Nutrition for Mountain Biking and Cyclocross.

Oosthuyse, T, Bownes, N, Wiemers, LA, and Bosch, AN. Validity of average power, total work, and exercise energy expenditure quantified by cycling mechanics. J Strength Cond Res XX(X): 000-000, 2025-Average power, work, and exercise energy expenditure (EEE) are useful metrics in cycling for gauging training load and targeting energy intake. These metrics are easily obtained from bicycle-mounted power meters but not all cyclists train with power meters. We used the laws of mechanics to estimate average power, total work, and EEE compared with power-meter measurements during n = 100 training sessions (n = 32 on road bicycles; n = 68 on mountain bikes [MTBs]) in competitive cyclists, with p < 0.05 as significant. Physics-derived average power and power-meter measures had a good agreement (Watts, mean difference ± SD -1.04 ± 10.38; SEM 1.038; coefficient of variability 4.2%; intraclass correlation coefficient 0.93), producing estimates of total work (-2 ± 24 kcal) and EEE (-10 ± 120 kcal) with negligible mean differences. Although average power was similar (MTB: 2.21 ± 0.31 W·kg-1; road: 2.24 ± 0.34 W·kg-1), total force produced (FTotal) was greater in MTB than in road training (25.8 ± 4.6 N; 20.7 ± 3.0 N). The components of FTotal differed, where forces to overcome gradient (12.9 ± 5.2 N; 8.5 ± 3.1 N) and rolling resistance (8.2 ± 1.6 N; 3.9 ± 1.1 N) were greater in MTB, and frictional air drag (4.7 ± 1.9 N; 8.4 ± 2.3 N) was greater in road training. Using the methodology applied, the laws of cycling mechanics produce fair measures of average power, total work, and EEE for cyclists without bicycle-mounted power meters. In addition, deriving the respective force components could support training prescription and equipment adjustments to optimize performance.

The physiological effects of low energy availability (EA) have been studied using a homogenous daily EA pattern in laboratory settings. However, whether this daily EA pattern represents those of free-living athletes and is therefore ecologically valid is unknown. To investigate this, we assessed daily exercise energy expenditure, energy intake and EA in 10 free-living elite male road cyclists (20 min Mean Maximal Power: 5.27 ± 0.25 W · kg−1) during 7 consecutive days of late pre-season training. Energy intake was measured using the remote-food photography method and exercise energy expenditure estimated from cycling crank-based power-metres. Seven-day mean ± SD energy intake and exercise energy expenditure was 57.9 ± 10.4 and 38.4 ± 8.6 kcal · kg FFM−1 · day−1, respectively. EA was 19.5 ± 9.1 kcal · kg FFM−1 · day−1. Within-participants correlation between daily energy intake and exercise energy expenditure was .62 (95% CI: .43 – .75; P < .001), and .60 (95% CI: .41 – .74; P < .001) between carbohydrate intake and exercise energy expenditure. However, energy intake only partially compensated for exercise energy expenditure, increasing 210 kcal · day−1 per 1000 kcal · day−1 increase in expenditure. EA patterns displayed marked day-to-day fluctuation (range: −22 to 76 kcal · kg FFM−1 · day−1). The validity of research using homogenous low EA patterns therefore requires further investigation.

This observational study investigated the use of continuous glucose monitoring (CGM) in a team of professional cyclists without diabetes during two consecutive annual training camps. The goal of the study was twofold: to present the aggregated CGM metrics such as day/overnight CGM average (DAYAVG/OVNAVG) for this group of professional cyclists and to study the association between exercise energy expenditure (megajoules per day), carbohydrate intake (grams), and minimum overnight CGM values (millimoles per liter). Linear mixed models were employed in the analysis. Data were available for 26 cyclists (22 participated in both training camps). CGM levels reported (DAYAVG = 6.37 ± 0.54mmol/L and OVNAVG = 5.30 ± 0.52mmol/L), are not typically seen in healthy individuals not engaged in intensive exercise routines. Results showed that minimum overnight CGM values significantly fluctuated throughout the training camp, but a statistically significant association between exercise energy expenditure (p = .0839) or carbohydrate intake (p = .059) and minimum overnight CGM values could not be detected. This research contributes to the literature on CGM use in professional athletes and underscores the need for further studies to fully understand the benefits and limitations of CGM to guide sports performance.

