distinct challenges presented by these new and emerging cycling disciplines. Key issues for these disciplines include in race nutrition targeting the specific needs of the event, noting that the logistics of consuming food and drinks in gravel racing and Esports are different to other modalities such as road cycling. Optimization of body mass is a shared concern particularly in Esports in which the requirement for a prerace "weigh-in" may lead to practices usually seen in weight division sports. Finally, a number of supplements including caffeine, creatine, buffering agents, and hyperhydrating agents such as glycerol may enhance performance when used according to evidence-based protocols.
Mouth rinsing with carbohydrates or salt solutions has been shown to attenuate the reduction in maximum voluntary contraction (MVC) strength during fatigue. Although central mechanisms, such as changes in voluntary activation (VA) and motor evoked potentials (MEP), have been proposed to explain this effect, direct evidence is limited. This study aimed to investigate the effects of carbohydrate or salt mouth rinses on central fatigue by examining whether central measures are affected. In a double-blind, randomized, crossover design, 19 male participants completed three experimental trials (carbohydrate, salt, or placebo mouth rinses), each involving a sustained knee isometric fatiguing protocol performed until volitional fatigue. MVC, VA, and MEP were assessed before and after the fatiguing protocol. Following the protocol, the torque output (MVC) and central measures (VA and MEP) showed significant reductions (p < .05). Although the reductions following carbohydrate and salt were less pronounced (MVC, VA, and MEP), both treatments showed better preservation than placebo (p < .001). In addition, the comparable reduction in resting twitch and maintenance of maximum compound muscle action potential (p > .05) suggest that the observed benefits were primarily central mediated. This is the first study to demonstrate that salt mouth rinsing is as effective as carbohydrate rinsing in attenuating neuromuscular fatigue via central mechanisms, preserving muscle activity, central drive, and corticospinal responsiveness following a localized fatiguing protocol.
High-amylose maize starch (HAMS), containing fermentable resistant starch (RS), is suggested to improve fluid absorption/retention in athletes but lacks supporting evidence and may increase gastrointestinal symptom (GIS) risk. This study investigated the use of HAMS in pre- and postexercise hydration protocols on hydration status and GIS before, during, and after exertional heat stress (EHS), and thermophysiological strain and exhaustive exercise performance during EHS. Ten endurance-trained runners (eight men and two women) completed two trials in randomized order, consuming a HAMS beverage (12.7 g RS) or placebo 12 hr pre-EHS as part of a 25-ml/kg hyperhydration protocol. Participants then completed 2 hr of steady-state running (60% maximum oxygen uptake, ∼30 °C, 35% relative humidity) followed by a time-to-exhaustion performance test. Post-EHS, participants consumed a HAMS recovery beverage (6.2 g RS) or placebo while replacing 150% of their fluid deficit over 3 hr. HAMS did not influence net fluid balance pre-EHS (HAMS: +44 ± 642 ml, placebo: +210 ± 697 ml) or post-EHS (HAMS: +1,636 ± 687 ml, placebo: +1,662 ± 697 ml; p = .40). Changes in plasma volume and osmolality, and thermophysiological variables, did not differ between trials (all p > .05). Time-to-exhaustion performance test was unaffected by the intervention (HAMS: 1,190 ± 508 s, placebo: 1,343 ± 631 s; p = .10). GIS incidence and severity scores were similar in both trials (all p > .05). A beverage containing RS from HAMS 12 hr before EHS, or immediately following EHS, does not alter retention of water volumes recommended for preexercise hyperhydration or postexercise rehydration nor GIS pre-, during, or post-EHS. As a result, no changes in hydration status, thermophysiological strain, or performance were observed.
