Sex-Related Differences in the Maximal Lactate Steady State

Cadence Paradox in Cycling-Part 1: Maximal Lactate Steady State and Carbohydrate Utilization Dependent on Cycling Cadence

PURPOSE

To assess (1) whether and how a higher maximal lactate steady state (MLSS) at higher cycling cadence (RPM) comes along with higher absolute and/or fractional carbohydrate combustion (CHOMLSS), respectively, and (2) whether there is an interrelation between potential RPM-dependent MLSS effects and the maximally achievable RPM (RPMMAX).

METHODS

Twelve healthy males performed incremental load tests to determine peak power, peak oxygen uptake, and 30-minute MLSS tests at 50 and 100 per minute, respectively, to assess RPM-dependent MLSS, corresponding power output, CHOMLSS responses, and 6-second sprints to measure RPMMAX.

RESULTS

Peak power, peak carbon dioxide production, and power output at MLSS were lower (P = .000, ω2 = 0.922; P = .044, ω2 > 0.275; and P = .016, ω2 = 0.373) at 100 per minute than at 50 per minute. With 6.0 (1.5) versus 3.8 (1.2) mmol·L-1, MLSS was higher (P = .000, ω2 = 0.771) at 100 per minute than at 50 per minute. No corresponding RPM-dependent differences were found in oxygen uptake at MLSS, carbon dioxide production at MLSS, respiratory exchange ratio at MLSS, CHOMLSS, or fraction of oxygen uptake used for CHO at MLSS, respectively. There was no correlation between the RPM-dependent difference in MLSS and RPMMAX.

CONCLUSIONS

The present study extends the previous finding of a consistently higher MLSS at higher RPM by indicating (1) that at fully established MLSS conditions, respiration and CHOMLSS management do not differ significantly between 100 per minute and 50 per minute, and (2) that linear correlation models did not identify linear interdependencies between RPM-dependent MLSS conditions and RPMMAX.

Physiological Profile, Metabolic Response and Temporal Structure in Elite Individual Table Tennis: Differences According to Gender

No research that has analyzed the structural characteristics, physiological profile, and energy demands in the game of table tennis as played by women is available. The present study aimed to evaluate the physiological, metabolic, and temporal variables of table tennis players and to observe gender differences. Forty-eight elite table tennis players participated in this study: 24 men (25.3 ± 4.07 years) and 24 women (22.3 ± 3.8 years). During simulated competition, temporal structure, heart rate (HR), and lactate (LA) were evaluated. The maximum ergospirometric evaluations were performed in a laboratory. The total table tennis (TT) time and the total resting time (TRT) were longer for men (p < 0.05), but game density was higher for women (p < 0.05). During rallies, the real playing time (RPT) was longer for women, while the TRT was longer for men (p < 0.05). The maximum HR, minimum HR, and maximum LA concentrations were higher for men (p < 0.05). The obtained data reveal gender differences in the physiological, metabolic, structural, and temporal variables in table tennis players. The analysis of the studied variables could allow training sessions to be planned and organized according to table tennis players’ gender.

Exercise Training of Secreted Protein Acidic and Rich in Cysteine (Sparc) KO Mice Suggests That Exercise-Induced Muscle Phenotype Changes Are SPARC-Dependent

We previously identified secreted protein acidic and rich in cysteine (Sparc) as an exercise-induced gene in young and elderly individuals. Via this animal experiment, we aim to identify selected implications of SPARC mainly within the muscle in the contexts of exercise. Mice were divided into eight groups based on three variables (age, genotype and exercise): Old (O) or young (Y) × Sparc knock-out (KO) or wild-type (WT) × sedentary (Sed) or exercise (Ex). The exercised groups were trained for 12 weeks at the lactate threshold (LT) speed (including 4 weeks of adaptation period) and all mice were sacrificed afterwards. Body and selected tissues were weighed, and lactate levels in different conditions measured. Expression of skeletal muscle (SM) collagen type I alpha 1 chain (COL1A1) and mitochondrially encoded cytochrome c oxidase I (MT-CO1) in addition to SM strength (grip power) were also measured. Ageing increased the body and white adipose tissue (WAT) weights but decreased SM weight percentage (to body weight) and MT-CO1 expression (in WT). Exercise increased SM COL1A1 in WT mice and MT-CO1 expression, as well as weight percentage of the tibialis anterior muscle, and decreased WAT weight (trend). Compared to WT mice, Sparc KO mice had lower body, muscle and WAT weights, with a decrease in SM MT-CO1 and COL1A1 expression with no genotype effect on lactate levels in all our blood lactate measures. Sparc KO effects on body composition, adiposity and metabolic patterns are toward a reduced WAT and body weight, but with a negative metabolic and functional phenotype of SM. Whereas such negative effects on SM are worsened with ageing, they are relatively improved by exercise. Importantly, our data suggest that the exercise-induced changes in the SM phenotype, in terms of increased performance (metabolic, strength and development), including lactate-induced changes, are SPARC-dependent.