Background : The physiological demands in mountain bike marathons consist of intensive intermitted intervals. While aerobic and anaerobic parameters were found to be of importance when predicting race performance (Inoue et al., 2012: J Strength Cond Res, 26(6), 1589-- ‐ 1593), gender associated differences may be possible and have been ignored in the previous male-- ‐ only studies. Purpose: to analyse lactate dynamics during repeated recuperative and intense intervals using a specific test that was designed to simulate the physiological anaerobic demands of mountain bike competitions. Methods : Nine ambitious female mountain bikers (age: 38.3 ±6.1 y; weight: 62.2 ±6.6 kg; 169.1 ±8.9 cm) performed a mountain bike specific test trial (see figure 1) on a SRM-- ‐ Ergometer. The test trial was designed to examine aerobic and anaerobic parameters and started with an incremental test. Beginning at 80 W the resistance was increased by 40 W every 3 minutes until exhaustion (peak power output: PPO). Lactate concentration was measured taking capillary blood samples at the end of each stage to determine the individual anaerobic threshold (IAT) according to Dickhuth et al. (1999: Int J Sports Med, 20(02), 122-- ‐ 127). After the incremental test, cyclists kept pedalling during regeneration periods and three all-- ‐ out intervals (AO) lasting 10 s, 1 min and 5 min, each with maximum effort. The afforded power output of each AO was measured and all laboratory parameters were scaled by body weight. After the incremental test and between all-- ‐ outs, cyclists regenerated at a power of 100 W. After performing the laboratory test, within one month (13.3 ±9.6 days) all athletes participated in the same official national mountain bike competition (83 km distance). Pearson's r was used to calculate the correlation of race performance (official racing time) and laboratory parameters. Results : The race time correlates nearly perfect with the power output of the 1 min-- ‐ AO (r=-- ‐ 0.90, p=0.001). Moreover, significant correlation was found between IAT and race time (r=-- ‐ 0.80, p=0.010) and PPO (r=-- ‐ 0.79, p=0.011) respectively. Due to the small sample size no significance but large correlation was found between race time and afforded power in the 10 s-- ‐ AO (r=-- ‐ 0.55, p=0.123) and 5 min-- ‐ AO (r=-- ‐ 0.61, p=0.078) respectively (see figure 2). Discussion : To the best of our knowledge, this is the first study which analysed the prediction of race performance of female mountain bikers. Despite the small sample size, the strong correlations of race performance and power output in the 1 min-- ‐ AO and IAT respectively, particularly demonstrate the importance of analysing besides aerobic also anaerobic parameters. Power output at the IAT correlates similarly to the results of male mountain bikers in Impellizzeri et al. (2005: J Sports Sci, 23(1), 41-- ‐ 47) and slightly stronger than in MA¼ller et al. (2014: Journal of Science and Cycling, 3(2), 85). The anaerobic parameters of male mountain bikers analysed in Inoue et al. (2012) with repeated 30 s Wingate tests, showed a slightly weaker correlation (r=-- ‐ 0,79). Assuming that in our study anaerobic intervals were driven after performing an incremental test, it can be concluded, that parameters to predict race performance in male and female athletes are similar. Conclusions : Due to the facts that all laboratory parameters correlate at least largely with race time and the laboratory test measures aerobic and anaerobic parameters within approximately one hour, we suggest to use this performance test to predict race performance for ambitioned amateur mountain bikers in daily clinical routine. Further research is needed to give training advice based on the power output for each AO duration and to confirm our results in a larger sample size.