The effects of Greek yogurt and whey protein supplementation on markers of bone turnover and inflammation were compared in university athletes over a competitive season. Participants (n = 32, 16 females) followed their habitual diets for an 8-week control period and were then randomly assigned to one of two trial arms: two servings per day of either 175 g of Greek yogurt (17 g protein) or isonitrogenous whey protein for a 16-week intervention period. Morning, fasting blood was collected at Weeks 0 (precontrol), 8 (postcontrol/preintervention), 16 (midintervention), and 24 (postintervention) and analyzed for osteocalcin, amino-terminal propeptide of Type I collagen, insulin-like growth factor 1, osteoprotegerin, C-telopeptides of Type I collagen, sclerostin, receptor activator of nuclear factor kappa-B ligand, tumor necrosis factor-alpha, interleukin 6, and interleukin 10. No main effects or interactions were found for markers of bone formation. In the Greek yogurt group, C-telopeptides of Type I collagen increased from pre- to postcontrol and returned to baseline concentrations postintervention while remaining stable throughout the study in whey protein (Time × Group interaction, p = .048). Receptor activator of nuclear factor kappa-B ligand increased from pre- to postcontrol (time effect, p = .014), returning to baseline by midintervention across groups. Males had higher sclerostin (sex effect, p = .021) and interleukin 10 (sex effect, p = .004) with no interactions. Interleukin 6 showed no main effects or interactions. Tumor necrosis factor-alpha increased pre- to postcontrol (time effect, p = .053) then decreased to baseline levels postintervention. Although protein supplementation, independent of source (wholefood or isolates), showed potential bone and inflammatory benefits during athletic training, it remains unclear whether these effects were solely attributable to the supplements.
As a group, cyclists tend to have lower bone mass compared with other athletes, and nonathlete controls which may have negative consequences for fracture risk and longer term bone health. There are several cycling-specific factors that may contribute to this finding. These include, the low-impact, repetitive load nature of cycling which provides limited stimulus for bone metabolism; metabolic perturbations that occur following prolonged cycling that may lead to a transient increase in the rate of bone resorption; and nutritional factors, including low energy availability or nutrient inadequacy. Furthermore, many endurance cyclists are naturally lean and light, which may result from both genetic predisposition and long-term training adaptations. In turn, they may also have lower bone mass. None of these factors stand out as the primary cause of the low bone mass reported in cyclists but, instead, may combine to create a "perfect storm" to challenge cyclist bone health. Given these multiple potential challenges to bone health, a multifaceted approach may be required to combat them. On an individual level, nutritional strategies, including ensuring adequate energy, carbohydrate, protein, calcium, vitamin D, and other important micronutrients may be key to protecting cyclist bone health. Integrating brief bouts of high-impact loading within the training regimen and ensuring adequate sleep and recovery are also recommended. The onus should not remain solely on the individual, however, and cycling teams and organizational bodies have a key role to play in providing screening and educational strategies to support cyclists bone health.
This study evaluated the rehydration efficacy of a commercially available milk permeate-containing sports drink with high osmolality (MPSD) compared with a traditional sports drink (TSD), a high-potassium sports drink (HKSD), and water (W). Twelve young, healthy adults (four women) underwent a 2-hr exercise-induced dehydration protocol in the heat (29.9 °C ± 1.5 °C) until losing 2% of body weight, followed by a 4-hr rehydration period. Participants consumed on four separate occasions one of the following beverages: (a) TSD (Na + : 20 mmol/L, K + : 3.6 mmol/L, osmolality: 385 mmol/kg); (b) HKSD (Na + : 3.6 mmol/L, K + : 37.9 mmol/L, osmolality: 364 mmol/kg); (c) MPSD (Na + : 21 mmol/L, K + : 28.7 mmol/L, osmolality: 576 mmol/kg); or (d) plain water (W). Fluids (150% of body weight loss) were administered in four doses every 15 min during the first hour. Whole-body net fluid balance remained negative, but MPSD resulted in significantly higher net fluid balance at 180 min (−0.38% ± 0.3%) and 240 min (−0.66% ± 0.3%) than in other trials ( p < .05). MPSD also led to lower cumulative urine volume (1,268 ± 173 ml) than HKSD (1,796 ± 459 ml), TSD (1,493 ± 211 ml), and W (1,565 ± 501 ml; p < .05). Osmotic excretion in MPSD was significantly higher than in all trials at 120, 180, and 240 min ( p < .05), and free water clearance was lower at 180 and 240 min ( p < .05). TSD promoted greater plasma volume restoration (1.5% ± 5%) than MPSD (−3.7% ± 6.5%) and HKSD (−5.5% ± 7.8%) at 60 min ( p < .05). A milk permeate-based sports drink is more effective for postexercise rehydration than TSD, HKSD, and water when consumed at 150% of the body weight lost.