Cut-Off Values in the Prediction of Success in Olympic Distance Triathlon

Cut-off points and performance-related tools are needed for the development of the Olympic distance triathlon. The purposes of the present study were (i) to determine cut-off values to reach the top three positions in an Olympic distance triathlon; (ii) to identify which discipline present the highest influence on overall race performance and if it has changed over the decades. Data from 1989 to 2019 (n = 52,027) from all who have competed in an official Olympic distance triathlon events (World Triathlon Series and Olympics) were included. The cut-off value to achieve a top three position was calculated. Linear regressions were applied for performance trends overall and for the top three positions of each race. Men had cut-off values of: swimming = 19.5 min; cycling = 60.7 min; running = 34.1 min. Women's cut-off values were: swimming = 20.7 min; cycling = 71.6 min; running = 38.1 min. The running split seemed to be the most influential in overall race time regardless of rank position or sex. In conclusion, cut-offs were established, which can increase the chances of achieving a successful rank position in an Olympic triathlon. Cycling is the discipline with the least influence on overall performance for both men and women in the Olympic distance triathlon. This influence pattern has not changed in the last three decades.

Differences between Males and Females in Determining Exercise Intensity

Even though there are physiological differences between males and females, heart rate (HR), ratings of perceived exertion (RPE), power output (PO), oxygen consumption (VO2), and blood lactate (BL) levels have been used as measures of exercise intensity independently of sex. The purpose of this study was to determine differences between sexes in different exercise intensity models. Thirty (15 females) young, healthy individuals were scheduled for two testing visits 48-72 hours apart. During the first testing visit, a graded exercise test (GXT), with BL obtained at the end of each exercise step, was administered on a stationary bicycle to determine peak PO and VO2max. BL during the GXT was used to determine three 5-min steady-state workloads (low: 0-2 mmol/L; moderate: 2-4 mmol/L; and high: >4 mmol/L) for the second test. HR, %HRmax, RPE, PO, %POmax, VO2, %VO2max, and BL were obtained at the end of each steady-state workload. A two-way repeated measures ANOVA was performed to compare all exercise intensity variables obtained during the second test between males and females (α=0.05). Only RPE, %PO, and BL did not differ between sexes on all 3 exercise intensities. HR, %HR, and PO differ between sexes on at least 2 exercise intensities. Females have higher HR and %HR than males for similar %PO. VO2 and %VO2max differ between sexes on at least 1 exercise intensity. Based on the current results, traditional exercise intensity markers are different between males and females. BL and %PO appear to be markers that might be used independently of sex.

American Masters Road Running Records-The Performance Gap Between Female and Male Age Group Runners from 5 Km to 6 Days Running

Recent studies investigating elite and master athletes in pool- and long-distance open-water swimming showed for elite swimmers that the fastest women were able to outperform the fastest men, and for master athletes that elderly women were able to achieve a similar performance to elderly men. The present study investigating age group records in runners from 5 km to 6 days aimed to test this hypothesis for master runners. Data from the American Master Road Running Records were analyzed, for 5 km, 8 km, 10 km, 10 miles, 20 km, half-marathon, 25 km, 30 km, marathon, 50 km, 50 miles, 100 km, 100 miles, 12 h, 24 h, 48 h and 144 h, for athletes in age groups ranging from 40 to 99 years old. The performance gap between men and women showed higher effects in events lengthening from 5 km to 10 miles (d = 0.617) and lower effects in events lengthening from 12 to 144 h (d = 0.304) running. Both other groups showed similar effects, being 20 km to the marathon (d = 0.607) and 50 km to 100 miles (d = 0.563). The performance gap between men and women showed higher effects in the age groups 85 years and above (d = 0.953) followed by 55 to 69 years (d = 0.633), and lower effects for the age groups 40 to 54 years (d = 0.558) and 70 to 84 years (d = 0.508). In summary, men are faster than women in American road running events, however, the sex gap decreases with increasing age but not with increasing event length.