Objective Acrobatics & Tumbling (A&T) is an emerging sport in the National Collegiate Athletic Association that lacks research regarding the dietary intake and health of A&T student-athletes (A&Tsa). This study assessed the dietary intake adequacy, estimated energy availability (EA), self-reported menstrual health, and body composition of A&Tsa. Methods Twenty-four female A&Tsa participated during week 8 of the preseason (11 top: Age= 20.1 ± 0.9 years; BMI= 22.1 ± 1.7 kg/m2; 13 base: Age= 19.5 ± 1.3 years; BMI= 26.2 ± 2.7 kg/m2). Total energy intake (TEI) and macronutrient intakes were assessed via a paper-based 3-day dietary recall. Resting Metabolic Rate [RMR = 500 + 22 * fat-free mass (FFM)] and energy availability [EA = (TEI – exercise energy expenditure)/FFM)] were estimated; and LEAF-Q assessed menstrual health. Body composition was measured using Dual-Energy X-Ray Absorptiometry. Macronutrient intakes and EA were compared to sports nutrition recommendations (carbohydrate: 6–10 g/kg; protein: 1.2–2.0 g/kg) and the Acceptable Macronutrient Distribution Range (carbohydrate: 45–65%; protein: 10–35%; fat: 20–35%). Results TEI was 1753 ± 467 kcal (top) and 1980 ± 473.8 kcal (base). A total of 20.8% of A&Tsa failed to meet RMR with TEI, with a higher prevalence in the top (-266 ± 219.2 kcal, n = 3) vs. base (-414.3 ± 534.4 kcal, n = 2) A&Tsa. Top and base A&Tsa had both low EA (28.8 ± 13.4 kcals·FFM−1; 23.8 ± 9.5 kcals·FFM−1) and inadequate carbohydrate intake averages (4.2 ± 1.3 g/kg; 3.5 ± 1.1 g/kg, p < 0.001), respectively. A total of 17% of A&Tsa reported secondary amenorrhea, with a higher prevalence in the top (27.3%, n = 3) vs. the base (7.7%, n = 1). Conclusion TEI and carbohydrate intake of the majority of A&Tsa were below recommendations. Sports dietitians should encourage and educate A&Tsa about following an adequate diet that meets energy and sports-specific macronutrient needs.

Purpose(1) To evaluate if energy availability (EA), macronutrient intake and body composition change over four training periods in young, highly trained, female cross-country skiers, and (2) to clarify if EA, macronutrient intake, body composition, and competition performance are associated with each other in this cohort.MethodsDuring a one-year observational study, 25 female skiers completed 3-day food and training logs during four training periods: preparation, specific preparation, competition, and transition periods. A body composition measurement (bioimpedance analyzer) was performed at the end of the preparation, specific preparation, and competition periods. Competition performance was determined by International Ski Federation (FIS) points gathered from youth national championships.ResultsEA (36–40 kcal·kg FFM−1·d−1) and carbohydrate (CHO) intake (4.4–5.1 g·kg−1·d−1) remained similar, and at a suboptimal level, between training periods despite a decrease in exercise energy expenditure (p = 0.002) in the transition period. Higher EA (r = −0.47, p = 0.035) and CHO intake (r = −0.65, p = 0.002) as well as lower FM (r = 0.60, p = 0.006) and F% (r = 0.57, p = 0.011) were associated with lower (better) FIS-points. CHO intake was the best predictor of distance competition performance (R2 = 0.46, p = 0.004).ConclusionsYoung female cross-country skiers had similar EA and CHO intake over four training periods. Both EA and CHO intake were at suboptimal levels for performance and recovery. CHO intake and body composition are important factors influencing competition performance in young female cross-country skiers.

Factors affecting body composition in African-American females (AAF) and Caucasian females (CF) females were examined. Dual energy x-ray absorptiometry was used to assess body composition in twenty-eight females (13 AAF, age 37.5± 7.7 yrs; 15 CF age 40.2 ± 4.6 yr). Resting energy expenditure(REE) was measured, following a 12 hour fast, via indirect calorimetry. VO2max was predicted from heart rate and VO2 values obtained during 6-minutes of cycling at 300kgm. Dietary intake was assessed from 3-day diet records. One-way ANOVAs were performed to evaluate each variable by race while correlations were performed to evaluate relationships among variables. The results demonstrated higher values in AAF than CF for weight(67.8±7.7kg to 60.2±4.3kg, p=.014)%body fat (%BF)(37.5±7.9% to 29.5±4.7%, p=.017) and body mass index(25±2.25kg/m2 to 21.9±1.4kg/m2, p<.01). REE values did not significantly differ between the groups but tended to be higher in the CF than AAF (2.8±0.4 mlO2/kg/min to 2.5±0.3 mlO2/kg/min, p=.07). Predicted VO2max was higher in the CF than AAF (40.3±11.1 mlO2/kg/min to 32±5.1 mlO2/kg/min, p=.033) indicating a higher fitness level in the CF. The groups did not differ in age, height, exercise energy expenditure (EEE), nor any of the dietary variables assessed. However, the AAF tended to consume fewer daily kcals with a slightly higher percentage coming from fat than the CF. EEE was correlated with%BF in all subjects (r=-0.59, p=.001) while a REE was correlated with VO2 max in the CF (r=0.86, p<.001).%BF was correlated with%carbohydrate intake (r=-0.61, p=0.026),%fat intake (r = 0.57, p=0.04) and%saturated fat intake (r = 0.63, p=0.02) in the AAF.%BF was correlated with predicted VO2max (r= -.058, p=0.02) in the CF. The results of this study suggest a “metabolic spiral” in which body composition, REE, fitness level and energy intake are interrelated. Thus, the higher%BF observed in the AAF may be associated with their lower REE, fitness level and energy intake.

ABSTRACTBackgroundThis study aims to determine low energy availability prevalence (LEA) in adolescent female artistic gymnasts and to compare the dietary habits and sleep between those with LEA and those without.MethodsHeight, weight, and body composition (BodPod) were measured following an overnight fast. Participants were then fitted with hip- and wrist-worn accelerometers to assess exercise energy expenditure (EEE) and sleep, respectively, for three consecutive days. Daily energy intake (EI) was assessed using a digital food log and evaluated against the International Society of Sports Nutrition (ISSN) dietary recommendations for athletic populations. As this was a free-living study, participants were asked to maintain their normal behaviors.ResultsTwelve female artistic gymnasts (15 ± 1 yrs, 160.6 ± 5.5 cm, 55.8 ± 4.6 kg, 14.9 ± 6.4% body fat, 47.4 ± 4.3 kg fat-free mass (FFM)) participated in the study. Mean EA was 28.9 ± 13.5 kcals/kg−1FFM with six gymnasts (50%) presenting in a LEA state. Gymnasts with LEA consumed significantly fewer calories than those without (1451 ± 447 vs 2388 ± 458 kcals; p = 0.008). Those in a LEA state also had significantly lower protein (0.8 ± 0.2 vs 1.5 ± 0.4 g/kg; p = 0.007) and carbohydrate (3.1 ± 0.8 vs 4.8 ± 0.8 g/kg; p = 0.004) intake compared to gymnasts without LEA. Based on ISSN recommendations, 33.3% of gymnasts met PRO (1.4–2.0 g/kg−1), 8.3% met CHO (5–7 g/kg−1), while 100% met recommendations for fat (20–35% of total EI). EEE was 550 ± 131 kcal−1, with no differences by EA status. Those with LEA spent less time in bed (390 ± 56 vs 498 ± 35 min; p = 0.002) and had a lower total sleep time (346 ± 57 vs 439 ± 33 min; p = 0.006), yet fewer number of awakenings (17 ± 6 vs 24 ± 4; p = 0.035) compared to gymnasts without LEA. No differences in body composition or other sleep parameters were observed.ConclusionsIn the present study, 50% of gymnasts presented in a LEA state. Regardless of EA status, most gymnasts did not meet the dietary recommendations for protein or carbohydrates. Additionally, those in a LEA state presented with sleep impairments, which could potentially impair recovery and performance. These findings underscore the need for future research to address the dietary and sleep habits in adolescent gymnasts to optimize health and athletic performance.

Physique competitors are an understudied group judged on muscular appearance and symmetry. This retrospective case study assessed a drug-free amateur female figure competitor over a 20-week contest prep (CP) period. PURPOSE: To describe changes in body mass, body composition, and menstrual cycle during figure CP. METHODS: Body mass and dietary intake were assessed daily and averaged weekly. Body composition was assessed pre-and post-CP via dual-energy x-ray absorptiometry (DXA) and 8 times during CP via 7-site skinfold measurements. RESULTS: Caloric intake before CP was 2010 kcal/d (45% carbohydrate, 24% protein, 31% fat, 48 g fiber). Intake decreased from 1798 kcal/d (42% carbohydrate, 33% protein, 25% fat, 40g fiber) in week 1, to 1541 kcal/d (37% carbohydrate, 39% protein, 24% fat, 24 g fiber) by week 10. At week 20, caloric intake had risen to 1712 kcal/d (44% carbohydrate, 35% protein, 21% fat, 34 g fiber). Body mass decreased from 54.9 to 49.8 kg. Percent body fat (assessed via DXA) decreased from 15.1 to 8.6% and lean mass was maintained at 44.3 kg pre-and post-CP. Total skinfold thickness decreased from 67 to 30 mm. Menstrual cycle irregularity was reported in the first month and the last menses was occurred at week 11. Exercise consisted of a high-volume resistance training program 5 d/wk, brief (10-30 min) high-intensity interval training 1-2 d/wk, and longer (45-120 min) aerobic exercise 1 d/wk, corresponding to an exercise energy expenditure (EEE) of 484, 459, and 440 kcal/d at week 1, 10, and 20, respectively. Energy availability [(kcal intake - EEE)/FFM] was 32.7, 28.2, 23.2, and 27.3 kcal/kg FFM before CP, and at week 1, 10, and 20, respectively. CONCLUSION: Carbohydrate intake fell below the Acceptable Macronutrient Distribution Range (AMDR) of 45-65% of total caloric intake and protein intake rose above the AMDR of 10-35%. Fiber intake decreased, but remained above the Dietary Reference Intake of 14 g/1,000 kcal. Fat mass decreased and lean mass was maintained during CP. Menstrual cycle dysfunction was reported early and amenorrhea occurred by the end of CP. EA was below ACSM Recommendation of 30 kcal/kg FFM during CP. Given the potential adverse health outcomes of chronic caloric restriction, future, prospective cohort studies on the physiological response to CP are warranted in drug-free, physique competitors.

The purpose of this study was to examine macronutrient intake, energy density and energy intake distribution that may be associated with low energy availability (EA) in Division I female soccer players. The energy intake, exercise energy expenditure and EA of 19 participants (18–21 years) was assessed during the pre-, mid- and postseasons. Repeated measures analysis of variance was performed to examine the changes across the season. Chi-square analysis was performed to examine the distribution of participants meeting the American College of Sports Medicine recommendations for carbohydrate and protein consumption. Independent t-tests were used to compare differences between groups. The proportion of athletes who did not meet the American College of Sports Medicine recommendations for carbohydrate intake (6–10 g . kg–1 BW) was significantly greater in the low (<30 kcal . kg–1 LBM) than higher (≥30 kcal . kg–1 LBM) EA group (χ2 (1) = 7.5; P = 0.006). Participants with low compared to higher EA consumed a lower energy dense dinner (0.8 ± 0.1 vs. 1.4 ± 0.1 kcal . g–1; P = 0.004) after a soccer match during midseason. No differences in the percentage (%) of kilocalories from food (84.5 ± 2.0% vs. 84.7 ± 2.6%), sports drinks (7.3 ± 1.4% vs. 6.0 ± 3.2%), other drinks (7.6 ± 1.5 % vs. 6.0 ± 1.5%) or bars/gels/beans (1.7 ± 0.6 vs. 3.0 ± 1.5) were observed in participants with low compared to higher EA (P > 0.05) during the pre- and midseasons. Identifying inadequate carbohydrate intake and the practice of consuming lower energy dense meals may be important in preventing low EA conditions and consequently the Female Athlete Triad.

Daily food intake is crucial to maintain health and determine endogenous fuel to practice endurance exercise. We investigated the association between quantity of macronutrient and micronutrient daily intake and inflammation induced by long-distance exercise. Methods. Forty-four Brazilian male amateurs' marathon finishers from 30 to 55 years old participated in this study. Blood samples were collected 1 day before, immediately after, and 1 day and 3 days after São Paulo International Marathon. The serum levels of IL-6, IL-1β, IL-10, IL-8, IL-12p70, and TNF-α were measured to evaluate inflammation. Dietary intake was determined using a prospective method of three food records in the week before marathon race. Results. Marathon race promoted an elevation on IL-6, IL-8, IL-1-β, and IL-10 immediately after the race. The energy intake (EI), carbohydrate, fiber, folic acid, vitamin E, vitamin D, calcium, magnesium, and potassium intakes was below recommended. Immediately after the marathon race, we observed a negative correlation between IL-8 and daily EI, carbohydrate, fiber, fat, iron, calcium, potassium, and sodium intakes, and higher levels of IL-8 on runners with <3 g/kg/day of carbohydrate intake compared to runners with >5 g/kg/day. We demonstrated a positive correlation between daily carbohydrate intake and IL-10 and a negative correlation between TNF-α and % of energy intake recommended, carbohydrate and fiber intakes. Finally, runners with adequate EI had lower levels of IL-1β and TNF-α compared with low EI immediately after the race. Conclusion. Nutrition strategies to promote balanced diet in amateur runners seem to be as important as immunonutrition sports market. Daily food intake, mainly EI, electrolyte and carbohydrate intakes, may modulate exacerbated inflammation after endurance exercise.

Relationship between physical activity and HDL-cholesterol in healthy older men and women: a cross-sectional and exercise intervention study

The purpose of this study was to assess energy availability (EA) and dietary patterns of 10 adult (29-49 years) male (n = 6) and female (n = 4) competitive (USA Cycling Category: Pro, n = 2; 1-4, n = 8) endurance cyclists (5 road, 5 off-road), with lower than expected bone mineral density (BMD; Z score < 0) across a season. Energy intake (EI) and exercise energy expenditure during preseason (PS), competition (C), and off-season (OS) were estimated from 3-day dietary records, completed once per month, across a cycling season. BMD was measured by DXA at 0 months/5 months/10 months. The Three-Factor Eating Questionnaire (TFEQ) was used to assess cognitive dietary restraint. Seventy percent of participants had low EA [(LEA); < 30 kcal · kg fat-free mass (FFM) (-1) · day(-1)] during PS, 90% during C, and 80% during OS (range: 3-37 kcal · kg FFM(-1) · day(-1)). Ninety percent of cyclists had LEA during ≥ 1 training period, and 70% had LEA across the season. Seventy percent of cyclists were identified as restrained eaters who consciously restrict EI as a means of weight control. Mean daily carbohydrate intake was below sport nutrition recommendations during each training period (PS: 3.9 ± 1.1 g · kg(-1) · day(-1), p < .001; C: 4.3 ± 1.4 g · kg(-1) · day(-1), p = .005; OS: 3.7 ± 1.4 g · kg(-1) · day(-1), p = .01). There were no differences in EA and EI · kg(-1) between male and female cyclists and road and off-road cyclists. Low EI, and specifically low carbohydrate intake, appears to be the main contributor to chronic LEA in these cyclists. Adult male and female competitive road and off-road cyclists in the United States may be at risk for long-term LEA. Further studies are needed to explore strategies to prevent and monitor long-term LEA in these athletes.

Substrate oxidation and energy expenditure in athletes and nonathletes consuming isoenergetic high- and low-fat diets

The primary purpose of this study was to examine dietary intake in endurance-trained athletes during a week of high-volume and a week of low-volume training while measuring exercise energy expenditure (EEE), resting metabolic rate (RMR), and nonexercise activity thermogenesis (NEAT). In addition, compliance with current American College of Sports Medicine/American Dietetic Association nutrition and performance recommendations for macronutrients was evaluated. Energy expenditure and dietary intake were measured in 15 male endurance athletes during 2 nonconsecutive weeks resembling a high-volume and a low-volume training period. Anthropometric measurements were taken and percentage body fat was determined at the beginning and end of each week of training. Total daily energy expenditure (TDEE) was calculated by summing RMR, NEAT, and EEE. Dietary intake was assessed with an online food-frequency questionnaire completed at the end of each week of data collection. Despite significant differences between TDEE and energy intake, no difference in body composition between the beginning and end of either week of training was observed, suggesting underreporting of caloric intake. Further, no changes in total caloric intake or macronutrient intake occurred even though TDEE increased significantly during the high-volume training. Reported carbohydrate intake (4.5g·kg(-1)) and fiber intake (25g·day(-1)) were below recommendations, whereas fat intake (1.3g·kg(-1)) was slightly above recommendations. In summary, no short-term dietary adjustments occurred in response to differences in training regimen. Because these athletes were generally consuming a Western diet, they may have required some support to achieve desirable intakes for health and performance.